[Music]
You already know how objects, like the Moon and artificial satellites,
manage to orbit the Earth.
But there's all kinds of stuff up there orbiting other stuff that's not the Earth.
So, how do those orbits in space work?
Are they the same as here at home or different?
Or maybe... both!
[Music]
Now as much as I enjoy our little chats,
unfortunately, I don't have the time to talk about every single object in space
that orbits something else and explain how their orbits work.
So how about we just go over a few of the important kinds of orbit instead.
Lets begin with what we're most familiar with, and look at how and why the Earth orbits the Sun.
The Sun might just be a medium-sized star,
but its gravity is strong enough to hold several planets in orbit.
Not to mention countless comets, asteroids, and other things.
And the planet orbits the Sun sort of the same way the Moon or artificial satellites orbit the Earth.
It travels in a nearly circular path around the star.
Completing the whole trip every 365 days.
But why do we orbit the Sun and not the other way around?
Well, lighter objects tend to orbit heavier ones.
And the Sun is the heaviest object in our solar system.
It's about a thousand times heavier than Jupiter,
our largest planet, and certainly heavier than Earth.
So the Earth, the lighter object in this scenario,
is easily drawn towards the larger object, the Sun,
by its intense force of gravity.
As we learned earlier, though,
the Earth doesn't totally get sucked into the Sun
because it's moving fast enough around it
to avoid that very hot, and probably very horrible, fate.
That's why the Earth, plus the other planets
and all kinds of space rocks, orbit around the Sun.
Okay, let's zoom out a little more.
Why does our whole galaxy orbit a black hole?
What? You didn't know?
Well, it's true, but it's nothing to be freaked out about.
Let's start by defining some of those terms.
You know what a sun is, but what is a galaxy?
And what is a black hole?
A galaxy is a group of stars, gas, and dust bound together by gravity.
Our Sun is just one of billions of stars
that are hanging out together in what scientists call the Milky Way Galaxy.
If it shares its name with a chocolate bar, you know it's gotta be a good galaxy!
And a black hole is an object that has a gravitational pull
stronger than anything else in space.
It's so strong, even light can't escape it.
That's why they say it's black.
Think of it like a bottomless pit swallowing up whatever other objects get near it.
Our Milky Way Galaxy has a black hole at its center.
But don't freak out.
Luckily, Earth is located thousands and thousands of light years away from this black hole.
So we won't be swallowed up by it.
But we are close enough to it that the mass of stars, planets, dust, and gas inside of our galaxy
combined with the ginormous mass of this black hole, holds us in our orbit.
So for us on Earth, the black hole is actually a good thing.
Okay, so bringing things back to our solar system.
You know why everything in it orbits our Sun.
But does everything orbit it in the same way?
Not so much.
Let's visit one of our dwarf planets.
Which has a super odd orbit, at least when compared to the other planets.
[Music]
The eight main planets tend to orbit the Sun in a relatively circular way
on the same imaginary plane, or level.
But the orbit of the dwarf planet Pluto is weird,
because not only is it off-center from the Sun,
but it's also not on the same plane.
Depending on where it is on the path around the Sun,
it can be on a higher or lower level than the other eight planets.
Pluto, you rebel!
So why does it do that?
Well, while orbiting the Sun,
Pluto passes through an orbital path of another planet.
Because of its strange orbital path,
Pluto is actually sometimes closer to the Sun than Neptune is.
It actually crosses Neptune's orbit.
When this happens, Neptune's gravitational pull forces Pluto into a lower orbit
for a short period before it swings back into its higher orbit.
[Music]
So gravity has a lot to do with Pluto's odd orbit.
And it's proof that not everything in our solar system orbits the Sun in the same way.
Let's bring this back to our big question.
How do other orbits in space work?
Well, they work a lot like things that do orbit the Earth.
And also...they sometimes don't.
Each object in space follows orbital patterns we can sometimes predict.
But there are always oddballs out there that keep us on our toes.
So don't ever let me catch you saying space is boring.
[Music]