Login

why does only earth has water and not the other planets?   Thank you.

Mercury has no atmosphere and is so close to the Sun that any nascent atmosphere was likely swept away by the solar winds.  Venus may well have had water (and certainly does still have water trapped in the atmosphere), but it's too close to the Sun and thus too hot for liquid water to be maintained.  Mars has lots of frozen water and once had even more liquid water, but because of its size, it's molten core solidified and its magnetosphere went away, THIS fact, combined with its lower gravity, allowed the air to escape into space and be swept away by the solar winds.  

Earth, with its reasonable gravity and powerful magnetosphere to protect itself from the solar winds, is unique in its ability to maintain liquid water.  That said, Europa has more water than Earth.   Jupiter CERTAINLY has more water than the Earth.

Like plzzzz.....

  • 3
View Full Answer

The water was already present when the Earth assembled itself out of the accretionary disk. Continued outgassing of volcanoes transferred the water into the atmosphere which was saturated with water. And rain transferred the water onto the surface.

Compared to other planets and smaller solar system object Earth has a big advantage. It is large enough to prevent water molecules to leave the gravitational field, and it has a magnetic field which prevents atmospheric erosion
. This is due to the Earth's outer core being liquid (Moving charged liquid = magnetic field). Mars probably had oceans until its outer core solidified so much, that the convection was stopped. After the magnetic field disappeared a few million years of solar radiation removed all of the atmosphere and the oceans.

  • 1
What are you looking for?