Space exploration is an expensive business, so increasingly NASA and other space agencies are using remote methods to look at other planets and their moons in a bid to find water. Specialist equipment like thermal imaging cameras, such as the ones developed by Andor.com, are used to detect differences in temperature above and below the crust of a planet or moon. Sharp or sudden temperature changes can indicate seismic or volcanic activity, or even liquid water – the basic requirement of life!
So far we’ve found 23 places in our solar system that have water, either as ice, liquid or even vapour – here are just seven.
This, the smallest of Jupiter’s Galilean moons, has been our most serious prospect for life for a long time. The tidal pull of Jupiter creates friction inside this moon, generating heat that keeps water in a liquid state and even at a temperature that could harbour life. There’s a chance Europa could have an ocean with warm water radiating from its equator in Hadley Cells, so this could mean fairly complex life, too.
Ganymede is Jupiter’s largest moon and also the largest moon in our solar system. It has a 100-mile thick ice crust, but underneath it is believed to be a warm and salty ocean. As this moon is further out from Jupiter than Europa, it doesn’t get the same strong tidal effects to keep the water liquid, but there’s still strong evidence to say an ocean is there.
Uranus and Neptune
We’ve been calling them gas giants for years, but some astronomers have started to call these huge planets ice giants. This is partly due to the large amounts of ice in the planet’s inner layers – this ice is probably in some very strange states due to the unbelievable pressure exerted upon it. Water in the form of vapour has also been detected in the upper layers of the gas giants, and some astronomers believe there could be floating oceans there too. Come on in, the water’s, errr…lethal.
Venus, Jupiter and Saturn
There are countless places in our solar system where water could exist, from tiny un-named moons to comets travelling through. There have also been trace amounts found on Venus, Saturn and Jupiter – in Jupiter it’s believed to be massively compressed and super-heated to thousands of degrees at the planet’s core.
All these discoveries change our view of the rest of the solar system as a dry, barren place to one which has the possibility – however small – of life.
For now, however, Earth is the only place with liquid water that has generated life – we know this for certain, as we’re part of it! We tend to think that life can only exist here because we’re the right distance from the Sun, at the right temperature, with the right mix of atmospheric gases. However, life could be out there in forms that we can’t even imagine – we just have to keep looking, and the presence of water is always a good sign.