yes, millions/billions
No. BY definition, an exo-planet is OUTSIDE our solar system, orbiting some other star.
There is no other planet in the Solar System that can, without assistance, support human life.
Mars is the other planet in our solar system besides Earth that has water.
Also the first planet outside our solar system ,HD 209458b, is told to have water, they found this because of the vapour in it's atmosphere.
Saturn has more moons than any other planet in our solar system
It makes sense to talk about the climate on other planets, not on other galaxies. Not much is known about the climate on any planet outside the Solar System.
Jupiter rotates faster than any other planet in the solar system, with a day lasting about 9.9 hours.
Jupiter is the biggest planet in the solar system.
The meaning of the term "alien world" is somewhat ambiguous. No evidence of life on any planet in the solar system except earth, or on any planet around any other star, has yet been found.
no it is not the 8th largest. Infact it is the 8th smallest or in other words it's the smallest
No. Astronauts have not visited any planet outside of the earth.The only other body in the universe besides earth that humans have ever stood on is the moon,and that hasn't happened in the last 32 years.
Saturn