origin of the universe essay

How did the universe begin—and what were its early days like?

The most popular theory of our universe's origin centers on a cosmic cataclysm unmatched in all of history—the big bang.

The best-supported theory of our universe's origin centers on an event known as the big bang. This theory was born of the observation that other galaxies are moving away from our own at great speed in all directions, as if they had all been propelled by an ancient explosive force.

A Belgian priest named Georges Lemaître first suggested the big bang theory in the 1920s, when he theorized that the universe began from a single primordial atom. The idea received major boosts from Edwin Hubble's observations that galaxies are speeding away from us in all directions, as well as from the 1960s discovery of cosmic microwave radiation—interpreted as echoes of the big bang—by Arno Penzias and Robert Wilson.

Further work has helped clarify the big bang's tempo. Here’s the theory: In the first 10^-43 seconds of its existence, the universe was very compact, less than a million billion billionth the size of a single atom. It's thought that at such an incomprehensibly dense, energetic state, the four fundamental forces—gravity, electromagnetism, and the strong and weak nuclear forces—were forged into a single force, but our current theories haven't yet figured out how a single, unified force would work. To pull this off, we'd need to know how gravity works on the subatomic scale, but we currently don't.

It's also thought that the extremely close quarters allowed the universe's very first particles to mix, mingle, and settle into roughly the same temperature. Then, in an unimaginably small fraction of a second, all that matter and energy expanded outward more or less evenly, with tiny variations provided by fluctuations on the quantum scale. That model of breakneck expansion, called inflation, may explain why the universe has such an even temperature and distribution of matter.

After inflation, the universe continued to expand but at a much slower rate. It's still unclear what exactly powered inflation.

Aftermath of cosmic inflation

As time passed and matter cooled, more diverse kinds of particles began to form, and they eventually condensed into the stars and galaxies of our present universe.

By the time the universe was a billionth of a second old, the universe had cooled down enough for the four fundamental forces to separate from one another. The universe's fundamental particles also formed. It was still so hot, though, that these particles hadn't yet assembled into many of the subatomic particles we have today, such as the proton. As the universe kept expanding, this piping-hot primordial soup—called the quark-gluon plasma—continued to cool. Some particle colliders, such as CERN's Large Hadron Collider , are powerful enough to re-create the quark-gluon plasma.

Radiation in the early universe was so intense that colliding photons could form pairs of particles made of matter and antimatter, which is like regular matter in every way except with the opposite electrical charge. It's thought that the early universe contained equal amounts of matter and antimatter. But as the universe cooled, photons no longer packed enough punch to make matter-antimatter pairs. So like an extreme game of musical chairs, many particles of matter and antimatter paired off and annihilated one another.

Somehow, some excess matter survived—and it's now the stuff that people, planets, and galaxies are made of. Our existence is a clear sign that the laws of nature treat matter and antimatter slightly differently. Researchers have experimentally observed this rule imbalance, called CP violation , in action. Physicists are still trying to figure out exactly how matter won out in the early universe.

A tiny, ghostly particle called a neutrino and its antimatter counterpart, an antineutrino, could shed some light on the matter, and two big experiments, called DUNE and Hyper-Kamiokande , are using these chargeless, nearly massless particles to try to solve the mystery.

Building atoms

Within the universe's first second, it was cool enough for the remaining matter to coalesce into protons and neutrons, the familiar particles that make up atoms' nuclei. And after the first three minutes, the protons and neutrons had assembled into hydrogen and helium nuclei. By mass, hydrogen was 75 percent of the early universe's matter, and helium was 25 percent. The abundance of helium is a key prediction of big bang theory, and it's been confirmed by scientific observations.

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Despite having atomic nuclei, the young universe was still too hot for electrons to settle in around them to form stable atoms. The universe's matter remained an electrically charged fog that was so dense, light had a hard time bouncing its way through. It would take another 380,000 years or so for the universe to cool down enough for neutral atoms to form—a pivotal moment called recombination. The cooler universe made it transparent for the first time, which let the photons rattling around within it finally zip through unimpeded.

We still see this primordial afterglow today as cosmic microwave background radiation , which is found throughout the universe. The radiation is similar to that used to transmit TV signals via antennae. But it is the oldest radiation known and may hold many secrets about the universe's earliest moments.

From the first stars to today

There wasn't a single star in the universe until about 180 million years after the big bang. It took that long for gravity to gather clouds of hydrogen and forge them into stars. Many physicists think that vast clouds of dark matter , a still-unknown material that outweighs visible matter by more than five to one, provided a gravitational scaffold for the first galaxies and stars.

Once the universe's first stars ignited , the light they unleashed packed enough punch to once again strip electrons from neutral atoms, a key chapter of the universe called reionization. Scientists have tried to glimpse this “cosmic dawn,” but the results have been mixed. Back in 2018, an Australian team announced detected signs of the first stars forming around 180 million years after the big bang, though other groups haven't been able to recreate their results. By 300 million years after the big bang , the first galaxies were born. In the billions of years since, stars, galaxies, and clusters of galaxies have formed and re-formed—eventually yielding our home galaxy, the Milky Way, and our cosmic home, the solar system.

Even now the universe is expanding . To astronomers' surprise, the pace of expansion is accelerating . Estimates of the expansion rate vary, but data from the James Webb Space Telescope adds to a growing body of evidence that it's significantly faster than it should be.

It's thought that this acceleration is driven by a force that repels gravity called dark energy. We still don't know what dark energy is, but it’s thought that it makes up 68 percent of the universe's total matter and energy. Dark matter makes up another 27 percent. In essence, all the matter you've ever seen—from your first love to the stars overhead—makes up less than five percent of the universe.

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13.7 Cosmos & Culture

The origin of the universe: from nothing everything.

Marcelo Gleiser

A computer simulation of the formation of large-scale structures in the Universe, showing a patch of 100 million light-years and the resulting coherent motions of galaxies flowing towards the highest mass concentration in the centre. The snapshot refers to an epoch about 10 billion years back in time. Klaus Dolag/VIMOS-VLT Deep Survey/ESO hide caption

A computer simulation of the formation of large-scale structures in the Universe, showing a patch of 100 million light-years and the resulting coherent motions of galaxies flowing towards the highest mass concentration in the centre. The snapshot refers to an epoch about 10 billion years back in time.

Last week, I started a discussion of what I call "The Three Origins," focusing first on the origin of life. Although we are far from knowing how non-living matter became living organisms on primitive Earth some 3.5 billion years ago (or more), or how to repeat the feat in the laboratory, I consider this the "easiest" of the three questions.

Contrary to the origin of the Universe and the origin of mind, the origin of life is something we can study from the outside in, where we can have an external and objective view of what is going on. Even if, as I have argued, it seems impossible to know exactly how life originated on Earth (unless it could be proven that there is only one pathway from nonlife to life), we can still investigate the biochemical pathways leading to what we may call a living organism. In the case of the cosmos or the mind, things are subtler.

From what we know, all cultures have a creation narrative describing the origin of the world, of how everything came from nothing. As I explored in The Dancing Universe: From Creation Myths to the Big Bang , there are only a small number of possible answers to the origin of the cosmos. All creation myths presuppose the existence of some kind of divine or absolute power capable of creating the world. In the vast majority of cases, the Bible being one example, this absolute power is embodied in God, or a group of gods. In others, the Universe is eternal, without a starting moment in the distant past: it has existed forever and will exist forever. In others still, the cosmos emerges without any divine interference from a primal Nothingness, from an innate tendency to exist. This Nothing can be complete emptiness, a primal egg, or even a struggle between chaos and order. Not every creation myth uses divine intervention or supposes that time started in some moment in the past.

According to modern science, the origin of the universe is part of cosmology. In trying to describe a creation process through scientific language we encounter a serious challenge: if every effect results from a cause, we can follow the chain of causation backwards in time until we arrive at the First Cause. But what caused this cause? Aristotle, for one, used some kind of divine entity to solve this conundrum, the Unmoved Mover, the one that can cause without having been caused. Very convenient, but not scientifically satisfying.

As current astronomical observations resolutely point to a Universe with a beginning in the distant past (according to the latest measurements from the Planck satellite related here last week , at about 13.8 billion years ago), scientific models of the origin of the Universe must face the challenge of explaining or doing away with the problem of the First Cause.

The fundamental question is this: even if a scientific explanation exists, is it an acceptable answer to the question of the origin of the Universe? Defenders of scientism might argue that this is the best that we can do, that it is the only reasonable thing that we can do. Fair enough, if you believe that science should provide an answer to this question and if you are happy with the answers given.

The best answer we have at this point is that the Universe emerged spontaneously from a random quantum fluctuation in some sort of primordial quantum vacuum, the scientific equivalent of "nothing." However, this quantum vacuum is a very loaded nothing: it assumes the whole machinery of quantum field theory, the modern description of how elementary particles of matter interact with one another, was already in operation.

In the quantum realm, even the lowest energy state, the "vacuum," is not empty. Even if the energy of a quantum system is zero, it is never really zero due to the inherent quantum fluctuations about this state. A zero energy quantum state is as impossible as a perfectly still lake, with absolutely no disturbances on its surface. This quantum jitteriness amounts to fluctuations on the value of the energy; if one of these fluctuations is unstable it may grow big, like a soap bubble that blows itself up. The energy remains zero on average because of a clever interplay between the positive energy of matter and the negative energy of attractive gravity. This is the result that physicists like Stephen Hawking, Lawrence Krauss, Mikio Kaku and others speak of when they state that the "universe came out of quantum nothingness," or something to that extent.

The essential question, though, is whether this is indeed a satisfactory explanation to the question of cosmic origins, or simply part of one. The philosopher David Albert raised similar points in a recent review of Lawrence Krauss's book. Here is Krauss's response.

It is obvious that this quantum nothingness is very different from an absolute nothingness. Physicists may shrug this away stating that concepts like absolute nothingness are not scientific and hence have no explanatory value. It is indeed true that there is no such thing as absolute nothingness in science, since the vacuum is pregnant with all sorts of stuff. Any scientific explanation presupposes a whole conceptual structure that is absolutely essential for science to function: energy, space, time, the equations we use, the laws of Nature. Science can't exist without this scaffolding. So, a scientific explanation of the origin of the universe needs to use such concepts to make sense. It necessarily starts from something, which is the best that science can ever hope to do.

Even if we move on to the multiverse, things still need to be formulated in terms of fields, energy, spacetime, derivatives, etc. Furthermore, scientific hypotheses need to be testable and falsifiable, and we don't yet know how to do this with a quantum fluctuation that generates a universe. We can't set this experiment in the laboratory and examine the right conditions for universes to emerge from the quantum vacuum. Contrary to the origin of life question, we can't step out of the Universe to examine it from the outside in. At best, and this should be quite enough for a scientific explanation of cosmic origins, a model for the quantum origin of the Universe should lead to a cosmos compatible with current observations. Stepping out into the abstract multiverse may provide us with different plausible cosmoids and help us understand why our own Universe is so special. But unless there is a very clear selection principle that doesn't predicate our existence, the question as to why this Universe and not another will remain open.

And this is not at all bad. The fact that science answers so many questions doesn't mean it should answer all; or that some questions should only be answered through science. Before I am accused of advocating obscurantism, let me be clear. What I mean is that a scientific explanation to the origin of the Universe, at least one based in the current way we do science, cannot be self-contained. Sometimes we must have the humility to accept that our modes of explanation have limits and make peace with what we can do; and marvel at how much we can do without the pretense of knowing how to do everything.

You can keep up with more of what Marcelo is thinking on Facebook and Twitter: @mgleiser

• the big bang

October 1, 1994

17 min read

The Evolution of the Universe

Some 15 billion years ago the universe emerged from a hot, dense sea of matter and energy. As the cosmos expanded and cooled, it spawned galaxies, stars, planets and life

By P. James E. Peebles , David N. Schramm , Edwin L. Turner & Richard G. Kron

GALAXY CLUSTER is representative of what the universe looked like when it was 60 percent of its present age. The Hubble Space Telescope captured the image by focusing on the cluster as it completed 10 orbits. This image is one of the longest and clearest exposures ever produced. Several pairs of galaxies appear to be caught in one another’s gravitational field. Such interactions are rarely found in nearby clusters and are evidence that the universe is evolving.

Editor’s Note (10/8/19): Cosmologist James Peebles won a 2019 Nobel Prize in Physics for his contributions to theories of how our universe began and evolved. He describes these ideas in this article, which he co-wrote for  Scientific American  in 1994.

At a particular instant roughly 15 billion years ago, all the matter and energy we can observe, concentrated in a region smaller than a dime, began to expand and cool at an incredibly rapid rate. By the time the temperature had dropped to 100 million times that of the sun’s core, the forces of nature assumed their present properties, and the elementary particles known as quarks roamed freely in a sea of energy. When the universe had expanded an additional 1,000 times, all the matter we can measure filled a region the size of the solar system.

At that time, the free quarks became confined in neutrons and protons. After the universe had grown by another factor of 1,000, protons and neutrons combined to form atomic nuclei, including most of the helium and deuterium present today. All of this occurred within the first minute of the expansion. Conditions were still too hot, however, for atomic nuclei to capture electrons. Neutral atoms appeared in abundance only after the expansion had continued for 300,000 years and the universe was 1,000 times smaller than it is now. The neutral atoms then began to coalesce into gas clouds, which later evolved into stars. By the time the universe had expanded to one fifth its present size, the stars had formed groups recognizable as young galaxies.

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When the universe was half its present size, nuclear reactions in stars had produced most of the heavy elements from which terrestrial planets were made. Our solar system is relatively young: it formed five billion years ago, when the universe was two thirds its present size. Over time the formation of stars has consumed the supply of gas in galaxies, and hence the population of stars is waning. Fifteen billion years from now stars like our sun will be relatively rare, making the universe a far less hospitable place for observers like us.

Our understanding of the genesis and evolution of the universe is one of the great achievements of 20th-century science. This knowledge comes from decades of innovative experiments and theories. Modern telescopes on the ground and in space detect the light from galaxies billions of light-years away, showing us what the universe looked like when it was young. Particle accelerators probe the basic physics of the high-energy environment of the early universe. Satellites detect the cosmic background radiation left over from the early stages of expansion, providing an image of the universe on the largest scales we can observe.

Our best efforts to explain this wealth of data are embodied in a theory known as the standard cosmological model or the big bang cosmology. The major claim of the theory is that in the largescale average the universe is expanding in a nearly homogeneous way from a dense early state. At present, there are no fundamental challenges to the big bang theory, although there are certainly unresolved issues within the theory itself. Astronomers are not sure, for example, how the galaxies were formed, but there is no reason to think the process did not occur within the framework of the big bang. Indeed, the predictions of the theory have survived all tests to date.

Yet the big bang model goes only so far, and many fundamental mysteries remain. What was the universe like before it was expanding? (No observation we have made allows us to look back beyond the moment at which the expansion began.) What will happen in the distant future, when the last of the stars exhaust the supply of nuclear fuel? No one knows the answers yet.

Our universe may be viewed in many lights—by mystics, theologians, philosophers or scientists. In science we adopt the plodding route: we accept only what is tested by experiment or observation. Albert Einstein gave us the now well-tested and accepted Theory of General Relativity, which establishes the relations between mass, energy, space and time. Einstein showed that a homogeneous distribution of matter in space fits nicely with his theory. He assumed without discussion that the universe is static, unchanging in the large-scale average [see “How Cosmology Became a Science,” by Stephen G. Brush; SCIENTIFIC AMERICAN, August 1992].

In 1922 the Russian theorist Alexander A. Friedmann realized that Einstein’s universe is unstable; the slightest perturbation would cause it to expand or contract. At that time, Vesto M. Slipher of Lowell Observatory was collecting the first evidence that galaxies are actually moving apart. Then, in 1929, the eminent astronomer Edwin P. Hubble showed that the rate a galaxy is moving away from us is roughly proportional to its distance from us.

MULTIPLE IMAGES of a distant quasar ( left ) are the result of an effect known as gravitational lensing. The effect occurs when light from a distant object is bent by the gravitational field of an intervening galaxy. In this case, the galaxy, which is visible in the center, produces four images of the quasar. The photograph was produced using the Hubble telescope.

The existence of an expanding universe implies that the cosmos has evolved from a dense concentration of matter into the present broadly spread distribution of galaxies. Fred Hoyle, an English cosmologist, was the first to call this process the big bang. Hoyle intended to disparage the theory, but the name was so catchy it gained popularity. It is somewhat misleading, however, to describe the expansion as some type of explosion of matter away from some particular point in space.

That is not the picture at all: in Einstein’s universe the concept of space and the distribution of matter are intimately linked; the observed expansion of the system of galaxies reveals the unfolding of space itself. An essential feature of the theory is that the average density in space declines as the universe expands; the distribution of matter forms no observable edge. In an explosion the fastest particles move out into empty space, but in the big bang cosmology, particles uniformly fill all space. The expansion of the universe has had little influence on the size of galaxies or even clusters of galaxies that are bound by gravity; space is simply opening up between them. In this sense, the expansion is similar to a rising loaf of raisin bread. The dough is analogous to space, and the raisins, to clusters of galaxies. As the dough expands, the raisins move apart. Moreover, the speed with which any two raisins move apart is directly and positively related to the amount of dough separating them.

The evidence for the expansion of the universe has been accumulating for some 60 years. The first important clue is the redshift. A galaxy emits or absorbs some wavelengths of light more strongly than others. If the galaxy is moving away from us, these emission and absorption features are shifted to longer wavelengths—that is, they become redder as the recession velocity increases. This phenomenon is known as the redshift.

Hubble’s measurements indicated that the redshift of a distant galaxy is greater than that of one closer to the earth. This relation, now known as Hubble’s law, is just what one would expect in a uniformly expanding universe. Hubble’s law says the recession velocity of a galaxy is equal to its distance multiplied by a quantity called Hubble’s constant. The redshift effect in nearby galaxies is relatively subtle, requiring good instrumentation to detect it. In contrast, the redshift of very distant objects—radio galaxies and quasars—is an awesome phenomenon; some appear to be moving away at greater than 90 percent of the speed of light.

Hubble contributed to another crucial part of the picture. He counted the number of visible galaxies in different directions in the sky and found that they appear to be rather uniformly distributed. The value of Hubble’s constant seemed to be the same in all directions, a necessary consequence of uniform expansion. Modern surveys confirm the fundamental tenet that the universe is homogeneous on large scales. Although maps of the distribution of the nearby galaxies display clumpiness, deeper surveys reveal considerable uniformity.

The Milky Way, for instance, resides in a knot of two dozen galaxies; these in turn are part of a complex of galaxies that protrudes from the so-called local supercluster. The hierarchy of clustering has been traced up to dimensions of about 500 million light-years. The fluctuations in the average density of matter diminish as the scale of the structure being investigated increases. In maps that cover distances that reach close to the observable limit, the average density of matter changes by less than a tenth of a percent.

To test Hubble’s law, astronomers need to measure distances to galaxies. One method for gauging distance is to observe the apparent brightness of a galaxy. If one galaxy is four times fainter in the night sky than an otherwise comparable galaxy, then it can be estimated to be twice as far away. This expectation has now been tested over the whole of the visible range of distances.

HOMOGENEOUS DISTRIBUTION of galaxies is apparent in a map that includes objects from 300 to 1,000 million light-years away. The only inhomogeneity, a gap near the center line, occurs because part of the sky is obscured by the Milky Way. Michael Strauss of the Institute for Advanced Study in Princeton, N.J., created the map using data from NASA’s Infrared Astronomical Satellite .

Some critics of the theory have pointed out that a galaxy that appears to be smaller and fainter might not actually be more distant. Fortunately, there is a direct indication that objects whose redshifts are larger really are more distant. The evidence comes from observations of an effect known as gravitational lensing. An object as massive and compact as a galaxy can act as a crude lens, producing a distorted, magnified image (or even many images) of any background radiation source that lies behind it. Such an object does so by bending the paths of light rays and other electromagnetic radiation. So if a galaxy sits in the line of sight between the earth and some distant object, it will bend the light rays from the object so that they are observable [see “Gravitational Lenses,” by Edwin L. Turner; SCIENTIFIC AMERICAN, July 1988]. During the past decade, astronomers have discovered more than a dozen gravitational lenses. The object behind the lens is always found to have a higher redshift than the lens itself, confirming the qualitative prediction of Hubble’s law.

Hubble’s law has great significance not only because it describes the expansion of the universe but also because it can be used to calculate the age of the cosmos. To be precise, the time elapsed since the big bang is a function of the present value of Hubble’s constant and its rate of change. Astronomers have determined the approximate rate of the expansion, but no one has yet been able to measure the second value precisely.

Still, one can estimate this quantity from knowledge of the universe’s average density. One expects that because gravity exerts a force that opposes expansion, galaxies would tend to move apart more slowly now than they did in the past. The rate of change in expansion is therefore related to the gravitational pull of the universe set by its average density. If the density is that of just the visible material in and around galaxies, the age of the universe probably lies between 12 and 20 billion years. (The range allows for the uncertainty in the rate of expansion.)

Yet many researchers believe the density is greater than this minimum value. So-called dark matter would make up the difference. A strongly defended argument holds that the universe is just dense enough that in the remote future the expansion will slow almost to zero. Under this assumption, the age of the universe decreases to the range of seven to 13 billion years.

DENSITY of neutrons and protons in the universe determined the abundances of certain elements. For a higher density universe, the computed helium abundance is little different, and the computed abundance of deuterium is considerably lower. The shaded region is consistent with the observations, ranging from an abundance of 24 percent for helium to one part in 1010 for the lithium isotope. This quantitative agreement is a prime success of the big bang cosmology.

To improve these estimates, many astronomers are involved in intensive research to measure both the distances to galaxies and the density of the universe. Estimates of the expansion time provide an important test for the big bang model of the universe. If the theory is correct, everything in the visible universe should be younger than the expansion time computed from Hubble’s law.

These two timescales do appear to be in at least rough concordance. For example, the oldest stars in the disk of the Milky Way galaxy are about nine billion years old—an estimate derived from the rate of cooling of white dwarf stars. The stars in the halo of the Milky Way are somewhat older, about 15 billion years—a value derived from the rate of nuclear fuel consumption in the cores of these stars. The ages of the oldest known chemical elements are also approximately 15 billion years—a number that comes from radioactive dating techniques. Workers in laboratories have derived these age estimates from atomic and nuclear physics. It is noteworthy that their results agree, at least approximately, with the age that astronomers have derived by measuring cosmic expansion.

Another theory, the steady state theory, also succeeds in accounting for the expansion and homogeneity of the universe. In 1946 three physicists in England—Hoyle, Hermann Bondi and Thomas Gold—proposed such a cosmology. In their theory the universe is forever expanding, and matter is created spontaneously to fill the voids. As this material accumulates, they suggested, it forms new stars to replace the old. This steady state hypothesis predicts that ensembles of galaxies close to us should look statistically the same as those far away. The big bang cosmology makes a different prediction: if galaxies were all formed long ago, distant galaxies should look younger than those nearby because light from them requires a longer time to reach us. Such galaxies should contain more shortlived stars and more gas out of which future generations of stars will form.

The test is simple conceptually, but it took decades for astronomers to develop detectors sensitive enough to study distant galaxies in detail. When astronomers examine nearby galaxies that are powerful emitters of radio wavelengths, they see, at optical wavelengths, relatively round systems of stars. Distant radio galaxies, on the other hand, appear to have elongated and sometimes irregular structures. Moreover, in most distant radio galaxies, unlike the ones nearby, the distribution of light tends to be aligned with the pattern of the radio emission.

Likewise, when astronomers study the population of massive, dense clusters of galaxies, they find differences between those that are close and those far away. Distant clusters contain bluish galaxies that show evidence of ongoing star formation. Similar clusters that are nearby contain reddish galaxies in which active star formation ceased long ago. Observations made with the Hubble Space Telescope confirm that at least some of the enhanced star formation in these younger clusters may be the result of collisions between their member galaxies, a process that is much rarer in the present epoch.

DISTANT GALAXIES differ greatly from those nearby—an observation that shows that galaxies evolved from earlier, more irregular forms. Among galaxies that are bright at both optical ( blue ) and radio ( red ) wavelengths, the nearby galaxies tend to have smooth elliptical shapes at optical wavelengths and very elongated radio images. As redshift, and therefore distance, increases, galaxies have more irregular elongated forms that appear aligned at optical and radio wavelengths. The galaxy at the far right is seen as it was at 10 percent of the present age of the universe. The images were assembled by Pat McCarthy of the Carnegie Institute.

So if galaxies are all moving away from one another and are evolving from earlier forms, it seems logical that they were once crowded together in some dense sea of matter and energy. Indeed, in 1927, before much was known about distant galaxies, a Belgian cosmologist and priest, Georges Lemaître, proposed that the expansion of the universe might be traced to an exceedingly dense state he called the primeval “super-atom.” It might even be possible, he thought, to detect remnant radiation from the primeval atom. But what would this radiation signature look like?

When the universe was very young and hot, radiation could not travel very far without being absorbed and emitted by some particle. This continuous exchange of energy maintained a state of thermal equilibrium; any particular region was unlikely to be much hotter or cooler than the average. When matter and energy settle to such a state, the result is a so-called thermal spectrum, where the intensity of radiation at each wavelength is a definite function of the temperature. Hence, radiation originating in the hot big bang is recognizable by its spectrum.

In fact, this thermal cosmic background radiation has been detected. While working on the development of radar in the 1940s, Robert H. Dicke, then at the Massachusetts Institute of Technology, invented the microwave radiometer—a device capable of detecting low levels of radiation. In the 1960s Bell Laboratories used a radiometer in a telescope that would track the early communications satellites Echo-1 and Telstar. The engineer who built this instrument found that it was detecting unexpected radiation. Arno A. Penzias and Robert W. Wilson identified the signal as the cosmic background radiation. It is interesting that Penzias and Wilson were led to this idea by the news that Dicke had suggested that one ought to use a radiometer to search for the cosmic background.

Astronomers have studied this radiation in great detail using the Cosmic Background Explorer (COBE) satellite and a number of rocket-launched, balloon-borne and ground-based experiments. The cosmic background radiation has two distinctive properties. First, it is nearly the same in all directions. (As George F. Smoot of Lawrence Berkeley Laboratory and his team discovered in 1992, the variation is just one part per 100,000.) The interpretation is that the radiation uniformly fills space, as predicted in the big bang cosmology. Second, the spectrum is very close to that of an object in thermal equilibrium at 2.726 kelvins above absolute zero. To be sure, the cosmic background radiation was produced when the universe was far hotter than 2.726 degrees, yet researchers anticipated correctly that the apparent temperature of the radiation would be low. In the 1930s Richard C. Tolman of the California Institute of Technology showed that the temperature of the cosmic background would diminish because of the universe’s expansion.

The cosmic background radiation provides direct evidence that the universe did expand from a dense, hot state, for this is the condition needed to produce the radiation. In the dense, hot early universe thermonuclear reactions produced elements heavier than hydrogen, including deuterium, helium and lithium. It is striking that the computed mix of the light elements agrees with the observed abundances. That is, all evidence indicates that the light elements were produced in the hot, young universe, whereas the heavier elements appeared later, as products of the thermonuclear reactions that power stars.

The theory for the origin of the light elements emerged from the burst of research that followed the end of World War II. George Gamow and graduate student Ralph A. Alpher of George Washington University and Robert Herman of the Johns Hopkins University Applied Physics Laboratory and others used nuclear physics data from the war e›ort to predict what kind of nuclear processes might have occurred in the early universe and what elements might have been produced. Alpher and Herman also realized that a remnant of the original expansion would still be detectable in the existing universe.

Despite the fact that significant details of this pioneering work were in error, it forged a link between nuclear physics and cosmology. The workers demonstrated that the early universe could be viewed as a type of thermonuclear reactor. As a result, physicists have now precisely calculated the abundances of light elements produced in the big bang and how those quantities have changed because of subsequent events in the interstellar medium and nuclear processes in stars.

Our grasp of the conditions that prevailed in the early universe does not translate into a full understanding of how galaxies formed. Nevertheless, we do have quite a few pieces of the puzzle. Gravity causes the growth of density fluctuations in the distribution of matter, because it more strongly slows the expansion of denser regions, making them grow still denser. This process is observed in the growth of nearby clusters of galaxies, and the galaxies themselves were probably assembled by the same process on a smaller scale.

The growth of structure in the early universe was prevented by radiation pressure, but that changed when the universe had expanded to about 0.1 percent of its present size. At that point, the temperature was about 3,000 kelvins, cool enough to allow the ions and electrons to combine to form neutral hydrogen and helium. The neutral matter was able to slip through the radiation and to form gas clouds that could collapse to star clusters. Observations show that by the time the universe was one fifth its present size, matter had gathered into gas clouds large enough to be called young galaxies.

A pressing challenge now is to reconcile the apparent uniformity of the early universe with the lumpy distribution of galaxies in the present universe. Astronomers know that the density of the early universe did not vary by much, because they observe only slight irregularities in the cosmic background radiation. So far it has been easy to develop theories that are consistent with the available measurements, but more critical tests are in progress. In particular, different theories for galaxy formation predict quite different fluctuations in the cosmic background radiation on angular scales less than about one degree. Measurements of such tiny fluctuations have not yet been done, but they might be accomplished in the generation of experiments now under way. It will be exciting to learn whether any of the theories of galaxy formation now under consideration survive these tests.

The present-day universe has provided ample opportunity for the development of life as we know it—there are some 100 billion billion stars similar to the sun in the part of the universe we can observe. The big bang cosmology implies, however, that life is possible only for a bounded span of time: the universe was too hot in the distant past, and it has limited resources for the future. Most galaxies are still producing new stars, but many others have already exhausted their supply of gas. Thirty billion years from now, galaxies will be much darker and filled with dead or dying stars, so there will be far fewer planets capable of supporting life as it now exists.

The universe may expand forever, in which case all the galaxies and stars will eventually grow dark and cold. The alternative to this big chill is a big crunch. If the mass of the universe is large enough, gravity will eventually reverse the expansion, and all matter and energy will be reunited. During the next decade, as researchers improve techniques for measuring the mass of the universe, we may learn whether the present expansion is headed toward a big chill or a big crunch.

In the near future, we expect new experiments to provide a better understanding of the big bang. As we improve measurements of the expansion rate and the ages of stars, we may be able to confirm that the stars are indeed younger than the expanding universe. The larger telescopes recently completed or under construction may allow us to see how the mass of the universe affects the curvature of spacetime, which in turn influences our observations of distant galaxies.

We will also continue to study issues that the big bang cosmology does not address. We do not know why there was a big bang or what may have existed before. We do not know whether our universe has siblings—other expanding regions well removed from what we can observe. We do not understand why the fundamental constants of nature have the values they do. Advances in particle physics suggest some interesting ways these questions might be answered; the challenge is to find experimental tests of the ideas.

In following the debate on such matters of cosmology, one should bear in mind that all physical theories are approximations of reality that can fail if pushed too far. Physical science advances by incorporating earlier theories that are experimentally supported into larger, more encompassing frameworks. The big bang theory is supported by a wealth of evidence: it explains the cosmic background radiation, the abundances of light elements and the Hubble expansion. Thus, any new cosmology surely will include the big bang picture. Whatever developments the coming decades may bring, cosmology has moved from a branch of philosophy to a physical science where hypotheses meet the test of observation and experiment.

Origins of the Universe 101

How old is the universe, and how did it begin? Throughout history, countless myths and scientific theories have tried to explain the universe's origins. The most widely accepted explanation is the big bang theory. Learn about the explosion that started it all and how the universe grew from the size of an atom to encompass everything in existence today.

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The early universe

All matter in the universe was formed in one explosive event 13.7 billion years ago – the Big Bang

The Big Bang

In 1929 the American astronomer Edwin Hubble discovered that the distances to far-away galaxies were proportional to their redshifts. Redshift occurs when a light source moves away from its observer: the light's apparent wavelength is stretched via the Doppler effect towards the red part of the spectrum. Hubble’s observation implied that distant galaxies were moving away from us, as the furthest galaxies had the fastest apparent velocities. If galaxies are moving away from us, reasoned Hubble, then at some time in the past, they must have been clustered close together.

Hubble’s discovery was the first observational support for Georges Lemaître’s Big Bang theory of the universe, proposed in 1927. Lemaître proposed that the universe expanded explosively from an extremely dense and hot state, and continues to expand today. Subsequent calculations have dated this Big Bang to approximately 13.7 billion years ago. In 1998 two teams of astronomers working independently at Berkeley, California observed that supernovae – exploding stars – were moving away from Earth at an accelerating rate. This earned them the Nobel prize in physics in 2011 . Physicists had assumed that matter in the universe would slow its rate of expansion; gravity would eventually cause the universe to fall back on its centre. Though the Big Bang theory cannot describe what the conditions were at the very beginning of the universe, it can help physicists describe the earliest moments after the start of the expansion.

In the first moments after the Big Bang, the universe was extremely hot and dense. As the universe cooled, conditions became just right to give rise to the building blocks of matter – the quarks and electrons of which we are all made. A few millionths of a second later, quarks aggregated to produce protons and neutrons. Within minutes, these protons and neutrons combined into nuclei. As the universe continued to expand and cool, things began to happen more slowly. It took 380,000 years for electrons to be trapped in orbits around nuclei, forming the first atoms. These were mainly helium and hydrogen, which are still by far the most abundant elements in the universe. Present observations suggest that the first stars formed from clouds of gas around 150–200 million years after the Big Bang. Heavier atoms such as carbon, oxygen and iron, have since been continuously produced in the hearts of stars and catapulted throughout the universe in spectacular stellar explosions called supernovae.

But stars and galaxies do not tell the whole story. Astronomical and physical calculations suggest that the visible universe is only a tiny amount (4%) of what the universe is actually made of. A very large fraction of the universe, in fact 26%, is made of an unknown type of matter called " dark matter ". Unlike stars and galaxies, dark matter does not emit any light or electromagnetic radiation of any kind, so that we can detect it only through its gravitational effects. 

An even more mysterious form of energy called “dark energy” accounts for about 70% of the mass-energy content of the universe. Even less is known about it than dark matter. This idea stems from the observation that all galaxies seems to be receding from each other at an accelerating pace, implying that some invisible extra energy is at work.

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big-bang model

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• Swinburne University of Technology - COSMOS - The SAO Encyclopedia of Astronomy - Big Bang
• Space.com - What is the Big Bang Theory?
• Physics LibreTexts - The Basic Big Bang Model
• Weber State University - Department of Physics and Astronomy - The Four Pillars of Big Bang Cosmology
• The University of Western Australia - Evidence for the Big Bang
• NASA - Wilkinson Microwave Anisotropy Probe's Universe - Big Bang Cosmology
• LiveScience - The Big Bang Theory: How the Universe Began
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big-bang model , widely held theory of the evolution of the universe . Its essential feature is the emergence of the universe from a state of extremely high temperature and density —the so-called big bang that occurred 13.8 billion years ago. Although this type of universe was proposed by Russian mathematician Aleksandr Friedmann and Belgian astronomer Georges Lemaître in the 1920s, the modern version was developed by Russian-born American physicist George Gamow and colleagues in the 1940s.

The big-bang model is based on two assumptions. The first is that Albert Einstein ’s general theory of relativity correctly describes the gravitational interaction of all matter . The second assumption, called the cosmological principle , states that an observer’s view of the universe depends neither on the direction in which he looks nor on his location. This principle applies only to the large-scale properties of the universe, but it does imply that the universe has no edge, so that the big-bang origin occurred not at a particular point in space but rather throughout space at the same time. These two assumptions make it possible to calculate the history of the cosmos after a certain epoch called the Planck time . Scientists have yet to determine what prevailed before Planck time.

According to the big-bang model, the universe expanded rapidly from a highly compressed primordial state, which resulted in a significant decrease in density and temperature. Soon afterward, the dominance of matter over antimatter (as observed today) may have been established by processes that also predict proton decay. During this stage many types of elementary particles may have been present. After a few seconds, the universe cooled enough to allow the formation of certain nuclei. The theory predicts that definite amounts of hydrogen , helium , and lithium were produced. Their abundances agree with what is observed today. About one million years later the universe was sufficiently cool for atoms to form. The radiation that also filled the universe was then free to travel through space. This remnant of the early universe is the cosmic microwave background radiation—the “three degree” (actually 2.728 K) background radiation—discovered in 1965 by American physicists Arno A. Penzias and Robert W. Wilson.

In addition to accounting for the presence of ordinary matter and radiation, the model predicts that the present universe should also be filled with neutrinos , fundamental particles with no mass or electric charge . The possibility exists that other relics from the early universe may eventually be discovered.

Early Universe

The universe began 13.8 billion years ago, and in its early years, it looked completely different than it does now. For nearly 400,000 years, the entire cosmos was opaque, which means we have no direct observations of anything that happened during that time. Even after the universe became transparent, it was still a long time before the first stars and galaxies formed, leaving us with limited information about that period. Despite those problems, the early epochs of cosmic history are essential for everything that came after, leading researchers to find ways to figure out exactly what happened when our universe was in its infancy.

Center for Astrophysics | Harvard & Smithsonian scientists study the early universe in a variety of ways:

Hunting for signs of inflation using the twisting of CMB light called polarization. Even though this hypothetical rapid expansion of the universe happened a split-second after the Big Bang, it would have left observable traces behind. CfA researchers lead or are involved in CMB polarization observatories including the South Pole Telescope (SPT), the Keck Array, and the BICEP3 observatory. BICEP3 and Keck Array

Using the Murchison Wide-field Array (MWA) telescope, the Large-Aperture Experiment to Detect the Dark Ages (LEDA), and other observatories to look for the onset of reionization and the first stars. These instruments are designed to detect radio waves emitted by hydrogen gas during the cosmic “dark age”. Preparing to Study the Epoch of Reionization

Looking for different ways to test the predictions of various models of cosmic inflation, along with alternative theories to explain how the early universe behaved. Different theories predict different traces in the CMB, which can potentially be distinguished by sensitive observations. Theorists Propose a New Method to Probe the Beginning of the Universe

Hunting for traces of the first stars in the cosmos in surveys of galaxies and black holes. The earliest stars were likely very massive compared with their modern cousins, which means many exploded as supernovas and collapsed into black holes. Explosion Illuminates Invisible Galaxy in the Dark Ages

The Early Years

Until roughly 380,000 years after the Big Bang, the entire universe was a thick opaque cloud of plasma of electrons and nuclei. As the universe expanded, it cooled off enough to let the plasma become atoms, and the cosmos became transparent. We observe the light from this time as the cosmic microwave background (CMB).

The CMB is remarkably uniform in temperature all across the sky, which is surprising. Usually for two things to be exactly the same temperature, they need to be in contact. However, two points on the CMB on opposite sides of the sky would never have been close together since the Big Bang — unless something else was going on to connect them.

The most widely accepted hypothesis for that “something else” is cosmic inflation. In a tiny fraction of a second after the Big Bang, quantum fluctuations drove the universe to “inflate” much faster than the rate we observe at later eras. The part of the cosmos that became our observable universe was smaller than it would seem today, so the points opposite to each other on the sky now would have been in contact before inflation happened.

Much of the research on inflation involves understanding how it worked, and determining how we can detect its effects. For example, inflation would have created gravitational waves in the early universe, leaving small but potentially observable traces in the CMB. Observatories such as the South Pole Telescope (SPT) are looking for these effects.

This artist's impression traces the early history of Universe from with the Big Bang on the left to the first galaxies on the right. The black region in the middle is the "dark ages", the mysterious era setting the stage for the first stars to be born.

Cosmic Dark Ages and First Light

When the CMB formed, the ordinary matter in the universe transitioned from a hot opaque plasma to incandescent hydrogen and helium gas. Astronomers call this the “dark age” of the universe, since no stars had formed yet.

Researchers are using the best observatories in the world both to study the dark age and to find evidence for the first stars in the universe. As the first stars and black holes formed, they turned much of the hydrogen gas in the universe into plasma again , a process astronomers call “reionization”. The environment producing the earliest stars was radically different than star-forming regions today. The raw ingredients were almost exclusively hydrogen and helium, since stars themselves produce heavier elements through nuclear fusion .

Astronomers think the first stars may have been very massive compared with modern stars, and may have formed the first black holes in the cosmos. Individual stars are too small to be seen from so great a distance, so researchers look for indirect evidence about the nature of these objects, through how they influenced their surroundings.

Studying the dark ages and first stars is a way to understand the genealogy of all stars, including our own Sun. These original stars began the process of making most of the elements heavier than helium, which includes the atoms like oxygen and carbon necessary for life. The earliest stars, galaxies, and black holes changed the cloudy universe of the dark ages into the vast cosmic structures we see today.

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Home Essay Samples Science Universe

Unraveling the Cosmos: About the Origin of the Universe

Table of contents, ancient myths and cosmologies, the big bang theory, inflation and cosmic evolution, open questions and frontiers of knowledge, philosophical reflections.

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Astronomy > How Did the Universe Begin?

How Did the Universe Begin?

When you look up at the night sky, what do you see?

If it's a clear night, you might see hundreds of thousands of tiny points of light, too numerous to count. Some are planets, some are stars, and some are even galaxies!  Where did all these cosmic objects come from? Discover the answer below and  play a game ! 

Edwin Hubble looking through the telescope at Mt. Wilson Observatory in 1924.

In the 1920s in California, astronomer  Edwin Hubble observed distant galaxies using an extremely powerful telescope . He made two mind-boggling discoveries.

First, Hubble figured out that the Milky Way isn’t the only galaxy.  He realized that faint, cloud-like objects in the night sky are actually other galaxies far, far away. The Milky Way is just one of billions of galaxies.

Second, Hubble discovered that the galaxies are constantly moving away from each other.  In other words, the universe is expanding. The biggest thing that we know about is getting bigger all the time.

A few years later,  Belgian astronomer Georges Lemaître used Hubble‘s amazing discoveries to suggest an answer to a big astronomy question: How did the universe begin?

If the universe is always getting bigger, then long ago it was smaller. And long, LONG ago, it was much smaller. That means billions of years ago, everything in the universe was contained in a tiny ball that exploded! Wow!

This breakthrough idea later became known as the  Big Bang!

The  Big Bang  was the moment 13.8 billion years ago when the universe began as a tiny, dense, fireball that exploded. Most astronomers use the Big Bang theory to explain how the universe began. But what caused this explosion in the first place is still a mystery.

So, what has happened since the Big Bang?

Since the Big Bang, the universe has been expanding. In the early years, everything was made of gas. This gas, mostly hydrogen and helium, expanded and cooled. Over billions of years, gravity caused gas and dust to form galaxies, stars , planets, and more.

The matter that spread out from the Big Bang developed into everything in the universe, including you. You are made of star stuff!

Timeline of the Universe

Astronomers have figured out that the universe is about 13 billion years old. (We’d better skip the candles on the birthday cake!) They have also determined, approximately, when different cosmic events happened, such as when our galaxy and our planet formed.

Can you put these cosmic events in order from the oldest to the most recent? To play, click and drag the pictures left or right to place them in the correct order. 

Can you put these cosmic events in order from the oldest to the most recent? To play, click and drag the pictures up or down to place them in the correct order.

You got it!  Check out the timeline below to explore exactly when these cosmic events occurred. See how the earliest humans didn't even appear until 1.8 million years ago? That's just a blink of an eye in the history of the universe!

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Find out why a ball thrown in the air will return to the ground. 

What is Astronomy?

Astronomy is a BIG subject. We've brought learning about it down to size with these big ideas.

Image Credits:

Milky Way over Thailand, ©  Matipon Tangmatitham ; Hubble at telescope, courtesy of NASA; George LeMaitre illustration by Amanda Duffy © AMNH; Icon illustrations by Daryl Collins © AMNH.

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How did the universe begin? That's a question scientists and philosophers have pondered throughout history as they looked at the starry sky above. It's the job of astronomy and astrophysics to provide an answer. However, it's not an easy one to tackle.

The first major glimmerings of an answer came from the sky in 1964. That's when astronomers Arno Penzias and Robert Wilson discovered a microwave signal buried in data they were taking to look for signals being bounced from Echo balloon satellites. They assumed at the time that it was simply unwanted noise and attempted to filter out the signal.

However, it turns out that what they detected was coming from a time shortly after the beginning of the universe. Although they didn't know it at the time, they had discovered the Cosmic Microwave Background (CMB). The CMB had been predicted by a theory called the Big Bang, which suggested that the universe began as a densely hot point in space and suddenly expanded outward. The two men's discovery was the first evidence of that primordial event.

The Big Bang

What started the birth of the universe? According to physics, the universe sprang into existence from a singularity — a term physicists use to describe regions of space that defy the laws of physics. They know very little about singularities, but it's known that such regions exist in the cores of black holes . It's a region where all the mass gobbled up by a black hole gets squeezed into a tiny point, infinitely massive, but also very, very small. Imagine cramming Earth into something the size of a pinpoint. A singularity would be smaller.

That's not to say the universe began as a black hole, however. Such an assumption would raise the question of something existing before the Big Bang, which is pretty speculative. By definition, nothing existed prior to the beginning, but that fact creates more questions than answers. For instance, if nothing existed prior to the Big Bang, what caused the singularity to be created in the first place? It's a "gotcha" question astrophysicists are still trying to understand. 

However, once the singularity was created (however it happened), physicists have a good idea of what occurred next. The universe was in a hot, dense state and began to expand through a process called inflation. It went from very small and very dense, to a very hot state. Then, it cooled as it expanded. This process is now referred to as the Big Bang, a term first coined by Sir Fred Hoyle during a British Broadcasting Corporation (BBC) radio broadcast in 1950.

Although the term implies some kind of explosion, there really wasn’t an outburst or a bang. It was really the rapid expansion of space and time. Think of it like blowing up a balloon: as someone blows air in, the exterior of the balloon expands outward.

The Moments after the Big Bang

The very early universe (at a time a few fractions of a second after the Big Bang began) was not bound by the laws of physics as we know them today. So, no one can predict with great accuracy what the universe looked like at that time. Yet, scientists have been able to construct an approximate representation of how the universe evolved.

First, the infant universe was initially so hot and dense that even elementary particles  such as protons and neutrons could not exist. Instead, different types of matter (called matter and anti-matter) collided together, creating pure energy. As the universe began to cool during the first few minutes, protons and neutrons began to form. Slowly, protons, neutrons, and electrons came together to form hydrogen and small amounts of helium. During the billions of years that followed, stars, planets, and galaxies formed to create the current universe.

Evidence for the Big Bang

So, back to Penzias and Wilson and the CMB. What they found (and for which they won a Nobel Prize ), is often described as the “echo” of the Big Bang. It left behind a signature of itself, just like an echo heard in a canyon represents a “signature” of the original sound. The difference is that instead of an audible echo, the Big Bang's clue is a heat signature throughout all of space. That signature has been specifically studied by the Cosmic Background Explorer (COBE) spacecraft and the Wilkinson Microwave Anisotropy Probe (WMAP) . Their data provide the clearest evidence for the cosmic birth event. 

Alternatives to the Big Bang Theory

While the Big Bang theory is the most widely accepted model that explains the origins of the universe and is supported by all the observational evidence, there are other models that use the same evidence to tell a slightly different story.

Some theorists argue that the Big Bang theory is based on a false premise — that the universe is built on an ever-expanding space-time. They suggest a static universe, which is what was originally predicted by Einstein’s theory of general relativity . Einstein’s theory was only later modified to accommodate the way the universe appears to be expanding. And, expansion is a big part of the story, particularly as it involves the existence of  dark energy . Finally, a recalculation of the mass of the universe seems to support the Big Bang theory of events. 

While our understanding of the actual events is still incomplete, CMB data are helping shape the theories that explain the birth of the cosmos. Without the Big Bang, no stars, galaxies, planets, or life could exist. 

• The Big Bang is the name given to the birth event of the universe.
• The Big Bang is thought to have occurred when something kicked off the expansion of a tiny singularity, some 13.8 billion years ago.
• Light from shortly after the Big Bang is detectable as the cosmic microwave radiation (CMB). It represents light from a time when the newborn universe was lighting up some 380,000 years after the Big Bang occurred.
• “The Big Bang.”  NASA , NASA, www.nasa.gov/subject/6890/the-big-bang/.
• NASA , NASA, science.nasa.gov/astrophysics/focus-areas/what-powered-the-big-bang.
• “The Origins of the Universe.”  National Geographic , National Geographic, 24 Apr. 2017, www.nationalgeographic.com/science/space/universe/origins-of-the-universe/.

Updated and edited by Carolyn Collins Petersen.

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How the Universe Was Created According to Physics Essay

Introduction, before the big bang, the big bang theory, the inflation theory, the destiny of the universe, works cited.

Mankind has always been faced with the challenge of explaining how the Universe came into existence. Many individuals have from antiquity attempted to develop theories that provide explanations of how the universe was formed. However, as time moved by, most scientists have come to believe that the universe created itself (Zuckerman and Malkan 15). They argue that it is formed through a process that takes place when random chemicals are mixed together resulting in a volatile reaction and consequently the creation of the Universe. An estimation of the time that the Universe formed dates back several billion years long before the existence of mankind. Different times are characterized by dominant theories advanced by scientists, particularly by physicists. Some of these theories include; the Big Bang theory to the most recent String theory (Grupen 214). At the beginning of the book, Greene puts forward provocative questions concerning the nature of the universe. He observes that space and time have remained to be the most mysterious of the concepts of the universe. Some of the questions that need to be reflected upon include whether space is a physical entity, the reasons that make time have direction, and the possibility of the universe existing without there being no space and time (Greene 325). This paper explores how the universe came into existence according to the writings of one of the prominent physicists, Professor Greene.

In his book, Professor Greene elaborates on the concept of the universe from a number of perspectives and offers the readers an understanding of Newtonian physics, quantum mechanics, cosmological studies, and string theory. It has been difficult to provide a sequential explanation of how the universe came into existence due to a lack of adequate facts about what existed before the “Big Bang”, the supposed birth of the universe. According to Greene (341), space and time constitute the very fabric of the cosmos, a platform upon which all occurrences, both human and non-human, take place. Most of the early scientists like Newton believed that, despite being invisible, considered space to be an almost physical entity. That it was a substance that could permit, for instance, light to propagate from one point to the next. According to these scientists, space provided the medium through which light could travel as water provides the medium through which waves can travel (Zuckerman and Malkan 19).

Scientists have remained skeptical as far as what was there before the bang is concerned. One may wonder whether there was a condensed universe suspended in an empty field. However, even if it did, it would be interesting to know what this emptiness had in respect to mankind. Due to inadequate explanation, it is believed that the universe was condensed millions of billions of times much smaller than a millimeter which is approximately 10 -26 of a centimeter (Grupen 194). This condensed universe must have existed in “something”. Scientists have provided a much easier explanation of the existence of the Higg’s field which exists in all of space. The uniqueness of this “field” is the fact that its highest value is 0. This implies that reactions and effects concerning the field operate on a scale that could be less than 0. The proponents of this theory argue that the Higg’s field fluctuated at some point and when it accidentally reached a value of 0, the “Big Bang” occurred simultaneously (Grupen 214). It is at this point that most scientists trace the origin of the universe.

The Big Bang, according to many cosmological scientists, refers to an event that resulted in the formation of the universe (Grupen 213). The fundamental assumption of the theory is that the universe was initially very hot and in a state of high density that it started to expand rapidly. The continuing expansion has caused the universe to cool to its current dilute state (Zuckerman and Malkan 38). It is estimated that the initial state of the universe dates back to about 13.7 billion years. Many scientists have confirmed this theory as being the most reliable since it is based on empirical evidence and observations (Greene 367). However, this model implies that the universe was initially in a near-infinite state. It was at this point that known laws of physics failed to apply and hence there was a need to develop a new theory that combine general laws of relativity with those of quantum mechanics (Grupen 227).

This forced a focus on what existed before the epic Big Bang. Therefore, attempts have been made to offer some explanation of the pre-Bang period. Many believe that this side of the universe was packed with highly uniform microwave energy. This kind of energy was high uniform with only about.01% being different from the majority. When the “Big Bang” occurred, the universe expanded to a size that was about 10 30 of its original (Greene 386). This occurred within an extremely short time, a billion billionth of a second which was about (10 -35 ). Due to the conflicts arising from backdating the creation of the universe, the modern physicists have tried reconciling relativity and Einstein’s quantum perspectives and this has given birth to the most recent theory, the String theory (Greene 3). The theory has 11 dimensions; 10 of space and 1 of time.

There is a newer theory that refutes the claim that the universe was created as a result of an explosion. Instead, it claims that it was due to rapid inflation. The inflation theory states that the universe expanded and continues to expand at the moment. The mechanism that facilitated the expansion was gravity’s repulsive effect, which takes place when there is negative pressure around it.

The proponents of the inflation theory posit that upon the expansion of the universe, all the energy that was released from the form increased the temperature. The resultant small irregularities condensed into the universe and which existed in the pre-Bang period were scattered (Zuckerman and Malkan 27). However, as the Higg’s field started cooling from the initial increase in temperature, these irregularities formed the protons, neutrons, and electrons, which ended up forming the first forms of matter. Further cooling of the Higg’s field caused the protons to separate into two particles; the weak nuclear forces that are, the W and Z particles. Continued cooling of the Higg’s field caused these to separate further resulting in the creation of strong nuclear particles, the gluons (Greene 435). Moreover, the Higg’s field led to the creation of resistance for these particles when it came to traveling through space, causing them to have masses.

As time passed by, the protons, neutrons, and electrons begin to group in spatial un-uniformities and begin to grow in size. As these particles are brought together in large numbers, they are bound by the gravity of their surrounding un-uniformed space. As they grow larger and larger, the masses begin to assert their own gravitational field (Grupen 241). As the gravity of the individual masses become stronger, it pulls even more particles towards it, resulting in increased size. Eventually, when the object becomes reasonably big and as long as it has enough energy from all of its constituent particles, it will burn up hence making a star.

It is the continued ignition of the star that will lead to the next stage of element formation. The intense heat generated within the star will cause hydrogen atoms which are made of one electron orbiting a nucleus to weld to another hydrogen atom. Consequently, a new element (helium) will be formed which will, in turn, be welded to another hydrogen atom to make a three-electron element, lithium. This trend will continue, resulting in the formation of more elements within a single star with a possible maximum of making the 26 electron element, iron (Zuckerman and Malkan 42).

The highly energized star will continue to live and burn and eventually weld all of its hydrogen atoms to others, and eventually run out of pure hydrogen. In spite of the fact this process may take billions of years, it is at that point in time that it will run out of nuclear fuel. This implies that the star will not be able to sustain its own mass (Grupen 242). The star will subsequently collapse under its weight and spew out its contents. The remains of the collapsed stars will result in the formation of stardust. The heat energy generated from the exploded star will cause the stardust to continue being welded to other particles and form more other elements, with the possibility of making every imaginable element. The stardust will remain suspended around the area and a number of things will happen.

The first possibility is the star exploding or going supernova resulting in the creation of more disturbances in the uniformity of space, causing more celestial bodies to form. It is this particular process that will facilitate the self-catalytic renewal of stars, and hence the rapid formation of second generation stars (Grupen 253). One of the most visible stars is the sun. The next possibility for the star going supernova is the creation of a planetoid which occurs when there is not enough nuclear fuel to cause the star to burn up. The planet may either have all the elements on or inside its core. This argument is reinforced by the fact that our planet has all of the occurring elements in spite of having any real origin other than cosmic intervention.

Furthermore, the conditions on the planet earth are ripe enough for basic organisms to come into existence from the compounds left in the wake of the planet formation. This perspective provides an explanation of how we eventually came into being and became inhabitants of this section of the larger universe. Cosmologists have argued that the destiny of the universe will either be in the Big Freeze or the Big Crunch depending on the density and hence gravity of the universe (Zuckerman and Malkan 53).

Despite the complex nature of the universe and our approximately 14 billion-year journey from nowhere to the present vast, highly unexplored universe, our responsibilities seem to have just started and the seemingly unending frontier for us to explore. As human intelligence continues to grow, there are possibilities of discovering more about the universe since what we currently know seems like a grain of sand on the sea-show compared to those in the earth. It can be concluded, therefore, that if the conflicting opinions raised by physicists is anything to go by, the nobody real knows how and the time when the universe came into existence and how it will eventually die out!

Greene, Brian. The Fabric of the Cosmos: Space, Time, and the Texture of Reality . A. A. Knopf, 2004: pp. 325-471.

Grupen, Claus. Astroparticle Physics . 2005: pp. 191-264.

Zuckerman, Ben & Malkan, M. Arnold. The origin and evolution of the universe . John and Bartlett Publishers, Inc. 1996: pp. 15-56.

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The Origin, History, Evolution & Future of the Universe

SPECIAL REPORT: Our universe is both ancient and vast, and expanding out farther and faster every day. This accelerating universe, the dark energy that seems to be behind it, and other puzzles like the exact nature of the Big Bang and the early evolution of the universe are among the great puzzles of cosmology .

There was a time when scientists thought Earth was at the center of the universe. As late as the 1920s, we did not realize that our galaxy was just one of many in a vast universe. Only later did we recognize that the other galaxies were running away from us — in every direction — at ever greater speeds. Likewise in recent decades, our understanding of the universe has accelerated.

In this 8-part series of stories, videos, pictures and infographics, SPACE.com looks at some of the most amazing revelations  about the universe  and the enduring enigmas still to be solved.

Video Show: A Blueprint for the Universe The universe is filled with stars, galaxies, planets and more, plus a veritable buffet of invisible stuff like dark matter astronomers have yet to see. But scientists have pinned down some of the major ingredients of our universe. Take a look at star stuff and more in this video show.

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The Universe: Big Bang to Now in 10 Easy Steps The widely accepted theory for the origin and evolution of the universe is the Big Bang model, which states that the universe began as an incredibly hot, dense point roughly 13.7 billion years ago. Here's a breakdown of the Big Bang to now in 10 easy steps.

The History & Structure of the Universe (Infographic Gallery) Tour the universe's 13.7-billion-year history, from the Big Bang to planet Earth today, in this SPACE.com infographic series.

The Big Bang: What Really Happened at Our Universe's Birth? Big Bang theory holds that our universe began 13.7 billion years ago, in a massive expansion that blew space up like a balloon. Here's a brief rundown of what astronomers think happened.

The Universe's Dark Ages: How Our Cosmos Survived The dark ages of the universe — an era of darkness that existed before the first stars and galaxies — mostly remain a mystery because there is so little of it to see, but scientists intensely desire to shed light on them in order to learn secrets about how the universe came into being.

The Universe Today: What It All Looks Like Now     In the 1920s, astronomer Georges Lemaître proposed what became known as the Big Bang theory, which is the most widely accepted model to explain the formation of the universe.

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Home — Essay Samples — Science — Universe — The Beginning of the Universe

The Beginning of The Universe

• Categories: Creation Myth Universe

About this sample

Words: 1323 |

Published: Nov 16, 2018

Words: 1323 | Pages: 3 | 7 min read

Works Cited

• Greene, B. (2004). The Fabric of the Cosmos: Space, Time, and the Texture of Reality. Knopf.
• Guth, A. H. (1997). The Inflationary Universe: The Quest for a New Theory of Cosmic Origins. Perseus Books.
• Hawking, S. (1988). A Brief History of Time: From the Big Bang to Black Holes. Bantam Books.
• Krauss, L. M. (2012). A Universe from Nothing: Why There Is Something Rather Than Nothing. Free Press.
• Lemaître, G. (1931). The Primeval Atom Hypothesis and the Problem of Clusters of Galaxies. Monthly Notices of the Royal Astronomical Society, 91(5), 483-490.
• Linde, A. (1990). Particle Physics and Inflationary Cosmology. Contemporary Concepts in Physics, 5, 295-339.
• Peebles, P. J. E. (1993). Principles of Physical Cosmology. Princeton University Press.
• Penrose, R. (2004). The Road to Reality: A Complete Guide to the Laws of the Universe. Vintage Books.
• Rees, M. J. (2000). Just Six Numbers: The Deep Forces That Shape the Universe. Basic Books.
• Weinberg, S. (1972). Gravitation and Cosmology: Principles and Applications of the General Theory of Relativity. John Wiley & Sons.

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Science and Creationism: A View from the National Academy of Sciences, Second Edition (1999)

Chapter: the origin of the universe, earth, and life, the origin of the universe, earth, and life.

The term "evolution" usually refers to the biological evolution of living things. But the processes by which planets, stars, galaxies, and the universe form and change over time are also types of "evolution." In all of these cases there is change over time, although the processes involved are quite different.

In the late 1920s the American astronomer Edwin Hubble made a very interesting and important discovery. Hubble made observations that he interpreted as showing that distant stars and galaxies are receding from Earth in every direction. Moreover, the velocities of recession increase in proportion with distance, a discovery that has been confirmed by numerous and repeated measurements since Hubble's time. The implication of these findings is that the universe is expanding.

Hubble's hypothesis of an expanding universe leads to certain deductions. One is that the universe was more condensed at a previous time. From this deduction came the suggestion that all the currently observed matter and energy in the universe were initially condensed in a very small and infinitely hot mass. A huge explosion, known as the Big Bang, then sent matter and energy expanding in all directions.

This Big Bang hypothesis led to more testable deductions. One such deduction was that the temperature in deep space today should be several degrees above absolute zero. Observations showed this deduction to be correct. In fact, the Cosmic Microwave Background Explorer (COBE) satellite launched in 1991 confirmed that the background radiation field has exactly the spectrum predicted by a Big Bang origin for the universe.

As the universe expanded, according to current scientific understanding, matter collected into clouds that began to condense and rotate, forming the forerunners of galaxies. Within galaxies, including our own Milky Way galaxy, changes in pressure caused gas and dust to form distinct clouds. In some of these clouds, where there was sufficient mass and the right forces, gravitational attraction caused the cloud to collapse. If the mass of material in the cloud was sufficiently compressed, nuclear reactions began and a star was born.

Some proportion of stars, including our sun, formed in the middle of a flattened spinning disk of material. In the case of our sun, the gas and dust within this disk collided and aggregated into small grains, and the grains formed into larger bodies called planetesimals ("very small planets"), some of which reached diameters of several hundred kilometers. In successive stages these planetesimals coalesced into the nine planets and their numerous satellites. The rocky planets, including Earth, were near the sun, and the gaseous planets were in more distant orbits.

The ages of the universe, our galaxy, the solar system, and Earth can be estimated using modem scientific methods. The age of the universe can be derived from the observed relationship between the velocities of and the distances separating the galaxies. The velocities of distant galaxies can be measured very accurately, but the measurement of distances is more uncertain. Over the past few decades, measurements of the Hubble expansion have led to estimated ages for the universe of between 7 billion and 20 billion years, with the most recent and best measurements within the range of 10 billion to 15 billion years.

A disk of dust and gas, appearing as a dark band in this Hubble Space Telescope photograph, bisects a glowing nebula around a very young star in the constellation Taurus. Similar disks can be seen around other nearby stars and are thought to provide the raw material for planets.

The age of the Milky Way galaxy has been calculated in two ways. One involves studying the observed stages of evolution of different-sized stars in globular clusters. Globular clusters occur in a faint halo surrounding the center of the Galaxy, with each cluster containing from a hundred thousand to a million stars. The very low amounts of elements heavier than hydrogen and helium in these stars indicate that they must have formed early in the history of the Galaxy, before large amounts of heavy elements were created inside the initial generations of stars and later distributed into the interstellar medium through supernova explosions (the Big Bang itself created primarily hydrogen and helium atoms). Estimates of the ages of the stars in globular clusters fall within the range of 11 billion to 16 billion years.

A second method for estimating the age of our galaxy is based on the present abundances of several long-lived radioactive elements in the solar system. Their abundances are set by their rates of production and distribution through exploding

supernovas. According to these calculations, the age of our galaxy is between 9 billion and 16 billion years. Thus, both ways of estimating the age of the Milky Way galaxy agree with each other, and they also are consistent with the independently derived estimate for the age of the universe.

Radioactive elements occurring naturally in rocks and minerals also provide a means of estimating the age of the solar system and Earth. Several of these elements decay with half lives between 700 million and more than 100 billion years (the half life of an element is the time it takes for half of the element to decay radioactively into another element). Using these time-keepers, it is calculated that meteorites, which are fragments of asteroids, formed between 4.53 billion and 4.58 billion years ago (asteroids are small "planetoids" that revolve around the sun and are remnants of the solar nebula that gave rise to the sun and planets). The same radioactive time-keepers applied to the three oldest lunar samples returned to Earth by the Apollo astronauts yield ages between 4.4 billion and 4.5 billion years, providing minimum estimates for the time since the formation of the moon.

The oldest known rocks on Earth occur in northwestern Canada (3.96 billion years), but well-studied rocks nearly as old are also found in other parts of the world. In Western Australia, zircon crystals encased within younger rocks have ages as old as 4.3 billion years, making these tiny crystals the oldest materials so far found on Earth.

The best estimates of Earth's age are obtained by calculating the time required for development of the observed lead isotopes in Earth's oldest lead ores. These estimates yield 4.54 billion years as the age of Earth and of meteorites, and hence of the solar system.

The origins of life cannot be dated as precisely, but there is evidence that bacteria-like organisms lived on Earth 3.5 billion years ago, and they may have existed even earlier, when the first solid crust formed, almost 4 billion years ago. These early organisms must have been simpler than the organisms living today. Furthermore, before the earliest organisms there must have been structures that one would not call "alive" but that are now components of living things. Today, all living organisms store and transmit hereditary information using two kinds of molecules: DNA and RNA. Each of these molecules is in turn composed of four kinds of subunits known as nucleotides. The sequences of nucleotides in particular lengths of DNA or RNA, known as genes, direct the construction of molecules known as proteins, which in turn catalyze biochemical reactions, provide structural components for organisms, and perform many of the other functions on which life depends. Proteins consist of chains of subunits known as amino acids. The sequence of nucleotides in DNA and RNA therefore determines the sequence of amino acids in proteins; this is a central mechanism in all of biology.

Experiments conducted under conditions intended to resemble those present on primitive Earth have resulted in the production of some of the chemical components of proteins, DNA, and RNA. Some of these molecules also have been detected in meteorites from outer space and in interstellar space by astronomers using radio-telescopes. Scientists have concluded that the "building blocks of life" could have been available early in Earth's history.

An important new research avenue has opened with the discovery that certain molecules made of RNA, called ribozymes, can act as catalysts in modem cells. It previously had been thought that only proteins could serve as the catalysts required to carry out specific biochemical functions. Thus, in the early prebiotic world, RNA molecules could have been "autocatalytic"—that is, they could have replicated themselves well before there were any protein catalysts (called enzymes).

Laboratory experiments demonstrate that replicating autocatalytic RNA molecules undergo spontaneous changes and that the variants of RNA molecules with the greatest autocatalytic activity come to prevail in their environments. Some scientists favor the hypothesis that there was an early "RNA world," and they are testing models that lead from RNA to the synthesis of simple DNA and protein molecules. These assemblages of molecules eventually could have become packaged within membranes, thus making up "protocells"—early versions of very simple cells.

For those who are studying the origin of life, the question is no longer whether life could have originated by chemical processes involving nonbiological components. The question instead has become which of many pathways might have been followed to produce the first cells.

Will we ever be able to identify the path of chemical evolution that succeeded in initiating life on Earth? Scientists are designing experiments and speculating about how early Earth could have provided a hospitable site for the segregation of

molecules in units that might have been the first living systems. The recent speculation includes the possibility that the first living cells might have arisen on Mars, seeding Earth via the many meteorites that are known to travel from Mars to our planet.

Of course, even if a living cell were to be made in the laboratory, it would not prove that nature followed the same pathway billions of years ago. But it is the job of science to provide plausible natural explanations for natural phenomena. The study of the origin of life is a very active research area in which important progress is being made, although the consensus among scientists is that none of the current hypotheses has thus far been confirmed. The history of science shows that seemingly intractable problems like this one may become amenable to solution later, as a result of advances in theory, instrumentation, or the discovery of new facts.

Creationist Views of the Origin of the Universe, Earth, and Life

Many religious persons, including many scientists, hold that God created the universe and the various processes driving physical and biological evolution and that these processes then resulted in the creation of galaxies, our solar system, and life on Earth. This belief, which sometimes is termed "theistic evolution," is not in disagreement with scientific explanations of evolution. Indeed, it reflects the remarkable and inspiring character of the physical universe revealed by cosmology, paleontology, molecular biology, and many other scientific disciplines.

The advocates of "creation science" hold a variety of viewpoints. Some claim that Earth and the universe are relatively young, perhaps only 6,000 to 10,000 years old. These individuals often believe that the present physical form of Earth can be explained by "catastrophism," including a worldwide flood, and that all living things (including humans) were created miraculously, essentially in the forms we now find them.

Other advocates of creation science are willing to accept that Earth, the planets, and the stars may have existed for millions of years. But they argue that the various types of organisms, and especially humans, could only have come about with supernatural intervention, because they show "intelligent design."

In this booklet, both these "Young Earth" and "Old Earth" views are referred to as "creationism" or "special creation."

There are no valid scientific data or calculations to substantiate the belief that Earth was created just a few thousand years ago. This document has summarized the vast amount of evidence for the great age of the universe, our galaxy, the solar system, and Earth from astronomy, astrophysics, nuclear physics, geology, geochemistry, and geophysics. Independent scientific methods consistently give an age for Earth and the solar system of about 5 billion years, and an age for our galaxy and the universe that is two to three times greater. These conclusions make the origin of the universe as a whole intelligible, lend coherence to many different branches of science, and form the core conclusions of a remarkable body of knowledge about the origins and behavior of the physical world.

Nor is there any evidence that the entire geological record, with its orderly succession of fossils, is the product of a single universal flood that occurred a few thousand years ago, lasted a little longer than a year, and covered the highest mountains to a depth of several meters. On the contrary, intertidal and terrestrial deposits demonstrate that at no recorded time in the past has the entire planet been under water. Moreover, a universal flood of sufficient magnitude to form the sedimentary rocks seen today, which together are many kilometers thick, would require a volume of water far greater than has ever existed on and in Earth, at least since the formation of the first known solid crust about 4 billion years ago. The belief that Earth's sediments, with their fossils, were deposited in an orderly sequence in a year's time defies all geological observations and physical principles concerning sedimentation rates and possible quantities of suspended solid matter.

Geologists have constructed a detailed history of sediment deposition that links particular bodies of rock in the crust of Earth to particular environments and processes. If petroleum geologists could find more oil and gas by interpreting the record of sedimentary rocks as having resulted from a single flood, they would certainly favor the idea of such a flood, but they do not. Instead, these practical workers agree with academic geologists about the nature of depositional environments and geological time. Petroleum geologists have been pioneers in the recognition of fossil deposits that were formed over millions of years in such environments as meandering rivers, deltas, sandy barrier beaches, and coral reefs.

The example of petroleum geology demonstrates one of the great strengths of science. By using knowledge of the natural world to predict the consequences of our actions, science makes it possible to solve problems and create opportunities using technology. The detailed knowledge required to sustain our civilization could only have been derived through scientific investigation.

The arguments of creationists are not driven by evidence that can be observed in the natural world. Special creation or supernatural intervention is not subjectable to meaningful tests, which require predicting plausible results and then checking these results through observation and experimentation. Indeed, claims of "special creation" reverse the scientific process. The explanation is seen as unalterable, and evidence is sought only to support a particular conclusion by whatever means possible.

While the mechanisms of evolution are still under investigation, scientists universally accept that the cosmos, our planet, and life evolved and continue to evolve. Yet the teaching of evolution to schoolchildren is still contentious.

In Science and Creationism , The National Academy of Sciences states unequivocally that creationism has no place in any science curriculum at any level.

Briefly and clearly, this booklet explores the nature of science, reviews the evidence for the origin of the universe and earth, and explains the current scientific understanding of biological evolution. This edition includes new insights from astronomy and molecular biology.

Attractive in presentation and authoritative in content, Science and Creationism will be useful to anyone concerned about America's scientific literacy: education policymakers, school boards and administrators, curriculum designers, librarians, teachers, parents, and students.

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This Timeline Shows The Entire History of The Universe, And Where It's Headed

If you're the type of person who sometimes wakes up at 3am and lies in bed trying to wrap your tiny mind around the achingly vast Universe and where it's all headed, well, we have something for you (also, same).

This incredible (and incredibly long) infographic from 2015  just keeps going and going and going. Which makes sense, because we're talking about the entire lifespan of the Universe, from the moment of the Big Bang to the 'heat death' of everything we know and love.

Created by Slovak graphic designer Martin Vargic, the Timeline of the Universe covers the past 13.8 billion years of space, and then plots out what's likely to occur in the next 10 billion or so.

He's even separated everything out into things that affect space, Earth, life, and humanity, just so you can really easily see what's going to hit us the hardest in our end of days.

We start out with the beginning of everything - the Big Bang, which gave rise to the Universe 13.8 billion years ago.

The event birthed the oldest known star in the Universe, Methuselah, located about 190.1 light-years away from Earth.

This strange star has caused quite a bit of trouble for astronomers in the past, because estimates had at one point put its age at around 16 billion years - well before the birth of the Universe, which doesn't make sense at all.

It was only in 2013 that scientists were able to reconcile the age of Methuselah with the age of the Universe, using a new method of combining data on its distance, brightness, composition and structure to come up with a significantly younger age for the oldest known star.

"Put all of those ingredients together, and you get an age of 14.5 billion years, with a residual uncertainty that makes the star's age compatible with the age of the Universe," lead researcher Howard Bond from Pennsylvania State University said at the time . 

As Mike Wall from Space.com explains, while 14.5 billion is still younger than the estimated birth of the Universe, the uncertainty Bond is referring to allows for plus or minus 800 million years, which means their calculations could put the formation of Methuselah  at 13.7 billion years old - just after the Big Bang, although only just.

Fast-forward to 10.4 billion years ago, and the Universe achieves habitability for the first time, and life is finally given a chance to emerge.

Having said that, we're going to have to wait for the 4.2-billion-years-ago mark to actually see any life on Earth at all, but from there, things start to happen very quickly. (The timeline also includes the more conservative estimate of 3.9 billion years ago for when life on Earth first emerges.)

Want to know when the first natural nuclear reactor formed on Earth, or how far back the brightest star in the night sky appeared? Well, I sure hope you like scrolling, because be prepared to do a lot of it to find out.

And once you get the the bottom of the timeline, enjoy, because you'll be steeped in all the gory details of the predicted death of the Universe, including when Saturn 's rings will decay into dust, Earth's orbit goes completely out of whack, and the Sun runs out of hydrogen. Good times.

If you love this timeline, head to Vargic's website to download it as an app for Android and iOS.

A version of this article was first published in December 2015.