This gas cloud
located 500 light years away
from our solar system
is about to become a planet.
This process usually takes
a few hundred million years,
but what if we made it happen much quicker?
And instead of it happening so far away,
what if it happened right next to Earth?
When a new planet forms,
it's a pretty cataclysmic event.
It happened with our Solar System
4.5 billion years ago.
The process created
all the planets we know today,
as well as our Sun.
But instead of all that happening,
what if it was just one new planet,
in an already existing solar system?
If a planet formed in our Solar System,
it would take over 100 million years.
But for the sake of this video,
we're going to speed that up just a bit.
First, it could start with a gas cloud
entering our Solar System.
The Sun's gravitational pull
could cause the gas cloud
to start spinning rapidly.
Eventually, dust and rocks would form.
Depending on the gas cloud's location,
we might be able to see this happening,
just not with the naked eye.
You'd need a decent telescope
to be able to see the planet form.
Most likely,
you'd just see a big ball of space dust.
Although you won't be able to see this
planet very well,
what you could see
are thousands of asteroids and other space debris
potentially hurtling towards Earth.
That's because as this gas cloud continues to spin,
more and more dust and debris begins to form.
These grain-sized pieces of dust
would start to heat up.
Then they'd start smashing into each other,
forming bigger and bigger rocks.
This is known as accretion.
This could continue to happen
until some rocks grew to
a few kilometers in size,
creating a planetesimal.
Planitesimals are like the building blocks of planets.
Eventually, the planetesimal
could become so big
that it starts to attract other large objects,
all throughout space.
And with all these objects flying around space,
there's a good chance some of them could hit Earth.
As Earth is getting hit by asteroids,
our new planetesimal would continue to get larger and larger,
and will continue to attract
other planetesimals or other large objects.
This will continue until the planetesimal gets so big
that it collapses in on itself,
and becomes a planet.
A sphere would form and
any heavy elements like iron
would sink to the center of the sphere,
and the silicates would float to the top.
If the planet were big enough
and close enough to Earth,
there's a good chance this new planet
could suck up and destroy Earth completely.
We'd have no choice but to wait
and watch the Earth get completely destroyed
as it crashes into the new planet.
And then Earth would be gone.
Millions of years later,
this new planet would cool off,
and life could form.
So sure, we'd have a shiny new planet,
but it probably wasn't worth it.
If a new planet were to develop in our Solar System
it could be the end of humanity.
It's probably best we keep the Solar System
just the way it is.
What if instead of discovering the creation of a new planet,
we discovered an interstellar visitor?
Well that’s a story for another WHAT IF.