Okay. It would be really cool if there were an earth-like planet orbiting the star nearest us. Now there’s news dribbling out about a putative discovery of a rocky planet in the habitable zone of Proxima Centauri. Except, unfortunately, the story is grossly premature and unreliable. A few warning signs:
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It’s a rumor published in Der Spiegel, a news magazine, not a scientific publication.
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The discoverers are unnamed. What science publication uses unidentified sources?
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The general source is the La Silla observatory, which previously claimed to have found an earthlike planet around Alpha Centauri B…a claim that was later retracted.
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The story gets stuff wrong.
Knowing that there is a habitable planet that a mission from Earth could reach within our own lifetimes is nothing short of amazing!
Whose lifetime?
The fastest spacecraft we’ve ever fired off, Voyager, is traveling at about 17 km/sec, which is fast alright — but it would still take tens of thousands of years to get there.
Fraser Cain, usually a reliable source, has already made a video about the ‘discovery’.
Nope, I still don’t buy it. There’s no evidence there. You could make the same video with generic science-fictiony images declaring that scientists have discovered little green men on Mars, and it would be just as convincing, that is, not.
The video also mentions Project Starshot, which would be one way of getting man-made objects to velocities somewhat closer to the speed of light. This scheme involves building 100-billion-watt laser arrays and firing them at laser sails hauling teeny-tiny chips with built-in micro-gadgets to do everything our regular space probes do and transmit the data back to Earth. Project Starshot is the baby of a Silicon Valley billionaire, so of course it must be a good idea.
You know, we’re kind of in a golden age of space exploration, with all kinds of information coming in from robots on Mars or flying around Jupiter. The real data is exciting, but these impractical fantasies are not.
I’m pretty sure there is definitely a rocky planet orbiting the star nearest us. In fact I doubt that’s in dispute at all ;)
Ah, there’s nothing more reliable than science by press release!
So, we know that there most definitely, positively, most assuredly may or may not be a planet orbiting Alpha Centuri B, as reported by an outfit that botched the last “discovery”.
No paper released, no peer review, no replication of observations and by the press, which has gotten more science reporting wrong than it’s gotten right.
That’s slightly more reliable than whale.to and infowars.
Ah, but don’t forget the brown dwarf that was “discovered” in our own outer solar system – on a highly inclined orbit – and just as good, based upon a sparse few observations.
I forget which live orbiting that one, the greens or grays. Or was it the plaid aliens?
I’ve lost track of the bullshit being reported as a scientific discovery, just in the past year!
Just having a rocky planet in the Goldilocks zone is not enough. Mars and Venus are also in the habitable zone for our solar system, and look at them. The planet has to be big enough so that it can build and hold a decent atmosphere over the long term. (Mars is not big enough), and it has to have the right balance of distance versus volcanic activity to not have an excessive greenhouse effect from volcanic outgassing (that summarizes Venus’ problem). There are probably other parameters that need to fall into place as well.
I understand how much of a long shot it is. And yes, a mission to that star in our life time us complety impossible. But a part of me gets a thrill that the odds of a conversation (Well, highly delayed call and response) between humanity and other intelligent life just got better, not worse.
I know it’s unbelievably unlikely, but it is cool
“Premature” would be the key thing here, since this isn’t even a press release. It’s somebody leaking possible info about a discovery by the La Silla folks, who themselves are refusing to confirm or deny it. It’s certainly possible that they found a planet with an Earth-like radius in what we would estimate the habitable zone of Proxima to be, but we’ll only know for sure if or when they publish the data (observations have already ruled out any possibility of a “super-earth”-sized planet in orbit around it).
Even if they found that, though, I’d be skeptical of its habitability until we can observe it directly and do spectrography on its light. Proxima Centauri is a very small (only 40% greater radius than Jupiter), flare-prone star. Any planet around it in its “habitable zone” would be tidally locked and periodically hammered by flares or frozen by sunspots.
@PZ Myers
It’s not something we’re going to be doing any time soon, but if we did want to do an interstellar probe at some point it would draw upon similar ideas: small-as-possible destination probe, front-loaded acceleration here in the solar system so the mass can be kept lower, etc.
@wzrd1
It wasn’t a “botch”, just a possible detection that was at the edge of what is possible in terms of planet detection. Nobody was really surprised when it couldn’t be confirmed or detected.
Brett @ 5
Technically we don’t need to observe it directly to do spectroscopy, if it is transiting. We can use the fact that we can get a spectrum of Proxima Centauri when the planet is behind the star, then one where we would get both star and planet, and subtract them. We’ve only done this with gas giants, though, which would be brighter. And red dwarf spectra are annoying because they are cool enough to have molecular bands, rather than nice sharp lines.
(The downside is that the folks at La Silla search for planets using radial velocities of the planet, measuring the Doppler Effect as planets nudge their stars, which means it is harder to get things like atmospheric spectra. Also they tend to find larger planets than the transit searches, but looking at red dwarfs lets you find smaller planets.)
Another thing that occurs to me is that the fact about red dwarf spectra means that a lot of radial velocity searches stick to more sunlike stars. They’re trickier to measure their spectral lines shifting as a planet tugs them around, because they are faint, and they have these annoying broad molecular bands.
Pshaw. Rocky planet around a nearby star? Who cares? We’ve got Tabby’s star with anomalous dimming that one scientist thinks can only be explained by a Dyson sphere. Of course, other scientists have poked some holes in that idea.
While the relatively small mass of Mars and rapid cooling of the core are the primary reasons for its very low atmospheric pressure (rapid cooling also means that there is a lack of volcanic activity), the lack of a significant magnetic field and the solar wind are currently important factors.
http://www.skyandtelescope.com/astronomy-news/mars-losing-gas-to-solar-wind-0911201523/
Another reason to be cautious (as if we really need more) is that Proxima Centauri is a red dwarf, a type of star that is quite likely to experience large fluctuations in output. As a result of which, they are generally considered terrible candidates for alien life.
#1
Zing!
#3, marcoli
A sufficiently strong magnetosphere and a relatively cool atmosphere can apparently be traded off against mass, when it comes to retaining an atmosphere. Exhibit A: Titan (which lies within Saturn’s magnetosphere). The larger problem is that we have far too little data to work with… just 4 different atmospheres. Even the notion of a Goldilocks zone may not be particularly useful in the search for extraterrestrial life.
As an astronomer I fully agree that skepticism and patience are warranted. Nevertheless, as some colleagues have pointed out to me there is a project likely connected to this, and they have a webpage at palereddot.org. That website lists a paper that is in refereeing. So most likely the der Spiegel reporter has jumped the gun on acceptance of the paper by a month or so.
Pando’s?
I wish people wouldn’t use Voyager as an index of how fast we could get to the stars. It wasn’t designed for that. There are several plausible (though, of course, not yet tested) ways of getting to Proxima Centauri within a human lifetime*. Not, admittedly, within my lifetime or yours, so the story is wrong to that extent.
* The Centauri Dreams website has interesting discussions: http://www.centauri-dreams.org/?p=34937
If you want some really cool results, wait for the release of the first catalog from the Gaia astrometric satellite this September!