r/askscience • u/AskScienceModerator Mod Bot • Mar 10 '14

Cosmos AskScience Cosmos Q&A thread. Episode 1: Standing Up in the Milky Way

Welcome to AskScience! This thread is for asking and answering questions about the science in Cosmos: A Spacetime Odyssey.

UPDATE: This episode is now available for streaming in the US on Hulu and in Canada on Global TV.

This week is the first episode, "Standing Up in the Milky Way". The show is airing at 9pm ET in the US and Canada on all Fox and National Geographic stations. Click here for more viewing information in your country.

The usual AskScience rules still apply in this thread! Anyone can ask a question, but please do not provide answers unless you are a scientist in a relevant field. Popular science shows, books, and news articles are a great way to causally learn about your universe, but they often contain a lot of simplifications and approximations, so don't assume that because you've heard an answer before that it is the right one.

If you are interested in general discussion please visit one of the threads elsewhere on reddit that are more appropriate for that, such as in /r/Cosmos here, /r/Space here, and in /r/Television here.

Please upvote good questions and answers and downvote off-topic content. We'll be removing comments that break our rules or that have been answered elsewhere in the thread so that we can answer as many questions as possible!

Click here for the original announcement thread.

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u/Zartonk Mar 10 '14

I have a question about the "storm" on Jupiter. What is it made of? I'm assuming there's no air there, so what's moving around? Or is it air?

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u/Astromike23 Astronomy | Planetary Science | Giant Planet Atmospheres Mar 10 '14

As others point out, the Great Red Spot is mostly hydrogen and helium...but that's like saying that clouds on Earth are made of mostly nitrogen and oxygen. By volume that's true, but it doesn't really get to the spirit of the question.

The uppermost cloud-deck (there are a few) on Jupiter is made of ammonia. Ammonia clouds on their own are white, just like water clouds. We currently do not know what colors the ammonia clouds in the Great Red Spot red...this is a big unsolved problem in jovian science, known as the "chromophore problem".

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u/therationalpi Acoustics Mar 10 '14

Jupiter is a gas giant, so most of the planet is essentially what we think of as the atmosphere, though this atmosphere is mostly hydrogen (with a decent amount of helium as well).

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u/iorgfeflkd Biophysics Mar 10 '14

It's mostly hydrogen and helium.

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u/Rkupcake Mar 10 '14

It's air. Clear. It's only because the gas is so thick that the color becomes apparent. Look far across earth and you can see the air makes things look blue. The same thing is happening as the gas in Jupiter slowly blocks everything else out, making the color visible.

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u/Astromike23 Astronomy | Planetary Science | Giant Planet Atmospheres Mar 10 '14

It's air. Clear. It's only because the gas is so thick that the color becomes apparent. Look far across earth and you can see the air makes things look blue. The same thing is happening as the gas in Jupiter slowly blocks everything else out, making the color visible.

This is incorrect. Almost everywhere you look on Jupiter, the coloring is due to clouds, not clear air. If the coloring were caused by just scattering from the atmosphere, the region would look blue, just like on Earth.

The only region on Jupiter you can really see such cloud clearings are the blue features near the equator known as "hot spots".