In the search for potentially habitable worlds beyond our own solar system, astronomers from the Univesite de Montreal and University of Michigan announced a major new discovery this week of an apparent Earth-like planet orbiting a stable low-mass red dwarf just 48 light years away from us.
From phys.org:
"This is the first time we have ever seen a hint of an atmosphere on a habitable zone rocky or ice-rich exoplanet. Detecting atmospheres on small, rocky worlds is a major goal for JWST [James Webb Space Telescope] but these signals are much harder to see than for giant planet atmospheres," said Ryan MacDonald, NASA Sagan Fellow in the U-M Department of Astronomy, who was key in the analysis of LHS 1140 b's atmosphere.
"LHS 1140 b is one of the best small exoplanets in the habitable zone capable of supporting a thick atmosphere, and we might just have found evidence of air on this world."
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"Of all currently known temperate exoplanets, LHS 1140 b could well be our best bet to one day indirectly confirm liquid water on the surface of an alien world beyond our solar system," said Charles Cadieux, lead author of the science paper and doctoral student at Université de Montréal. "This would be a major milestone in the search for potentially habitable exoplanets."
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MacDonald conducted the atmospheric retrieval analysis that suggests LHS 1140 b has a nitrogen-rich atmosphere, potentially similar to the Earth's atmosphere, which is 78% nitrogen. While it is still only a tentative result, the presence of a nitrogen-rich atmosphere would suggest the planet has retained a substantial atmosphere, creating conditions that might support liquid water.
This discovery favors the water world/snowball scenario as the most plausible. Current models indicate that if LHS 1140 b has an Earth-like atmosphere, it would be a snowball planet with a bull's-eye ocean about 4,000 kilometers in diameter, equivalent to half the surface area of the Atlantic Ocean. The surface temperature at the center of this alien ocean could even be a comfortable 20 degrees Celsius.
Meanwhile in other space news concerning a future manned mission to Mars, also from phys.org:
Crew of NASA's earthbound simulated Mars habitat emerge after a year
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The quartet lived and worked inside the space of 1,700 square feet (157 square meters) to simulate a mission to the red planet, the fourth from the sun and a frequent focus of discussion among scientists and sci-fi fans alike concerning a possible voyage taking humans beyond our moon.
The first CHAPEA [Crew Health and Performance Exploration Analog] crew focused on establishing possible conditions for future Mars operations through simulated spacewalks, dubbed "Marswalks," as well as growing and harvesting vegetables to supplement their provisions and maintaining the habitat and their equipment.
They also worked through challenges a real Mars crew would be expected to experience including limited resources, isolation and delays in communication of up to 22 minutes with their home planet on the other side of the habitat's walls, NASA said.
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Brockwell, the crew's flight engineer, said the mission showed him the importance of living sustainably for the benefit of everyone on Earth.
"I'm very grateful to have had this incredible opportunity to live for a year within the spirit of planetary adventure towards an exciting future, and I'm grateful for the chance to live the idea that we must utilize resources no faster than they can be replenished and produce waste no faster than they can be processed back into resources," Brockwell said.
