earth and mars
Our home, the planet Earth, is a terrestrial and rocky planet. It has a solid and active surface with mountains, valleys, canyons, plains and much more. The Earth is special because it is an ocean planet. 70% of the surface of the Earth is covered by water.
Our atmosphere is mostly nitrogen and has a lot of oxygen so we can breathe. The atmosphere also protects us from the incoming meteoroids, many of which break up in the atmosphere before
Mars is a desert and cold planet. It's half the size of Earth. Sometimes, Mars is called the Red Planet. It is red because of the rusty iron in the ground.
Like Earth, Mars has stations, polar ice caps, volcanoes, canyons and weather. It has a very thin atmosphere made of carbon dioxide, nitrogen and argon.
There are signs of ancient floods on Mars but now water exists mainly in frozen dirt and thin clouds. On some Martian slopes, there is evidence of salty liquid water in the soil.
Scientists want to know if Mars may have had living beings in the past. Also, they want to know if Mars could harbor life now or in the future