🔴 Why is Mars red? Sample
The Red Planet is, in a way, covered in rust.
The mystery
From Earth, Mars glows a clear reddish-orange in the night sky. But rocks are usually grey or brown — so where does that colour come from?
The answer
Mars's surface dust is rich in iron oxide — the same compound we call rust. Winds lift this fine dust high into the thin atmosphere, so even the sky takes on a butterscotch tint by day.
Now think about this
If Mars is red because of rust, what does that tell us about water and oxygen on Mars long ago?
