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Press Releases | Science | Technology | UW and the community
June 25, 2018
An artist's design of what life might look like on the surface of a distant planet.NASA
Researchers at the Virtual Planetary Laboratory led by the University of Washington are at the center of a group of articles published by NASA researchers in the journal Astrobiology describing history – and suggesting the Future – looking for life on exoplanets or stars in orbit. Sun.
The research effort is coordinated by Nexus for the Science of Exoplanets Systems of NASA, or NExSS, a global network dedicated to finding new ways to study the secular question: "Are we we alone?
A theme through the research and the discussions that underlie it is the need to consider the planets in an integrated way, involving multiple disciplines and perspectives.
"In order for life to be detectable in a distant world, it must dramatically alter its planet in a way that we can detect," said UW astronomy professor Victoria Meadows, lead author of the journal. one of the articles and principal investigator of the Virtual Planetary Laboratory. VPL for short. "But for us to properly recognize the impact of life, we must also understand the planet and the star – the environmental context is the key."
The work done by NExSS researchers will help identify the measures and instruments needed to search for life using NASA's future flagship missions. The detection of the atmospheric signatures of some potentially habitable planets could take place before 2030, although the study of the planets is actually habitable, or that it has a longer life.
The articles are the result of two years of efforts by some of the world's leading researchers in astrobiology, planetary sciences, earth sciences, heliophysics, astrophysics, chemistry and biology, including several of the world's leading astrophysicists. UW and the Virtual Planetary Laboratory. The coordinated work was born from online meetings and a face-to-face workshop held in Seattle in July 2016.
The pace of exoplanet discoveries has been rapid, with more than 3,700 discoveries since 1992. NASA has formed the international NExSS network to focus various disciplines on understanding characterization and possibly looking for signs of life, called biosignatures, on the exoplanets.
Niki Parenteau, an astrobiologist and microbiologist at NASA's Ames Research Center, said the NExSS network has advanced the field of exoplanet biosignatures and promoted communication between researchers looking for signs of life on the body's system. solar and those seeking signs of life on the exoplanets. Moffett Field, California, and member of the VPL team. "This allowed to share the" lessons learned "by both communities."
The first article reviews the types of signatures that astrobiologists have proposed as a means of identifying life on an exoplanet. Scientists plan to look for two main types of signals: one is in the form of gases that life produces, such as oxygen produced by plants or photosynthetic microbes. The other might come from the light reflected by the life itself, such as the color of the leaves or pigments.
Such signatures can be seen on Earth from orbit, and astronomers study concepts of telescope concepts that might be able to detect them on planets around nearby stars. Meadows is a co-author, and the main author is Edward Schwieterman, a member of the VPL team who earned his PhD in astronomy and astrobiology from UW and is now a post-graduate researcher. Ph.D. at the University of California, Riverside.
Meadows is the lead author of the second article that discusses recent research on "false positives" and "false negatives" for biosignatures, or how nature could "trick" scientists into thinking that a planet would live without life, or vice versa.
In this article, Meadows and his co-authors examine how a planet could produce oxygen abiotically, or without life presence, and how the planets with life may not have the signature of oxygen that is abundant on Earth.
The purpose of the paper, said Mr. Meadows, was to discuss these changes in our understanding of biosignatures and propose a "more comprehensive" treatment. She said, "There are many things in the universe that could potentially put two atoms of oxygen together, not just photosynthesis – let's understand what they are. they are more likely to happen, and how can we avoid being fooled?
Schwieterman is co-author of this paper, as well as PhD students Jacob Lustig-Yaeger, Russell Deitrick and Andrew Lincowski.
With such anticipation, scientists are now better prepared to distinguish false positives from planets that truly welcome life.
Two other articles show how scientists are trying to formalize the lessons we have learned from Earth and extend them to the great diversity of worlds that we have not yet discovered.
David Catling, UW Professor of Space and Space Science, is the lead author of a paper that proposes a framework for evaluating exoplanet biosignatures, taking into account variables such as the chemicals present in the atmosphere, the presence of oceans and continents. PhD student Joshua Krissansen-Totton is a co-author.
By combining all this information in a systematic way, scientists can analyze whether data from a planet can be better explained statistically by the presence of life, or its absence.
"If future data from an exoplanet perhaps suggest life, what approach can distinguish if the existence of life is a near-certainty or if the planet is really as dead as a doornail? ? "Said Catling. "Basically, NASA asked us to determine how to assign a probability to the presence of exoplanet life, as a chance of 10, 50 or 90 percent." Our article presents a general method for doing so. "
The data collected by astronomers on exoplanets will be rare. They will not have samples of these distant worlds and, in many cases, will study the planet as a single point of light. By analyzing these imprints of the atmospheric gases and the surfaces incorporated in this light, they will discern as much as possible the properties of this exoplanet.
"Because life, planet and parent star are changing over time together, a biosignature is no longer a single target but a series of features of the system, "said Nancy Kiang, a biometeorologist at the University of Ottawa. NASA Goddard Institute in New York and member of the VPL team. . She said that more biologists and geologists will be needed to interpret the observations "where the processes of life will be adapted to the particular environmental context."
The last article deals with terrestrial and space telescopes that astronomers will use to search for life beyond the solar system. This includes a variety of observatories, from those in operation today to those that will be built decades into the future.
Taken together, this group of articles explains how the exoplanet community will evolve from their current assessments of the size and orbit of these distant worlds, to an in-depth analysis of their chemical makeup and, possibly, of their life.
"I'm excited to see how this research will progress over the next few decades," said Shawn Domagal-Goldman, an astrobiologist at NASA's Goddard Space Flight Center, Greenbelt, Maryland, and a member of the VPL team. He is also co-author of four of the five articles.
"NExSS has created a diverse network of scientists that will allow the community to more rigorously assess planets for biosignatures than would otherwise be possible."
NExSS is an interdisciplinary research coordination network of NASA.
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Based on a version of NASA. For more information, contact Meadows at [email protected] or Catling at [email protected].
Label (s): David Catling • Edward Schwieterman • Joshua Krissansen-Totton • NExSS • Nexus for the Science of Exoplanet Systems • Russell Deitrick • Victoria Meadows
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