Re: What is the relationship between the sun and the earth?

You're absolutely right that the sun is essential to life on earth. The light from the sun keeps the planet warm (and the oceans liquid!), gives plants their energy, and through the plants give animals their energy as well.

However, the reverse is not true - the sun can get along just fine without the earth! To the sun, the earth is just a tiny little speck that revolves around it. The sun is about 200,000 times more massive than the earth, which means that it barely even notices the pull of the earth as we move around.

The sun will continue to produce light pretty much as it does now for another 5 billion years or so. Then it will become a "red giant" - meaning that it will become more red and grow until it actually engulfs the earth! So, if you could wait long enough, you'd even be able to see the sun destroy the earth.

Also, there are many billions of stars out there, and it is likely that not all of them have planets. So the moral is, life on a planet needs a nearby star, but stars don't need planets!