we launch into the Earth's orbit,

we're trapping ourselves on our own planet.

This is WHAT IF,

and here's what would happen

if we trashed Earth's orbit with space junk.

Almost everything that we've launched into space

ends up either falling down and burning up in the atmosphere,

or getting caught in the Earth's lower orbit for thousands of years.

The Earth's lower orbit is surrounded

by just 200 kg (440 lbs) of small, rocky debris

in the form of meteoroids.

But it's also got a belt

of about 3 million kg (6.6 million lbs) of space junk.

20,000 pieces of debris as large as softball,

500,000 pieces larger than a marble

and many millions of pieces of debris too small to track

are orbiting the Earth.

What makes these floating parts of old satellites

and spent rocket bodies so dangerous?

It's the speed they move at.

This junk is hurtling through space at a speed of 8 km/s (5 mi/s).

At this speed, one small bolt

is enough to shatter a working satellite

into hundreds of pieces.

But it's what comes next that could hold off our dreams

of building Moon bases,

colonizing Mars,

and any space exploration whatsoever.

The more junk we leave uncontrolled in the Earth's lower orbit,

the harder it is not to get hit by it.

Things are running into each other.

Fragments of debris are colliding and breaking up,

multiplying the number of items

flying through the space junkyard.

And they're hitting working spacecraft, too.

One day they could hit enough satellites

to initiate an unstoppable, destructive chain reaction.

The cascade of collisions would make our lower orbit

so congested with man-made debris,

that eventually there would be no active spacecraft left.

Everything in the Earth's orbit would be turned into

a deadly wall of celestial scrap.

Near-Earth space would become unusable.

No rockets could be safely launched

until we cleaned up the orbit.

We'd have to put our space missions on pause,

and we'd be trapped on the planet for generations.

Well, the debris belt wouldn't rain down on Earth

and cause massive destruction.

Space rubbish would disintegrate in the atmosphere

before it reached our planet's surface.

But the collisions would produce a lot of dust.

That dust, illuminated by sunlight,

would cause an ever-present twilight on the planet.

With this form of light pollution,

you'd forget what nights used to look like.

What's even more unpleasant -

all of our satellite networks would go down.

There'd be no satellite communications,

no GPS navigation,

no weather data,

and no way to do any science in the Earth's orbit.

You'd have to go back to paper maps,

and get your cash out.

Welcome to the 1970s.

On a positive note, science has already come up with a few ideas

for cleaning up our lower orbit mess.

They're looking at capturing space debris with a net,

or harpoon,

or vaporizing the small bits of junk with lasers.

Whatever action we deploy,

we should act quick if we want to launch humanity

on far-space missions

and finally colonize that red planet.

But that's a story for another WHAT IF.