Proxima B

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Profile BernardProject Donor
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Message 1834000 - Posted: 4 Dec 2016, 11:51:23 UTC

Hi everybody,

Proxima B is not far away some light-years so if there is some possible life there as some people say it's probably no more than crocodiles otherwise we should had received some message.

Sending probes there is technically possible to get infos within 2 human generations (laser pulsed small sailing ships) is it worth?
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Message 1834075 - Posted: 4 Dec 2016, 18:02:51 UTC - in response to Message 1834000.  

Hi Bernard. We humans have only had radio communications for a little over 100 years, and the ability to detect any signals from space, let alone weak signals, for much less time. I don't think we should draw any conclusions at all based on hearing nothing from Proxima B. I would agree that this star system is a good candidate for a probe, or probably several probes. But this would be a major project for anyone but a science fiction writer. It would require lots of technology that doesn't exist today, and lots of money. And as always, the real barriers are political, not technical. Namaste.
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Message 1834251 - Posted: 5 Dec 2016, 8:30:41 UTC - in response to Message 1834075.  

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Message 1837128 - Posted: 21 Dec 2016, 1:38:09 UTC
Last modified: 21 Dec 2016, 1:39:56 UTC

There has been some frequently-expressed doubt about the true fitness-for-life of the planets of red dwarf stars, even if they lie within the calculated habitable zone. The article linked below suggests that in many cases such planets could have strong magnetic and gravitational fields.

These would tend to protect the atmosphere from erosion by strong stellar flares, common in red dwarfs, and moderate their effects on the planets' surfaces, and any life there.

In the case of Proxima Centauri b, we see that the minimum mass is greater than that of Earth; probably quite a bit greater. We also see that this planet is thought to be several hundred million years older than Earth. That could have allowed ample time for a technological civilization to arise there; perhaps even one surpassing our own.

The problem of why we've seen no evidence of a civilization there, in the form of radio messages, has no one clear solution. There are a number of speculative scenarios that could account for this, however. Perhaps we simply haven't listened with sufficient sensitivity, at the correct frequency, at a time that their signals happened to be pointing our way.

http://www.universetoday.com/132462/new-study-says-proxima-b-support-life/
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Message 1848552 - Posted: 13 Feb 2017, 19:44:17 UTC - in response to Message 1837128.  

The new study took such characteristics into account, developing a new model of red dwarf "habitable zones" — the range of distances from a star at which liquid water should be stable on a world's surface — that considers more than just a parent star's heat.

"By the classical definition, the habitable zone around red dwarfs must be 10 to 20 times closer in than Earth is to the sun," study lead author Vladimir Airapetian, a solar scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, said in a statement. "Now we know these red dwarf stars generate a lot of X-ray and extreme ultraviolet emissions at the habitable zones of exoplanets through frequent flares and stellar storms."

This is bad news from a habitability perspective. The team's modeling results suggest that such radiation can strip the electrons off molecules in orbiting planets' atmospheres. These electrons escape into space easily, and they drag the newly created, positively charged ions with them as they go.

Light elements, such as hydrogen, are lost fairly easily via this process. And superflare radiation can kick the "atmospheric erosion" up a notch, driving off oxygen and nitrogen — key building blocks of life — as well, the new study found.

"Considering oxygen escape alone, the model estimates a young red dwarf could render a close-in exoplanet uninhabitable within a few tens [of millions] to a hundred million years," NASA officials wrote in the same statement. "The loss of both atmospheric hydrogen and oxygen would reduce and eliminate the planet’s water supply before life would have a chance to develop."

The team's work suggests that this fate has likely befallen the recentl
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Message 1848561 - Posted: 13 Feb 2017, 20:59:09 UTC
Last modified: 13 Feb 2017, 21:12:57 UTC

The fate of planets closely orbiting M dwarf stars is far from clear. Scientifically oriented models may suggest that such planets could quickly lose their atmospheres, on the geological time scale. On the observational side of things, we have the recent finding that Gliese 1132 b, an exoplanet orbiting very closely to its star, has a thick, un-eroded atmosphere.

The fact that such a planet was found very nearby in space, just 39 light years away, suggests that such planets may be common. How such planets could avoid having their atmospheres scoured away by stellar radiation is an open question, though I offered a few suggestions in a previous post in this thread.
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Message 1851866 - Posted: 27 Feb 2017, 16:58:33 UTC - in response to Message 1848561.  
Last modified: 27 Feb 2017, 17:18:37 UTC

we have the recent finding that Gliese 1132 b, an exoplanet orbiting very closely to its star, has a thick, un-eroded atmosphere.

Could you post link to such observation report please.

EDIT: saw your link on news article and did search through last few issues of that journal http://iopscience.iop.org/issue/0004-637X/837/1 seems not published still. Either pending or not passed review...
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Message 1851890 - Posted: 27 Feb 2017, 19:09:21 UTC
Last modified: 27 Feb 2017, 19:22:21 UTC

Scientific American reported in late January that the scientific paper was under review for publication in Astrophysical Journal. That's presumably still the case. Link to journalistic article, below:

https://scientificamerican.com/article/signs-of-alien-air-herald-a-new-era-of-exoplanet-discoveries
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Message 1851911 - Posted: 27 Feb 2017, 20:31:32 UTC - in response to Message 1851890.  

Scientific American reported in late January that the scientific paper was under review for publication in Astrophysical Journal. That's presumably still the case. Link to journalistic article, below:

https://scientificamerican.com/article/signs-of-alien-air-herald-a-new-era-of-exoplanet-discoveries

yes, thanks. I found that article already but failed to find paper itself. Will see if it appears in some upcoming issue.
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