We live in a fortuitous time. The universe is neither too hot nor too cold. The neighbouring stars are not going bang all the time and blowing up into gigantic supernova nor any black hole is orbiting close by us. When we assemble the fragments of the universe together to see where we fit in, we find ourselves mysteriously lucky enough to be at the right place at the right time. Not just this, if you consider the concept of the multiverse, if there is an a minuscule chance of change in any of the physical constants which rule our universe, we might simply be non-existing. Before staring at how it would end, let’s have a glance at how it began (don’t worry, it’s quick and short). Universe is a chaotic place, both beautiful and terrifying. For now, we’ve known that the universe is nearly 13.8 billion years old. The number seems narrow, but if you compress to make the universe age into a calendar – a cosmic calendar, we’ll find that the modern human life came into existence just 14 seconds before the midnight of December 31st. Before plunging into how the universe dies, let’s talk about how it began and on a compressed cosmic calendar, where we are. (P.S. the timeline of these dates is accurate enough and is given by Carl Sagan). Let’s begin.
In this cosmic calendar, the seconds, minutes, and hours are adjusted according to actual cosmic timeline-in the sense-
1 Second =438 years
1 hour = 1.58 million years and hours 1 day = 37.8 million years
January 1st, 12:00 am – The big bang. It is illustrated that the big bang is like firecrackers, lights, and sound in all the directions, but it was quiet. For light and sound to be produced, we need subatomic particles, which doesn’t occur until a few million years. (actual time scale-13.8 billion years ago)
January 22nd–As subatomic particles were brought together by gravity nearly after a billion years, forming atoms and molecules, the first galaxies emerged. (The first atoms formed in our universe when it was only 380,000 years old.) (actual time scale 12.85 billion years ago).
March 16th- As there were fierce collisions of asteroids, planets, comets, satellites forming planets, solar systems and galaxies; our galaxy The Milky Way galaxy was born. (actual time period -11 billion years ago)
After nearly 5 months on
August 28th- Our solar system was formed. It was still young when compared with the milky way. (4.57 billion years ago)
September 6th- As per the recordings of Earth, it was formed on this day. Our tiny little lovely planet was brought to life through collisions of asteroids and Thea. It might not have sounded lovely if you’ve seen it during formation. Deadly constant collisions, death from everywhere, earth in a molten form, oceans of lava flowing all over the world, intense volcanic eruptions(not that lovely isn’t it?). Just a few days before our planet formation, the Sun was born. (actual time 4.54 billion years ago)
September 7th- Our neighbouring satellite-the Moon– took its form. This happened just one day after the formation of the earth. (nearly a million years on a cosmic scale) (actual time 4.53 billion years ago).
September 14th- Just a week after the formation of the Moon, the beginning of life occurred on this primordial earth- the birth of single-celled primitive bacteria. This was the only recorded evidence of early life on earth (4.1 billion years ago).
2 months later, on
December 5th- after a very long time, multicellular organisms were taking their shape. (800,000,000 years ago)
Until now, it has been a long journey for the formation of the landmasses on earth. From furious oceans of lava to deep oceans of water.
On December 20th- Water-based creatures took their first step onto land. The populations of reptiles and amphibians increased exponentially. (0.45 billion years ago)
Around 23 million years ago, just 6 days before the 31st of December
December 25th- Dinosaurs roamed the earth (0.23 million years ago)
Sadly, just after 5 days
December 30th- Cretaceous extinction event took place. A meteorite slammed into the earth which wiped out the era of dinosaurs. But it paved a way for the evolution of mammals to roam the earth. (0.065 billion years ago)
The final day of the year, December the 31st, everything transformed drastically from this day onwards. During the late hours of the 30th and early hours of 31st, mammals ruled all over the earth.
(remember: 1 Second =438 years 1 hour = 1.58 million years )
6:05 am- Apes started to roam.
Nearly half a day later,
2:34 pm (14: 34)- as apes evolved, hominids came into existence.
10:24 pm (22:24)–the evolution sprung strong and primitive humans started to use stone tools.
At almost half an hour later
11:44 pm (23:44)–domestication of fire occurred.
8 minutes to midnight
11:52 pm (23:52)–Modern humans
As seconds ticked…
11:55 pm (23:55) – the earth was completely covered with ice (also known as the glacial period)
It was not until the last two minutes early humans started to make sculptures and draw paintings.
At 23:59:47–we started to write- the beginning of bronze age
From there, we can see the recorded history, from invasions to developments to science and technology.
Where do we stand now?
We are at
Everything we have ever known, everything we have ever done, from food industries to moon landings, from the first telescope to modern telescopes, from mechanical cars to electric cars, from sand to smartphones; all the chaos, all the wars, all the protests, the empires built, families destroyed, flights built, satellites sent, advances we’ve made, is in this tiny second, here we are.
Considering the massive cosmic scale, we are insignificant on this vast scale; but we feel mighty enough to construct and invent plethora of things within this tiny second. Imagine the timescale of the universe vs the timescale of humans; yet here we are, reading this.
So, how the universe might end? And when would it be? How long does it take?
To explore this aspect, let us consider a few scenarios of how the universe might end.
The Big Rip; The Big Crunch; The Big Chill. Each of these scenarios is equally horrifying. It all started with the Big Bang.
As the universe came from nothingness, it could be stated that it would go back to nothingness. The way this process occurs depends on several cosmological factors and loads of physics. Dark energy and dark matter; these are mindboggling concepts in cosmology/astrophysics, which on discovering would lead to a new era of cosmology. Dark matter can be described as that matter which we can’t see but we know they exist and play a major role in connecting galaxies together. In fact, Einstein himself said through his equations that, the mass of the galaxies doesn’t add up until we involve the dark matter. Dark matter might be several times larger than normal matter and that rules the galaxies. Dark energy, on the other hand, is an invisible energy that literally pushes the universe. This kind of energy cannot be detected that easily. It has the least/ no interaction with normal matter. It was first thought that dark matter over took dark energy. Because of this and by considering gravity, we can see that, whatever we throw up (on earth), the gravity seems to pull it back down. Similar case can be considered in the macroscopic universe. As the universe expanded, gravity held this together. After a long time in future, if the force of dark energy is not enough, gravity can dominate and pull back everything in the universe back to its singularity. This squeezing up of all the cosmic entities into a single speck/into a singularity can be referred to as Big Crunch.
Death, not an interesting thing to talk about all the time, but it’s the ultimate truth. We all are going to an end at some or other point in time. For the universe, it’s a bit different. Dark energy and Dark matter. These play an important role in us the fate of the universe. The compositions of the universe are nearly Dark matter (25%), dark energy(75%). Dark matter is not normal matter, not antimatter (if so, it produces unique gamma rays when interacted with normal matter) and is not made up of black holes. Yet, these are spread all over the universe. We can’t see dark matter, but we know it exists. A phenomenon called gravitational lensing allows scientists to observe at which rate the normal matter is bent around a galaxy. By calculating this we can know the content on how much dark matter can exist in a galaxy. During later discoveries, it was found that normal matter isn’t enough to form up the galaxies; and hence the dark matter. On the other hand, we’ve got dark energy. dark energy is totally of a different kind. We cannot detect it, we cannot see it, we can’t feel it but it exists, and it covers 75% of the universe. We have a few abstract ideas on what dark energy is.
It can be just another property of space. Another idea was given by Einstein through the concept of the cosmological constant. The cosmological constant is that kind of force which is completely opposite to gravity. When scientists tried to calculate it, it just kept on adding more confusion among the scientific community. Even Einstein himself said that introducing cosmological constants to his equations was his biggest blunder. A new idea of dark energy is that virtual particles are constantly emerging in the universe which are appearing and annihilating. It’s like being born and died at the same time, (no, not Schrodinger’s cat!). Virtual particles would come into existence from nothing and annihilate into nothing.
Dark energy and dark matter are completely different. Dark matter interacts with normal matter in at a subtle level which we can’t detect but predict. It is for gravity. Dark energy, on the other hand, is the most powerful energy which we have known which pushes the universe all the way long without interacting with normal matter. Understanding this difference is essential for understanding the ways in which the universe might die. Besides dark matter and dark energy, there are 2 other factors that need to be analysed. The rate of expansion of the universe and the dominance of these forces.
We know that the universe is expanding; it is just a question about how fast it’s expanding. The need to determine the speed is quite essential as it directly tells us which forces dominates and what might be the fate of the universe. If the universe is expanding fast, the end is going to be very disastrous and dramatic. As the universe continues to expand by the force of dark energy, everything will start to rip apart, from the galaxies to the tiniest of subatomic particles. The view for one( who is still alive) might be like darkness approaching from every possible direction. Everything would instantly just vanish as even the atoms are torn apart, creation would just cease to exists. It is the end. This is the consequence if we consider the Big Rip.
How can we know that as the velocity increases, things rip apart? It can be experimented by yourself. Consider your going on a slope(for easy comparison) using a car. Now, if you point a few markers all along your way on the beforehand, while going down the road, if you drop paint marks or drops at same interval; you’ll find that while measuring, you can literally see the increase of the distance between the dots from one marker to another although the markers are at the same place. This crazy simple phenomenon goes with the Big Rip.
Now the final scene. What if the universe is expanding at a constant rate? It would just keep on expanding forever. This ending is a kind of dark, sad and lonely . As the last stars cool which would happen in about 10^10 years, the universe would be entering the dark ages. The empty space just keeps on expanding pushing away our neighbouring stars and galaxies far away from us. For billions of light years, we would see nothing but darkness. The whole of our sky would be dark, not even a single star would be shining in our night sky. Slowly the sun dies (in about 4.5 billion years). This is the last chance for any civilization (not just on earth, but over anywhere in the universe) to have the last light. As eons pass by, stars degrade, everything would go haywire, planetary displacements would occur (cold and lonely). Slowly, black holes dominate the whole of the universe. This is the era of black holes. But in time, even these black holes would evaporate in about 10^100 years (through Hawking radiation). After this, the universe would be in the darkness for incredibly long time maybe forever until there is any occurrence of quantum fluctuations and a new bang which might give birth to a new universe.
Besides these scenarios, there is another aspect which we need to consider which is the shape of the universe itself. This can be seen below:
In this tiny span , we were able to map out the leftover energy from the big bang. it was taken by WMAP satellite. A history which is 13.8 billion years old.
Despite all the odds from the formation to the death, here we are lucky enough to lead a meaningful life. Enormous forces are acting upon us all the time just to keep this little place-the earth -in its orbit and solar system safe. Besides the fact the cosmos itself is taking care of us, it is sensible enough to make the most of this life as a human being.
From nothingness to nothingness.
Open to all ideas and suggestions 🙂