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Thousands of satellites
and other debris currently orbit our Earth.
They provide us with television,
internet, and communications.
But what if
all these satellites suddenly went offline?
And then came crashing down to Earth?
Currently, there are over 5,000 satellites in orbit.
That number is expected to, at least,
double by 2025.
And that doesn't include all of the 12,000
satellites SpaceX's Starlink program
plans to launch by 2027.
So, nearly 20,000 satellites
in space by the end of the decade?
What would happen if they all came crashing down?
First, we need to understand that satellites,
and other debris in space,
falling to Earth is nothing new.
Over 100 tons of space debris
heads toward Earth every year.
You don't notice any of it,
because it all gets burned up
in our atmosphere before it can hit the ground.
But that's only with a few chunks of satellites
coming in our direction.
If 20,000 satellites
came heading for Earth,
you'd definitely notice it.
You wouldn't see any football field-sized
spaceships crashing down to Earth,
at least not yet.
Instead, you'd immediately notice
that you couldn't contact anyone.
Phone lines would be down.
And this video would immediately shutoff,
since the internet would stop working as well.
But one of the most dangerous effects
of our satellites falling to Earth
would be GPS systems shutting down.
Planes in the sky wouldn't be able to navigate
without any air traffic control.
With up to 12,000 planes up in the sky at any given moment,
that would make the chance of them crashing into each other
greater than ever.
Global economies would grind to halt,
and people would be cut off from the rest of the world.
Credit cards, and any other forms of electronic payment,
would be useless.
And don't expect to get any cash
from an ATM or bank, as those wouldn't work either.
It would be like going back in time to the 1800s.
In theory, we'd eventually be able to replace all those things
without using satellites,
and bounce back from this mess.
But remember, all those satellites are still headed for Earth.
So what would happen next?
If 20,000 satellites were falling to Earth,
it wouldn't happen instantly.
That's because the satellites' speed and positions in space
could make some of them take longer to come crashing down.
If a satellite was 1,000 km (621 mi)
above the Earth's atmosphere,
it might take over 100 years before it finally fell to the ground.
So all these satellites
falling to Earth would be a long,
drawn-out process.
Luckily for us,
when they do finally fall on Earth,
a lot of them will get burned up by our atmosphere.
But that still doesn't mean we'd be completely safe.
Sure, the pieces would be smaller than a satellite,
but they wouldn't completely disintegrate.
Usually, before a satellite comes back down to Earth,
we have some sort of control over it.
Scientists will use the satellite's last bit of fuel
to guide it towards somewhere in the ocean,
or an unpopulated desert.
But if 20,000 satellites fell to Earth,
they'd go wherever they please.
Many of them would dive into the oceans,
since they take up 71% of our Earths surface.
But lots of these satellites would end up on land.
They could destroy entire buildings and towns,
as they'd be traveling at speeds up to 28,000 km/h (17,400 mph.)
Even if small chunks of satellites managed to hit the ground,
their shockwaves could cause considerable damage.
The kinetic energy of all these satellites hitting Earth
would be like dropping nuclear bombs.
And another similarity these satellites have with nuclear bombs?
Many of them would be radioactive.
Lots of satellites are nuclear powered,
and there's a chance that when they come crashing down to Earth
they could still be radioactive,
causing even more harm to the planet after they hit it.
After decades,
when all the satellites finally came crashing down,
Earth would look like it had been hit by thousands of nukes.
Luckily, the chances of something like this happening
are incredibly low.
The only real possibility of it happening
would be if Earth were hit by a solar storm.
And if that were to happen,
falling satellites would be the least of our worries.
But that sounds like a story, for another WHAT IF.