Not so many years ago, our solar system was the only one with known planets.
(But you know, there was still life on one in eight known planets (depending on how you consider Pluto))
Then it was a sensation when the first exoplanets were found, and now we are close to finding a new exoplanet a day.
Want to see the list:
http://exoplanetarchive.ipac.caltech.edu/(No, none of them are mentioned in any of the iron age scriptures, dictated by the all-knowing magic entity)
we have found 3285 so far.
If we look for planets that could have "life as we know it" (notice the "as we know it" part) it must have an approximately earth-like size and temperature.
There are 8 of those identified so far (one actually being earth. We are pretty sure that there is life here. Whether it is intelligent or not is an open topic).
If you are more optimistic/hopeful there are a further 25 known exoplanets that maybe could have life.
Ahaaa, I hear you squeal triumphantly between the soft bumps of forehead against prayer rug:
"And not one of those have been proven to have life, and only a small fraction are considered candidates! Allaaaaahu Snackbar, there is no life anywhere but on earth (insert scripture of your own choice here)".
The thing is, that we have so far seen, that it is pretty normal to have planets in all sizes around stars.
The problem is, that other stars are so annoyingly far away and pretty shiny, and the planets are much smaller than the stars.
We have only imaged a very few directly.
The other have been found by indirect methods, primarily by measuring the light from the star, seeing a small dip when the planet passes in front of it and by seeing it "wobble" because of the circling planets.
These methods favor finding large planets, the smaller ones (earth-like size) simply not being large enough to get above the detection limit.
That does not mean that they are not there, it just means, that we can't see them.
We have so far managed to land things on the Moon, Mars, Venus, Titan, one comet and two asteroids. We have not found (nor really expected to find) life any of those places.
regarding life on earth, it was thought to be frail an choosy about where to be possible, but we have found life in some form or another in all but the most extreme places.
It seems that life is almost a consequence of thermodynamics, not that it is existing in spite of it.
Topic: Challenge