Until recently it was believed that all the water on Mars is frozen and unlikely to turn into liquid form any time soon. This assumption was based on the fact that the planet’s surface is considerably colder than our own and there’s very little chance of it heating up without outside intervention. However, the latest findings by the Curiosity rover suggest that the water on Mars can actually become liquid, but only when some very specific conditions are met. As strange as it seems, the rover discovered that liquid water on the Red Planet only seems to be present during winter nights.
The water found over there is pretty different compared to what you can find on Earth for the most part, as it takes the form of a salty solution known as brine. The salt is actually the key ingredient which allows liquid water to exist on Mars thanks to its propriety of lowering the water’s freezing point. Generally speaking, water freezes at -100C and this is the case everywhere as far as we know, even on Mars. The average temperature on Mars coupled with other atmospheric conditions make it very difficult for water to remain liquid as it usually either freezes or evaporates. However, beneath the surface and near the equator of Mars, Curiosity has found that a small amount of liquid water does exist, although it’s very salty and tends to evaporate quickly after the sun rises.
To make a long story short, yes there is liquid water on Mars, but it is not able to sustain life, which is what I’m sure most people were wondering about. We have certain life forms here on Earth that are able to survive in salty environments and even harsher conditions, so it would be reasonable to assume that similar organisms might be able to live on or under the surface of the Red Planet. That being said, Mars is still much too cold and dry for life as we know it. Liquid water is just one of the necessary conditions needed for life (again, as we know it) to survive, but it does require some other things as well and unfortunately Mars doesn’t seem to be able to provide them. Despite this apparent disappointment, scientists are actually very excited about finally finding liquid water on Mars and are continuing their exploration of the Red Planet via the Curiosity rover, which is currently climbing Mount Sharp found inside Gale crater.