news

The Perseverance rover has discovered chemical signatures and structures in a Martian rock that may have been left by ancient life.

See those leopard prints? The Perseverance rover has discovered chemical signatures and structures in a Martian rock that could be left by ancient life.NASA / JPL-Caltech / MSSS

On July 21, the Perseverance Mars rover discovered evidence of suspected ancient life activities in a Martian rock. However, scientists are still cautious while being ecstatic, and look forward to further analyzing the evidence in the future to confirm this discovery.

The evidence emerged in an arrow-shaped rock that contains chemical signatures and structures that may have been created by Martian microbes billions of years ago when Mars was still wet. Perseverance detected organic matter in it, which are precursors to the chemistry of life. The rock contains veins composed of calcium sulfate, the presence of which indicates that the rock was once washed by water.

What surprised the researchers most were dozens of strange spots in the rocks. These spots are about a few millimeters in diameter, and each is surrounded by a black ring, which looks very much like leopard spots. The black ring contains iron and phosphates - on Earth, they are produced in chemical reactions dominated by microorganisms.

The researchers said all three types of features had never been found together in a single rock on Mars before.

The rock is located at the edge of an ancient river valley about 400 meters wide. Researchers suspect that the valley was formed as water poured into Jezero Crater. The valley runs along the inner wall of the crater. It is possible that mud poured into the valley and eventually solidified to form the rock discovered by Perseverance. After the rock was formed, it was infiltrated by water, forming the calcium sulfate veins in the sample, as well as the leopard spots.

To be clear, these visible features are not yet definitive evidence that the rock was once affected by ancient Martian microbes. The calcium sulfate in the samples could have entered the rock in a hot environment that was not hospitable to life, such as a volcanic eruption. But no one knows whether chemical reactions unrelated to life could have formed the leopard patterns in the rock.

Researchers have directed Perseverance to analyze the rock repeatedly, using lasers and X-rays from every conceivable angle. The information obtained so far has reached the limit of Perseverance's capabilities, so people are eager to bring it back to Earth and study it in the laboratory with much more powerful equipment.

According to the current plan, bringing samples back to Earth is a complex process that requires multiple launches to complete. There may be a combined spacecraft landing on the surface of Mars, and then the Perseverance will transport the collected samples to the spacecraft; or it may be delivered to a special helicopter that arrives on Mars with the combined spacecraft, and the helicopter will transport the samples to the combined spacecraft. After the delivery is completed, the ascender in the combined spacecraft will send the samples into orbit and dock with another spacecraft waiting in space, and the latter will bring the samples back to Earth.