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Last week, news of the discovery of a potentially habitable "Earth-like" exoplanet orbiting the nearest star to our Sun (Proxima Centauri) leaked to Der Spiegel. Today, the European Southern Observatory confirmed the news about Proxima b:
Astronomers using ESO telescopes and other facilities have found clear evidence of a planet orbiting the closest star to Earth, Proxima Centauri. The long-sought world, designated Proxima b, orbits its cool red parent star every 11 days and has a temperature suitable for liquid water to exist on its surface. This rocky world is a little more massive than the Earth and is the closest exoplanet to us — and it may also be the closest possible abode for life outside the Solar System. A paper describing this milestone finding will be published in the journal Nature on 25 August 2016.
[...] At times Proxima Centauri is approaching Earth at about 5 kilometres per hour — normal human walking pace — and at times receding at the same speed. This regular pattern of changing radial velocities repeats with a period of 11.2 days. Careful analysis of the resulting tiny Doppler shifts showed that they indicated the presence of a planet with a mass at least 1.3 times that of the Earth, orbiting about 7 million kilometres from Proxima Centauri — only 5% of the Earth-Sun distance.
A note on the press release discusses the potential habitability of Proxima b, given that it is orbiting close to a red dwarf star:
[Continues...]
The actual suitability of this kind of planet to support water and Earth-like life is a matter of intense but mostly theoretical debate. Major concerns that count against the presence of life are related to the closeness of the star. For example gravitational forces probably lock the same side of the planet in perpetual daylight, while the other side is in perpetual night. The planet's atmosphere might also slowly be evaporating or have more complex chemistry than Earth's due to stronger ultraviolet and X-ray radiation, especially during the first billion years of the star's life. However, none of the arguments has been proven conclusively and they are unlikely to be settled without direct observational evidence and characterisation of the planet's atmosphere. Similar factors apply to the planets recently found around TRAPPIST-1.
A terrestrial planet candidate in a temperate orbit around Proxima Centauri (DOI placeholder) (DX)
Two more papers are available (currently in peer review). They discuss the habitability of Proxima b (at a site that appears to be dedicated to the subject).
Related: Internal Temperature of Exoplanets Could Determine Habitability Rather Than "Goldilocks" Distance
Previously: "Earth-Like" Exoplanet Found in Habitable Zone of Proxima Centauri
(Score: 4, Interesting) by takyon on Thursday August 25 2016, @08:29PM
What's "pie in the sky"? Sending humans there?
All that's really needed is life extension or a little deep freeze. We'll likely have that worked out before the century is over, or even before 2050.
5% speed of light average (going from 0 to 0.1c and back to 0 maybe?) would be an 85 year trip. There are a few propulsion methods that might make it possible. Advanced ion drives, fusion rockets, and emdrive seem like the top contenders (to be clear, emdrive is the bottom top contender, and will probably never work). Energy source should be nuclear decay or fusion.
Shielding for interstellar particle hazards is an engineering problem. We could embed a ship in a small asteroid and use that for shielding.
There is no need to rush, because the star is getting closer to Earth ever so slightly:
Long before any manned mission gets planned, our understanding of the planet's atmosphere, temperature, and possible lifeforms will be a top focus for our next-generation space observatories and ground telescopes [nextbigfuture.com]. In particular, the James Webb Space Telescope [wikipedia.org], the unnamed successor to James Webb (such as ATLAST [wikipedia.org] or HDST [wikipedia.org]), Giant Magellan Telescope [wikipedia.org], and European Extremely Large Telescope [wikipedia.org]. This exoplanet is now probably on par with Planet Nine [wikipedia.org] in terms of imaging importance.
Once we have confirmed where it actually is, its mass and radius, composition of the atmosphere, any possible satellites it might have, the presence of liquid water on the surface, the presence of life/vegetation on the surface, and other planets in the Proxima system, then we can talk or whine about manned missions.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 4, Disagree) by TrumpetPower! on Thursday August 25 2016, @10:15PM
Sorry to burst your bubble, but humans ain't never no way nohow ever going to any other stars, period, full stop, end of story.
The energy budget to send a spacecraft the size of the shuttle (which has about as much living space as a schoolbus) so it arrives in a mere decade is roughly the same as our entire civilization's energy budget.
You suggest going slower using cryonics. That's a nice idea at first blush...but now you're pushing the travel time out closer to the age of our civilization itself...and the thought that anything technological will survive the harshness of interstellar space over such timescales is laughable. All your plastics and rubber will have long since crumbled into dust. Your hydrogen will all have leaked out of your steel tanks. Your circuitry will be completely fried by cosmic rays.
The other popular suggestion is a generation ship that takes as long as cryonics. But now you need just as much total energy as the fast version, plus you've got to keep a modern manufacturing civilization going in perfect isolation for longer than (did I mention?) civilization has existed in the first place.
Interstellar travel doesn't even begin to make sense until you've got a sizable fraction of a star's energy output to play with...at which point the Fermi Paradox slaps you full in the face. If you're using up your star that fast, you're on an exponential growth curve. Your main interest in interstellar travel will be to get to another star you can use to sustain your growth before you use up your own star. But even if you assume that the process to colonize another star takes (repeat after me) as long as our civilization has existed, you're going to run out of stars in the galaxy in far less time than our species has existed. And even if it takes as long as our species has existed, you're again running out in much less time than since the asteroid wiped out the dinosaurs.
(Take however long you think it takes to colonize a star and multiply by 26 and that's how long until all the stars in the galaxy are colonized.)
Since it's pretty clear that all the stars in this or any other galaxy have not been converted into Dyson Spheres, we can be overwhelmingly certain that that's not something that happens.
So...yeah. Interstellar travel makes for great space opera, but it has exactly as much to do with reality as faery dust that makes you fly and instructions to turn right at the third star and go straight until morning, where you'll meet hook-armed crocodile pirates....
Cheers,
b&
All but God can prove this sentence true.
(Score: 1) by cyberthanasis on Friday August 26 2016, @09:51AM
humans ain't never no way nohow ever going to find out what any other stars are made of, a prominent scientist said at the beginning of last century.
Then spectroscopy did exactly that.