'There's no water left on Mars': Researchers reveal in a new study; here's why

According to a study from Washington University in St. Louis, there is no water left on Mars. Although all evidence suggested the presence of flowing water on Mars' surface, numerous flybys, orbiters, landers, and rovers have established one incontrovertible fact that whatever liquid water once existed on the planet's surface is now long gone.

The 'Mars Ocean Hypothesis' implies that Mars had a lot of liquid water, not just a little. However, Kun Wang, a co-author of the current study, says his team's findings, which were published this week in the Proceedings of the National Academy of Sciences, put that theory to rest.

Mars' reduced mass and gravity responsible for escape of water into space

In a press release, Wang stated, "Mars' fate was decided from the beginning. The size requirements for rocky planets to maintain enough water to support habitability and plate tectonics are most likely limited. This is due to Mars' reduced mass and gravity, which makes it simpler for volatile elements and compounds like water to escape into space from its surface."

The researchers, led by Zhen Tian, a graduate student in Wang's group, examined 20 Martian meteorites ranging in age from around 200 million to 4 billion years old, dating from a time when the solar system was still forming. The researchers looked at potassium, a somewhat volatile metal, to see how water might have behaved on Mars' surface. Potassium-39 is more easily lost to space in lower gravity situations, such as Mars, leaving a higher ratio of the heavier isotope, potassium-41. Water behaves similarly, implying that the majority of it would have been lost to space during Mars' creation. It's something Wang and his colleagues noticed even in the earliest meteorites, implying that this has always been a problem for Martian water.

To analyse the potassium isotopes in samples from the moon and an asteroid, which are both much smaller and drier than either Earth or Mars, the researchers looked at samples from the moon and an asteroid. They discovered a link between mass and the presence — or absence — of volatiles in the samples. Wang claims that the liquid water that did remain on Mars' surface sculpted out the now-desiccated canyons, riverbeds, and other landforms that we see in the present. But that water, too, would have vanished if it hadn't been stored as ice at the Martian poles when the planet's environment cooled.

Discoveries may aid in search for habitable extrasolar planets

The study has ramifications beyond our solar system as well. The holy grail of astronomers' search for planets surrounding other stars is to identify ones that can support life — that is, worlds that are neither too hot nor too cold. Even if a planet circles its star in the so-called Goldilocks Zone, where the temperature is just ideal for liquid water without being too hot to support life, it may be too small to hold on to the water.

(Image: Pixabay)