For any kind of life to exist as we understand it, certain biochemical functions must be performed. These reactions are contingent on a relatively stable temperature around where water is liquid. Liquid water turns out to be rare in our solar system; the temperature range where water is liquid is only a small fraction of all available temperatures. Only Earth, and maybe one of the moons of Jupiter has water, and therefore life, within this temperature range.
The first part of this question has been thoroughly answered. However, the second part comes from an incorrect premise.
We can live on other planets. It's just that we need a very large amount of technology and supplies in order to do so. Currently, the cost of this support is too large for us to feasibly establish a colony on another world, and there are no locations we have yet discovered which do not require extensive life support just to get there, let alone to live there.
Terraforming is one procedure that might circumvent this. Terraforming is the act of altering a planet's ecosystem in order to be more like Earth. Some extreme examples imagine turning Mars or Venus into "second Earths" complete with oceans and atmospheres, but this is a bit of a stretch. Mars lacks important features, such as an active magnetic field, that would be necessary for habitability and cannot be engineered through current human technology.
However, terraforming could create localized regions in which human life is, at least, more generously supported than the rest of the planet. For example, living underground on Mars would be a lot easier than living on the surface, or trying to alter the entire planet.
We have yet to discover another planet which can support human life. Those explored thus far have all been too close to the sun, too far away, had too little oxygen, too dense of an atmosphere, or other similar problems.
Yes! You took too much space.
The reason we live on Earth is because all the other planets are inhabitable, and Earth has the food, water, and oxygen we need to survive.
We can live on earth because there is breatheable air. The earth also has enough water and food for us to survive. there is gravity and loads of nutrients.
It was not our wish to live on Earth. The earth was a deadly place to ive billions of years ago, it ws a big ball of fire and mercury. Slowly and gradually it cooled down but there was still no sign of life. A asteroid from somwhere in the space crashed the Earth and rhis led to life formation on Earth. We would not live here if there was no oxygen and the reqirements to survive.
ITS A BIG LUCK!!
And we don't live in other planets because there is nothing to support life.
But now we have become very modern, every thing is possible for us now. Scientists are planning to explode carbon-dioxide bombs to grow plants on other planets but not in the gass giants especially in the mars and the moon. But there place are asteroids prone area. In a few decades I think humans will rule the RED PLANET.
But I want to go back to my sweet home Kepler 22b.
The Earth is set at the right distance from the Sun. This makes life possible for humans because it is not freezing like on Venus and it's not so hot like on Mars. On the Earth there are proper terms for life to exists.
Because we haven't yet discover a habitable planet like earth, and by habitable I mean, not too far nor too near to the sun, the air is breathable and stuff like that
Oh! Thats really silly! because this is a habitable zone, everything is there to be alive.
U R sinior to me but U don't know more than me.