Life beyond Earth: No plate tectonics, no problem

Scientists prepare to look in unexpected places for ‘exoplanet biosignatures’.

An artist’s impression of Ross 128 b, a temperate, rocky planet about 11 light-years from Earth that could have the necessary conditions for maintaining liquid surface water. (Photo courtesy of European Southern Observatory/M. Kornmesser)
This artist’s impression shows the temperate planet Ross 128 b, with its red dwarf parent star in the background. This planet, which lies only 11 light-years from Earth, was found by a team using ESO’s unique planet-hunting HARPS instrument. The new world is now the second-closest temperate planet to be detected after Proxima b. It is also the closest planet to be discovered orbiting an inactive red dwarf star, which may increase the likelihood that this planet could potentially sustain life. Ross 128 b will be a prime target for ESO’s Extremely Large Telescope, which will be able to search for biomarkers in the planet's atmosphere.

Researchers searching for life on removed planets are making arrangements to look non-Earth-like planets in view of disclosures inside our close planetary system that are testing long-standing thoughts regarding tenable zones, plate tectonics and then some.

In another paper distributed online this week, Rice University geophysicist Adrian Lenardic and in excess of twelve co-creators plot a way for both discovering potential life signs around different stars and deciding how likely it is that those signs are caused by outsider life. The paper, “Exoplanet Biosignatures: Future Directions,” is accessible on the web and due to be distributed in Astrobiology.

Lenardic, who specializes in studying planetary dynamics, also authored an associated paper said, ”

Volcanic-Tectonic Modes and Planetary Life Potential,” that will be published as a chapter in the upcoming “Handbook of Exoplanets” from Springer Publishing.

“It used to be the thought that life could only exist in a narrow zone near a planet’s star because you need to be there to maintain liquid water,” said Lenardic, professor of Earth, environmental and planetary sciences. “Then, we send Voyager out to a moon of Jupiter and, lo and behold, it shows strong indications of a subsurface ocean. That’s because there is another energy source that did not get its proper due — tidal forces from the intense gravitational pull of Jupiter.

“This has opened up the range over our own solar system in which life can exist, and I think a lot of the gist of the forthcoming papers is that much of what we’re seeing is expanding the zone and expanding our thinking about the conditions needed for life. So, as we look for life around other stars, we should also expand our search strategies or we might miss something.”

Stargazers have recorded in excess of 3,700 planets around far-off stars. The 21-foot measurement reflect on the James Webb Space Telescope, which is set to dispatch in 2019, will have the capacity to analyze the climates of rough planets around far-off stars, and stargazers are now planning future missions and instruments that will search for particular barometrical marks of life.

“An objective was to outline the issue,” Lenardic said of the new biosignature paper, which sprang from an exoplanet workshop that united a scope of researchers. “The workshop group needed to concoct methods for appointing a probability of life in view of a given arrangement of perceptions of a far-off planet.”

Adrian Lenardic (Photo by Jeff Fitlow/Rice University)
Adrian Lenardic (Photo by Jeff Fitlow/Rice University)

The search for life is a team sport that involves biologists, astronomers, planetary scientists and others who collaborate through groups such as NASA’s Nexus for Exoplanet System Science (ECSS) project and the European Space Agency’s International Summer School in Astrobiology.

“When I teach planetary science, one question I actually give students is, ‘What is life? Give me a definition.’ And it’s not easy,” Lenardic said. He noted that students and working scientists have put forward a range of answers.

“But if we can agree on one thing, it’s that life needs energy,” he said. “We’ve thought about the sun as an energy source for a long time, and we’ve come to appreciate a planet’s internal energy, which comes from the decay of radioactive elements within its rocky interior. Jupiter’s moons have taught us to also appreciate tidal forcing, and we’re starting to find exoplanets that have orbits that allow for significant tidal forcing.”

Lenardic said plate tectonics, much like the narrow habitable zone, is another long-held criterion for planetary habitability that is being challenged by recent findings.

On Earth, plate tectonics assumes a part in balancing atmosphere, yet the possibility that plate tectonics is significant forever is tested by progressively advanced models of planetary atmospheres. For instance, in a January contemplate in the Journal of Geophysical Research, Lenardic and partners indicated how water could be kept up on universes without plate tectonics.

The part in the up and coming “Handbook of Exoplanets” additionally investigates this thought by considering planetary life potential under a scope of structural modes that contrast from Earth’s.

“I’m an optimist,” Lenardic said. “We’re at the first point in our history as humans where we might actually have some observations from other planets that we can use to test any of these ideas about life beyond our own. It can be easy to be Earth-centric and assume that life requires a planet like our own.”

“But what we are seeing within our solar system is causing us to question this. One of the things I have learned from the history of exploring our own solar system is to be prepared for a surprise. As we move beyond our solar system, in our search for life, that lesson is driving us to adapt our search strategies.”