The 3 Ends to our Future

On the pursuit for a unified theory of our universe (The theory of everything), we often find ourselves constantly looking back into the past in the hopes of unravelling something much more brilliant or far more ingenious then we once thought could be. This constant urge to utilize what the past and the present holds, has propelled us to achieve astounding advancements in technology and science, bringing us closer to the heart of our universe. However, the past shall not bound us, but instead, catapult us further into the future. Perhaps it’s time we look into what lay among us, even bigger questions that are certainly more uncertain then our past.

Before we diverge into the fate of our future, lets understand how our universe expands. The expansion of our universe is a battle against the strength of the force of gravity which depends primarily on the density and pressure of matter, and somewhat rather bizarre forces as a result of Dark Energy. One may ask, what is dark energy? Well, that’s a question we’ve all been yearning to obtain answers for. There’s so much more we don’t know than actually do know about it even though our universe is to be composed of: 68% Dark Energy, 27% Dark Matter, and 5% Normal Matter. (New article on dark matter and energy to be linked soon! :)

On the quest to calculate the rate of deceleration of the universe, scientists we shocked to find out that quite the opposite was happening. The universe was expanding, that too at an accelerated rate! But what are parameters and factors that were chosen to determine such a conclusion?

Let’s keep it simple. Imagine you’re holding a bright, shiny red ball. You pass it on to your friend and tell her to take the ball as far as she possibly could. As your friend slowly walks away metres, kilometres, megametres, gigametres, petametres, zettametres and beyond away from you (basically, reaaallly far), It’s quite obvious that the ball would slowly become dimmer and eventually fade away from sight. Galaxies could be linked by a similar comparison. By observing the doppler shift leading to the red shift of galaxies, the change in the wavelength of radiation obtained from distant galaxies, showed that it was proportional to the distance of them from earth. Just like how the ball changed in size and faded away, galaxies similarly changed and stretched in wavelength which allowed us to understand that galaxies further away from earth were moving much faster away from us, thus concluding that the universe were to be expanding at an accelerated rate. This observation was made by no other than the famous American astronomer, Edwin Hubble.

Now that we’ve taken a glance at how our universe is accelerating, what’s next for the universe? Will it forever expand or will it simply collapse into itself and cause a catastrophic destruction of matter around it too? Here are the 3 probable theories to the end of our future:

1) The Big Freeze

The big freeze, quite ironically also known as the “Heat Death”, is surprisingly one of the most probable of three predicted theories out there! To begin with, lets understand what entropy is. Entropy is the measure of thermal energy that is unavailable to do work. In short, it’s the degree of randomness, with all the things in the universe moving from order to disorder, it is predicted that we would reach a state where all the heat would be evenly distributed to a point where density is below critical density. Critical density is the average density of matter just to halt expansion. Below this point, the forces of gravity aren’t not strong enough to stop the expanding universe which will result into further expansion during a state where no more reactions can be sustained, leading to a cooling/freezing life effect.

2) The Big Crunch:

The big crunch would be observed at a state above critical density, with gravity dominating, it would lead to the entire universe reversing or collapsing. Imagine rewinding a movie or a time-lapse of the universe. Hypothetically, the big crunch would be like rewinding and replaying the universe expanding but played backwards. The universe would be seen contracting with a high possibility to collapse into itself.

3) The Big Rip:

The big rip would give us a more comical appeal to the fate of our universe. In such a state, the forces due to dark energy would fiercely dominate over gravity so that as it continues to expand, it would eventually rip apart due to the high rate of accelerated expansion resulting in the tragic tearing apart of our solar system, galaxy and then…our universe as a whole. The big rip hypothesis is definitely a more appalling and unfortunate turn of tales for the future.

These theories have given us an eye-opening glance into our universe and its mysteries. Looking back into the past has certainly been a tool to understand the future, but for now, the end of our future shall remain a probability.

Sources!

https://www.nasa.gov/missions/deepspace/f_dark-energy.html

https://science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy

http://www.jb.man.ac.uk/distance/exploring/course/strobel/cosmolgy/cosmlgyc.htm

https://wmap.gsfc.nasa.gov/universe/uni_fate.html

https://wmap.gsfc.nasa.gov/universe/uni_expansion.html

https://starchild.gsfc.nasa.gov/docs/StarChild/questions/redshift.html

https://www.wired.co.uk/article/how-will-universe-end