Astronomers have found evidence that leads them to think that there is a saline ocean under the H2O ice that dominates the surface of Europa. A saline environment would be amenable to life.
They don't. No sensible astronomer thinks this is possible.
They believe there is liquid water underneath its frozen surface. If there is liquid water on Europa, there might also be life.
Astronomers have not yet made any findings regarding the possibility of life on Mars.
Actually, people think from the light reflected of that its blue, though in real life, it is actually orangish in color according to astronomers.
Gliese 581g has been discovered recently and scientists and astronomers think that there could be life on it - as it is in the 'Goldilocks zone' - a zone where there could well be water and land on planets in this area.
Earth
They believe there is liquid water underneath its frozen surface. If there is liquid water on Europa, there might also be life.
Good question. Astronomers, believe it or not believed that venus had life since it is Earth's twin planet.
This sort of question is designed to make you think about your own life and what you think could be different. You're going to have to use your own mind to answer it.
Astronomers use luminosity to measure the total amount of energy a star emits in all directions. By knowing a star's luminosity, astronomers can calculate its distance, size, and temperature. Luminosity helps astronomers understand the life cycle of stars and their evolution.
Other than us, not yet.
It's very unlikely.