Hi. I love astronomy and being able to see some live views of some. I recently saw SAturn,my favorite planet. What I want to know is how do we know the composition of a planet? Like how do we know it's a gas giant,etc?


Hello Cindy...thanks for using AllExperts
We know gas giants are made of gas because with powerful telescopes we can see their surfaces. Those surfaces reveal immense, constantly moving bands that could be nothing other than some kinds of gases. With our telescopes we see the entire surface of gas giants moving about, something that wouldn't happen if there was any solid surface.

For your information we can also analyze the light coming from gas giants in a special way (called "spectroscopy") and even tell what kinds of gases are present, like helium, hydrogen, methane, etc.,.

Be sure and let me know if I can answer any other questions you might have.


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Patrick Weiler


I`d be pleased to answer questions about any aspect of astronomy, particularly those related to cosmology, astrophysics, and planetary sciences. I can also provide reliable information on unique topics like dark energy, dark matter, black holes, etc.,.


Teacher, adult after-hours education at local community college, including frequent "star parties." I have my own telescope system, and continue to stay apace of recent developments and emerging theories in the field.

BA, liberal arts with emphasis on sciences. BS, computer technology.

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