Tag: Astrobiology

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Cosmic Space

Hubble uses eclipse to practice hunt for alien life

An illustration shows the Hubble Space Telescope against the background of a total lunar eclipse. (NASA / ESA / M. Kornmesser)

Astronomers made use of the Hubble Space Telescope — and a total lunar eclipse — to rehearse their routine for seeking signs of life in alien atmospheres.

You’ll be relieved to know that the experiment, conducted on Jan. 20-21, 2019, determined that there are indeed signs of life on Earth.

The evidence came in the form of a strong spectral fingerprint for ozone. To detect that ultraviolet fingerprint, Hubble didn’t look at Earth directly. Instead, it analyzed the dim reddish light that was first refracted by Earth’s atmosphere, and then reflected back by the moon during last year’s lunar eclipse.

“Finding ozone is significant because it is a photochemical byproduct of molecular oxygen, which is itself a byproduct of life,” said Allison Youngblood of the Laboratory for Atmospheric and Space Physics in Boulder, Colo., lead researcher of Hubble’s observations.

Other ground-based telescopes made spectroscopic observations at other wavelengths during the eclipse. They were looking for the fingerprints of different atmospheric ingredients linked to life’s presence, such as oxygen and methane.

This wasn’t just an academic exercise. Astronomers hope future observatories, such as the James Webb Space Telescope and the Roman Space Telescope, will be able to detect life’s fingerprints in the atmospheres of faraway exoplanets. But that takes practice.

“One of NASA’s major goals is to identify planets that could support life,” Youngblood said in a Hubble news release. “But how would we know a habitable or an uninhabited planet if we saw one? What would they look like with the techniques that astronomers have at their disposal for characterizing the atmospheres of exoplanets? That’s why it’s important to develop models of Earth’s spectrum as a template for categorizing atmospheres on extrasolar planets.”

Check out the news release for further details, or delve into the research paper published today in The Astronomical Journal. And to learn more about how lunar eclipses work, check out this “Inconstant Moon” interactive (after you enable Flash in your browser).

This report was published on Cosmic Log. Accept no substitutes.

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SETI deals with new tools and new troubles

Two PANOSETI telescopes are installed in the recently renovated Astrograph Dome at the Lick Observatory in California. PANOSETI will use a configuration of many SETI telescopes to allow simultaneous monitoring of the entire observable sky. (© Laurie Hatch Photo via UCSD)

The search for extraterrestrial intelligence, better known as SETI, is taking advantage of a widening array of strategies — ranging from sophisticated laser searches, to a new type of wide-angle optical observatory, to arrangements to conduct the search simultaneously with other scientific efforts.

But new technologies are also bringing new challenges: For example, how will radio astronomers deal with the noise created by a fast-growing number of satellites in low Earth orbit?

The technological pluses and minuses for the SETI quest, and for other strategies aimed at detecting life beyond our solar system, took the spotlight in Seattle last weekend during a session presented at the annual meeting of the American Association for the Advancement of Science.

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Space bits suggest CO2 blanketed ancient Earth

Iron-rich spherules like the ones shown here can contain chemical clues about the composition of the early Earth’s atmosphere. (UW Photo / Don Brownlee)

Today, rising carbon dioxide in the atmosphere is a cause for concern, but 2.7 billion years ago, high levels of CO2 probably kept our planet warm enough for life even though the sun was about 20% fainter than it is today.

A newly published study, based on analyses of ancient micrometeorites and a fresh round of computer modeling, estimates just how high those CO2 levels were. The likeliest level is somewhere in excess of 70% CO2, scientists from the University of Washington report today in the open-access journal Science Advances.

Based on the modeling, global mean temperatures would have been in the mid-80s Fahrenheit (roughly 30 degrees Celsius).

All that is good news for astrobiologists, because such an environment matches up well with the picture that scientists have of Earth during what’s known as the Archean Eon. The high CO2 levels wouldn’t be livable for us humans, but they’d be fine for the early organisms that ruled the Earth before oxygen levels rose.

The findings “could also inform our understanding of Earth-like exoplanets and their potential habitability,” said the study team, led by UW researcher Owen Lehmer.

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Did life emerge from carbonate-rich lakes?

Eastern California’s Mono Lake has no outflow, allowing salts to build up over time. The high salts in this carbonate-rich lake can grow into pillars. (Matthew Dillon Photo via Flickr / AAAS)

Where did life on Earth get its start? In a newly published study, researchers from the University of Washington argue that carbonate-rich lakes would have been the best place for life’s chemical building blocks to come together.

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Scientists fine-tune standards for habitable planets

An artist’s conception shows a hypothetical planet with two moons orbiting within the habitable zone of an M-dwarf star. (NASA / Harvard-Smithsonian Center for Astrophysics Illustration / D. Aguilar)

Astronomers have identified thousands of stars that have planets, and that number could mushroom even faster when waves of next-generation telescopes come online. But where are the best places to look for life?

A newly released study focuses on the most plentiful category of stars in our Milky Way galaxy — M-dwarf stars, also known as red dwarfs — and delivers good news as well as bad news for astrobiologists.

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NASA decides to send a nuclear drone to Titan

An artist’s conception shows the Dragonfly probe on the dunes of Titan. (NASA / JHUAPL Illustration)

Update for Nov. 28, 2023: NASA has postponed formal confirmation of the Dragonfly mission to Titan mission until mid-2024, and the launch readiness date is now estimated to be in 2028 rather than 2026.

Previously: NASA has chosen to commit up to $850 million to creating an interplanetary probe unlike any seen before: a rotor-equipped spacecraft that will fly through the smoggy atmosphere of Titan, Saturn’s biggest moon.

The Dragonfly mission will be managed by Johns Hopkins University’s Applied Physics Laboratory on NASA’s behalf, with its launch scheduled for 2026 on a rocket to be named later, and its landing due amid the dunes of Titan in 2034.

This won’t be the first landing on Titan: That happened back in 2005, when the Cassini spacecraft dropped off the Huygens lander to send back the first pictures from the moon’s cloud-obscured surface. Observations from Cassini and Huygens confirmed that chilly Titan held rivers and lakes of liquid methane and ethane, and that methane fell like rain on the icy terrain.

“Titan is the only other place in the solar system known to have an Earthlike cycle of liquids flowing across its surface,” Thomas Zurbuchen, NASA’s associate administrator for the Science Mission Directorate, said in a tweet. “Dragonfly will explore the processes that shape this extraordinary environment filled with organic compounds – the building blocks to life as we know it.”

Today’s announcement was the climax of a years-long process to choose the next mission for NASA’s New Horizons portfolio, which supports projects costing no more than $850 million. Past selections include the New Horizons mission to Pluto and the Kuiper Belt, the Juno mission to Jupiter. and the OSIRIS-REx mission to bring back a sample from asteroid Bennu.

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Cave-exploring rover tested for moon and Mars

NASA’s robotics team drives the test rover, CaveR, into Valentine Cave at Lava Beds National Monument in California. One of the CaveR engineers is perched on a lava ledge, a marker of one of the lava flows in the cave. (NASA Photo)

BELLEVUE, Wash. — Underground lava tubes are great places to set up bases on the moon, or look for life on Mars — but they’ll be super-tricky to navigate. Which is why a NASA team is practicing with a cave rover in California.

Scientists are sharing their experiences from the Biologic and Resource Analog Investigations in Low Light Environments project, or BRAILLE, here at this week’s Astrobiology Science Conference.

The site of the experiment is California’s Lava Beds National Monument, which houses North America’s largest network of lava tubes. These are tunnel-like structures left behind by ancient volcanic flows of molten rock. They’re known to exist on the moon and Mars, and in some places there are even openings that make those lava tubes accessible from the surface.

The underground passageways provide shelter from the harsh radiation hitting the surface of the moon and Mars, which would be a big plus for would-be settlers. There’s even a chance that microbes could find a foothold in lava tubes on Mars, as they do on Earth.

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Martian methane fades away but mystery remains

This image was taken by NASA’s Curiosity rover on June 18. It shows part of Teal Ridge, which the rover has been studying in a region called the “clay-bearing unit.” (NASA / JPL-Caltech Photo)

BELLEVUE, Wash. — NASA says the record-setting belch of Martian methane that its Curiosity rover detected last week has faded away, leaving some big questions hanging in the air: Where did the gas come from, and what were its origins?

Much of the methane on Earth is produced biologically, from sources ranging from microbes to the digestive tracts of cows and humans. But methane can also be produced through geological, completely non-biological processes. For example, methane makes up about 5 percent of the atmosphere of the Saturnian moon Titan, which is so cold that methane and other hydrocarbons pool up in lakes and rivers.

Curiosity’s onboard chemistry lab — known as Sample Analysis at Mars, or SAM — has an instrument that can sense methane levels in the Red Planet’s atmosphere, and those levels usually amount to less than 1 part per billion by volume. But SAM has registered several curious methane spikes during its seven years of surface operations — including a rise to 6 parts per billion in 2013 that got NASA’s attention, and another detection that rose even higher during the following Martian year.

Last week, methane levels spiked to the highest levels ever detected by Curiosity: 21 parts per billion. That caused the SAM science team to change their plans for the weekend and make follow-up measurements.

Those measurements were sent back to the science team this morning, and they showed that methane levels were back to their usual level.

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Is there life on Mars? The answer may be squishy

NASA’s Curiosity rover took this selfie in June 2018 by capturing a series of pictures with a camera mounted on its robotic arm. (NASA / JPL-Caltech Photo)

BELLEVUE, Wash. — NASA’s Curiosity rover has detected fresh whiffs of Martian methane, once again sparking speculation about a potential biological source — but researchers at the space agency say it’s too early to raise the alert for life on Mars.

Scientists who are gathering here for the annual Astrobiology Science Conference, or AbSciCon, acknowledge that depending on the context, methane could be an indicator of biological activity, as it is on Earth. But it could just as well be of purely geological origin.

“It’s not in itself a biosignature,” Abigail Allwood, a field geologist at NASA’s Jet Propulsion Laboratory, told GeekWire today during a media workshop.

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Saturn’s moon Enceladus may offer ‘free lunch’

This composite image shows how plumes of water emanate from fissures in the surface ice of Enceladus, one of Saturn’s moons. (NASA / JPL Illustration)

The sea that lies beneath the icy surface of Enceladus, one of Saturn’s moons, could provide even more fuel for extraterrestrial organisms than previously thought.

That’s the upshot of a study to be presented at AbSciCon 2019, an astrobiology conference taking place next week in Bellevue, Wash. Hundreds of researchers will be sharing their findings about the prospects for life elsewhere in the solar system and the universe.

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