Buckle up.
We’re going to take the orbit of this rock
and kick it into high gear.
Behold the Moon
breaking its planetary speed limit.
The Moon orbits
around our blue marble of a planet
at a comfortable
and reliable speed of 1 km/s (0.6 mi/s).
And if that seems fast to you,
well, hold on.
You haven’t seen anything yet.
So how could this happen?
If the Moon kept getting closer to Earth,
the gravitational pull
from our planet would increase.
That would make the Moon’s orbit
speed up tremendously.
That’s the basis for Kepler’s third law.
So if the Moon kept creeping toward Earth,
it would orbit faster and faster.
And if that happened,
Every 27 days, the Moon completes a trip
around Earth.
Well, not anymore.
Get ready to see
this celestial body more often.
And with the Moon’s increased
visibility and speed,
lunar eclipses would be a regular sight.
But that lovely view in the sky
wouldn’t make up
for the hell on Earth below.
If the Moon moved closer,
the gravitational pull
would rip into the Earth’s crust.
This increased force
would create earthquakes
and increase volcanic eruptions
across the globe.
And don’t think you could
cool off by the ocean
to escape the heat.
Let me explain.
The oceans ebb and flow
thanks to the Moon’s orbit,
the Earth’s gravity and the Sun.
So as the Moon inches closer,
the ocean tides
would become much larger.
How large are we talking?
They would be eight times higher than average.
Coastal cities would flood,
and some islands
would become blanketed underwater
for most of the day.
Almost 700 million people
living in low-lying coastal areas
would be in constant danger
if they weren’t evacuated.
But what would happen
if the Moon started to move
even faster?
Well, remember Kepler's third law?
The Moon would only orbit faster
if it got closer.
Now, if it came
within 18,470 km (11,470 mi),
it would reach what's called
the Roche limit.
That’s the point
where the Moon is so close to Earth
that the tidal forces between us
would get strong enough
to tear this grey rock apart.
Thankfully,
this wouldn’t be able to happen.
Because as its speed increased,
our Moon
would be launched into the cosmos.
Yeah, that’s because
once our natural satellite reached 1.4 km/s (0.87 mi/s),
it would have enough momentum
to escape Earth’s gravity.
As it fades from sight,
you might feel relieved at first.
After all, the Earth’s rotation
would slow down without the Moon,
so the days would become longer.
And finally, you’d see an end
to the constant earthquakes
and devastating floods.
But in reality,
this is where the real nightmare begins.
The tides would become smaller
and weaker without the Moon.
Any coastal ecosystems
that weren’t already destroyed
by the massive flooding
would now be completely upended.
Without churning tides,
animals that depend on food sources
normally floating in the ocean
wouldn’t get the nutrients
they need to live.
And without the Moon’s light,
nocturnal predators
would have difficulty completing
a successful hunt.
This could create a mass extinction event
of creatures on land and at sea.
And while life on Earth
would be flipped on its ear,
so would the planet.
Earth has a tilt of about 23.5 degrees.
This angle of its orbit
makes the seasons possible.
But it’s the Moon’s gravity
that stabilizes this tilt
from going any further.
So without it,
the seasons could stop.
Weather patterns might hold in place
until the end of time.
But if the tilt increased,
it could cause
extreme weather conditions.
And once again,
the Earth could be plunged
into an ice age.
Yeah, a faster lunar orbit
could fast-track all life on Earth
to extinction.
OK, so instead of losing the Moon,
what if we crowded the sky
with the moons of Jupiter?
Well, that’s a story for another WHAT IF.