two orbiting massive black holes,

circling each other at 250 times a second,

collided in a violent, universe-rippling explosion

that sent waves of energy

throughout the cosmos.

In its wake, a new supermassive black hole

formed over 60 times bigger than our Sun.

Fast forward to September 2015,

gravitational waves

from this ancient cosmic event

finally struck Earth.

Luckily, the gravitational waves weakened

over such a great distance.

But what if we weren't so lucky?

If a couple of black holes

in our Solar System collided,

could we survive?

This is WHAT IF,

and here's what would happen

In 1916, Albert Einstein made waves himself

with his groundbreaking theory of general relativity,

known famously by the formula E=MC*2,

He proved energy and mass are interchangeable,

and that space, or space-time,

curves in relation to the energy and momentum

of whatever matter and radiation are present.

With great foresight,

Einstein inferred the collision of black holes

or massive stellar objects

create distortions in gravity

which are pushed out in all directions.

Thanks to incredible developments

in atomic measurement,

scientists in Washington and Louisiana,

in the U.S.,

at the Laser Interferometer Gravitational-Wave Observatory,

were able to detect and measure

the first ever gravitational waves

here on Earth in 2015.

This was a historic moment in science,

as it was the first definitive proof

of Einstein's theory of relativity.

Using laser interferometry,

observatories can detect a change

less than ten-thousandth the diameter of a proton.

That's one million times smaller

than the width of a human hair.

Since then, LIGO has measured

50 detections of gravitational waves.

There are many sources of gravitational waves,

including the collision of black holes,

the rotation of asymmetrical neutron stars,

supernovae or even remnants

of gravitational radiation

caused by the Big Bang.

These waves travel at the speed of gravity,

equal to the speed of light,

and emanate outward in all directions.

Like a rock being thrown in a pond,

the ripples it creates

dissipate over great distances

and become smaller and smaller.

Luckily, in our pocket of the Universe,

we are over 400 million light years away

from any orbiting black holes.

We're generally safe,

but if these black holes happened

to be in our Solar System,

the implications are much more dire.

When gravitational waves

pass through a planet,

one side is compressed

as the other expands,

kind of like squeezing a stress ball.

I could use one of those right now.

As a result, time and space itself

are stretched causing a slight wobble.

But if we were closer

to this violent event

and the waves were much bigger,

this impact could potentially

tear our planet apart,

triggering powerful

continent-splitting earthquakes,

volcanic eruptions

and epic storms.

Earth wouldn't really be a habitable place anymore,

except for maybe extremophiles

like bacteria that thrive in hydrothermal vents.

Let's imagine our Sun was a neutron star

of an imperfect, non-spherical shape,

sending gravitational ripples

outward as it spins.

Earth would likely look more like Io,

one of Jupiter's moons,

which is put under great gravitational pressure by Jupiter

and, as a result,

is one of the most volcanically active

moons in the Solar System.

Our landscape would be covered in lava

and volcanic fallout

with an atmosphere made up of toxic gases

like hydrogen sulfide.

This would cause massive global warming

and intense storms,

constant tsunamis,

tornados,

and well, you get the idea.

Climate chaos.

We can count our blessings

we are nowhere near

any massive objects

shooting out gravitational waves,

but thankfully, we can still measure them

and learn more about

the complexities of our Universe.

Even though we get hit by gravitational waves,

they are generally so small

we can't even feel any impact.

But on the flipside,

what would it be like

if we suddenly lost our gravity?

That sounds like a story for another What If.