What if all the stars disappeared tomorrow?
Together with all the planets,
solar systems and galaxies?
This is WHAT IF,
and here's what would happen
if the Universe ended tomorrow.
Some 50 million years from now,
the Martian moon Phobos
will slam into Mars and shatter to pieces.
In 100 million years, Earth will likely get hit by an asteroid
the size of the one that caused all the dinosaurs to go extinct.
In about 1.5 billion years, the Sun will become so luminous,
that it will force the habitable zone to move outwards,
leaving what's left of Earth to get crispy.
Everything will eventually come to an end.
Even our almost 14-billion-year old Universe.
What would it be like
to witness of the epic end of the cosmos?
Don't get too comfy.
The end of the Universe would mean the end of everything in it.
Two trillion galaxies that we can observe from Earth,
filled with a tremendous amount of everything
from enormous gas giants
to weird shaped asteroids.
Everything would be gone,
including you and whoever else is out there.
But your last moments could be very different
depending on how the Universe shut down.
Here are three ways it might happen.
The Universe is expanding.
Galaxies are moving away from each other at an ever-increasing rate,
despite the attempts of gravity to pull them back together.
That's because a theoretical force called dark energy
is opposing the force of gravity.
If one day, this dark energy pulled a little too hard,
the pieces of raw material needed for star formation
would become too far away from each other.
All the existing stars would eventually run out of fuel,
and there would be no new ones to replace them.
It would get very dark and very cold.
Once the temperature reached absolute zero,
nothing would be able to move, not a single atom.
The Universe would become the most boring, static place,
and would probably remain an endless void forever.
I bet you were hoping for a more spectacular ending to this story.
If the dark energy became so intense
that it was able to nullify the force of gravity altogether,
it would rip the Universe apart.
It would start with the galaxies, tearing them down one by one.
Black holes would be next to disintegrate,
followed by stars,
planets,
asteroids...
As the expansion of the Universe ramped up,
every form of matter would collapse on itself
and decay into radiation.
That, of course, includes you.
The Universe would end up full of single particles.
Would it ever come together after its death?
If the force of gravity fought back
hard enough to overthrow the dark energy,
the Universe would stop expanding.
It would shrink back instead.
Planets would collide with other planets.
The stars would slam into each other.
Galaxies would merge together.
Earth wouldn't be able to dodge all the space matter for too long.
The Universe would compress into a very dense singularity,
just the way it was before the Big Bang began spewing out galaxies.
From that singularity, it could make a fresh cosmic start:
with new planets, new stars, new life forms.
One way or another, the Universe and everything in it will end.
But it won't happen in just one day.
We still have time to become a more advanced civilization,
and maybe even find a cozy exoplanet to settle on.
But that's a story for another WHAT IF.