I would like to know how do scientists know what other planets are like billions of light years away from us, i know there are powerful telescopes but even then the planets on the pictures are super tiny
How do they know there is water there or that it has an atmosphere,
Always wanted to ask thanks
In: Physics
We can see what kind of materials it *might* be made of by the spectrum of light that is reflected. Keep in mind, this is light outside the spectrum visible to us.
Think of it like gems; we know what diamond, sapphire, emerald, ruby, etc. are because of what color they appear to us. Similarly planets made up of largely hydrogen will appear a different “color” than ones that are made up of largely iron or nickel.
This requires us knowing the spectrum of the light source, so first we have to analyze the planets star.
Usually this process is done by monitoring the planet passing in front of the star and observing what spectrums are blocked by the planet.
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