Liquid water on Mars is just a dusty plain

Italian scientists thought in 2018 they saw a lake of liquid water under an ice sheet at the south pole of Mars, but according to a new study, it may not be water at all. Radar analyzes from 2018 showed unexpected strong radar reflections under the ice sheet. This would refer to liquid water. Now planetary scientists from Texas have come up with a new, more plausible explanation for strong reversals.

Dusty volcanic plains beneath the ice sheet likely contributed to the strong reversal. who – which I finish Researchers based on computer simulations and radar images also used by Italian researchers. They published the results in the journal this week Geophysical Research Letters.

Mars is a planet next to Earth and is a kind of icy desert. The temperature averages 55 degrees below zero and there are sandstorms that are sometimes larger than in Russia. Water has not flowed to the surface for billions of years. However, layers of frozen water several kilometers thick cover the planet. But even if the temperature rises and the water ice melts, the liquid water on the surface doesn’t stand a chance. Due to the low air pressure (less than a hundredth of the air pressure on Earth), liquid water evaporates instantly. Under the icy plains, in theory, liquid water would have a chance. After all, the pressure is higher under icy surfaces.

Antarctica pictures

In 2018, Italian scientists thought they could actually see water under the icy plains on radar images of Mars. These radar images were taken by the Marsis instrument, aboard the European Mars Express probe. The instrument sends radio signals that penetrate the ice for miles and then bounce back to the Marsis. The amount of back reflection says something about the properties of the surface under the ice. For example, a strong reflection can refer to liquid water. Scientists on Earth see that, too. Radar images of Antarctica, for example, show a lot of inversion in some places. And when scientists dig under the ice there, they actually find lakes with liquid water. On Planum Australe, an ice field on Mars’ south pole, scientists also saw a remarkable amount of inversion. Italian researchers estimated that the meltwater should be at least one meter deep and about twenty kilometers wide. she published Results at that time in the journal Science.

These results were quickly called into question. To have a near-surface chance of liquid water, the water must be very salty and there must be a heat source nearby. This is not what scientists see on Mars, books 2019 study critics. last year Researchers at Arizona State University have come up with alternative explanations for strong reversals in the Antarctic. In the lab, they studied what different materials on Mars would look like in radar images. They have seen that these materials give off powerful radar reflections in the lab.

Thousands of square kilometers

Now, Texas researchers have confirmed that material on the Red Planet also strongly reflects radar signals when buried under an ice sheet. To do this, the researchers simulated different reflections in a computer model. The simulated reflections from the volcanic plains, of which Mars has many, perfectly match the strong radar reflections from Mars. In addition, radar images from Marsis also showed strong reflections in places other than Antarctica. These locations are consistent with those of the volcanic plains, according to the Texas researchers.

We should not think about the Earth when we study the neighboring planet

Bart Root planet explorer

Bart Root, a planetary researcher at TU Delft who was not involved in the study, found that the presence of liquid water under Mars’ polar cap is less credible. Texas researchers don’t rule out liquid water, but they do offer a more reasonable alternative to conditions on Mars. This once again confirms that we should not think about the Earth when we study the neighboring planet. On Earth, bright radar reflections may indicate underground lakes like Antarctica, but that doesn’t mean the same is true of Mars. Mars has a different makeup and conditions than Earth. “

Roberto Orossi, an astronomer at the Italian research institute INAF and lead author of the 2018 study, wasn’t convinced by the Texas researchers’ alternative. “It doesn’t make sense that there is a volcanic plain under the ice in the Antarctic. Volcanic plains on Mars are often thousands of square kilometers in area. The spot with strong reflection on the South Pole is only twenty. In addition, no volcanoes have been found in the Antarctic to Mars. Until researchers prove that there is indeed a volcanic plain in the Antarctic, I will stick to my own conclusion.”