Mars is the second closest planet to Earth after Venus. Venus is roughly the same size as Earth and is often called the evil twin due to its extreme temperatures and run away greenhouse effect. Venus is surrounded by a cloudy toxic atmosphere that makes studying it difficult compared to that of Mars.
Mars is known as the Red Planet and there's a good reason for it. The planet is red to look at both up close and from a distance. Earth is known as the blue planet, because of the oceans that make up the vast majority of the planet.
The red comes from the abundance of Iron Oxide on the surface and in the air when its been whipped up into the atmosphere. For there to be oxide, you need oxygen. There is a tiny amount of oxygen in the atmosphere, not enough for humans to breathe and survive with.
There's no register feature and no need to give an email address if you don't need to. All messages will be reviewed before being displayed. Comments may be merged or altered slightly such as if an email address is given in the main body of the comment.
You can decline to give a name which if that is the case, the comment will be attributed to a random star. A name is preferred even if its a random made up one by yourself.