Astronomers using Hubble telescope detect water vapor on exoplanet in habitable zone

EviLore

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Scientists Find Water Vapor on the Most Habitable Exoplanet Yet
A so-called super-Earth with water in its atmosphere has many appealing attributes. But that doesn't mean it hosts life.

On Wednesday, a team of astronomers from University College London announced that they detected water vapor in the atmosphere of a “super-Earth” planet outside our own solar system. This is the first time water has been detected in the atmosphere of an exoplanet that is not a gas giant, which the researchers say makes it the most habitable exoplanet currently known. The planet, known by the catchy name K2-18b, is 110 light years away and orbits a red dwarf star about half the size of the sun. The planet is twice the size of Earth, eight times as massive, and orbits its host star once every 33 days.

“This is the only planet outside the solar system that has the correct temperature to support water and has an atmosphere that has water in it, making this planet the best candidate for habitability that we know right now,” says Angelos Tsiaras, an astronomer at University College London and the lead author of the study published today in Nature Astronomy.

A planet’s atmosphere holds many tantalizing clues. It can help determine if there are oceans on the surface, or if there’s a surface at all. It can tell you about a planet’s structure and evolution. And it can reveal whether a planet is capable of sustaining life. In this case, the data suggests that K2-18b either has a dense rocky core and a thick atmosphere, like Neptune, or is covered in a planet-wide ocean.

The detection of water vapor in the atmosphere of K2-18b brings some clarity to this exoplanet, but like any big discovery, the data raised more questions than it answered. For example, the researchers developed three models that fit the observational data and led to wildly different estimates of atmospheric water. In one model, the planet has a hydrogen-rich atmosphere with a lot of water and nothing else. Another had a lot of hydrogen and nitrogen, and very little water. The third model had a bit of water floating around in the upper atmosphere, but a lot of high-altitude clouds that obscured any water that may have been lower in the atmosphere. So how much water is in the atmosphere of K2-18b? According to the models, it could be anywhere between 0.01 percent to 50 percent of the atmosphere.

To detect K2-18b’s vapor, astronomers used a custom algorithm to analyze data that the Hubble Space Telescope collected in 2016 and 2017. By observing how the light from an exoplanet’s host star changes as the planet passes in front of it, they can pick up signatures of its atmosphere. Different atmospheric molecules absorb different amounts of light, and water in particular produces a strong signal, even if it’s present in only small amounts.

But there are limitations. The Hubble camera used to study K2-18b can detect wavelengths associated with water, but not all other molecules. It can see water in the atmosphere and little else, making it a bit like a photographer taking pictures in one color. To learn how much water vapor is in the atmosphere, or what it’s like on the surface, you need access to a broader spectrum of wavelengths.

The UCL astronomers used Hubble data collected by a group of researchers led by Björn Benneke, an astronomer at the University of Montreal’s Institute for Research on Exoplanets. Hubble data becomes public after a year, and although Benneke says his team has been analyzing K2-18b for nearly three years and originally commissioned the observation, the UCL team swooped in on the data and published its own analysis first.

 

Skyfox

Formerly 'Believer1'
Oct 24, 2017
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Perhaps someday humanity will learn how to bend space/time a little.

Out of reach for now.
 
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VysePSU

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I wonder what civilizations live on these alien worlds. Are they similar to us or vastly different?
 
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highrider

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One of the great bummers of my life at the half century mark is how little we still know. Even a lot of our own planet we don’t understand or haven’t observed and studied. I gotta get on some crazy inventions myself apparently!
 

Ornlu

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Oct 31, 2018
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IF we got there, the only reason we would have made it is we’d have anti-gravity and anti-matter technology, rendering rockets useless.
Chuck a generation ship with a rocket in the right direction, and let them sleep for 400 years!
 

Lord Oso

Formerly 'Oso Torpedoes'
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We don't have the tech on reaching FAR into the stars. It's scary af thinking of the unknown... Especially deep in the cosmos. Finding planets on the habitable zone gets me excited.
 
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John Day

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We are such a delicate result of the right elements at the right time... Life is out there, and can develop out there, but we need to broaden our expectation of life.
 
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Weilthain

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They’ve been saying there is water shooting out of stars as well. I think it’s more likely that space is really water.
 

triplestation

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im getting ideas now

that one day way long ago our original planet was not earth

and that we saw planet earth from where ever the fuck we're originally from and said "yeah, there's water there but we gotta kill those big lizards first or we can't live in that shit tell gary to send some comets"

we came here, kill off the dinos and blame comets, lie but not a lie, brilliant, suddenly 1940s, omg aliens, government knows it's just gary's descendants

2019

"oh we found some vapor we can live there"

flash forward millions of years and someone is posting the exact same shit i'm posting
 
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Weilthain

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Aug 6, 2013
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im getting ideas now

that one day way long ago our original planet was not earth

and that we saw planet earth from where ever the fuck we're originally from and said "yeah, there's water there but we gotta kill those big lizards first or we can't live in that shit tell gary to send some comets"

we came here, kill off the dinos and blame comets, lie but not a lie, brilliant, suddenly 1940s, omg aliens, government knows it's just gary's descendants

2019

"oh we found some vapor we can live there"

flash forward millions of years and someone is posting the exact same shit i'm posting
Isn’t that Scientology?
 

womfalcs3

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May 11, 2007
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"The planet is twice the size of Earth, eight times as massive, and orbits its host star once every 33 days. "

Meaning that our skeletons would not hold up.