But no, this end is not the one that would pave way for another beginning. Yet if you really persist on one not existing without the other (the end without a beginning and vice versa), call it the beginning of an eternal void? Whose end are we discussing and why does it sound so depressing? The quietus of our entire existence...physical, for those with faith in the alternate forms of existence. No, not just life...that would be so human of us, the conclusion of everything there ever was and will be, the grand stage...our universe (and all others perhaps?)

Of course, there are many around the world that have, do and will devote their lives to unraveling the early expansion of the Universe popularly known as the Big-Bang! That indeed, is a topic worthy enough of catching the imagination of young and old scientists alike. But, little thought is given or at least publicized on what awaits all of it at the end, what is the final fate? 

Inherently, we favor the availability of options, and just like the menu of a restaurant, we can choose from many available options to end things for good (haha?!) What would you like to treat yourself with today, sir? How about a Big Crunch or a Big Rip, perhaps a Big Freeze...I think you'd enjoy a Big Bounce! As appetizing as these may sound, with enough understanding, you'd want to get rid of them from your thoughts because they are the hypothesized endings of all of existence. Take, for example, the Big Freeze..ironically, it is nicknamed- heat death. Now, don't worry it is not death by heat...but rather, the death of heat itself. For what it's worth, the ambient temperature will be just 0K!

Geometry & Scale

What in fact is a Closed or an Open Universe? Alexander Friedmann, a Russian Physicist, introduced the Density Parameter denoted by Omega () which is the ratio of observed to critical density as determined from the Friedmann Universe (spatially homogeneous and isotropic). The value of omega determines the geometry of the Universe. For values larger than 1, the Universe is closed like the surface of a sphere and for ratios less than 1, the Universe is open like the surface of a saddle. The critical value of 1 is a Universe that is flat. 

NASA's WMAP (Wilkinson Microwave Anisotropy Probe) confirmed that the Universe is flat indeed, with less than a percent of margin of error. Are you think how can the Universe be considered flat when we clearly argue against Flat Earth! How is it so when you can see the spatial difference between the seas and the mountain peaks, the streets and the skyscrapers...the planets, the suns and the moons. It all is a matter of perspective after all! No it does not mean that the Earth is flat, that one's still a big NO. But, these measurements hold true for scales ~100 Mpc (mega parsec, it's a HUGE distance). To put things into further perspective, a parsec is about 3.26 light-years which is 31 trillion km's. Do the calculations for 100 Mpc (mind=blown?). The existence of dark energy plays a trivial role, and that has made the fate of Universe more inclined towards that with an Open Universe geometry (Big Freeze, Big Rip).

Sometimes, to understand the macro, it becomes essential to study the micro scale. In either cases of Big Freeze and Big Rip, what's left for the finale is either the exhaustion of Black Holes by Hawking Radiation or the disintegration of everything to the smallest of particles and their further decay.

Now that the grand scale has been covered, let's dive into the grandeur of...time.

Content hereafter inspired by: Sophia Nasr

About Time

This is an atom, helium to be exact. Two protons, two neutrons and two electrons. As opposed to humans, elementary particles tend not to go rogue when required to confine themselves to a group for stability. While the atom itself is stable, the elementary particles that make up, this and infinite other combinations of atoms and molecular compounds, are not always stable on their own. This phenomenon of transformation of the free elementary particle, is termed as decay. How is the decay of subatomic entities pertinent the end of the Universe or the grandeur of time? If the Big Rip and Big Freeze do indeed happen, what will be left? These elementary particles, and only they shall live to see the end of it all. Their decay is perhaps the last event to mark the finale. And that will be a long and slow one! Better than a slow death to the conscious mind, eh?

Let's take a free neutron, if you'd been reading carefully, we know what's going to happen next- decay. A neutron, slightly heavier than the proton, is not as stable as a proton can be. Nature strives for stability with far more determination than we do, but then again, we are a microcosm of all that we see. A neutron (neutral), to attain a more stable state, decays into a proton (positive charge). But wait, as do the Lannisters, chemical reactions also always pay their debts...to Thermodynamics. THE LAW OF CONSERVATION. Mass must always be conserved in any transformation and so, along with the generation of a slightly lighter proton, an electron (negative) and an electron anti-neutrino is formed. Now, there is balance!

So, we started with a neutron and ended up with proton, electron and electron anti-neutrino. Not only was the mass conserved but also the charge (n0 → 
p+ + 
e− + 
ν
e). It is essential also to know how long this process takes. The concept of Half-Life explains the time it requires for a particle to decay to half the amount it started with. For a free neutron, this half-life is 10 minutes 11 seconds and it completely decays in 14 minutes 42 seconds (it is a logarithmic function).

But this is just the beginning.


The Big Rip scenario concludes with the disintegration of all matter to its most elementary form. Let's assume that we end up with a bunch of stable protons. Combining this with Big Freeze, we also have quite many Black Holes floating around the Cosmos. We can't just stop here. The quest of Science does not end at answers, it really also begins questioning those answers. What happens once we have stable protons? Do they NOT decay?  Of course they do! And how do we find that? Calculating its half life! Nothing is invincible.

Proton's have a half-life of 10³² years. To give some perspective, the estimated age of our Universe is ~10¹⁰ years. Did it ever occur to you reading this, why don't we decay, we're made out of protons?! Yes, we do have protons, every atom has a proton at its center, the nucleus. But, the game is all about the stability. Life is made from carbon compounds, these are variations on the arrangement of molecules of carbon and other atoms. But they are stable! And we need not worry about their decay (TGIM- thank god its mortality).

Fast-forward 10⁵⁰ years, we have reached the period where all the protons have decayed. Nothing to make up matter anymore, what's left now? BLACK HOLES (which aren't black really, but does it matter if you can't see them?) A Universe full of giant black holes BUT they die too. As we learned earlier, Hawking Radiation at the event horizon of a black hole is responsible for its death. How long would it take for a Black Hole to disappear? For a Black Hole the mass of our Sun (~10³⁰ kg), it would evaporate by the radiation in 10⁷⁴ seconds. Knowing that a year has ~ 10⁷ seconds, it will take approximately 10⁶⁷ years. But black holes are rarely as small as our Sun. How about a Black Hole that is 10 billion times more massive than Sun? That's an enormous 10¹⁰⁴ seconds or 10⁹⁷ years!

That's it then, first the protons decay and then the Black Holes evaporate. Darkness shall prevail. No.

...until its over.

There is an elephant in this cosmic ballet that has elusively pirouetted swiftly across our vision. 

Let's see the composition of our Universe. You would be surprised to know, all that we can see around us and through our ginormous telescopes, matter- makes up only 4.6% of the observable Universe. Dark Matter (responsible for gravitational effects) constitutes 24%. Although it has never been directly observed, the effects are measurable on its surrounding. But that still leaves 71.4% of unexplained composition of the Universe. And this is Dark Energy. The 'dark' reflecting its mysterious nature, yet to be known. Don't be surprised, we have had encounters with Dark Energy many times in this post. Remember the Flat Universe, resulting in the same fate as an Open Universe. All thanks to the effects of Dark Energy. The extreme expansion in the Big Rip, that's also a consequence of Dark Energy. And finally the Big Freeze situation, I believe you know it, yes, Dark Energy.

a pursuit beyond the equations.

That is exactly the nature of the pursuit of science. Questions lead you to answers only to lead you to many more questions! What must Dark Energy be? How gravely could it alter the fate of our Universe. Is this where after-life is, or the higher dimension? We are witnessing less than 1/25th of the Universe, how can we then assume we have all the answers based on observations of limited facts.  How do we pretend to be so sure of existence and why do we believe in absolutism. Is this our naivety or unbending conviction? It is everywhere around us, yet nowhere in our existence, nowhere in our thoughts. Can we afford to neglect what makes up more than three quarters of our Universe and expect our truths and facts to be the ultimate answers? Astronomy is indeed a humbling experience.