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Will We Know if TRAPPIST-1e has Life?
The search for extrasolar planets is currently undergoing a seismic shift. With the deployment of the Kepler Space Telescope and the Transiting Exoplanet Survey Satellite (TESS), scientists discovered thousands of exoplanets, most of which were detected and confirmed using indirect methods. But in more recent years, and with the launch of the James Webb Space Telescope (JWST), the field has been transitioning toward one of characterization. In this process, scientists rely on emission spectra from exoplanet atmospheres to search for the chemical signatures we associate with life (biosignatures).
However, there’s some controversy regarding the kinds of signatures scientists should look for. Essentially, astrobiology uses life on Earth as a template when searching for indications of extraterrestrial life, much like how exoplanet hunters use Earth as a standard for measuring “habitability.” But as many scientists have pointed out, life on Earth and its natural environment have evolved considerably over time. In a recent paper, an international team demonstrated how astrobiologists could look for life on TRAPPIST-1e based on what existed on Earth billions of years ago.
The team consisted of astronomers and astrobiologists from the Global Systems Institute, and the Departments of Physics and Astronomy, Mathematics and Statistics, and Natural Sciences at the University of Exeter. They were joined by researchers from the School of Earth and Ocean Sciences at the University of Victoria and the Natural History Museum in London. The paper that describes their findings, “Biosignatures from pre-oxygen photosynthesizing life on TRAPPIST-1e,” will be published in the Monthly Notices of the Royal Astronomical Society (MNRAS).
The TRAPPIST-1 system has been the focal point of attention ever since astronomers confirmed the presence of three exoplanets in 2016, which grew to seven by the following year. As one of many systems with a low-mass, cooler M-type (red dwarf) parent star, there are unresolved questions about whether any of its planets could be habitable. Much of this concerns the variable and unstable nature of red dwarfs, which are prone to flare activity and may not produce enough of the necessary photons to power photosynthesis.
With so many rocky planets found orbiting red dwarf suns, including the nearest exoplanet to our Solar System (Proxima b), many astronomers feel these systems would be the ideal place to look for extraterrestrial life. At the same time, they’ve also emphasized that these planets would need to have thick atmospheres, intrinsic magnetic fields, sufficient heat transfer mechanisms, or all of the above. Determining if exoplanets have these prerequisites for life is something that the JWST and other next-generation telescopes – like the ESO’s proposed Extremely Large Telescope (ELT) – are expected to enable.
But even with these and other next-generation instruments, there is still the question of what biosignatures we should look for. As noted, our planet, its atmosphere, and all life as we know it have evolved considerably over the past four billion years. During the Archean Eon (ca. 4 to 2.5 billion years ago), Earth’s atmosphere was predominantly composed of carbon dioxide, methane, and volcanic gases, and little more than anaerobic microorganisms existed. Only within the last 1.62 billion years did the first multi-celled life appear and evolve to its present complexity.
Moreover, the number of evolutionary steps (and their potential difficulty) required to get to higher levels of complexity means that many planets may never develop complex life. This is consistent with the Great Filter Hypothesis, which states that while life may be common in the Universe, advanced life may not. As a result, simple microbial biospheres similar to those that existed during the Archean could be the most common. The key, then, is to conduct searches that would isolate biosignatures consistent with primitive life and the conditions that were common to Earth billions of years ago.
This artistic conception illustrates large asteroids penetrating Earth’s oxygen-poor atmosphere. Credit: SwRI/Dan Durda/Simone MarchiAs Dr. Jake Eager-Nash, a postdoctoral research fellow at the University of Victoria and the lead author of the study, explained to Universe Today via email:
“I think the Earth’s history provides many examples of what inhabited exoplanets may look like, and it’s important to understand biosignatures in the context of Earth’s history as we have no other examples of what life on other planets would look like. During the Archean, when life is believed to have first emerged, there was a period of up to around a billion years before oxygen-producing photosynthesis evolved and became the dominant primary producer, oxygen concentrations were really low. So if inhabited planets follow a similar trajectory to Earth, they could spend a long time in a period like this without biosignatures of oxygen and ozone, so it’s important to understand what Archean-like biosignatures look like.”
For their study, the team crafted a model that considered Archean-like conditions and how the presence of early life forms would consume some elements while adding others. This yielded a model in which simple bacteria living in oceans consume molecules like hydrogen (H) or carbon monoxide (CO), creating carbohydrates as an energy source and methane (CH4) as waste. They then considered how gases would be exchanged between the ocean and atmosphere, leading to lower concentrations of H and CO and greater concentrations of CH4. Said Eager-Nash:
“Archean-like biosignatures are thought to require the presence of methane, carbon dioxide, and water vapor would be required as well as the absence of carbon monoxide. This is because water vapor gives you an indication there is water, while an atmosphere with both methane and carbon monoxide indicates the atmosphere is in disequilibrium, which means that both of these species shouldn’t exist together in the atmosphere as atmospheric chemistry would convert all of the one into the other, unless there is something, like life that maintains this disequilibrium. The absence of carbon monoxide is important as it is thought that life would quickly evolve a way to consume this energy source.”
Artist’s impression of Earth in the early Archean with a purplish hydrosphere and coastal regions. Even in this early period, life flourished and was gaining complexity. Credit: Oleg KuznetsovWhen the concentration of gases is higher in the atmosphere, the gas will dissolve into the ocean, replenishing the hydrogen and carbon monoxide consumed by the simple life forms. As biologically produced methane levels increase in the ocean, it will be released into the atmosphere, where additional chemistry occurs, and different gases are transported around the planet. From this, the team obtained an overall composition of the atmosphere to predict which biosignatures could be detected.
“What we find is that carbon monoxide is likely to be present in the atmosphere of an Archean-like planet orbiting an M-Dwarf,” said Eager-Nash. “This is because the host star drives chemistry that leads to higher concentrations of carbon monoxide compared to a planet orbiting the Sun, even when you have life-consuming this [compound].”
For years, scientists have considered how a circumsolar habitable zone (CHZ) could be extended to include Earth-like conditions from previous geological periods. Similarly, astrobiologists have been working to cast a wider net on the types of biosignatures associated with more ancient life forms (such as retinal-photosynthetic organisms). In this latest study, Eager-Nash and his colleagues have established a series of biosignatures (water, carbon monoxide, and methane) that could lead to the discovery of life on Archean-era rocky planets orbiting Sun-like and red dwarf suns.
Further Reading: arXiv
The post Will We Know if TRAPPIST-1e has Life? appeared first on Universe Today.
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Earth Day 2024: Witness our changing planet in 12 incredible satellite images
NASA Nurtures Promising Tech Ideas from Small Businesses
New space technology ideas emerge every day from innovators across the country, and NASA’s Small Business Innovation Research (SBIR) program on Monday selected more than 100 projects for funding. This program offers small businesses in the United States early-stage funding and support to advance the agency’s goals of exploring the unknown in air and space while returning benefits to Earth.
Specifically, NASA’s SBIR program awarded $93.5 million in Phase II contracts to bring 107 new ideas to life from 95 selected small businesses. Of these businesses, nearly 80% have less than 50 employees, and 21% are receiving their first Phase II award, valued at up to $850,000 each. Each small business was also eligible to apply for up to $50,000 in Technical and Business Assistance program funding to help find new market opportunities and shape their commercialization roadmap.
“We are thrilled to support this diverse set of companies as they work diligently to bring their technologies to market,” said Jenn Gustetic, director of Early Stage Innovation and Partnerships with NASA’s Space Technology Mission Directorate (STMD) at the agency’s headquarters in Washington. “Inclusive innovation is integral to mission success at NASA, and we’re excited to see that 29% of the awardees are from underrepresented groups, including 11% women-owned businesses.”
In Phase II, awardees will build on their success from the program’s first phase to bring their technologies closer to real-world use. The companies have 24 months to execute their plans, which focus on their technologies’ path to commercialization.
For example, NASA selected women-owned and first-time NASA Phase II awardee nou Systems, Inc. in Huntsville, Alabama, for its genetic testing instrument. While portable genetic sequencing already exists, field sequencing – that would allow DNA analysis anywhere on Earth or off planet – remains unfeasible as the preparation of the DNA Library remains an intensely manual process, needing a trained wet lab technician and several pieces of laboratory equipment. The Phase II technology takes advantage of several cross-enabling technologies, creating an instrument to automate the genetic sequencing process.
“Our program works directly with small businesses to forge innovative concepts and technologies that drive impact for NASA projects as well as a myriad of commercial endeavors,” said Jason L. Kessler, program executive for NASA’s SBIR and Small Business Technology Transfer (STTR) program at NASA Headquarters. “This collaboration results in realized opportunities not only for NASA but all of humanity.”
This includes technologies aiming to reduce astronaut workload and improve robotic scientific endeavors on the Moon and Mars. PickNik Inc. based in Boulder, Colorado, will use its Phase II award to continue developing a hardware-agnostic platform for supervised autonomy that empowers humans to command a remote robot to complete complex tasks with minimal input, which could support the Artemis program. Outside of NASA, PickNik’s software product may be of interest to commercial space customers working on low Earth orbit destinations, in-space servicing, and more, as well as on Earth in areas like warehouse management, oil rig maintenance, and deep-sea exploration.
The NASA SBIR program is open to U.S. small businesses to develop an innovation or technology. The program is part of STMD and managed by NASA’s Ames Research Center in California’s Silicon Valley.
To learn more about the NASA SBIR program, visit:
-end-
Jimi Russell
Headquarters, Washington
james.j.russell@nasa.gov
202-358-1600
Our Beautiful Water World
This Jan. 30, 2012 image of Earth was created from photographs taken by the Visible/Infrared Imager Radiometer Suite (VIIRS) instrument aboard the Suomi NPP satellite. Many features of North America and the Western Hemisphere are particularly visible. The composite was created from the data collected during four orbits of the robotic satellite taken earlier in January 2012 and digitally projected onto the globe.
VIIRS collects visible and infrared imagery along with global observations of Earth’s land, atmosphere, cryosphere, and ocean, extending observational records collected by similar instruments aboard previously launched satellites, such as NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) and NOAA’s Advanced Very High Resolution Radiometer (AVHRR).
Help us celebrate Earth Day by sharing a #GlobalSelfie.
Image Credit: NASA
Our Beautiful Water World
Watch a Hotspot Orbit Our Galaxy's Black Hole
Astronomers have reconstructed a 3D video of hot gas orbiting a stone’s throw away from our galaxy’s central black hole.
The post Watch a Hotspot Orbit Our Galaxy's Black Hole appeared first on Sky & Telescope.
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Six mind-blowing facts about Galileo
Did you know Galileo was born in the Netherlands in the 1990s? Europe’s own global navigation satellite system was developed in ESA’s technological heart, ESTEC, in Noordwijk, almost three decades ago. Since then, it has grown to become one of the most complex and critical infrastructures ever built in Europe, as well as the largest European satellite constellation and ground segment.
The Earth Day 2024 Google doodle is a climate change reminder
‘Vast and Rich:’ Studying the Ocean With NASA Computer Simulations
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A tool developed at NASA’s Advanced Supercomputing division provides researchers with a global view of their ocean simulation in high resolution. In this part of the global visualization, the Gulf Stream features prominently. Surface water speeds are shown ranging from 0 meters per second (dark blue) to 1.25 meters (about 4 feet) per second (cyan). The video is running at one simulation day per second. The data used comes from the Estimating the Circulation and Climate of the Ocean (ECCO) consortium. Credits: NASA/Bron Nelson, David Ellsworth“Every time I help with visualizing [ocean] simulation data, I learn about an entirely new area of ocean or climate research, and I’m reminded of how vast and rich this area of research is. And…the real magic happens at the intersection and interaction of simulated and observed data.
It is a great honor – and a thrill – to collaborate with devoted, world-class scientists doing such important, cutting-edge research and sometimes to even help them learn something new about their science.”
Dr. Nina McCurdy
Data visualization scientist with the NASA Advanced Supercomputing division at NASA’s Ames Research Center in California’s Silicon Valley
This Earth Day, learn more about the work of Nina and other Ames researchers studying our planet: Celebrating Our Ocean World at NASA in Silicon Valley.
Biden Kicks Off Earth Week with Solar Funding, Expanding Climate Corps
The Biden administration is marking Earth Week with announcements of solar power funding for lower-income communities, an expansion of the Climate Corps and Clean Air Act rules
Why is Methane Seeping on Mars? NASA Scientists Have New Ideas
Maksym Bocharov
The most surprising revelation from NASA’s Curiosity Mars Rover — that methane is seeping from the surface of Gale Crater — has scientists scratching their heads.
Living creatures produce most of the methane on Earth. But scientists haven’t found convincing signs of current or ancient life on Mars, and thus didn’t expect to find methane there. Yet, the portable chemistry lab aboard Curiosity, known as SAM, or Sample Analysis at Mars, has continually sniffed out traces of the gas near the surface of Gale Crater, the only place on the surface of Mars where methane has been detected thus far. Its likely source, scientists assume, are geological mechanisms that involve water and rocks deep underground.
If that were the whole story, things would be easy. However, SAM has found that methane behaves in unexpected ways in Gale Crater. It appears at night and disappears during the day. It fluctuates seasonally, and sometimes spikes to levels 40 times higher than usual. Surprisingly, the methane also isn’t accumulating in the atmosphere: ESA’s (the European Space Agency) ExoMars Trace Gas Orbiter, sent to Mars specifically to study the gas in the atmosphere, has detected no methane.
Why do some science instruments detect methane on the Red Planet while others don’t?
“It’s a story with a lot of plot twists,” said Ashwin Vasavada, Curiosity’s project scientist at NASA’s Jet Propulsion Laboratory in Southern California, which leads Curiosity’s mission.
Methane keeps Mars scientists busy with lab work and computer modeling projects that aim to explain why the gas behaves strangely and is detected only in Gale Crater. A NASA research group recently shared an interesting proposal.
Reporting in a March paper in the Journal of Geophysical Research: Planets, the group suggested that methane — no matter how it’s produced — could be sealed under solidified salt that might form in Martian regolith, which is “soil” made of broken rock and dust. When temperature rises during warmer seasons or times of day, weakening the seal, the methane could seep out.
Led by Alexander Pavlov, a planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, the researchers suggest the gas also can erupt in puffs when seals crack under the pressure of, say, a rover the size of a small SUV driving over it. The team’s hypothesis may help explain why methane is detected only in Gale Crater, Pavlov said, given that’s it’s one of two places on Mars where a robot is roving and drilling the surface. (The other is Jezero Crater, where NASA’s Perseverance rover is working, though that rover doesn’t have a methane-detecting instrument.)
Pavlov traces the origin of this hypothesis to an unrelated experiment he led in 2017, which involved growing microorganisms in a simulated Martian permafrost (frozen soil) infused with salt, as much of Martian permafrost is.
Pavlov and his colleagues tested whether bacteria known as halophiles, which live in saltwater lakes and other salt-rich environments on Earth, could thrive in similar conditions on Mars.
The microbe-growing results proved inconclusive, he said, but the researchers noticed something unexpected: The top layer of soil formed a salt crust as salty ice sublimated, turning from a solid to a gas and leaving the salt behind.
Permafrost on Mars and Earth
“We didn’t think much of it at the moment,” Pavlov said, but he remembered the soil crust in 2019, when SAM’s tunable laser spectrometer detected a methane burst no one could explain.
“That’s when it clicked in my mind,” Pavlov said. And that’s when he and a team began testing the conditions that could form and crack hardened salt seals.
Pavlov’s team tested five samples of permafrost infused with varying concentrations of a salt called perchlorate that’s widespread on Mars. (There’s likely no permafrost in Gale Crater today, but the seals could have formed long ago when Gale was colder and icier.) The scientists exposed each sample to different temperatures and air pressure inside a Mars simulation chamber at NASA Goddard.
Periodically, Pavlov’s team injected neon, a methane analog, underneath the soil sample and measured the gas pressure below and above it. Higher pressure beneath the sample implied the gas was trapped. Ultimately, a seal formed under Mars-like conditions within three to 13 days only in samples with 5% to 10% perchlorate concentration.
This is a sample of mock Martian regolith, which is “soil” made of broken rock and dust. It’s one of five samples that scientists infused with varying concentrations of a salt called perchlorate that’s widespread on Mars. They exposed each sample to Mars-like conditions in the Mars simulation chamber at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. The brittle clumps in the sample above show that a seal of salt did not form in this sample because the concentration of salt was too low. NASA/Alexander Pavlov This image is of another sample of mock Martian “soil” after it was removed from the Mars simulation chamber. The surface is sealed with a solid crust of salt. Alexander Pavlov and his team found that a seal formed after a sample spent three to 13 days under Mars-like conditions, and only if it had 5% to 10% perchlorate salt concentration. The color is lighter in the center where the sample was scratched with a metal pick. The light color indicates a drier soil underneath the top layer, which absorbed moisture from the air as soon as the sample was removed from the simulation chamber, turning brown. NASA/Alexander PavlovThat’s a much higher salt concentration than Curiosity has measured in Gale Crater. But regolith there is rich in a different type of salt minerals called sulfates, which Pavlov’s team wants to test next to see if they can also form seals.
Curiosity rover has arrived at a region believed to have formed as Mars’ climate was drying.
Improving our understanding of methane generation and destruction processes on Mars is a key recommendation from the 2022 NASA Planetary Mission Senior Review, and theoretical work like Pavlov’s is critical to this effort. However, scientists say they also need more consistent methane measurements.
SAM sniffs for methane only several times a year because it is otherwise busy doing its primary job of drilling samples from the surface and analyzing their chemical makeup.
In 2018, NASA announced that the Sample Analysis at Mars chemistry lab aboard the Curiosity Rover discovered ancient organic molecules that had been preserved in rocks for billions of years. Findings like this one help scientists understand the habitability of early Mars and pave the way for future missions to the Red Planet.Credit: NASA’s Goddard Space Flight Center
Download this video in HD formats from NASA Goddard’s Scientific Visualization Studio
“Methane experiments are resource intensive, so we have to be very strategic when we decide to do them,” said Goddard’s Charles Malespin, principal investigator for SAM.
Yet, to test how often methane levels spike, for instance, would require a new generation of surface instruments that measure methane continuously from many locations across Mars, scientists say.
“Some of the methane work will have to be left to future surface spacecraft that are more focused on answering these specific questions,” Vasavada said.
By Lonnie Shekhtman
NASA’s Goddard Space Flight Center, Greenbelt, Md.