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.