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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: 0) by Anonymous Coward on Thursday August 25 2016, @09:16PM
Look how quickly humans have developed technology since the steam engine was invented less than 320 years ago.
Aren't we worried that aliens will come along and do a Hollywood sci-fi flick number on us?
(Score: 4, Interesting) by takyon on Thursday August 25 2016, @10:03PM
Nah. We've already had retired Air Force officers speak out at places like the National Press Club and say that UFOs are probably alien spacecraft and have caused nuclear missile sites to malfunction.
In the light of allegations like that, there are a few questions to consider:
1. Are we being visited by aliens right now?
2. Is faster-than-light travel possible?
3. If no to #2, are aliens really close by? (instead of Proxima Centauri b proximity, say, within 100 light years)
Imagine that faster-than-light travel is never invented, but we undergo another 1,000 years of technological development without destroying ourselves. The humanity of 3016 would be able to SPAM humans or bots or uploaded minds or whatever to every nearby star. We would be able to colonize "Earth-like" planets with our fleshy bodies, sure, but we'd also be able to put robots or enclosed human habitats on every rock. We'll send something to literally every rock within our solar system within the next 200 years. Ceres, Pallas, Enceladus, Europa, Pluto, Charon, Sedna, whatever, we will be able to put a probe or tiny base on it. The humans of the next millennium will be able to put a presence on every rock out to 10-25 light years, and will begin to reach objects that are 100 light years or more away.
If we were to be scared of life that may be on Proxima Centauri b, it would likely have to be life that didn't originate there. Let's say we discover life on Proxima b by 2025. The first telescopes were created around 1608 (Galileo made his in 1609). That's 417 years from the invention of the telescope to the detection of life on an exoplanet 4.25 light years away.
If Proxima b has a native-born population of alien life, they aren't likely to be at the same stage of development as us. They either discovered the telescope and built space observatories a long time ago, and discovered the watery Earth in their stellar backyard, or are too rudimentary (at the stage of microbes or lungfish) to do anything. If Proxima b is occupied by non-native life, then they can travel to Earth just as easily as we would be able to travel (spam) to other stars in the coming centuries. Another factor to consider is that Proxima Centauri is getting closer to the Sun, and was once further away. It will be around 3.11 light years from the Sun at closest approach in around 27,000 years.
If we are already being visited, and it's not just crazies spouting off, then it's a wrap. Aliens can clearly get to Earth. If faster-than-light travel (such as a warp drive) is possible, then it's even more of a wrap, since they could arguably get here in a convenient manner, and on a whim. Since there is no widespread acceptance that we are being visited by aliens, we have to rely on detecting life on other planets using our next generation telescopes. We should have some answers within the next 2-3 decades.
And to bring in the Fermi Paradox, one of the popular explanations for detecting no signals (since we are at a point where we now think that almost every star in the galaxy has a rocky planet in the habitable zone) is that civilizations tend to wipe themselves out. We have reached a point on Earth where we are still stuck on or near Earth (not even colonizing or traveling back to the nearby Moon), despite any efforts of NASA or Elon Musk or whomever. But we have plenty of nuclear weapons, and some exciting new biological weapons coming now that we are gaining a greater understanding of genomics. Even if we do manage to make a small and self-sustaining colony on Mars, it would take a long time for such a colony to gain a deep foothold on Mars and repopulate the Earth in the case of widespread disaster there. Humanity is still fragile.
So no, I'm not really worried about aliens within the nearest 100 light years. They are either already visiting, don't exist, can't do shit, or won't do shit. And if they were close to us in terms of technological development but could reach us fairly quickly with slower-than-light travel, they'd already have the upper hand and there's nothing we can do but bulk up our own technologies. Luckily, the first ships capable of traveling here in such a #rare scenario would be the least capable in terms of energy and weapons.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 2) by deimtee on Friday August 26 2016, @01:28PM
The ability to travel to another star system pretty much automatically includes the ability to wipe out life on any planet you can reach. If you have a starship drive then it is no big deal to drop a rock that makes the Chicxulub impact look like a pebble in a pond.
If you cough while drinking cheap red wine it really cleans out your sinuses.
(Score: 0) by Anonymous Coward on Friday August 26 2016, @09:43AM
Aren't we worried that aliens will come along and do a Hollywood sci-fi flick number on us?
https://en.wikipedia.org/wiki/Venus_and_the_Seven_Sexes [wikipedia.org]