The Big Bang Theory (Not the serial)

You know why I love Astronomy and Physics? Astronomy keeps reminding us how insignificant we all are, how insignificant our problems are and how there are things going on which is much greater than us and out of our control, for we are but a tiny speck in the infinite Cosmos.

And Physics takes an effort to explain everything that is happening around us, all the natural phenomena, among which the creation of the universe is one of the most sought after discovery which is stlll in progress.

If you’re an avid lover too, you must definitely check out this blog, maintained by Phil Plait, famously known as the BadAstronomer. You can get up-to-date information served to you in a colloquial manner. Also here is another page to check out, updated with latest information regarding science, astronomy and technology.

 

Nowadays when you say ‘Big bang theory’ you get responses such as ‘Oh I love Sheldon’, ‘Howard is so funny’, ‘Leonerd looks like a nerd’. A theory which explains the origin of our entire species from nothing has been thoroughly overshadowed by a sitcom. Oh, But definitely an enjoyable one.

The Bible explains how we came into existence with a simple answer : God created us. The first line literally starts with ‘In the beginning God created the heavens and the earth’. That’s an easy way out don’t you think? Fortunately we have had some pretty mind-blowing thinkers such as Edwin Hubble, Carl Sagan, Steohen Hawking, Albert Einstein, etc who decided to take the rough path and find out the actual truth instead of building up a facade of lies.

 

The ancient Greeks recognized that it was difficult to imagine what an infinite universe might look like. But they also wondered that if the universe were finite, and you stuck out your hand at the edge, where would your hand go? The Greeks’ two problems with the universe represented a paradox – the universe had to be either finite or infinite, and both alternatives presented problems.

 

Gravity being an adamant puller, anybody would expect the universe to keep shrinking, But Edwin Hubble, an astronomer at Caltech, in 1929 proved that wrong  by his critical discovery that the universe is in fact expanding and not contracting. He observed a Cepheid variable star(one that could determine distances of galaxies) over a period of months and finally came to the conclusion. For more information, look here. Meanwhile, other physicists and mathematicians working on Einstein’s theory of gravity discovered the equations had some solutions that described an expanding universe. In these solutions, the light coming from distant objects would be redshifted as it traveled through the expanding universe. The red shift would increase with increasing distance to the object.

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Also another notion was that, since the universe must have been insanely hot in the beginning, it would have emitted radiation, whose remnants should still be present since the universe is assumed to be isotropic and homogeneous. And this in fact turned out to be true when Scientists discovered it in the 1940’s, and named it the CMB(Cosmic microwave background).

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Discoveries in astronomy and physics have shown beyond a reasonable doubt that our universe did in fact have a beginning. This theory is a strenuous effort taken not to explain how we originated(a common misinterpretation), but to explain how we developed from a tiny, dense state. It is difficult and daunting to imagine a time 13.7 billion years ago, When we were nothing but.. Well nothing. Our entire universe existed as a singularity. What is a ‘Singularity‘? We don’t quite know for sure. Singularities are zones which defy our current understanding of physics. They are thought to exist at the core of “black holes”.

 

As you all are aware of, the treacherous ‘Black Holes’ are areas of intense gravitational pressure. The pressure is thought to be so intense that finite matter is actually squished into infinite density (a mathematical concept which truly boggles your mind). These infinite density zones are known as Singularities. Our universe is thought to have begun as an infinitesimally small, infinitely hot, infinitely dense, something – a singularity.

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A common misconception is that the Big bang is an explosion. Fortunately, it’s not. It’s an expansion that has spanned over billions of years.

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What was the universe like at the beginning of the big bang? According to the theory, it was extremely dense and extremely hot. There was so much energy in the universe during those first few moments that matter as we know it couldn’t form. But it kept expanding relentlessly and that helped it to cool down and matter started to take shape while radiation began losing energy. In a few seconds the universe went from being nothing(a singularity actually) to something that stretched across space.

 

The four fundamental forces that we know of now were formed at that instant. A better word would be ‘segregated’, as they were all unified initially under the Grand Unified Theory. Because of certain unmistakable limitations of laws of science, we can’t take a random guess at the first second of the creation. But we’re close. Scientists are able to go as far as t=1×10^(-43), where ‘t’ represents the time after the creation. The study of these phenomena’s are known as quantum cosmology, as these vehemently defy the laws of classical physics.

 

At t = 1 x 10-43 seconds, the universe was incredibly small, dense and hot. This homogenous area of the universe spanned a region of only 1 x 10-33 centimeters (3.9 x 10-34 inches). Today, that same stretch of space spans billions of light years. As the universe expanded, it cooled. At around t = 1 x 10-35 seconds, matter and energy decoupled. Cosmologists call this baryogenesis — baryonic matter is the kind of matter we can observe. In contrast, we can’t observe dark matter, but we know it exists by the way it affects energy and other matter. A period of particle cosmology followed the quantum age. This period starts at t = 1 x 10-11 seconds. This is a phase that scientists can recreate in lab conditions with particle accelerators.

Next came the period of standard cosmology, which begins .01 second after the beginning of the big bang. From this moment on, scientists feel they have a pretty good handle on how the universe evolved. The universe continued to expand and cool, and the subatomic particles formed during baryogenesis began to bond together. They formed neutrons and protons. By the time a full second had passed, these particles could form the nuclei of light elements like hydrogen (in the form of its isotope, deuterium), helium and lithium. This process is known as nucleosynthesis. But the universe was still too dense and hot for electrons to join these nuclei and form stable atoms.

So that’s a pretty nifty one second! But then comes the next 13 billion years.

After 100 seconds, the universe’s temperature cooled to 1 billion degrees Kelvin (1 billion degrees Celsius, 1.8 billion degrees Fahrenheit). By mass, the distribution of elements was approximately 75 percent hydrogen nuclei and 24 percent helium nuclei.

For the next 100 million years or so, the universe continued to expand and cool. Small gravitational fluctuations caused particles of matter to cluster together. Gravity caused gases in the universe to collapse into tight pockets. As gases contract, they become more dense and hot. Some 100 to 200 million years after the initial creation of the universe, stars formed from these pockets of gas.

Stars began to cluster together to form galaxies. Eventually, some stars went supernova. As the stars exploded, they ejected matter across the universe. This matter included all the heavier elements we find in nature (everything up to uranium). That’s where the famous quote by Carl Sagan originated “We all are made up of star-stuff”.

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Coming to today, the temperature of the universe is 2.725 degrees Kelvin, which is only a couple of degrees above absolute zero. The homogeneous section of the universe we can theorize about reaches 1 x 10^29 centimeters across, which is a humongous number which is beyond anyone’s imagination.

 

And still our universe keeps expanding. But there are three models which were formed – The Open, Closed and Flat. For the last eighty years, astronomers have been making increasingly accurate measurements of two important cosmological parameters: Ho – the rate at which the universe expands – and – the average density of matter in the universe. Knowledge of both of these parameters will tell which of the three models- Flat, Open or Closed, describes the universe we live in, and thus the ultimate fate of our universe.

Although the theory efficiently answers many questions, it also raises as many. And although we feel like we’ve discovered a lot, there are still questions hovering about whose answers we’re unable to find. What happened before singularity? Where did it come from? What will be the fate of our universe? Are there multiple universes? Will a collision between universes occur?

Yet that is the beautiful difference between Science and Religion. Religion claims something and let’s it hanging in the air without any support. But Science puts forth its theory and carries the burden of the evidence. Even if the theories pan out to be wrong, it comes up with a new one and the process goes on evolving.

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To me, Science is the best religion!

 

 

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