"The sky is falling!"
The sky isn't falling.
It's getting sucked into outer space!
And so are all the oceans,
and the trees,
and cars,
and roads,
and bridges,
and the Earth's core,
and you!
So get a grip and hold on tight.
"Hang on, kid!"
You're in for a wild ride!
Unless you're an astronaut,
you probably don't spend a lot of time
thinking about gravity.
We all take gravity for granted,
and it would be hard not to!
Aside from a tiny sliver
of the world's population,
most humans don't know
a life without gravity.
From the Universe to our Solar System,
to each planet,
all the way down to our own bodies,
gravity holds everything together.
But since we tend to see gravity as a given,
it's hard for us to imagine
just how helpless we'd be without it
... until it's actually gone.
Gravity is an attractive force
between any two masses.
The greater the mass, the greater the gravity.
The greater the gravity,
the stronger the pull.
Gravity is the reason why
Earth rotates around the Sun,
why we experience high and low tide,
and why we can walk on this planet
without floating away!
Most importantly though,
gravity secures our atmosphere,
holding in the air we need to breathe.
In fact, there are a lot of things
we can thank gravity for.
So many though that
if we tried to list them all here,
we'd probably end up with a
video longer than "Titanic."
So to give you an idea of
how important gravity is,
in a really, really short amount of time,
we're going to take it away from you.
But not for too long.
Just five seconds.
Are you ready?
With the world still spinning at its usual
1,600 km/h (1,000 mph) speed,
everything that isn't secured firmly
to the ground would go flying.
Cars,
boats,
trains,
planes,
well, obviously, but not like they normally do.
More like this.
The Earth spins faster along the equator,
so the impact of zero gravity
would be felt hardest there.
At the equator, you could experience winds
almost six times stronger than
the ones produced by Hurricane Katrina.
That means that in just five seconds,
you could be blown as far as
2.3 km (1.4 mi) in any direction!
And not just you.
There will be plenty of people,
objects,
and animals to look out for.
Not to mention trees,
soil,
and mid-air floods from the world's
ponds, lakes, rivers and oceans!
At the same time,
the gases in the atmosphere
would drift out into space.
Not only are we now losing
huge amounts of oxygen,
but the sudden and sharp drop in air pressure
would instantly shatter everyone's inner ears.
And then there's the planet itself,
which is literally held together by gravity.
Without gravity,
the pressure of the Earth’s inner core
will cause the planet to expand.
It's not like five seconds without gravity
would cause the world to explode,
but even a five-second expansion
of the Earth's inner core
would cause some major earthquakes,
and trigger huge volcanic eruptions.
Add one more item to your list of
dangerous things flying through the sky:
Out in space,
the planets in our Solar System
that normally orbit the Sun,
would instead start drifting away from it.
Earth would follow its neighbors
at a speed of 30 km/s (19 mi/sec).
In just five seconds,
it would have traveled 150 km (93 mi).
That's not far enough for our planet
to be out of the habitable zone,
but how habitable would Earth be
after five deadly seconds without gravity?
When gravity was restored,
you'd hit the ground hard.
If the impact didn't kill you,
or if you weren't crushed by a heavy object,
you would still be severely injured.
"My back!"
Hopefully, you'd catch your breath in time,
with gravity pulling oxygen
back down to Earth,
and bringing the atmosphere
back around the planet.
But there would still be earthquakes
and volcanic eruptions as
the Earth's core becomes compressed again.
And there would still be massive flooding
due to the significant displacement
of the oceans.
The number of casualties
would be astronomical.
Not just from flying debris, lack of oxygen,
or simultaneous natural disasters,
but because in those five seconds
without gravity,
the Earth's crust literally opened up
and swallowed several major cities.
So, yeah.
A lot can happen in just five seconds.
And that just goes to show
how essential gravity is to life on Earth,
and beyond!
You may think you're special,
and you most certainly are!
But just remember that
you're part of something bigger than you,
and that's what keeps you grounded.
But don't sink too low!
Can you imagine how heavy you'd be
if Earth's gravity doubled?
Well, that's a story for another WHAT IF.