Questions About Jupiter
Hi all.
So earlier this morning I was reading about Jupiter and the Galileo probe, and I suddenly realized that I don't understand Jupiter. What I mean is that I've always just sort of said "Yeah. It's a gas giant" an gone on about my daily business, but now I realize that I don't really understand what that is. An article I was reading said that Jupiter "has no surface," which, again, I had kind of known but never really thought about. How does a ball of gas become a planet? Why does a ball of gas look like a planet and not like some kind of cloud? Why a ball? How does a ball of gas have so much gravity? Is there something at the center of Jupiter?
Can someone dumb Jupiter down for me?
So earlier this morning I was reading about Jupiter and the Galileo probe, and I suddenly realized that I don't understand Jupiter. What I mean is that I've always just sort of said "Yeah. It's a gas giant" an gone on about my daily business, but now I realize that I don't really understand what that is. An article I was reading said that Jupiter "has no surface," which, again, I had kind of known but never really thought about. How does a ball of gas become a planet? Why does a ball of gas look like a planet and not like some kind of cloud? Why a ball? How does a ball of gas have so much gravity? Is there something at the center of Jupiter?
Can someone dumb Jupiter down for me?
Comments
Hi all.
So earlier this morning I was reading about Jupiter and the Galileo probe, and I suddenly realized that I don't understand Jupiter. What I mean is that I've always just sort of said "Yeah. It's a gas giant" an gone on about my daily business, but now I realize that I don't really understand what that is. An article I was reading said that Jupiter "has no surface," which, again, I had kind of known but never really thought about. How does a ball of gas become a planet? Why does a ball of gas look like a planet and not like some kind of cloud? Why a ball? How does a ball of gas have so much gravity? Is there something at the center of Jupiter?
Can someone dumb Jupiter down for me?
You need the 'burb.
(If I see him around before he spots this, I'll send him over.)
Jupiter does have a small core that is solid or at least made of heavy elements and has a mass several times that of Earth. As for the surface that we see, that is all gas, and a lot of it. THe overall density of the planet is quite low.
Check out
http://en.wikipedia.org/wiki/Jupiter...ry_composition
http://www.nineplanets.org/jupiter.html
http://www.nasa.gov/worldbook/jupiter_worldbook.html
End of term marking getting to you, Midwinter?
Yes. Started at 10:00 am and haven't stopped yet. I haven't even made a dent.
Jupiter does have a small core that is solid or at least made of heavy elements and has a mass several times that of Earth. As for the surface that we see, that is all gas, and a lot of it. THe overall density of the planet is quite low.
Well, does it have a surface or not? Do we know? I mean, if you could, would you fall all the way to the core? And then, how the hell does a ball of gas have a core?
And on that note, I'm back to reading essays about Swinburne.
I mean, if you could, would you fall all the way to the core?
You'd be crushed and vaporized before you got there.
You'd be crushed and vaporized before you got there.
if you could
. . . How does a ball of gas become a planet? Why does a ball of gas look like a planet and not like some kind of cloud? Why a ball? How does a ball of gas have so much gravity?
What you see on Venus is a gas cloud too, CO2. I think Jupiter has methane and ammonia. It's a ball because of gravity pulling equally toward the center. The only reason we have fluffy clouds is because they are mixed in with the atmosphere. If Earth's atmosphere were opaque, from outer space you would see it shaped as a ball too.
Jupiter has high gravity because it is so big. There is a lot of it. It is actually approaching being a star, and is sometime called a brown star. It gives off its own radiation, not just reflected light, thought its light is dim.
What makes a star? Mass, lots of it. The core temperature depends upon how heavy the body is. All that weight causes pressure at the center which in turn raises temperature. (Ever put a penny on a train track and pick it up just after the train passes? It is hot.) When a ball of mass in the universe is hot enough, a thermonuclear reaction begins and it becomes a star. Jupiter's core is hot enough to radiate visible light, but not hot enough for a reaction to start.
I hope this helps.
What you see on Venus is a gas cloud too, CO2. I think Jupiter has methane and ammonia. It's a ball because of gravity pulling equally toward the center. The only reason we have fluffy clouds is because they are mixed in with the atmosphere. If Earth's atmosphere were opaque, from outer space you would see it shaped as a ball too.
Jupiter has high gravity because it is so big. There is a lot of it. It is actually approaching being a star, and is sometime called a brown star. It gives off its own radiation, not just reflected light, thought its light is dim.
What makes a star? Mass, lots of it. The core temperature depends upon how heavy the body is. All that weight causes pressure at the center which in turn raises temperature. (Ever put a penny on a train track and pick it up just after the train passes? It is hot.) When a ball of mass in the universe is hot enough, a thermonuclear reaction begins and it becomes a star. Jupiter's core is hot enough to radiate visible light, but not hot enough for a reaction to start.
I hope this helps.
Yeah, but we have a surface, and IIRC, Venus does, too. How can a planet not have a surface?
uhoh.
Don't think about it that way... yet...
Gravity is a force between all objects of mass; there is an energy associated with taking an object from an area of no gravity to an area of gravity, there is a velocity which gives an object the same amount of kinetic energy -- this velocity is the escape velocity, because it is the amount of kinetic energy to take an object far far away from a source of gravity. Temperature is a measure of the average kinetic energy of a group of massive objects, if the kinetic energy associated with the temperature of a gas is lower than the escape velocity it will remain around creating an atmosphere. If there is enough gas to generate gravity which causes the escape velocity to be higher than the thermal kinetic energy, you get a gas giant...
oh dear...
How does a planet not have a surface??
We are just a 'gas' of high density. (this isn't explicitly true for physical chemical reasons, but it will work for the moment)...
Earth doesn't have a surface if you are cosmic ray.
Huh?! You're just making shit up, now!
Seriously, though. It's a real question: how is it possible that a planet cannot have a surface? Is there some pedantic definition of "surface" I'm missing?
You could have a wet giant as well...
Imagine a giant ball of floating water with a decent concentration of radioactive uranium to keep it liquid by the heat generated by nuclear decay. In space it will be a nearly perfect sphere, but have no solid core...
Yes.
You could have a wet giant as well...
Imagine a giant ball of floating water with a decent concentration of radioactive uranium to keep it liquid by the heat generated by nuclear decay. In space it will be a nearly perfect sphere, but have no solid core...
AH! Ok! That helps!! So the fact that it's a sphere is simply a function of the various gravitational forces working on it. So it LOOKS like a solid planet, but it's not.
Is the "core" solid?
AH! Ok! That helps!! So the fact that it's a sphere is simply a function of the various gravitational forces working on it. So it LOOKS like a solid planet, but it's not.
Is the "core" solid?
Not in my water model for a variety of reasons (water is most dense in its liquid form)... but on jupiter? who knows? More than likely yes...
Oh, and yes, gravity is a spherically symmetric force (at least everything we know suggests it is)
Not in my water model for a variety of reasons (water is most dense in its liquid form)... but on jupiter? who knows? More than likely yes...
Oh, and yes, gravity is a spherically symmetric force (at least everything we know suggests it is)
god this is confusing.
OK. Simple question: does it have a surface in the sense that Earth does? Something that, if it were possible, you could walk around on?
Nobody does.
Does it *need* one? No.
I am a scientist and my natural inclination is to qualify all statements. We don't know enough about jupiter to say that it HAS any sort of core definitively; hell, it might be hollow. But theoretically, you could have a planet that is just a gas cloud, because the definition of planet is so vague...
Ugh. Jupiter is an epistemological nightmare.
How does a planet not have a surface??
Does it make sense to you that stars are just bunches of gas that are big enough that the self-imposed gravity is enough to create nuclear fusion?
I do have to apologize, midwinter.
I am a scientist and my natural inclination is to qualify all statements. We don't know enough about jupiter to say that it HAS any sort of core definitively; hell, it might be hollow. But theoretically, you could have a planet that is just a gas cloud, because the definition of planet is so vague...
That's really what I'm getting at, I guess. My working definition of "planet" seems to be wrong...or at least problematic when it comes to Jupiter.
But no. No apologies! I'm asking honest-to-God questions here.