On Earth wherever we have found water we have found life.

At both polar regions of Mars there is some water. The surfaces of both Enceladus (the sixth largest of Saturn's 82 moons) and Europa (the 4th largest of Jupiter's 79 moons) are permanently covered in ice. But beneath the ice on both these moons there are oceans of water.

So we may find microbes in these places. The best experts in this field reckon that if any such life is found in any of these places then our galaxy must be teeming with life. This is because there are between 250 billion and 500 billion stars (i.e. suns) in our galaxy with probably all of them having planets orbiting them.

NASA has recently discovered that there are likely to be approximately 2,000 billion galaxies in the known universe.