Scientists say they found first potentially habitable planet with water in its skies - Calgary Herald - Canadanewsmedia
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Scientists say they found first potentially habitable planet with water in its skies – Calgary Herald

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Twice as large as our own planet and eight times as massive, K2-18b orbits close to a red dwarf star and has an atmosphere of mostly hydrogen gas


A handout artist’s impression released on September 11, 2019, by ESA/Hubble shows the K2-18b super-Earth, the only super-Earth exoplanet known to host both water and temperatures that could support life. – For the first time, water has been discovered in the atmosphere of a exoplanet with Earth-like temperatures that could support life as we know it, scientists revealed on September 11, 2019.


M. KORNMESSER / ESA/Hubble / AFP

In the dim, red light of an alien sun, scientists have found the first evidence for water in the atmosphere of a rocky planet – offering a tantalizing new target in the search for life in the universe.

The intriguing world, which goes by the impersonal designation K2-18b, lies 110 light-years away in the constellation Leo. More important: It sits in its star’s “habitable zone,” where it is bathed in the right amount of warmth to allow for liquid water on its surface.

Twice as large as our own planet and eight times as massive, K2-18b possesses powerful gravity that would make it difficult to walk upon. It orbits close to a red dwarf star, much smaller and cooler than our sun. And aside from water vapour, its atmosphere contains mostly hydrogen gas – a molecule that makes up less than 1 part per million of our own atmosphere.

It is no “second Earth,” said astronomer Angelos Tsiaras, the lead author of a study on the planet published Wednesday in the journal Nature Astronomy. But he believes it is “the best candidate for habitability that we know right now.”

The paper by Tsiaras draws on publicly available data produced by Björn Benneke, a planetary astronomer at the University of Montreal in Canada. On Tuesday, Benneke’s team posted its own analysis of K2-18b on the preprint server arXiv, which hosts academic papers not yet published in peer-reviewed journals.

Benneke and his colleagues also found signatures of water vapour in K2-18b’s skies. But they were less optimistic than Tsiaras about the potential habitability of this world. The Montreal-based team’s interpretation of its data suggests the hydrogen atmosphere forms a thick, gaseous envelope around the planet. This would generate intense pressures at the planet’s surface – perhaps enough to push hydrogen into a liquid form.

It’s definitely the smallest and coolest planet that we’ve had a glimpse into the atmosphere of so far …. But I don’t think it’s potentially habitable

“It is not a true Earth analogue,” the researchers report.

Laura Kreidberg, an astronomer at the Harvard-Smithsonian Center for Astrophysics, said that K2-18b might be better described as a “mini-Neptune” than a “super Earth.” Extensive research with computer models suggests that, at 1.6 to 1.8 times the mass of Earth, planets tend to become huge and gaseous, rather than rocky.

Though K2-18b is likely solid at its core, the temperatures and pressures at the “surface” would be so high that few complex molecules would survive, let alone any life forms.

“I think the result is amazing,” said Kreidberg. “It’s definitely the smallest and coolest planet that we’ve had a glimpse into the atmosphere of so far …. But I don’t think it’s potentially habitable.”

Scientists had detected water only in the atmospheres of “gas giants” — huge exoplanets that lack solid surfaces, much like Jupiter and Saturn in our solar system. Rocky exoplanets are smaller, making them harder to find and more difficult to study. Even a planet like K2-18b can be examined only with humanity’s most sensitive space telescope — the Hubble.

When K2-18b was discovered in 2015, Tsiaras and his colleagues thought it would be a good candidate for a form of analysis called transit spectroscopy, which involves studying the changes in a star’s light as a planet “transits,” or passes in front of it.

The planet is so close to its cool host star that it takes just 33 days to orbit. So, month after month, the researchers waited with Hubble to capture the moment of transit.

As the starlight filtered through the planet’s atmosphere, some of it would be absorbed by the gases in the planet’s air. By separating the light into its component parts, the scientists could look for signatures of particular molecules.

What they found suggests that the composition of K2-18b’s atmosphere could range from 0.1 percent water vapor (about the proportion in Earth’s upper atmosphere) to a whopping 50 percent. (At its highest, water vapor concentration in Earth’s lower atmosphere is about 4 percent.)

The Hubble isn’t sensitive to the right types of light to detect other important molecules, such as nitrogen or methane, so the researchers can only speculate about the precise composition of the atmosphere. The planet could have thick clouds, like Venus, that would heat its surface to an intolerable degree. Or its atmosphere might be so thin and insubstantial that it offers no protection from the perils of space, like the atmosphere of Mars.

Researchers must wait for more sophisticated tools, such as the long-delayed James Webb Space Telescope, to reveal more details about the distant world.

Yet Giovanna Tinetti, a colleague of Tsiaras’s at University College London and a co-author of the Nature study, suggested it’s still possible that there is liquid water somewhere below the atmosphere.

“We’re going to need more observations,” she said. “We need to know much more about the planet.”

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Mini Mercury skips across sun’s vast glare in rare transit – Fernie Free Press

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Mini Mercury skipped across the vast, glaring face of the sun Monday in a rare celestial transit.

Stargazers used solar-filtered binoculars and telescopes to spot Mercury — a tiny black dot — as it passed directly between Earth and the sun on Monday.

The eastern U.S. and Canada got the whole 5 1/2-hour show, weather permitting, along with Central and South America. The rest of the world, except for Asia and Australia, got just a sampling.

Mercury is the solar system’s smallest, innermost planet. The next transit isn’t until 2032, and North America won’t get another shot until 2049.

In Maryland, clouds prevented NASA solar astrophysicist Alex Young from getting a clear peek. Live coverage was provided by observatories including NASA’s orbiting Solar Dynamics Observatory.

“It’s a bummer, but the whole event was still great,” Young wrote in an email. “Both getting to see it from space and sharing it with people all over the country and world.”

At Cape Canaveral, space buffs got a two-for-one. As Mercury’s silhouette graced the morning sun, SpaceX launched 60 small satellites for global internet service, part of the company’s growing Starlink constellation in orbit.

ALSO READ: ‘Very surreal’: B.C. students help design space colony in NASA-backed competition

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The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.

Marcia Dunn, The Associated Press


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A Star Ejected from the Milky Way's 'Heart of Darkness' Has Reached a Mind-Blowing Speed – Space.com

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As humankind’s ancestors were learning to walk upright, a star was launched out of the supermassive black hole at the center of our galaxy at a staggering 3.7 million mph (6 million km/h). 

Five million years after this dramatic ejection, a group of researchers, led by Sergey Koposov of Carnegie Mellon University’s McWilliams Center for Cosmology, has spotted the star, known as S5-HVS1, in the Crane-shaped constellation Grus. The star was spotted traveling relatively close to Earth (29,000 light-years away) at unprecedented, searing speeds — about 10 times faster than most stars in our galaxy. 

“The velocity of the discovered star is so high that it will inevitably leave the galaxy and never return,” Douglas Boubert, a researcher at the University of Oxford and a co-author on the study, said in a statement

Related: Top 10 Star Mysteries of All Time

An artist’s impression of te star S5-HVS1 being ejected by the Milky Way galaxy’s supermassive black hole, Sagittarius A*.

(Image credit: James Josephides (Swinburne Astronomy Productions))

“This is super exciting, as we have long suspected that black holes can eject stars with very high velocities. However, we never had an unambiguous association of such a fast star with the galactic center,” Koposov said in the statement. 

The star was discovered with observations from the Anglo-Australian Telescope (AAT), a 12.8-foot (3.9-meter) telescope, and the European Space Agency’s Gaia satellite. The discovery was made as part of the Southern Stellar Stream Spectroscopic Survey (S5), a collaboration of astronomers from Chile, the U.S., the U.K. and Australia. 

Now that the star has been spotted, researchers could track the star back to Sagittarius A*, the black hole at the center of the Milky Way. It also serves as an incredible example of the Hills Mechanism, proposed by astronomer Jack Hills 30 years ago, in which stars are ejected from the centers of galaxies at high speeds after an interaction between a binary-star system and the black hole at the center of the galaxy.

The location and direction of the star S5-HVS1 in the night sky. The star is rocketing away from the center of our galaxy.

(Image credit: Sergey Koposov)

“This is the first clear demonstration of the Hills Mechanism in action,” Ting Li, a fellow  at the Carnegie Observatories and Princeton University who led the S5 collaboration, said in the statement. “Seeing this star is really amazing as we know it must have formed in the galactic center, a place very different to our local environment. It is a visitor from a strange land.”

“While the main science goal of S5 is to probe the stellar streams — disrupting dwarf galaxies and globular clusters — we dedicated spare resources of the instrument to searching for interesting targets in the Milky Way, and voila, we found something amazing for ‘free.’ With our future observations, hopefully we will find even more!” Kyler Kuehn, deputy director of technology at the Lowell Observatory who is part of the S5 executive committee, added in the statement.

This discovery was published in a study on Nov. 4 in the journal the Monthly Notices of the Royal Astronomical Society. 

Follow Chelsea Gohd on Twitter @chelsea_gohd. Follow us on Twitter @Spacedotcom and on Facebook.

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Most distant world ever explored gets new name: Arrokoth – Castlegar News

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The most distant world ever explored 4 billion miles away finally has an official name: Arrokoth.

That means “sky” in the language of the Native American Powhatan people, NASA said Tuesday.

NASA’s New Horizons spacecraft flew past the snowman-shaped Arrokoth on New Year’s Day, 3 1/2 years after exploring Pluto. At the time, this small icy world 1 billion miles (1.6 billion kilometres) beyond Pluto was nicknamed Ultima Thule given its vast distance from us.

“The name ‘Arrokoth’ reflects the inspiration of looking to the skies,” lead scientist Alan Stern of Southwest Research Institute said in a statement, “and wondering about the stars and worlds beyond our own.”

The name was picked because of the Powhatan’s ties to the Chesapeake Bay region.

New Horizons is operated from Johns Hopkins University’s Applied Physics Lab in Laurel, Maryland. The Hubble Space Telescope — which discovered Arrokoth in 2014 — has its science operations in Baltimore.

The New Horizons team got consent for the name from Powhatan Tribal elders and representatives, according to NASA. The International Astronomical Union and its Minor Planet Center approved the choice.

Arrokoth is among countless objects in the so-called Kuiper Belt, or vast Twilight Zone beyond the orbit of Neptune. New Horizons will observe some of these objects from afar as it makes its way deeper into space.

Marcia Dunn, The Associated Press

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