[ad_1]
Over the next few years, Mars will be visited by three new rovers, the Perseverance, Tianwen-1, is Rosalind Franklin missions. Like their predecessors – Pathfinder is Sojourner, Spirit is Opportunity, is Curiosity – these robotic missions will explore the surface, looking for evidence of past and present life. But even after years of exploration, an important question remains: what is the best place to look?
To date, all attempts to find evidence of life on the surface have yielded nothing, due to the fact that the Martian environment is extremely cold, dry and irradiated. According to a new study by an international team of researchers led by Cornell University and Madrid’s Centro de Astrobiología, the Atacama Desert in the mountains of Chile could hold the answer.
Located in northern Chile and with an elevation ranging between 2,400 meters (7,900 ft) and 4,800 m (15,700 ft), the Atacama Plateau Desert is the driest region on the planet. Due to its elevation and negligible cloud cover, this region is an ideal location for astronomical studies, which is why the European Southern Observatory (ESO) operates three main observatories there: La Silla, Paranal and Llano de Chajnantor.
These facilities house some of the most impressive telescopes in the world, such as the TRAPPIST telescope, the Very Large Telescope (VLT), the Atacama Large Millimeter Array (ALMA) and, soon, ESO’s highly anticipated Extremely Large Telescope (ELT). Additionally, Atacama’s natural dryness makes it a good analogue for Mars, where conditions are also extremely dry.
Scientists have long known that Mars wasn’t always like this. About 4 billion years ago, it had a denser, warmer atmosphere that allowed liquid water to flow over its surface. Unfortunately, Mars slowly lost its atmosphere over the eons, causing most of this water to disperse into space. What the water remains there today is largely confined to the polar ice caps or hidden underground.
If life had once existed on Mars, it too would have retreated underground and may still be there today. For this reason, Dr Armando Azua-Bustos of the Centro de Astrobiologí and Dr Alberto G. Fairén (a visiting scientist at Cornell and a NASA non-resident affiliate scientist) led an international team to study the wet clay deposits under the surface.
These deposits, located approximately 30 cm (1 foot) underground, were found to contain diverse populations of microbes. Furthermore, they are similar to clays found beneath the surface on Mars, which would be easily accessible to future rovers. Like Fairén, the study’s corresponding author appeared in Nature Science Reports, explained to the Cornell Chronicle:
“The clays are inhabited by microorganisms. Our discovery suggests that something similar could have happened billions of years ago – or could still happen – on Mars. If the microbes still exist today, the last possible Martian life could still rest there. “
The clay layer was excavated in the Yungay region of the Atacama Desert, a possible habitat for microbial life and previously unreported. It was here that they found at least 30 species of salt-loving bacteria of metabolically active bacteria and archaea (single-celled organism). This discovery strengthens the theory that Mars may have had similar protected habitable niches beneath its surface, particularly during the first billion years of its history.
NASA Perseverance rover and the rover element of China Tianwen-1 both will land on Mars in February 2021. ESA Rosalind Franklin rover, whose launch has been postponed to 2022 (due to the COVID-19 pandemic), will arrive by 2023. All three of these missions are tasked with searching for biomarkers in underground clay deposits, which will be easily accessible to them.
Here lies the value of using Mars-like environments on Earth to investigate predicted outcomes on Mars. As Fairen summed up:
“This document helps guide the research. to inform about where to look and what tools to use in the search for life. This is why clays are important. They store organic compounds and biomarkers extremely well and are abundant on Mars. “
In the coming years, scientific investigations of Mars will reach a whole new level. From this, one of two things will result: humanity will have compelling evidence that life exists beyond Earth or not. Both perspectives require that we continue to investigate so that we can learn all we can about where and how life in the Solar System emerged.
Further reading: Cornell Chronicle, Nature Science Reports
Source link
