This is the most powerful object
in the Universe.
The biggest spinning magnet to ever exist.
It's the cosmic equivalent
of a great white shark.
But it wouldn't eat you.
It would just turn all your atoms to dust...
If you thought neutron
stars were big and scary,
you haven't heard of their more
powerful stellar cousins yet.
Like neutron stars,
magnetars are leftovers
from supernova explosions.
They're just packed with a lot more matter.
Their density is so high that a
single teaspoon of a magnetar
could weigh in at a billion tons.
They are also the most
magnetic stars we know about.
We use a unit called a Gauss to measure
the strength of a magnetic field.
Earth's magnetic field is only about 0.6 Gauss.
A magnetic field of a magnetar
can be as strong as one quadrillion Gauss.
It wouldn't be the worst thing in the world
if a magnetar was sitting quietly
in our galactic neighborhood.
But if it decided to stop
minding its own business,
there are two ways a magnetar
could end all life on Earth
together with the planet itself.
It could get too close to the planet.
You'd start to feel its
presence when it was about
halfway between the Moon and the Earth.
At that distance, a magnetar
would erase the information
off all of your credit cards' magnetic strips.
Whatever you do,
try not to get any closer than 1,000 km
(620 mi) from a cosmic invader.
Because if you did, your atoms
would get stretched out of shape.
Your bioelectric field would get scrambled,
disintegrating your molecular structure.
And your body would just disappear.
Alternatively, a magnetar could destroy us
from much, much further away.
As if being the biggest spinning
magnets in the Universe isn't enough,
magnetars can also be affected
by something called starquakes.
Starquakes happen when a star's crust cracks,
letting massive amounts of
radiation out into space.
This blast of radiation could
compress the Earth's magnetic field
and partially ionize the Earth's atmosphere
even from 50,000 light years away.
We know this because we've
already come a little too close
on at least one occasion.
In 2004, gamma radiation from a magnetar
reached our planet from outside
of our Milky Way galaxy.
In just one-fifth of a second,
it released more energy
than our Sun has released
over the last 250,000 years. 
Move that magnetar and its starquake
up to 10 thousand light-years away,
and things would get much worse.
First, it would destroy our ozone layer.
Then, it would wipe clean
most of the planet’s surface,
along with all life as we know it.
The truly scary part of this is that
we wouldn't even know the
magnetar was heading toward us.
It would be a “blink and you're gone” scenario.
I won't lie to you.
There are magnetars close enough
that if one had a violent starquake right now,
we'd all get wiped out very fast.
When scientists began their search for
these interstellar monsters 40 years ago,
they didn't realize how many
of them exist out there.
You might find some
comfort in the fact that
most magnetars don't make it
much past their 10,000 birthday.
Their short lifespan ends with
them becoming neutron stars -
still dense and still magnetic,
but not nearly as dangerous as a magnetar.
But if one of them come
near our Solar System...
that would be a story for another WHAT IF.
