"The sun will come out tomorrow..."
That star at the center of our Solar System,
that superhot ball of plasma
that gives us heat and energy,
and amazing complexions...
well, it's a ticking time bomb.
After that, the Sun will expand,
becoming a red giant.
Then it will shrink to become a white dwarf,
a dying star,
cooling for the next several billion years.
Of course, we'll all be long gone
before any of that happens. But,
still, can you imagine what it would be like
to watch the Sun blow up
before your very eyes?
With a name like 'Supernova,'
you'd think that a solar explosion would be
the most magnificent fireworks show
the world has ever seen.
But in reality,
you likely wouldn't see anything!
The Sun is 150 million km (93 million miles)
away from Earth,
and it takes 8 minutes for light
from the Sun to reach us.
And while that may seem super far away,
in supernova terms,
we don't stand a chance.
For Earth to be completely safe
from a supernova,
we'd need to be at least
50 to 100 light-years away!
But the good news is that,
if the Sun were to explode tomorrow,
the resulting shockwave wouldn't be
strong enough to destroy the whole Earth.
Only the side facing the Sun
would boil away instantly.
The lucky other half would experience
a rise in temperature that would be
15 times hotter than the Sun's
current surface temperature,
and permanent darkness.
And without the Sun's mass keeping us in orbit,
Earth would likely start
floating off into in space
while its remaining inhabitants
desperately struggle to stay alive.
There's a chance that our planet
could lock into orbit around another star
that might provide
the same light and heat as our Sun.
But by the time that happened,
we'd all be long gone.
If we knew in advance the day that
the Sun would explode,
then we could buy ourselves
as many as 1,000 years of time,
provided we had the resources
to sustain ourselves for that long.
And we could!
Just a few meters below
the ground you walk on,
the Earth is maintaining
a temperature of about 17°C (62°F).
So, if we had enough time to prepare,
civilization could continue to live
by moving underground
into a huge network of fortified bunkers.
Within a week after the explosion,
the surface temperature on Earth
would drop to -18°C (0°F).
Within a year, temperatures would
plummet to about -73°C (-100°F).
At this point, the oceans would begin to freeze
from the top down.
Within 1,000 years,
Earth’s atmosphere would freeze and collapse,
leaving anything left on the surface
exposed to cosmic radiation
and meteor impacts.
Hopefully, by that point,
we'd have found ourselves a new home.
The good news is that
if the Sun were to explode
- and it will eventually happen -
it wouldn't happen overnight.
When the Sun does die,
it will be a long, slow, arduous process
taking place over billions of years.
The Sun will get hotter and brighter,
and it will start to expand.
During this process,
it will lose its outer layers to the cosmos,
leading to the creation of
other stars and planets
in the same way that
the violent burst of the Big Bang created Earth.
Who knows? Maybe new life could form.
Can you imagine another Earth?
A new humanoid species?
It's hard to predict how our galaxy
might look billions of years from now, and,
it's especially hard
to imagine our solar system
without the great, golden anchor
that keeps it all together.
But one day, in the very, very distant future,
the Sun will expand,
and then it will shrink,
maybe leaving room for
a new star to take its place.
And if, by some miracle,
humanity still exists at that point,
where might we be living?
Can you imagine your descendants
being born on a space station?
Well, that's a story for another WHAT IF.