Q: Hey Big Guy. Any truth to the rumor that you are so big because you're full of gas?

A: What I want to know is,why does everyone point at me when they smell something funny? OK, it's true, but I'm
not the only one. There are four of us called gas giants: me,Saturn, Uranus, and Neptune.I'm the biggest but we're all
HUGE. That's why another name for us is the jovian planets, after Jove, one of
nicknames. The four terrestrial guys are tiny compared to us. And they're all kind of clumped together near the Sun. We're
WAY out here.

Q: Wait a minute. Four Rocky and four gassy only makes eight planets. Our solar system has nine. What about Pluto?

A: Yeah, right! What about him? Some scientists don't even think he's a planet at all. He's that small and out of it. My personal opinion? He's a moon of something else. But time will tell, time will tell. Anyway, let's keep the conversation where it belongs: on ME. Ask me exactly how big I am. Go on, ask me.



Q: OK. How big are you?

A: I'm 300 times heavier than Earth and more than twice as heavy as all the other planets added together. If Earth is a golf ball, I'm a basketball. How big is that?


Q: That's big, all right. How did you get that way?

A: How long do you have? It's a long story. Goes back more than four billion years, to when the solar system was formed. Yep, we all came out of a cloud containing grains of dust and gas. The cloud spun and spun and the Sun started to take shape in the middle of it. And you know what that means.

Q: No, what?
A: Sun means heat. It was hot at the center of that activity too hot for the stuff we're made of. Planets that formed closest to the Sun had metal cores because only metallic grains could take that heat.
Q: What kind of stuff are you made of?

 A: Cold, gassy stuff like water vapor, ammonia, methane.. Icy stuff. That's what we were formed around. Plus hydrogen, helium, carbon, nitrogen, and oxygen. Because of the cold, greater amounts of materials were able to condense in the outer planets. That's how we got so big: the bigger the planet, the more gravity it had to pull other stuff close and merge with it. Hydrogen and helium kept getting sucked in. And we got bigger.

Q: But....does that mean.... You're not solid?

 A: Mostly not. How did you know? Sorry about that. We gas guys don't have a solid surface. It's not like on Earth, where

there's sky above and solid ground below. Our atmosphere just becomes denser with depth, as layer upon layer of it presses down. The boundary between it and my hydrogen "ocean" is kind of hazy. And then it's liquid all the way down to a tiny solid core. Tiny to me, that is. It's about the size of Earth!


Q: Really ! What else is different about you?

 A: We have rings. We have many moons. We're unbelievably cold. We're really

far out.

Q: Didn't you say that already?

 A:No, I said we are Way out.

Q: Well, in any event, I think I get it now.

 A: Yeah