EARTH AND OUR SOLAR SYSTEM
Earth is the only planet that has life on it because it is just the right temperature to grow plants , and as you know plants give us oxygen to breath and which is why me and you are still alive right now! If you ask someone why there is no life on Mercury, he or she would say it's way too close to the sun and is too hot to grow plants. Therefore Earth gets the right amount of heat and coolness. A extra fact is Earth is the only planet we've taken a really close look at. For all we know, there are half a dozen other planets and moons in our solar system supporting life this very moment.
It is not clear that Earth is the only planet with life. For all we know there might be, and most scientists expect that that there probably are, planets with life on them orbiting a significant fraction of the hundreds of billions of stars in each of the hundreds of trillions of galaxies in the universe. Present technology is barely able to detect that planets are there orbiting other stars, we cannot yet tell whether any planets have life on them. As for the other planets in this solar system, Mercury and Venus are too hot to have liquid water on them, and Neptune and Uranus are too cold to have water on them.
It is not clear that Earth is the only planet with life. For all we know there might be, and most scientists expect that that there probably are, planets with life on them orbiting a significant fraction of the hundreds of billions of stars in each of the hundreds of trillions of galaxies in the universe. Present technology is barely able to detect that planets are there orbiting other stars, we cannot yet tell whether any planets have life on them. As for the other planets in this solar system, Mercury and Venus are too hot to have liquid water on them, and Neptune and Uranus are too cold to have water on them.