Study shows some exoplanets may have more variety of lives than exist on Earth

A new study indicates that some exoplanets could offer better living conditions than the Earth itself. "It's a surprising finding," said Stephanie Olson, Senior Researcher, "This shows us that conditions on some exoplanets with favorable ocean circulation patterns might be better suited to a life more abundant or more active than life." on earth."

The discovery of exoplanets accelerated the search for life outside our solar system. The huge distances separating these exoplanets make it really impossible to reach them with space probes. Scientists are therefore working with remote sensing tools, such as telescopes, to understand the conditions prevailing on different exoplanets. To understand these remote observations, it is necessary to develop sophisticated models of global climate and evolution in order to allow scientists to determine which of these distant planets could harbor life.

Presenting a new synthesis of this work at a conference at the Goldschmidt Geochemistry Congress in Barcelona, ​​Stephanie Olson (University of Chicago) describes the research to identify the best environments for life on exoplanets:

"The search for life in the NASA universe is centered on the so-called" habitable areas ", which are worlds capable of generating oceans of liquid water, but all oceans are not as Some oceans will be better places to live, others because of their global circulation patterns. "

Olson's team modeled the likely conditions of different types of exoplanets using the ROCKE-3-D software, developed by NASA's Goddard Institute for Space Studies (GISS), to simulate climates and ocean habitats of different types of exoplanets.

"Our work was aimed at identifying the exoplanet oceans that have the greatest ability to host an active and abundant life on a global scale." Life in the Earth's oceans depends on upwelling (upward flow). ) that returns the nutrients from the dark depths of the ocean to the bright parts of the sun, the ocean where photosynthetic life lives.More upwell means more replenishment of nutrients, which means more biological activity. These are the conditions we must look for on exoplanets. "

They modeled a variety of possible exoplanets and were able to define the types of exoplanets with the best chance of developing and maintaining flourishing biospheres.

"We used an ocean circulation model to identify the planets that will present the most efficient upwelling and therefore offer particularly hospitable oceans.We found that a higher atmospheric density, lower rotational speeds and the presence of continents all resulted in higher upwelling rates Another implication is that the Earth may not be optimally habitable – and that life elsewhere may benefit from a planet even more hospitable than ours .

Our technology will always have limits, so life is almost certainly more common than "detectable" life. This means that, in our search for life in the universe, we should target the subset of habitable planets that will be most favorable to large active biospheres globally because these are the planets where life will be the easiest to detect – and where non-detections will be the most significant. "

Dr. Olson notes that we do not yet have telescopes capable of identifying the appropriate exoplanets and to verify this hypothesis, but indicates that "ideally, this work will inform the design of the telescope to ensure future missions, such as the proposed LUVOIR or HabEx telescope concepts, having the right capabilities, now we know what to look for, so we need to start looking. "

Commenting, Professor Chris Reinhard (Georgia Institute of Technology) said:

"We expect the oceans to play an important role in regulating some of the most compelling and remotely detectable signs of life on habitable worlds, but our understanding of the oceans beyond our solar system is currently very rudimentary. The work of Dr. Olson represents a significant and exciting step forward in our understanding of the oceanography of exoplanets. "

The first exoplanet was discovered in 1992 and, to date, more than 4000 exoplanets have been confirmed. The closest known exoplanet is Proxima Centauri b, a distance of 4.25 light-years. Currently, the search for life on the exoplanets is mainly focused on the inhabitants of the habitable zone, the distance that separates a star from the temperature where the temperature of the planet allows the oceans of liquid waters to be vital for the life on Earth.

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Goldschmidt Conference