Rovers need to dig deeper to find signs of life

Experiments conducted at NASA indicate that cosmic rays are able to completely destroy amino acids in the Martian soil at a small depth. Therefore, rovers who are looking for life on the red planet need to dig deeper.

Rover Curiosity, looking for life on Mars. Source: NASA/JPL-Caltech/MSSS

Cosmic rays destroy amino acids

NASA scientists conducted a laboratory experiment and determined that high-energy rays destroy amino acids in the Martian soil much faster than previously thought. This means that it will not be so easy for rovers looking for life on the surface of the red planet to find signs of life. 

Amino acids are organic molecules that make up proteins. They can be of biological and non-biological origin. However, the presence of some of them in the Martian soil could be regarded as direct evidence of the existence of life on it in the past.

Cosmic rays are high-energy charged particles born on the Sun and other stars. On earth, the atmosphere and the magnetic field protect us from them. On Mars, both are much weaker, but until now it was believed that complex organic molecules could persist on it even at a small depth for billions of years.

New laboratory experiments

Until now, scientists have conducted experiments on the effect of cosmic rays on pure samples of amino acids. And they showed good resistance. But the probability of finding such large clusters of organic matter on Mars is minuscule. Therefore, scientists created samples from a mixture of amino acids with silica, hydrated silica and silica with perchlorates.

All samples were stored for some time in a vacuum under the influence of various types of ionizing radiation. Some of them were at room temperature, some at minus 55 degrees Celsius. This range corresponds to the conditions on Mars.

Rovers need to dig deeper

Studies show that amino acids decompose under the influence of ionizing radiation in the conditions of Mars much faster than previously thought. For example, at a depth of about five centimeters, at which the Perseverance rover is currently taking samples, they are destroyed in about 20 million years.

However, the age of the youngest signs of life that scientists expect to find is measured in billions of years. Therefore, in order to find them, we need to look in the young emissions of meteorite craters. At a greater depth, the chance of amino acids to survive is much higher.

For example, the amino acid samples in the RBT 04262 meteorite were at a depth of at least one meter below its surface before being ejected from Mars. In general, it is estimated that in order to be guaranteed to find the intact DNA of the rover, it needs to dig deeper, at least 2 meters.

According to

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