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Cosmic Space

Hubble uses eclipse to practice hunt for alien life

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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Solving the case of the disappearing planet

More than a decade ago, Fomalhaut b was considered one of the first exoplanets to be directly imaged — but now it’s vanished, and scientists suspect it was actually nothing more than a huge cloud of dust created by a cosmic smashup.

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New Earth-sized planet ‘rescued’ from old data

Exoplanet
An artist’s conception shows Kepler-1649c orbiting around its host red dwarf star. (NASA / Ames Research Center Illustration / Daniel Rutter)

An alien Earth that just might be habitable has been discovered in years-old records, thanks to sharp-eyed astronomers who gave the data a second look.

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TESS adds new types of planets to its collection

TESS probe
An artist’s conception shows NASA’s Transiting Exoplanet Survey Satellite. (NASA Illustration)

Astronomers report that NASA’s Transiting Exoplanet Survey Satellite, or TESS, has detected its first Earth-sized planet lying in its parent star’s habitable zone, plus its first planet orbiting two stars.

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Real-life planet quest goes far beyond Star Wars

Luke Skywalker on Tatooine
Luke Skywalker’s home planet, Tatooine, and its two suns are a good example of science echoing Star Wars. Or is it the other way around? (Lucasfilm / 20th Century Fox Photo)

Over the past 42 years, filmgoers have seen exotic worlds come to life in a succession of Star Wars movies — a series that is now coming to a climax with “Star Wars: Episode IX, The Rise of Skywalker.” But are those exoplanets really all that exotic anymore?

Sure, we’ve seen two suns in the sky over the sands of Tatooine, Luke Skywalker’s home planet. We’ve been to an ice planet (Hoth) and a lava planet (Mustafar). We’ve even spent time on a habitable exomoon that’s in orbit around a gas giant (Endor).

Back in 1977, most of us might have thought those types of worlds to be science-fiction fantastical. Today, they’re seen as totally plausible categories in the study of thousands of planets beyond our solar system. And Rory Barnes, a University of Washington astronomer who focuses on astrobiology and the habitability of exoplanets, suspects Star Wars creator George Lucas knew this could happen.

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Scientists puzzle over ‘super-puff’ planets

Super-puff planets
An illustration depicts the sunlike star Kepler 51 and three giant planets that have an extraordinarily low density. (NASA / ESA / STScI / Hustak, Olmsted, Player and Summers)

Readings from the Hubble Space Telescope have shed light on a bizarre class of alien planets that have the density of cotton candy.

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Scientists fine-tune standards for habitable planets

M-dwarf planet
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?

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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TESS helps scientists find a super-cool super-Earth

Planet GJ 357 d
An artist’s conception depicts GJ 357 d orbiting its host star. (Cornell University Illustration / Jack Madden)

Astronomers are sharing a flood of findings from NASA’s Transiting Exoplanet Survey Satellite, or TESS, including the detection of a potentially habitable super-Earth far beyond our solar system.

The planet is said to circle an M-type dwarf star called GJ 357, about 31 light-years from Earth in the constellation Hydra. Known as GJ 357 d, the world is at least six times more massive than Earth — and orbits the star every 55.7 days, at a distance that’s only 20% as far away as Earth is from our own sun.

With that orbit, GJ 357 d would be broiling-hot if it were in our solar system. But its parent star is so much dimmer than our sun that the super-Earth could conceivably be just warm enough to have liquid water. That characteristic serves as the definition for habitable zones around alien suns.

“This is exciting, as this is humanity’s first nearby super-Earth that could harbor life – uncovered with help from TESS, our small, mighty mission with a huge reach,” astronomer Lisa Kaltenegger, who’s the director of Cornell University’s Carl Sagan Institute, said in a news release.

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A new search for more planets at Alpha Centauri

NEAR instrument at VLT
The NEAR instrument, shown here mounted on one of the telescopes at the European Southern Observatory’s Very Large Telescope facility, came into use with ESO’s VISIR imager and spectrometer on May 21. (ESO / NEAR Collaboration Photo)

The European Southern Observatory and the billionaire-backed Breakthrough Watch program say they have achieved first light with a new observing instrument designed to spot super-Earths in Alpha Centauri, the nearest star system to our own.

The NEAR instrument, which takes its name from the acronym for “Near Earths in the AlphaCen Region,” has been installed on an 8-meter (26.2-foot) telescope that’s part of ESO’s Very Large Telescope facility in Chile’s Atacama Desert.

NEAR takes advantage of a thermal-infrared coronagraph to block out most of the light coming from the stars in the Alpha Centauri system, a little more than 4 light-years away – including the sunlike stars Alpha Centauri A and B, plus a red dwarf called Proxima Centauri.

Cutting down on that glare makes it easier for an infrared imaging spectrometer known as VISIR to pick up the warm glow of planets orbiting the stars. The upgraded instrumentation, which took three years to develop, should be capable of detecting worlds down to twice the size of Earth.

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Could Barnard’s Star harbor an icy home for life?

Red dwarf and planets
An artist’s conception shows three planets around a red dwarf star. (NASA / JPL-Caltech Illustration)

Where’s the nearest exoplanet with conditions that are right for life? Over the past couple of years, astrobiologists have talked up Proxima Centauri b, which is sitting just 4.2 light-years away.

But Villanova University astrophysicist Edward Guinan favors a world that’s just a bit farther out, at least in astronomical terms. It’s Barnard’s Star b, a super-Earth that orbits Barnard’s Star, 6 light-years from our solar system.

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