How old are the planets? Which is oldest or youngest?
The Solar System, which includes the Sun, the planets, and all the comets and asteroids, is somewhere between 4.5 and 5.0 billion years old. We know this from a combination of our knowledge of the Sun and the ages of rocks here on Earth and those rocks returned from the Moon. All of the planets formed at about the same time, so we can’t say which planet is oldest or youngest. If you’d like more information about the Sun and planets, The Nine Planets website is a good starting place. • Is there life on other planets? One answer is no. The surface of the Moon and the planet Mars have been tested for life. No life was found. Many other objects in the Solar System have been investigated from orbit. There are no obvious signs of anything that we would identify as life. Another answer is yes, perhaps someplace we haven’t tested yet. The chemicals that make up life on Earth are common in space, in comets and meteorites, and probably exist on the surfaces of other planets here or around other
