Hi Bill Nye.
My name is Aria.
My question is where does all moons come from
and why does gas giants not have gas moons?
Wow.
That is a great question Aria.
Wow.
First of all I was alive when people figured
out or satisfied themselves as were our moon
came from.
And it's generally agreed that our moon was
created when the earth was hit with another
pretty big thing, another asteroid.
And the impact was very hard and the energy
of the smashing was converted to heat and
both the earth and the moon were hot and molten
and they both cooled off and here we are with
this other separate thing in orbit around
us.
Now why do gas giants not have gas moons is
a great question and the answer is almost
certainly because of gravity.
So when you have these little things that
spun off of let's say Jupiter or Saturn they
were too small to sustain themselves as just
balls of gas.
The gas shrunk down, gravity pulled it down
and formed a solid thing.
Whereas on Jupiter and Saturn there's so much
spin, so much heat created that there are
held in the gaseous state or what we call
gaseous state by the energy that's coming
out of them, where as the smaller ones cooled
off so much that they turned solid.
It is just a fantastic question Aria.
And astrophysicists or planetary scientists
speculate about this all the time, but what
a fantastic thing that you made this observation.
The moons of Jupiter, the big ones Io, Callisto,
Europa and Ganymede those big moves are cooled
off.
They're not gaseous like Jupiter what they
orbit.
That is fantastic.
Wow.
And maybe more will be learned about this.
And I got to tell you Aria it's very reasonable
that in your lifetime we will send the right
spacecraft to Europa and the moon of Saturn
Enceladus and Titan and look for signs of
life.
Instead of being a gas giant, in this one
example, Europa is the moon of Jupiter that
has twice as much seawater as the earth and
that water is under a layer of ice.
And I mention it because it's evidence of
how things cool off when they're in space
and they're small or relatively small.
The ice forms because the heat of creation
things smash together that heat is radiated
into space so there's a crust of ice, but
water underneath is kept liquid by the gravitational
exercising of its orbit around Jupiter.
It's amazing.
What an observation.
Aria you're making my day.
I hope you will be involved in missions to
Europa and you will look for signs of life
below the ice.
I mean who knows if you have an ocean for
four and a half billion years things are going
to happen.
There could be living things there.
There could be Europanians out there, fish
people that you'll interact with.
Keep us posted.
Thank you.
