10 billion earth-like planets in our galaxy

[Magical Realist]

https://www.businessinsider.com/10-billi...uZP0WvNaTA

"Our galaxy could be littered with warm, watery planets like Earth.

That's the conclusion of researchers at Penn State University, who used data from NASA's Kepler telescope to estimate the number of Earth-like planets in the Milky Way. Their results, published in The Astronomical Journal this week, suggest that an Earth-like planet orbits one in every four sun-like stars. Totaled up, that means there could be up to 10 billion Earth-like worlds in our home galaxy.

The estimate is an important step in the search for alien life, since any potential life on other planets would most likely be found on an Earth-like world warm enough to hold liquid water.

So a better understanding of the potential number of Earth-like planets in the galaxy can inform projects like the Wide-Field Infrared Survey Telescope, which will launch into space in the mid 2020s and hunt signs of for oxygen and water vapor on distant planets.

"We get a lot more return on our investment if we know when and where to look," Eric Ford, a professor of astrophysics and co-author of the new study, told Business Insider."

[C C]

This Rocky Super-Earth Had Its Atmosphere Vaporized
http://blogs.discovermagazine.com/d-brie...vaporized/

EXCERPT: . . . But finding worlds like ours out in the galaxy is difficult business. [...] One of the latest attempts involves a planet called LHS 3844b, a rocky world 1.3 times the width of Earth that orbits a dim star every 11 days. Astronomers stared at it with the Spitzer Space Telescope for 100 hours, but found that the planet probably lacks any atmosphere at all, let alone one friendly to life. Instead, it’s simply a hot, bare rock orbiting its star. Astronomers led by Laura Kreidberg from the Harvard-Smithsonian Center for Astrophysics reported their findings August 19 in the journal Nature.

[...] The researchers considered the possibility that the planet had at least a thin atmosphere (like Mars or Mercury), since that couldn’t be ruled out by the data. But even that seems unlikely. Modeling shows that the star gives off enough energy and is close enough to the planet that it would erode away a thin atmosphere on short timescales. [...] In the end, a cooler world is probably needed if scientists want to find a real Earth twin and with it, any chance of life in the universe. (MORE - details)

[C C]

K2-18b is like Earth, but not
https://cosmosmagazine.com/space/k2-18b-...th-but-not

INTRO: Astronomers have detected water vapour in the atmosphere of a rocky planet orbiting in the habitable zone of a star (the region that is neither too close nor too far from the star for it to be possible for planets to have liquid, surface water) 110 light-years away. “This is the first detection of this kind,” says Angelos Tsiaras, an astronomer at University College London (UCL), UK, and lead author of a paper published in the journal Nature Astronomy. “This is the only planet we know outside the Solar System that has the correct temperature to support water, has an atmosphere, and has water in it," he says, “making this planet the best candidate for habitability that we know right now.”

That said it’s not Earth’s twin. “We’re talking about a planet twice the size of the Earth and eight times the mass,” Tsiaras says. Not only does that mean that the surface gravity is nearly twice that of Earth, but even though its star is cool, dim, and red, it probably receives significantly more ultraviolet radiation than we do on Earth. “It’s not quite your vacation destination,” says Ingo Waldmann, also of UCL. “We would all get cancer relatively quickly.”

Not that this means the planet can’t support life. “Life there may have evolved differently,” Waldmann says. The planet, known as K2-18b... (MORE)

[Yazata]

"Our galaxy could be littered with warm, watery planets like Earth.

Given all the different kinds of exoplanets, a "warm, watery planet like Earth" might be fairly unusual.

That's the conclusion of researchers at Penn State University, who used data from NASA's Kepler telescope to estimate the number of Earth-like planets in the Milky Way. Their results, published in The Astronomical Journal this week, suggest that an Earth-like planet orbits one in every four sun-like stars. Totaled up, that means there could be up to 10 billion Earth-like worlds in our home galaxy.

That sounds awfully optimistic. The planet would have to be rocky, not too hot and not too cold, roughly Earth sized, with a reasonably Earth-like atmosphere and liquid water.

The estimate is an important step in the search for alien life, since any potential life on other planets would most likely be found on an Earth-like world warm enough to hold liquid water.

At least Earth-like life. There may be very different paths to chemical replicators subject to natural selection and capable of evolution. It might conceivably happen in very different conditions, by way of mechanisms that haven't even been imagined yet.

So a better understanding of the potential number of Earth-like planets in the galaxy can inform projects like the Wide-Field Infrared Survey Telescope, which will launch into space in the mid 2020s and hunt signs of for oxygen and water vapor on distant planets.

The results of that will be very interesting.

I'd guess that planets with something recognizably like life (as we know it) will still be very rare. I can't help thinking that the first appearance of life on Earth was an exceedingly unlikely event, hugely fortuitous. So there are probably lots of barren worlds out there where life might have gotten started, but didn't.

And even if life does start, would it evolve into intelligent beings like us? Or would it remain as something like bacteria?

[Zinjanthropos]

And even if life does start, would it evolve into intelligent beings like us? Or would it remain as something like bacteria?

Even if that's all we can expect then I'm all for getting off this rock. 

Could this declaration's intention be an disguised appeal to big business and government for more investment into space?

[C C]

K2-18b is like Earth, but not
https://cosmosmagazine.com/space/k2-18b-...th-but-not

INTRO: Astronomers have detected water vapour in the atmosphere of a rocky planet orbiting in the habitable zone of a star (the region that is neither too close nor too far from the star for it to be possible for planets to have liquid, surface water) 110 light-years away. “This is the first detection of this kind,” says Angelos Tsiaras, an astronomer at University College London (UCL), UK, and lead author of a paper published in the journal Nature Astronomy. “This is the only planet we know outside the Solar System that has the correct temperature to support water, has an atmosphere, and has water in it," he says, “making this planet the best candidate for habitability that we know right now.”

That said it’s not Earth’s twin. “We’re talking about a planet twice the size of the Earth and eight times the mass,” Tsiaras says. Not only does that mean that the surface gravity is nearly twice that of Earth, but even though its star is cool, dim, and red, it probably receives significantly more ultraviolet radiation than we do on Earth. “It’s not quite your vacation destination,” says Ingo Waldmann, also of UCL. “We would all get cancer relatively quickly.”

Not that this means the planet can’t support life. “Life there may have evolved differently,” Waldmann says. The planet, known as K2-18b... (MORE)

UPDATE: Not Only Didn't We Find Water On An Earth-Like Exoplanet, But We Can't With Current Technology
https://www.forbes.com/sites/startswitha...5565eb5069

EXCERPT: . . . Some of them are rocky; some are temperate; some have water. However, the idea that exoplanet K2-18b is rocky, Earth-like, and has liquid water is absurd, despite recent headlines. (MORE)