Our Universe - 2

This post is the second part of ‘Our Universe’. To read the first part, click here.

“Look up at the stars and not down at your feet. Try to make sense of what you see, and wonder about what makes the universe exist. Be curious." - Stephen Hawking

When you look up at the night sky, you can see everything shining. The constant stars, wandering planets, falling meteors and travelling comets are a few things one can notice with bare eyes. However, our universe is a lot more than these. Other than the matter that we can see, the universe also consists of invisible bodies that actually run the universe.

One of the first invisible bodies that comes to the mind is a black hole. The reason why it is invisible is because it sucks in everything in its way, even light. You might have seen illustrations of black holes as a black round object sucking in light like a whirlpool. This might not be true in reality. In fact, black holes have never been seen. Black holes are predicted and detected by their effect to the surroundings.

The universe is expanding. This rate of expansion is not constant. It is accelerating every minute. Suppose you are blowing air into a balloon and you want to increase the rate, you start blowing air faster. You spend energy. Similarly, the universe needs to spend energy in order to increase the rate of expansion. Where does this energy come from? All that we know that exists in the universe is matter and energy. We expect these two to make up our universe. However, calculations show that the energy and matter alone can’t drive the expansion all by themselves. There must be something else in the universe which drives the expansion. Something which can’t be seen. Something we haven’t found yet.

Scientists call this energy as the dark energy. The dark energy is said to be the most dominant constituent of the universe. It is so dominant that even today, it is reducing the amount and effect of the regular matter and energy. The dark energy is not practically discovered or studied yet. But what we do have are theoretical predictions about this energy.

Dark energy makes up 68% of the universe. 27% is the dark matter. The actual visible universe we see is only 5% of the whole. The universe is indeed magnificent! But how to detect dark energy? Unfortunately, we don’t have the sophisticated technology to study or detect the dark energy or matter. Imagine if we could detect the dark energy! Imagine if we could harness the energy! We could erase poverty and pollution forever and make this world pollution-free! But that’s pep-talk for another day.

Everything that is born, is destined to die. The same can be said for our universe. If the universe was born some time ago, it has to die some time in the future. As dark as it sounds, the death of the universe isn’t that bad. There are 3 major theories which predict how the universe will end.

The first theory is called as the Big Rip. The rate at which the universe is expanding is increasing every moment. After some time, dark energy dominates the universe so much that gravity can’t hold the universe together and it breaks. Gravity breaking apart is not a good thing to hear. It is not a piece of glass breaking. When gravity breaks, reality itself breaks apart. All our understanding of the universe becomes nothing. Luckily, you and me won’t be there to experience this event, if it happens so.

The second theory is called as the heat death. This has something to do with the thermodynamics of the universe. According to this, the fuel is spent and all matter dies. For a few years after all stars die, the universe will have nothing but black holes. After a while, even black holes collapse, leaving absolutely nothing. Just imagining this is so cold and uncomfortable.

Option 3 is that the universe starts contracting after some point of inflation. According to scientists, the universe has gone through such cycles of continuous expansion and contraction. But when the universe contracts, the heat of the universe starts increasing. At the maximum point of contraction, the heat increases so much that atoms don’t exist anymore. The universe becomes an infinitely dense and hot point and who knows, it might explode again as a new Big Bang, giving rise to a new universe?

To cheer you up, the end of the universe is an event which we won’t be seeing for sure. But imagine this… what if we live in a universe which is inside a balloon being filled with air. What if that balloon pops? What if that balloon is a part of a bigger universe?

We are truly alone aren’t we…?

-Sameer V Devipur