Antariksh ki khoj

“Is brahmand ki rachna kaise hui? kisne ki? kyun ki? Yeh itna bada kyun hai? Koi toh batao? And, if there are billions of galaxies and solar systems in the universe then will it be foolish to ask if life is present only on Earth in our solar system? Which is more frightening :- We are alone in Universe OR we are not alone in Universe? Will there be imperialism in universe also for more and more Earth(s) in future? How come Universe is so huge? Will it keep on increasing in size? etc etc”

Sometimes, when I look into clear night sky, there is this whole bunch of questions that gets activated thru my sensory root of vision that keeps on goading my mind for answers. I normally try to evade them by saying that scientists around the world are still trying to find answers to most of them but they never stop from sprouting time and again in my skull’s butter. And the issue is that those questions actually do not have any concrete answers and are still in their Beta phase! In this write-up, I will put light on two such questions to the best of my knowledge acquired thru books, documentaries and internet. These are the birth of Universe and its ultimate fate.

Singularity

Let me begin with the birth of Universe. One might argue that big bang theory has now well established the birth of Universe but on looking closely you will find that it assumes a lot of things and creates more doubts than solving them. It does explain how Universe evolved but it fails to answer how it was born. Let me rewind a little bit.

In 1929, Edwin Hubble, with the help of spectrum analysis and Doppler’s effect, discovered that galaxies were moving away from each other and that Universe was expanding. Hence, moving backwards in time (around 14 billion years ago), everything must have started from a single point (called, singularity) where all the matter and energy was concentrated. From this singularity, the Universe exploded and by this explosion, not only matter and energy was created but also space and time.

My question is that from where does all that matter come? Who created that singularity? Astrophysicists like Stephen Hawking, George Ellis, and Roger Penrose published papers related to measurement of space, time and singularity in 1980s. According to them, “The singularity didn’t appear in space; rather space begins inside singularity. Prior to singularity, nothing existed, not space, time matter or energy.” [Just imagine :)]

They say that it is of no use to speak of the period before the Big Bang as there is no 'before' because time (and space) did not exist! However, my contumacious mind refuses to accept this. It asks that from where did singularity come? In what did singularity appear? Why it was there? The answer is we don’t know.

For the time being, creation of singularity can be supposed to be a supernatural event which is outside our imagination or understanding. Scientists around the world are highly divided on this polemic thought but they don’t have any other alternative at least until further discoveries are made in this regards. (That gives us another reason to make our belief firm in God, though!!)

Dark Matter
Similarly, to predict the ultimate future of Universe is an equally complicated job if not more. According to scientists, as Universe expands, its expansion is slowed down by the combined gravity of all the matter within it (just like a rocket is pulled back by Earth’s gravity). If the pull is strong then the expansion will stop and reverse itself to form singularity yet again else it will continue to expand forever.

In terms of Astrophysics, the future of Universe will depend on its average density and a certain critical density. If the density of Universe is smaller than critical density then Universe will continue expand forever else it will collapse.

The problem is how to calculate the average density of Universe? There are billions of galaxies and trillions of stars. The density of galaxies and stars can be found out as they are visible but what about the matter between them? It was noted that there was an invisible “dark matter” besides the stars and galaxies which was sort of holding the things together and which may also be responsible for slowing down the expansion of Universe.

However, in 1998, the outlandish finding of astronomers in Australia suggested something really strange. Two independent teams of astronomers found that not only is there too little matter in the universe to ever halt the expansion of the universe on its own, but the outward motion appears to be speeding up, not slowing down.!!. (This finding was awarded “Breakthrough of the Year for 1998” by Science magazine.)

Logically, if the Universe was born 14 billion years ago, then its expansion since that time should have been slowed down by huge amounts. But Logics don’t work everywhere! It seems that there is an antigravity force which is responsible for the all this. Even scientists were flabbergasted at this discovery of “speeding cosmic expansion” but they couldn’t find any reason to doubt their work. I noted that back in 1916, even Einstein added an extra term to the equations of relativity called the cosmological constant which amounted to a force that opposed gravity. Though he later discarded it which I think was the biggest mistake of his life.

Currently, there is a lot of research going on around the World on Dark Matter and the nature of particle physics in Cosmos. One such experiment to look forward to is the Large Hadron Collider exp which lies in a 27Km long tunnel beneath Franco-Swiss border near Geneva, Switzerland. I hope it comes out with some concrete results pertaining to the nature of Dark Matter in next 2-3 years.


As far as the ultimate future of Universe is concerned, well, for now astronomers say that the galaxies which we can see now (like Andromeda galaxy) will zip out of range one by one leaving Milky Way galaxy the only one we are directly aware of. By then, our Sun will have engulfed the nearest 3 planets, Mercury, Venus and Earth in its red giant phase before shrinking to a white dwarf star. Finally, there will be only black holes, burnt planets and an extremely cold and black Universe.

Bid

I don’t know whether scientists will be able to provide concrete answers to these two questions in my lifetime but I have a hunch that at least there will be a few more discoveries in the coming years which will provide more answers rather than creating more questions!

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Special thanks to Nehru Planetarium, Science Magazine, TIME magazine, Discovery channel, Hubblesite.org, Nasa.gov, Stephen Hawkings's A brief history of Time and Black Holes and Baby Universes. All the information provided here is based on above resources and I am not biased towards any of them.