Twinkle, twinkle, little star.
How I wonder what you...
What!? Wait a minute,
why are you twinkling so much?
Woah, guys, that's no diamond in the sky.
That looks like a supernova.
As much as we love to blow stuff up
here on Earth,
no bombs or pyrotechnics could compare
to the incredible force
of nature's biggest explosion,
the supernova.
As a star reaches its grand finale
and explodes,
what would happen to life on Earth
if we were close by?
This is WHAT IF, and here's what would happen
Before you freak out,
Earth is in a relatively safe patch of space called
This peanut-shaped region of expanding gas
in our Milky Way galaxy
results from nearby supernovae explosions
that occurred 20 million years ago.
These explosions helped shape our Solar System,
spreading gas, dust, and heavier elements
like uranium and gold, to Earth.
Without these supernovae,
we wouldn't have any shiny gold bling
or powerful nuclear reactors.
So you can, literally, count your lucky stars.
Okay, but are we in danger
of any nearby supernovae?
On average, a supernova will occur
about once every 50 years in the Milky Way.
Thankfully, there are no stars massive enough
to become a supernova
within 50 light-years of the Earth.
There is, however, one binary star system
within 159 light-years of Earth
that could potentially put us at risk.
Binary star systems are Type I supernovae.
This happens in a tumultous dance
between two stars,
where matter is sucked from one star into another, typically a white dwarf.
Eventually, the white dwarf explodes,
resulting in an epic supernova.
On the other hand, Type II supernovae occur
when a star runs out of fuel,
and some of its mass flows into its core.
Over time, the core will start to grow
and get so heavy that it can't withstand
its gravitational force.
And then, kablooey!
The core collapses, and a supernova is born.
When these explosions occur,
a powerful blast of radiation is spread throughout space
that will kill anything within 50 light-years.
To put this into perspective,
our Solar System is only about two light-years wide.
So the supernova's blast would be the distance
of 25 of our Solar Systems in a row.
If a supernova occured as close as 30 light-years away
we'd have bigger problems than a pandemic on our hands.
The intense blast of radiation
would carry a massive influx of high energy neutrinos
that would boil any living creature from the inside out.
Hope you like your meals poached!
The entire Earth could be vaporized
in just a fraction of a second
if the supernova was close enough.
The shockwave would arrive with enough force
to wipe out our entire atmosphere
and even our oceans.
The exploded star would grow brighter
for about three weeks after the explosion,
casting shadows even during the day.
Even if life survived,
the superheated gas from the supernova
would emit deadly amounts
of UV and gamma radiation.
These rays would destroy the ozone layer,
leading to the formation of nitrous oxide smog.
We would all have to go deep underground
and embrace our new lives as mole people
to escape the lethal radiation
and poisonous atmosphere.
Unfortunately, there would be an increase
in mutations and deadly cancers.
And to top it all off, our phytoplankton,
which account for almost 50% of all photosynthetic activity on Earth,
would die off.
Phytoplankton is vital to us
and can absorb carbon dioxide
from our atmosphere.
Without it, we'd have a tougher time breathing.
Global warming would accelerate
even further beyond our control.
And as an essential food source
at the bottom of the marine food chain,
a lack of phytoplankton would result
in sea creatures becoming extinct.
And eventually,
humankind would too.
So, like many What Ifs,
almost everything dies.
"No!"
"Noooooooo!"
But there might still be
a few lucky species of extremophiles
that could survive the intense radiation.
After a few hundred, or thousands of years,
the supernova would leave an impressive nebula in its wake.
At the very least, we'd have a fantastic view
in our night sky.
Well, for those of us that can see.
Maybe these extremophiles would evolve
to have eyes someday
and become the size of humans.
Whatever might happen,
that's a story for another What If.