What are some characteristics and comparisons of Mars - Earth - and Venus?

Answer 1

Venus, Earth, and Mars have some striking similarities. They are all terrestrial planets, and they are all inner planets. But they also have some differences. Venus has a thick carbon-dioxide atmosphere, while Earth has a thin atmosphere made of hydrogen, oxygen, argon, and traces of other elements. Mars's atmosphere is very thin and localized. Venus and Earth are about the same size, their radii being 199 miles apart. Mars's radius is 2,106 miles, about half the radius of Earth. Finally, Venus orbits at 67 million miles on average, outside the habitable zone. But Earth and Mars are both in the habitable zone, Earth's orbit being at 93 million miles, and Mars' being at 142 million miles.