> 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.
Wow, amazing result. And talk about synchronicity - just last night I watched an interesting 2015 talk about the search for planets around Alpha Centauri using the radial velocity technique: https://www.youtube.com/watch?v=eieBXGpNYyE
The speaker even mentioned the previous incorrect HARPS announcement, which was later found to be an artefact due to the windowing function they used - a pretty embarrassing mistake. This new finding involves a completely different period: 11.2 days instead of the previous 3.24 day signal.
If you mean the previous claim of there being an Alpha Centauri Bb planet, later retracted, then this new finding involves a completely different star, not just a different period.
This is around Proxima Centauri, the previous one was around Alpha Centauri B. Proxima is a really really small red dwarf, just 12.3% the mass of sun, while Alpha Centauri B is a K-type star, ie somewhat smaller than sun but not that much; around 90% of Sun's mass (And there's also Alpha Centauri A, 10% more massive than the sun). We're not even 100% sure that Proxima is part of the Alpha Centauri system, though I gather it's considered highly likely - it's pretty distant from the Alpha Centauri system, some 15 000 AU (1 AU = distance between Sun and Earth), almost a quarter of a light year.
If the period is 11.2 days, seems like there is a high chance that it is tidally locked to the star. If that's the case, that side is probably pretty roasting hot, the other quite cool. But maybe life near the edge is OK. Probably some interesting weather patterns there as well.
Keep in mind that at best it would take maybe 1,000 years with current technology to get there with a probe or human-supporting ship. It would be highly unpopular however as it involves exploding nuclear bombs behind the craft to get it there that fast--that and it would probably cost trillions to build the thing.
I wonder what it would be like to be the Nth generation of guys-that-left-in-2016 finally arriving and be greeted by the descendants of the FTL guys that arrived 800 years before you.
It's not quite that bad. Have you heard of fission-fragment rockets? Highly feasible, and travel times to Alpha Centauri on the order of decades, not millennia. Baffles me that no one talks about them.
So there are concepts that could make unmanned interstellar travel possible, even within a humans life span, it's just that it costs so much and the incentive is pretty low compared to the incentive countries had for getting objects into space. (primarily military incentives - get spy satellites and nuclear warheads into space to not fall back behind adversaries)
I believe that given a strong enough incentive humans could do it, no matter what current consensus is telling us.
Humans set out to work on reaching outer space without even having a design on how this could be achieved and we did it anyway.
Fission fragment rockets are well within current technology and can achieve delta-vs of 0.1c at reasonable payload fractions, getting us there in ~ 40yr.
Edit: Nuclear pulse propulsion is good for about half that (80yr, not 1000).
Imagine the political implications of choosing who will go onto that ship, as well (assuming the intent is to colonize the world and fill it up with humans)
1.) A probe and a human spaceship are vastly different problems. Since all a probe really needs is electricity to sustain itself, you could get away with a tiny payload and some long lasting radioactive energy source, light sails or even sending the energy from earth's orbit. Such a thing would be either slow and cheap or fast (a few percent of light speed) and expensive, but not both at the same time and I doubt it would be in the trillion dollar range whatever you do.
2.) I completely agree that sending humans would currently not be feasible within a single nation's budget and the technology for that is still at the very least decades out (cryogenics, EM shielding, better propulsion systems, using mass from cheaper solar system bodies than earth etc.).
3.) 1000 years is what we'd need with conventional current technology. The theoretical limit for a nuclear impulse propulsion drive is 20% of light speed if you want to break or 40% for a fly-by.
Well using laser propulsion, we might be able to get a very lightweight probe up to 1/4 c using technology that isn't too far off.[0]
Coincidentally, the group working on this will be presenting some of their most recent work on this at 2:55 EST today. You can watch that live here[2].
What about a solar sail mixed[1] with, ion engine[2] and nuclear powered[3]? With all those things combined, you would constantly be accelerating for many years.
I'm interested in NASA's work on the Alcubierre drive [1]. Still likely to require much more energy than we'll be able to produce in the near future, but 100 years ago we were just getting a firm handle on the basic mechanics of flight.
How big of a space telescope would we need to see this planet in any actual detail?
One of my sci-fi fantasies is to take a photo of an extrasolar planet and see someone else's city lights. :) Of course if we could see that we could also probably detect their radio emissions, but seeing someone else's lights would somehow be cooler.
The most promising technique at this point is to use optical interferometry to resolve the surface of the planet. In this case, you will need two telescopes (likely in space) separated by a baseline distance, "d". The two telescopes will require extremely precise synchronization in both spatial position and timing so that the light they collect will interfere at precisely the right phase, but if this can be achieved, the angular resolution of such a telescope in radians is wavelength/d. An earth sized planet has a diameter of ~13,000 km. To "resolve the planet", we would need to be able to distinguish one half of the planet from the other, meaning we need to see at a resolution of ~6000 km on the surface. Proxima Centauri is ~4 light years away, meaning that this requires an angular resolution of 1.5e-10 radians or 30 microarcseconds. That's over 30,000 times smaller than the angular size of a human hair held at arms length!) To achieve 30 microarcsecond resolution with our optical interferometer operating at 600 nm (visible light), we need the two telescopes to be 4 km apart, which practically doesn't sound unfeasible.
Alternatively, you could construct a 4 km telescope, but that's far bigger than any optical telescope we have now or in the near future (the biggest telescope in the next 20 years will be 40 meter in diameter).
The planet is about 0.05 AU from Proxima Centauri, meaning we need an angular resolution of about 1.9e-7 radians to even distinguish it from its host star. Is that realistic?
In theory, an orbiting space telescope has a diffraction-limited resolution of approximately 1.22λ/D (λ = wavelength, D = aperture size). Modern image processing techniques can improve on this somewhat, but it makes a good order-of-magnitude estimate. Anyway, this formula tells us a 4-meter telescope has a maximum angular resolution of about 1.8e-7 radians at a typical visible light wavelength of 600 nm. That would be just good enough... except that we don't actually have a 4 meter orbiting space telescope. Resolving even large features on the planet would require a much larger telescope, probably kilometers or more.
For ground based telescopes, the situation is even worse because of atmospheric effects. Despite being 10 meters in aperture, the Keck telescopes in Hawaii are limited to an angular resolution of about 2e-7 radians because of the atmosphere. However, there is reason to hope that the even larger European Extremely Large Telescope will have enough resolution (about 5e-8 radians? hard to tell from their official publications) to image Proxima b directly. https://www.eso.org/sci/meetings/2011/VLTI2011/presentations... Again, this is still not enough to resolve surface features.
So, long story short the answer is unfortunately no at present. Maybe space-based manufacturing will let us build a big enough telescope someday?
At ~500 light years away, even if we did see lights, who would we be communicating with _now_? And would it be disappointing if we saw a technologically-similar civilization that hadn't contacted us yet, being 500 years ahead of us?
Sometimes it's romantic to look up at stars that probably died a long time ago. Sometimes I hate that we can't see what's happening now.
Since we're all rolling out our best fiction here, here's mine:
We'll get there animating matter by means of beaming laser instructions onto it. We just need to discover how we can move atoms by simply shinning a laser onto them, a controlled pulse of different light frequencies that allows us to arrange atoms in such way that they become tiny building blocks of nano-machines, like making pizza dough: twisting, throwing, rolling, until we have the right shape. Once the first Lego pieces are ready, we use the same laser to instill the energy required to move them. These animated nano-machines will then auto-assemble and become a bigger machine until we effectively, and remotely, build and operate a full-featured robot. Said bot will send back everything we need: images, audio, chemical reads, etc. Furthermore, our bot can build more bots and eventually build the laser that can be beamed into the next planet to repeat the process and expand colonization.
Unfortunately, even laser light has too much divergence (due to intrinsic behaviour of waves) to remain one focused tight spot by the time it reaches Proxima Centauri, or even the outskirts of our solar system. https://en.wikipedia.org/wiki/Laser#The_light_emitted does say that the rate of divergence is inversely proportional to the diameter of the beam, so maybe if we make the beam really wide, it could reach Proxima Centauri without spreading too much.. I don't know how wide that would have to be.
I think we started a long time ago. The planet is a new find, Proxima Centauri is not. If there were anyone there capable of responding, I think we would have heard from them by now.
It's not only temperature, presence of water and distance to star. It's also a large variety of factors.
For instance... what is the atmospheric pressure? boiling point of water is affected by atmospheric pressure. Even if temperature is low, if atmospheric pressure is also low, water would boil at a lower temperature. In Mars for instance, water boils all the time.
Some people might say you can probably create more atmospheric pressure by terraforming the atmosphere. But not all planets can retain an atmosphere. Solar activity, planet magnetic field and gravity can affect that.
Then, gamma ray exposure. Radiation can sterilize a planet. It would be good to measure what is it like there.
Its hard to draw definitive conclusions when you're speculating from a sample of one! Imagine showing a child with no knowledge of animals a snake and asking her to describe what she thinks the other animals on earth are like and the habitats they occupy. I think there'd be a risk that she'd describe a range of snakes and possibly lizards, but wouldn't be able to imagine something radically different like a whale/eagle. That's the risk we run when our only sample is the earth.
Although we can't image it with current technology (JWST and Hubble both have resolution of 100 milliarcseconds) we might be able to within a few years.
IR inferometers will be able to give us some data in just a few years, and the E-ELT/TMT will also let us "image" it. The "image" won't be anything you can really look at (E-ELT has resolution one milliarcsecond) but it'll give us important data.
In the medium term a 22 GHz radio interferometer using the sun as a gravitational lens would be able to resolve 80 km diameter water clouds on Proxima b. This talk by the inventor of the concept for SETI purposes explains it pretty well: https://www.youtube.com/watch?v=ObvKVe5H8pc
The real trick is getting out 600 AU to the gravitational focal line for the light opposite proxima centuari and staying with ~10m of it via station keeping. The only medium term solution to get out there in under 20 years are electrostatic solar sails. See Bruce Wiegmann of NASA Marshall Space Flight Center's talk from yesterday on the Heliopause Electrostatic Rapid Transit System. http://livestream.com/viewnow/NIAC2016/videos/133764483
Does anyone here have an idea of which kind of resolution https://en.wikipedia.org/wiki/James_Webb_Space_Telescope will provide? I'm assuming that this little rock might not even occupy a single pixel, but I'd love to be wrong.
Is it feasible to send deep space probes to such planet? Let's say the probe is accelerated to high sub light speeds with ion thrusters. Can it reach it in some sensible time then?
Assuming the recently announced deep space travel project [1] works out and their estimates are correct (unlikely), it would take 20 years of preparation + 20 years of travel + 4 years of data transfer.
Also mentioned in [1] is that if Voyager 1 was headed for Alpha Centauri it would take 70,000 years.
No, it's mandatory. Just like articles about black holes has to mention "not even light" and articles about quantum entanglement has to mention "spooky action at a distance" ;)
What's super confusing to me is: If the planet is so much closer to its star, and the star is so much larger than ours, why does the artist's conception show the star as being so "small" (perceived size, not actual size) as viewed from the planet? Was the artist just not thinking straight that day, or am I missing something? Yes I understand it's an "artist's conception" but the question remains.
not too sure about how incorrect the artist's concept is, but we have to remember that Promixa Centauri is a red dward with about 1/10 the radius of our Sun.
Posted this story when it came out a week ago but it got no traction. [1] This is quite exciting but as far as I understand we are not quite there in terms of technology to reach it within my lifetime.
Nick Lane's book/hypothesis really change the way I think about life on other planets. His hypothesis is basically that the chances of Eukaryotic cells emerging from bacteria (via natural selection) are so rare (it only happened once in two billion years on our planet) that we really shouldnt expect to find intelligent life on other planets - rather the life we will most likely find will be small cells like bacteria and archaea, that lack a nucleus (and never get very big). He does a much better job of explaining why, but it is interesting nonetheless.
[+] [-] mjhoy|9 years ago|reply
> 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.
[+] [-] taliesinb|9 years ago|reply
The speaker even mentioned the previous incorrect HARPS announcement, which was later found to be an artefact due to the windowing function they used - a pretty embarrassing mistake. This new finding involves a completely different period: 11.2 days instead of the previous 3.24 day signal.
Also, link to the Nature paper for the lazy: http://www.eso.org/public/archives/releases/sciencepapers/es...
[+] [-] WilliamDhalgren|9 years ago|reply
This is around Proxima Centauri, the previous one was around Alpha Centauri B. Proxima is a really really small red dwarf, just 12.3% the mass of sun, while Alpha Centauri B is a K-type star, ie somewhat smaller than sun but not that much; around 90% of Sun's mass (And there's also Alpha Centauri A, 10% more massive than the sun). We're not even 100% sure that Proxima is part of the Alpha Centauri system, though I gather it's considered highly likely - it's pretty distant from the Alpha Centauri system, some 15 000 AU (1 AU = distance between Sun and Earth), almost a quarter of a light year.
[+] [-] titzer|9 years ago|reply
[+] [-] kjell|9 years ago|reply
Previously on HN: https://duckduckgo.com/?q=site%3Anews.ycombinator.com+cixin+... https://hn.algolia.com/?query=Cixin%20Liu&sort=byPopularity&...
[+] [-] afreak|9 years ago|reply
[+] [-] sehugg|9 years ago|reply
[+] [-] ourmandave|9 years ago|reply
[+] [-] dTal|9 years ago|reply
https://en.wikipedia.org/wiki/Fission-fragment_rocket
[+] [-] DominikR|9 years ago|reply
https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls...
An updated design from the 80ties calculated a time of 100 years:
https://en.wikipedia.org/wiki/Project_Longshot
And a nuclear fusion design is calculated to achieve 12% of light speed, thereby reducing time to reach the fourth nearest sun system in 46 years.
https://en.wikipedia.org/wiki/Project_Daedalus
So there are concepts that could make unmanned interstellar travel possible, even within a humans life span, it's just that it costs so much and the incentive is pretty low compared to the incentive countries had for getting objects into space. (primarily military incentives - get spy satellites and nuclear warheads into space to not fall back behind adversaries)
I believe that given a strong enough incentive humans could do it, no matter what current consensus is telling us.
Humans set out to work on reaching outer space without even having a design on how this could be achieved and we did it anyway.
[+] [-] pjmlp|9 years ago|reply
It might be just around the corner in space travel time, but those are quite a few light years still.
[+] [-] beefman|9 years ago|reply
Edit: Nuclear pulse propulsion is good for about half that (80yr, not 1000).
[+] [-] the_rosentotter|9 years ago|reply
[+] [-] defen|9 years ago|reply
[+] [-] m_mueller|9 years ago|reply
1.) A probe and a human spaceship are vastly different problems. Since all a probe really needs is electricity to sustain itself, you could get away with a tiny payload and some long lasting radioactive energy source, light sails or even sending the energy from earth's orbit. Such a thing would be either slow and cheap or fast (a few percent of light speed) and expensive, but not both at the same time and I doubt it would be in the trillion dollar range whatever you do.
2.) I completely agree that sending humans would currently not be feasible within a single nation's budget and the technology for that is still at the very least decades out (cryogenics, EM shielding, better propulsion systems, using mass from cheaper solar system bodies than earth etc.).
3.) 1000 years is what we'd need with conventional current technology. The theoretical limit for a nuclear impulse propulsion drive is 20% of light speed if you want to break or 40% for a fly-by.
[+] [-] gene-h|9 years ago|reply
Coincidentally, the group working on this will be presenting some of their most recent work on this at 2:55 EST today. You can watch that live here[2].
[0] http://www.deepspace.ucsb.edu/projects/directed-energy-inter... [1]https://www.nasa.gov/sites/default/files/atoms/files/2016_sy... [2]http://livestream.com/viewnow/NIAC2016
[+] [-] kilroy123|9 years ago|reply
[1] http://www.planetary.org/explore/projects/lightsail-solar-sa... [2] http://www.nasa.gov/centers/glenn/about/fs21grc.html [3] https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_ge...
[+] [-] boxy310|9 years ago|reply
[1] http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/2011001...
[+] [-] api|9 years ago|reply
One of my sci-fi fantasies is to take a photo of an extrasolar planet and see someone else's city lights. :) Of course if we could see that we could also probably detect their radio emissions, but seeing someone else's lights would somehow be cooler.
[+] [-] semaphoreP|9 years ago|reply
Alternatively, you could construct a 4 km telescope, but that's far bigger than any optical telescope we have now or in the near future (the biggest telescope in the next 20 years will be 40 meter in diameter).
[+] [-] Thorondor|9 years ago|reply
In theory, an orbiting space telescope has a diffraction-limited resolution of approximately 1.22λ/D (λ = wavelength, D = aperture size). Modern image processing techniques can improve on this somewhat, but it makes a good order-of-magnitude estimate. Anyway, this formula tells us a 4-meter telescope has a maximum angular resolution of about 1.8e-7 radians at a typical visible light wavelength of 600 nm. That would be just good enough... except that we don't actually have a 4 meter orbiting space telescope. Resolving even large features on the planet would require a much larger telescope, probably kilometers or more.
For ground based telescopes, the situation is even worse because of atmospheric effects. Despite being 10 meters in aperture, the Keck telescopes in Hawaii are limited to an angular resolution of about 2e-7 radians because of the atmosphere. However, there is reason to hope that the even larger European Extremely Large Telescope will have enough resolution (about 5e-8 radians? hard to tell from their official publications) to image Proxima b directly. https://www.eso.org/sci/meetings/2011/VLTI2011/presentations... Again, this is still not enough to resolve surface features.
So, long story short the answer is unfortunately no at present. Maybe space-based manufacturing will let us build a big enough telescope someday?
[+] [-] evilduck|9 years ago|reply
Here's one that does the math for the previously closest known Earthlike exoplanet (36ly) and Alpha Centauri (4.5ly).
https://www.reddit.com/r/askscience/comments/137klp/will_the...?
[+] [-] throwanem|9 years ago|reply
Impossibly big. I'm sorry.
[+] [-] kyriakos|9 years ago|reply
[+] [-] darkerside|9 years ago|reply
[+] [-] themartorana|9 years ago|reply
Sometimes it's romantic to look up at stars that probably died a long time ago. Sometimes I hate that we can't see what's happening now.
[+] [-] bikamonki|9 years ago|reply
We'll get there animating matter by means of beaming laser instructions onto it. We just need to discover how we can move atoms by simply shinning a laser onto them, a controlled pulse of different light frequencies that allows us to arrange atoms in such way that they become tiny building blocks of nano-machines, like making pizza dough: twisting, throwing, rolling, until we have the right shape. Once the first Lego pieces are ready, we use the same laser to instill the energy required to move them. These animated nano-machines will then auto-assemble and become a bigger machine until we effectively, and remotely, build and operate a full-featured robot. Said bot will send back everything we need: images, audio, chemical reads, etc. Furthermore, our bot can build more bots and eventually build the laser that can be beamed into the next planet to repeat the process and expand colonization.
[+] [-] FreeFull|9 years ago|reply
[+] [-] thedangler|9 years ago|reply
[+] [-] excalibur|9 years ago|reply
[+] [-] ngoldbaum|9 years ago|reply
[+] [-] partycoder|9 years ago|reply
For instance... what is the atmospheric pressure? boiling point of water is affected by atmospheric pressure. Even if temperature is low, if atmospheric pressure is also low, water would boil at a lower temperature. In Mars for instance, water boils all the time.
Some people might say you can probably create more atmospheric pressure by terraforming the atmosphere. But not all planets can retain an atmosphere. Solar activity, planet magnetic field and gravity can affect that.
Then, gamma ray exposure. Radiation can sterilize a planet. It would be good to measure what is it like there.
[+] [-] oli5679|9 years ago|reply
[+] [-] owenversteeg|9 years ago|reply
IR inferometers will be able to give us some data in just a few years, and the E-ELT/TMT will also let us "image" it. The "image" won't be anything you can really look at (E-ELT has resolution one milliarcsecond) but it'll give us important data.
[+] [-] superkuh|9 years ago|reply
The real trick is getting out 600 AU to the gravitational focal line for the light opposite proxima centuari and staying with ~10m of it via station keeping. The only medium term solution to get out there in under 20 years are electrostatic solar sails. See Bruce Wiegmann of NASA Marshall Space Flight Center's talk from yesterday on the Heliopause Electrostatic Rapid Transit System. http://livestream.com/viewnow/NIAC2016/videos/133764483
[+] [-] dang|9 years ago|reply
[+] [-] throwaway_yy2Di|9 years ago|reply
http://www.eso.org/public/archives/releases/sciencepapers/es...
(PDF)
[+] [-] Diederich|9 years ago|reply
[+] [-] lutusp|9 years ago|reply
[+] [-] bcjordan|9 years ago|reply
[+] [-] shmerl|9 years ago|reply
[+] [-] megalodon|9 years ago|reply
Also mentioned in [1] is that if Voyager 1 was headed for Alpha Centauri it would take 70,000 years.
[1] http://www.nytimes.com/2016/04/13/science/alpha-centauri-bre...
[+] [-] hoodoof|9 years ago|reply
[+] [-] dragonwriter|9 years ago|reply
Fairly common, as I recall, for articles about planets that either appear to be gas giants or appear to be outside of the "habitable zone".
[+] [-] kowdermeister|9 years ago|reply
[+] [-] natch|9 years ago|reply
[+] [-] zman0225|9 years ago|reply
[+] [-] sakopov|9 years ago|reply
[1] https://news.ycombinator.com/item?id=12302489
[+] [-] justplay|9 years ago|reply
[+] [-] misiti3780|9 years ago|reply
[1] https://www.theguardian.com/books/2015/apr/22/the-vital-ques...