24/7 Space News
EXO WORLDS
A carbon-lite atmosphere could be a sign of water and life on other terrestrial planets
In the search for extraterrestrial life, MIT scientists say a planet's carbon-lite atmosphere, relative to its neighbors, could be a sure and detectable signal of habitability.
ADVERTISEMENT
     
A carbon-lite atmosphere could be a sign of water and life on other terrestrial planets
by Jennifer Chu | MIT News
Boston MA (SPX) Jan 01, 2024

Scientists at MIT, the University of Birmingham, and elsewhere say that astronomers' best chance of finding liquid water, and even life on other planets, is to look for the absence, rather than the presence, of a chemical feature in their atmospheres.

The researchers propose that if a terrestrial planet has substantially less carbon dioxide in its atmosphere compared to other planets in the same system, it could be a sign of liquid water - and possibly life - on that planet's surface.

What's more, this new signature is within the sights of NASA's James Webb Space Telescope (JWST). While scientists have proposed other signs of habitability, those features are challenging if not impossible to measure with current technologies. The team says this new signature, of relatively depleted carbon dioxide, is the only sign of habitability that is detectable now.

"The Holy Grail in exoplanet science is to look for habitable worlds, and the presence of life, but all the features that have been talked about so far have been beyond the reach of the newest observatories," says Julien de Wit, assistant professor of planetary sciences at MIT. "Now we have a way to find out if there's liquid water on another planet. And it's something we can get to in the next few years."

The team's findings appear in Nature Astronomy. De Wit co-led the study with Amaury Triaud of the University of Birmingham in the UK. Their MIT co-authors include Benjamin Rackham, Prajwal Niraula, Ana Glidden Oliver Jagoutz, Matej Pec, Janusz Petkowski, and Sara Seager, along with Frieder Klein at the Woods Hole Oceanographic Institution (WHOI), Martin Turbet of Ecole Polytechnique in France, and Franck Selsis of the Laboratoire d'astrophysique de Bordeaux.

Beyond a glimmer
Astronomers have so far detected more than 5,200 worlds beyond our solar system. With current telescopes, astronomers can directly measure a planet's distance to its star and the time it takes it to complete an orbit. Those measurements can help scientists infer whether a planet is within a habitable zone. But there's been no way to directly confirm whether a planet is indeed habitable, meaning that liquid water exists on its surface.

Across our own solar system, scientists can detect the presence of liquid oceans by observing "glints" - flashes of sunlight that reflect off liquid surfaces. These glints, or specular reflections, have been observed, for instance, on Saturn's largest moon, Titan, which helped to confirm the moon's large lakes.

Detecting a similar glimmer in far-off planets, however, is out of reach with current technologies. But de Wit and his colleagues realized there's another habitable feature close to home that could be detectable in distant worlds.

"An idea came to us, by looking at what's going on with the terrestrial planets in our own system," Triaud says.

Venus, Earth, and Mars share similarities, in that all three are rocky and inhabit a relatively temperate region with respect to the sun. Earth is the only planet among the trio that currently hosts liquid water. And the team noted another obvious distinction: Earth has significantly less carbon dioxide in its atmosphere.

"We assume that these planets were created in a similar fashion, and if we see one planet with much less carbon now, it must have gone somewhere," Triaud says. "The only process that could remove that much carbon from an atmosphere is a strong water cycle involving oceans of liquid water."

Indeed, the Earth's oceans have played a major and sustained role in absorbing carbon dioxide. Over hundreds of millions of years, the oceans have taken up a huge amount of carbon dioxide, nearly equal to the amount that persists in Venus' atmosphere today. This planetary-scale effect has left Earth's atmosphere significantly depleted of carbon dioxide compared to its planetary neighbors.

"On Earth, much of the atmospheric carbon dioxide has been sequestered in seawater and solid rock over geological timescales, which has helped to regulate climate and habitability for billions of years," says study co-author Frieder Klein.

The team reasoned that if a similar depletion of carbon dioxide were detected in a far-off planet, relative to its neighbors, this would be a reliable signal of liquid oceans and life on its surface.

"After reviewing extensively the literature of many fields from biology, to chemistry, and even carbon sequestration in the context of climate change, we believe that indeed if we detect carbon depletion, it has a good chance of being a strong sign of liquid water and/or life," de Wit says.

A roadmap to life
In their study, the team lays out a strategy for detecting habitable planets by searching for a signature of depleted carbon dioxide. Such a search would work best for "peas-in-a-pod" systems, in which multiple terrestrial planets, all about the same size, orbit relatively close to each other, similar to our own solar system. The first step the team proposes is to confirm that the planets have atmospheres, by simply looking for the presence of carbon dioxide, which is expected to dominate most planetary atmospheres.

"Carbon dioxide is a very strong absorber in the infrared, and can be easily detected in the atmospheres of exoplanets," de Wit explains. "A signal of carbon dioxide can then reveal the presence of exoplanet atmospheres."

Once astronomers determine that multiple planets in a system host atmospheres, they can move on to measure their carbon dioxide content, to see whether one planet has significantly less than the others. If so, the planet is likely habitable, meaning that it hosts significant bodies of liquid water on its surface.

But habitable conditions doesn't necessarily mean that a planet is inhabited. To see whether life might actually exist, the team proposes that astronomers look for another feature in a planet's atmosphere: ozone.

On Earth, the researchers note that plants and some microbes contribute to drawing carbon dioxide, although not nearly as much as the oceans. Nevertheless, as part of this process, the lifeforms emit oxygen, which reacts with the sun's photons to transform into ozone - a molecule that is far easier to detect than oxygen itself.

The researchers say that if a planet's atmosphere shows signs of both ozone and depleted carbon dioxide, it likely is a habitable, and inhabited world.

"If we see ozone, chances are pretty high that it's connected to carbon dioxide being consumed by life," Triaud says. "And if it's life, it's glorious life. It would not be just a few bacteria. It would be a planetary-scale biomass that's able to process a huge amount of carbon, and interact with it."

The team estimates that NASA's James Webb Space Telescope would be able to measure carbon dioxide, and possibly ozone, in nearby, multiplanet systems such as TRAPPIST-1 - a seven-planet system that orbits a bright star, just 40 light years from Earth.

"TRAPPIST-1 is one of only a handful of systems where we could do terrestrial atmospheric studies with JWST," de Wit says. "Now we have a roadmap for finding habitable planets. If we all work together, paradigm-shifting discoveries could be done within the next few years."

Research Report:"Atmospheric carbon depletion as a tracer of water oceans and biomass on temperate terrestrial exoplanets"

Related Links
MIT Kavli Institute for Astrophysics and Space Research
Lands Beyond Beyond - extra solar planets - news and science
Life Beyond Earth

Subscribe Free To Our Daily Newsletters

RELATED CONTENT
The following news reports may link to other Space Media Network websites.
EXO WORLDS
Astrophysicists publish Kepler Giant Planet Search, an aid to 'figure out where to find life'
Notre Dame IN (SPX) Dec 21, 2023
A team of astrophysicists led by Lauren Weiss, assistant professor in the Department of Physics and Astronomy at the University of Notre Dame, created the first-ever catalog of small, Earth-like planets with Jupiter-like siblings (planets that share the same star) - a critical component in the search for life elsewhere in our universe. Forthcoming in the Astrophysical Journal, the Kepler Giant Planet Search took a decade to complete. "This catalog is the first of its kind and an unprecedente ... read more

ADVERTISEMENT
ADVERTISEMENT
EXO WORLDS
Designing the 'perfect' meal to feed long-term space travelers

NASA Revamps Contracts with Blue Origin and Starlab for LEO Station Projects Post-ISS Era

Exploring Venus and Beyond: NASA Funds Innovative Space Concepts for 2024

Insect compasses, fire-fighting vines: 2023's nature-inspired tech

EXO WORLDS
SpaceX sues to stop US hearing over fired workers

DTI Develops Innovative Plasma Engine for Spacecraft: Reduces Earth Fuel Dependency

ULA's Vulcan Centaur launches first American Moon lander in over 50 years

SpaceX set for Falcon Heavy USSF-52 mission to launch X-37B military space plane

EXO WORLDS
Sols 4059-4061: New Year, Old Challenges

Sols 4056-4058 Blog: "Ringing" in a New Year

Recent volcanism on Mars reveals a planet more active than previously thought

Sussex research takes us a step closer to sustaining human life on Mars

EXO WORLDS
China begins 2024 with key Kuaizhou 1A satellite launch

Shenzhou XVII astronauts set for their first spacewalk

China's commercial space sector achieves milestones with series of successful launches

China's space programme: Five things to know

EXO WORLDS
Euroconsult forecasts $75 Billion in growth for Middle East's Space Sector by 2032

Terran Orbital Reports Key Payment from Rivada and Strong Year-End Cash Position

First Batch of Starlink Satellites for Direct-to-Cell Service Launched by SpaceX

Wiseband and Rivada Space Networks join forces for Middle Eastern network expansion

EXO WORLDS
Rocket Lab to launch Space Situational Awareness mission for Spire and NorthStar

Researchers 3D print components for a portable mass spectrometer

L-SAR 01 Satellite Group Begins Operations, Enhancing China's Disaster Response

GESTRA space radar successfully enters final test phase

EXO WORLDS
A carbon-lite atmosphere could be a sign of water and life on other terrestrial planets

Three iron rings in a planet-forming disk

Is oxygen the cosmic key to alien technology?

Astronomers Discover Early Ring and Spiral Structures in Young Planetary Disks

EXO WORLDS
New images reveal what Neptune and Uranus really look like

Researchers reveal true colors of Neptune, Uranus

The PI's Perspective: The Long Game

Webb rings in the holidays with the ringed planet Uranus

Subscribe Free To Our Daily Newsletters


ADVERTISEMENT



The content herein, unless otherwise known to be public domain, are Copyright 1995-2023 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.