It's just half the lunar distance away from us.

And... it's turning!

Looks like it's now heading towards the Sun.

What if this football-field-sized space rock didn't make that turn?

What if it kept moving towards us?

This is WHAT IF,

and here's what would happen

if an asteroid hit the Earth.

Asteroids are hitting the Earth all the time.

Every day, space bombards us with around 100 tonnes of dust and sand.

Car-sized asteroids make it to our atmosphere about once a year.

They burn up in the mesosphere, never reaching the Earth's surface.

The massive 10-kilometer wide, life-threatening rocks

like the one that wiped out all the dinosaurs,

don't come by too often - maybe once every few million years.

The ones we do have to worry about

are asteroids the size of a football field

hat actually make it to the Earth's surface.

They tend to come down to Earth every 2,000 years.

What if one of those was to hit us tonight?

The extent of an asteroid's devastation to our planet

all comes to where the it lands.

Just 3% of Earth's surface is populated.

That means, in all likelihood,

97 asteroids out of 100 would just plunge into the ocean

or flatten an uninhabited forest somewhere in Siberia

or northern Canada.

But 3 out of 100 asteroids would strike a populated city.

Imagine seeing a 100-meter-long (330-foot) rock speeding towards you,

traveling at 30 km (19 miles) per second...

From the moment it passed unharmed through the mesosphere,

it would take less than 3 seconds for it to crash down to Earth.

For a city like New-York, that would mean

A huge fireball would destroy everything in a 3 km (2 mile) radius,

and cause heavy damage to buildings within a 7 km (4.5 miles) radius.

Maybe it's not all bad...

Ever hear of the meteorite that slammed into the Russian city of Chelyabinsk?

That rock exploded with the force of 20 Hiroshima bombs

and caused around $33 million worth of damage.

Well, in our scenario, the meteorite is 5 times bigger.

The freshly fallen space rock may pose the risk of widespread radiation

if it were made up of radioactive heavy metals.

Of course, it wouldn't be as bad as a 10-kilometer wide asteroid hitting the Earth.

In that case, the shock wave would be enough

to wipe out a a good chunk of humanity right away.

The Earth would get a new crater over a 100 km (62 miles) across

and a ring of asteroid debris would give us a 'Saturn-like' appearance.

Most of this debris would rain back down on Earth,

setting cities and forests on fire and cooking everything that's not protected.

You might want to invest in an underground bunker before this happens.

Because on the surface, it would be very, very dusty.

All this dust and smoke would block the sunlight.

Without the sun, all plants and a lot of animals would die out.

After about a year, the atmosphere would clear up,

but there would be very little food left for humans.

And if we weren't resourceful enough, this would be the end of our race.

We would suffer the same fate as the dinosaurs did 65 million years ago.

The good thing is,

we have the atmosphere to protect us from most asteroids,

and NASA to keep an eye on the all the space rocks flying around us.

Bad thing is,

it's sometimes hard to detect the incoming rock until it's too late.

Tell us what you think.

Are you preparing for a sudden blast from space?