Planets outside of our solar system?

Question

How are scientists able to tell what type of atmosphere they have?

Answer 1

They can tell by loking at the light from that planets sun after it passes through the planets' atmosphere. Color will change depending upon the various gases that are present.

Answer 2

This is a very very very misunderstood topic among astronomy and deals a lot with understanding the relative size of planets, stars, and distances.

The simply answer to this is, they can't tell what type of atmosphere they have because planets are so small compared to stars that they are barely even detectable. In fact, until a few years ago, there was no proof that planets existed in other solar systems.

Our sun is about 50 times as big as our largest planet, Jupiter. So viewing an image of Jupiter from light years away would be impossible since it is so much smaller. Also, it would be drowned out by the sun's high luminosity. The only planets in other solar systems we can see are only nearby stars, maybe Jupiter sized planets, and all we see is that the luminosity of the star seems to be a little smaller at a certain frequency. It is assumed there periods of smaller luminosity are when large planets are passing in front of the star.

So, the idea of detecting atmospheres in these planets is very difficult.

Answer 3

Spectroscopy.