Is there solid ice on Mars?

It has been proved that Mars was once full of water. But for a long time, scientists have only found glaciers in the polar regions of Mars. Recently, scientists discovered a large "ice sea" in another non-polar place. What is even more surprising is that the "ice sea" is located near the equator of Mars, hidden under the surface. The British New Science Journal reported this on February 2 1 day.

■ It is 45 meters thick and covers an area of 720,000 square kilometers.

John Murray, the main leader of this discovery, recently announced this discovery at a scientific seminar in Nord Hui Ke, the Netherlands. Murray set up a research group in the Open University of England to study the terrain of Mars. Recently, they saw from the photos sent back by the high-tech image processing camera carried by the European Space Agency's "Mars Express" satellite that the plate crater near the equator of Mars was very unusual. General craters are deep, but these craters are shallow, and it seems that something has raised the crater floor. Then, they immediately thought of ice, because previous studies said that these craters were "containers" used to carry ice or water thousands of years ago, and later, because of the weathering of ice water, they left craters that they saw today. Murray's team found that there is indeed an "ice sea" under these craters. This boat-shaped "ice sea" is located at an angle of 5 degrees north of the equator of Mars, and its structure is very similar to the polar glaciers of the earth. The "Ice Sea" has an average thickness of 45 meters, a length of 900 kilometers, a width of 800 kilometers and an area of 720,000 square kilometers. Murray's team then dated it and found that it was 5 million years ago. The paper of Murray's research team will also be sent to the "Moon and Planetary Science Symposium" held in Texas on March 18 for many experts' reference and discussion.

■ How is the ice sea formed?

Although Mars looks extremely dry now, scientists have enough evidence to prove that Mars was once full of water in prehistoric times: in 2002, NASA's Odyssey spacecraft discovered hydrogen atoms on Mars. Subsequently, scientists discovered glaciers at the poles of Mars, confirming the existence of solid ice on Mars. However, the location of the "ice sea" discovered this time is so far away from the poles that people can't help wondering: How did such a huge "ice sea" "drift" to the equatorial region?

Question 1: There is no water vapor in the atmosphere of Mars.

The most amazing thing about this "ice sea" is that the sunshine of 5 million years has not swallowed it up. You know, the "ice sea" is located near the equator of Mars, only 5 degrees away from the center of the equator, and the covered "protective film" is only a few centimeters thick. The synchronous position on the earth has been sunny, but what is the reason for keeping such a large ice bank in such a sunny place on the ground? According to scientists' speculation, the biggest contributor is the "volcanic ash coat" of the "ice sea". This coat was put on before the "ice sea" dried up. Only a few centimeters thick, but it has a strong insulation effect. It is this super-strong function that enables the "ice sea" to live in a refrigerated environment and survive without the interference of sunlight. However, m carr, a Mars expert in the US Geological Survey, believes that even if there is a "volcanic ash coat" to protect the body, there should be a small amount of volatilization in the "ice sea". But scientists have not found the shadow of water vapor in the Martian atmosphere so far.

The second problem is that volcanic rocks are buried in similar plates.

There are plates with similar structures in other parts of Mars, but solid volcanic rocks are buried in those plates, not "ice seas". According to Murray's research team, these volcanic plates are twice as big as those on earth, and they are covered with smooth and straight channels. These channels show that the material that once flowed through the local area was a high-speed moving liquid, possibly a hot rock. They rushed through craters and islands and left these gullies. This is the opposite of the equatorial situation. Because the existence of the ice sea shows that the rapids on the ground at that time were water with ice. But scientists speculate that this liquid may have similar characteristics to water.

The problem is that it is difficult to detect underground ice in other structures.

According to Karl, the existence of similar structures in other areas means that there is more than one "underground water storage" at the equator, but it is difficult to finally confirm whether there is still underground ice sea or liquid water under those structures. To this end, the "Mars Express" satellite will be equipped with an ionospheric advanced detection radar Marsis for detecting underground liquid water on Mars. However, the ability of radar to distinguish solid ice from rocks is poor. At the same time, solid ice is usually buried underground, and satellite images are difficult to see, so it takes time to explore underground ice of other structures.