Why does earth have people and other planets dont?

Answer 1

This is a tricky question; scientists don't have any definitive answers but there are several compelling theories that explain why Earth has water while some of the other planets don't.

Compare Earth to its two neighbors; Venus and Mars.

Venus is about the same size as Earth, but it's a hot hot hellish place; bone dry, hundreds of degrees and shrouded in a thick atmosphere of mostly CO2 and sulfur compounds. Venus may have had water billions of years ago, but it had two problems: it was too close to the sun and it had a very weak magnetic field. Because of these two factors the hot solar wind (fast moving jets of ions flowing out from the sun) little by little stripped the water out of Venus' atmosphere, first because the water was mostly vapor (because Venus is close to the sun and so it is hot) and second because there was little to no magnetic field to push aside the solar wind. Earth has a magnetic field which acts like a shield to push aside the solar wind and this means the solar wind does not dry up our water and Earth is further from the sun so it is cooler so a lot of the water on Earth is either liquid or frozen.

Mars is a different problem. It is a much smaller, and colder place than Earth. It also has very little magnetic field, and a lot of its water may have been stripped away by the solar wind just like on Venus. Also because it is so small it has less gravity; less gravity means it takes less energy for water molecules to get bumped out into space by that solar wind. But in fact, Mars does seem to have water. There is recent evidence that most if any water on Mars is frozen and buried just beneath the surface of the ground. Still, there seems to be a lot less of it on Mars than on Earth.

It seems that if you are a planet and you want to have lots of water, several things need to be just right: you mustn't be too close to the sun (or the water will boil up into the atmosphere) or too far from the sun (or the water will freeze), you need to have a very strong magnetic field to protect your water from the solar wind, and you need to be large and heavy enough that your water doesn't just drift off into space.

Now the next questions are: Why does Earth have a magnetic field and Venus does not? Why is Earth so big and Mars so small? These questions are for another post.

Answer 2

it comes from tree and the wind come from air so year!

Answer 3

Because there is no air water food