While Mars is known as a frozen, red planet today, it has all the evidence we could ask for of a watery past.
Scientists who recently ran a computer simulation in order to examine water on Mars now indicates that most of its water molecules may now reside in the Red Planet's crust.
Specifically, the research by scientists at CalTech in California now suggests that most of Mars' water molecules may have become lodged inside the crystal structures of minerals on the planet's surface.
The simulation was based on observations made by rovers and orbiting spacecraft, in addition to lab analyses of Martian meteorites.
Ever since the 1700s, scientists have believed that water once existed in abundance on Mars in the ancient past.
Water still exists on Mars in the form of ice and small amounts of water vapour.
According to Science News, scientists have typically blamed Mars’ lack of water on the planet's weak atmosphere.
However, measurements of atmospheric water loss made by spacecraft like NASA’s MAVEN orbiter are not enough to account for all of Mars’ missing water.
In fact, Mars once contained so much water, it could have covered the whole planet in a sea up to 1,500 meters deep: more than half the volume of the Atlantic Ocean.
The results of the research have since been published in the journal Science.
In related space news, a separate group of scientists have proposed sending a gene bank or 'ark' to the moon in order to ensure our planet's future.