Curiosity rover discovers unusual carbon footprint on Mars

Miscellaneous / by admin / January 19, 2022

On Earth, a similar trace indicates the presence of life.

The rover landed inside Gale Crater on August 6, 2012. In less than 10 years he overcame about 27 km and took rock samples in various parts of the crater.

Curiosity drills holes in the surface of Mars, and then analyzes the chemical composition of the resulting powder. For example, he can estimate the ratio of different isotopes - atoms of the same element with different numbers of neutrons in their nuclei. This is called a carbon signature, or signature.

It was expected that near the geological formation of Stimson in the Gale crater, where the rover is now located, the carbon-13 isotope will be the most common. But about half of the samples taken here during a recent expedition, showed increased amount of carbon-12.

Image: Credits: NASA/Caltech-JPL/MSSS

Carbon could get on Mars both biological and non-biological ways. The lead author of the study explained:

On Earth, the processes that create a carbon signal like what we found on Mars are biological. We have to understand if the same explanation works for Mars or if there are other explanations because Mars is very different [from Earth].

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Christopher House

biophysicist, University of Pennsylvania, USA

Scientists have so far put forward two non-biological hypotheses about the source of carbon-12. Perhaps ultraviolet solar radiation interacted with carbon dioxide in the Martian atmosphere. As a result, carbon-rich molecules were formed, which then settled on the surface of the planet.

An alternative theory suggests that hundreds of millions of years ago, the solar system passed through a huge molecular cloud. Because of this, more carbon-12 fell on the surface of Mars than other isotopes.

But there is a third hypothesis - biological. Ancient bacteria that lived on the surface of Mars and directly below it could release methane into the planet's atmosphere. Then this gas interacted with ultraviolet radiation from the Sun and turned into more complex molecules. This could have led to the carbon signature that the Curiosity rover discovered billions of years later.

To say unambiguously which of the theories is correct, scientists can not yet. The co-author of the study noted:

The hardest part is letting go of the Earth, letting go of the preconceptions we have, and really trying to get into the basic chemistry, physics, and ecological processes on Mars.

Jennifer Eigenbroad

astrobiologist, Goddard Space Flight Center, NASA

Perhaps data from Curiosity, as well as information received by the new rover Perseverance, will help solve the mystery of the origin of carbon on Mars and establish whether this intriguing chemical signature is indeed evidence of life. Previously, scientists did not even suspect that there was a water, boron or other substances. But every year more and more is becoming known about Mars, so perhaps Curiosity's discovery has taken humanity one step closer to discovering life on other planets.