Why you should care about the planet found orbiting Alpha Centauri, even though it's not a good place to live

Last night, astronomers with the European Southern Observatory announced that they'd found a planet orbiting Alpha Centauri B — an orange star a little smaller and a little less bright than our own Sun. That's important, because, while more than 700 planets have been found outside our solar system, this one — Alpha Centauri Bb (yeah, I know) — is by far the closest. To give you an idea of what we're talking about in distance here, imagine that we are Kansas City and Mars is Toledo. Alpha Centauri Bb is like Tokyo — but you have to get there the long way around and nobody has invented the boat or the plane yet. Basically, it's closer than any other planet we know of outside our solar system, but not really close close. Just 4.37 light years is still more than 25 trillion miles, which is still a long ways away.

Likewise, Alpha Centauri Bb is classified as an "Earth-like" planet, but that shouldn't give you any ideas of colonizing it Zefram Cochrane-style. Bb is way too close to its star for that — closer, even, than Mercury is to our own Sun.

But you should still be excited about this. Terrible, filing-cabinet name aside, Alpha Centauri Bb is jeffing epic. Until now, we didn't think our closest neighboring solar system had any planets at all. And because of the way planets work, writes Lee Billings at the Centauri Dreams blog, this single find means we're much, much more likely to discover other Centaurian worlds. Billings is a former guest blogger here at BoingBoing and his work on exoplanets is second to none. I highly recommend reading his full piece:

Anyone in the Southern Hemisphere can look up on a clear night and easily see Alpha Centauri — to the naked eye, the three suns merge into one of the brightest stars in Earth’s sky, a single golden point piercing the foot of the constellation Centaurus, a few degrees away from the Southern Cross. In galactic terms, the new planet we’ve found there is so very near our own that its night sky shares most of Earth’s constellations. From the planet’s broiling surface, one could see familiar sights such as the Big Dipper and Orion the Hunter, looking just as they do to our eyes here.

Read Lee Billings' full post about Alpha Centauri Bb, and keep an eye on the Centauri Dreams blog for further updates/analysis.

Read Phil Plait's take at Bad Astronomy

A helpful NASA primer on distance in space

• In the late 1980s, NASA considered sending an unmanned probe to Alpha Centauri B. It would have taken 100 years to get there, using nuclear explosions to create thrust.

Image: Marco Lorenzi via NASA's Astronomy Picture of the Day



  1. Correction: 4.37 light years is over 25 MILLION MILLION miles. Saying it’s more than 20 million miles is technically true, but about as useful as saying that New York city has more than 8 people.

    1. This irritated my nerd bone.
      Kansas City to Tokyo = 6255.5 miles = Dkct
      Distance to Alpha Centauri = 2.57^7M miles = Dac
      Distance to Mars = 140M miles = Dm

      (Dm/Dac) * Dkct = ~40 ft

      In other words, our trip to Mars, if Tokyo was Alpha Centauri, would be the equivalent of travelling about 40 feet from the center of Kansas City.

      Space is mindbogglingly huge.
      (I don’t need to say this, but if I made an error let me know and I’ll fix)

    2. It’s a distance that would take CENTURIES to traverse, even with technology that today is only theoretical.

      It’s a waste of time. Let’s work on problems at home first. The universe can wait for us to grow up as a species, learn to controll ourselves and live without brutality and greed.

  2. The “Lost In Space” family was trying to get to Alpha Centauri; maybe this discovery will prompt a mission, which hopefully won’t get lost on the way.

        1. But throughout their peregrinations, they often know how to return to Earth. They just don’t have the fuel or aren’t willing to sell Will into prostitution.

          1. They sometimes know how to get back to Earth, or think they do, but for the most part they are indeed lost … in space.  However, they (excluding Dr. Smith, obviously) remain steadfast in their hopes of reaching Alpha Centauri.

            As for the family’s supposed unwillingness to sell Will into prostitution, I will merely note that they seem quite comfortable letting him hang out with Dr. Smith and leave it at that.

          2. Lemoutan: Smith had, on various occasions, diamonds the size of rock candy, platinum by the pound, even some cosmonium (“the quintessence of the living force”); he was also declared king of a well-off alien civilization, which has to count for something (until the regicide clause goes into effect, anyhow).

            The problem, of course, is that none of this bought him anything, except perhaps trouble.

    1. Yes, I’d like to think so (to both parts of that that).  But first, remember, “a series of deep-thrust telescopic probes” (no doubt prompted by the theories of planetary habitability developed by Dr. Donald West) must “conclusively [establish] a planet orbiting the star Alpha Centauri as the only one within range of our technology able to furnish ideal conditions for human existence.”  The one just discovered certainly doesn’t fit that bill.

      Note, however, the propitious day of the announcement!

  3. If we’re roughly 100 million miles from the sun, that makes the distance from us to that planet approximately 250,000 times further.  So if it takes us about a year to get from here to the sun, it would take us about 250,000 years to get to that planet using our current technology.  Maybe that puts it in a different perspective.

    1. Not that we’d even want to attempt it with our current technology, to be sure.  However, when our technology is up to the task, consider that the benefits of relativistic time-dilation may come into play, improving the trip duration somewhat.

  4. I want to be excited about this.  However, given we can’t even seem to be bothered going to Mars any time soon, it’s hard to get excited about planets in other solar systems.

    1. But consider, Dan: this is perhaps the most dramatic evidence to date suggesting that ours is a universe (or at least a galaxy) full of planets.  Even our [next-]nearest stellar neighbor has them!  Consider the implications of that.

  5. According to my back of the envelope, I may well have dropped a zero somewhere calculations, if the distance from here to Alpha Centauri is scaled to the distance between Kansas City and Tokyo than Earth and Mars (at opposition, when they are at opposite sides of the sun are a bit less than 3cm apart. 

  6. In distance terms, travelling to Alpha Centauri compares to going to our Moon as travelling to the Moon does to hopping 12 feet.

    25 x 10^8  / 238 x 10^3

  7. So… about 25 years ago the tech existed, at least on paper, to send a probe that would get there in around 100 years. Had it been sent then, we’d be expecting photos from another planetary system in 80 years or so. Beyond my lifetime, but within those of many people now alive.

    Have there been any advances in rocketry that would make it possible to get cameras/instruments there any faster? Do we now have the potential to send a 50-year probe? Without the risks involved in blasting hundreds of tons of fissionable material from surface to space?

    Or is there any hope of a leap in telescope technology that would allow us to resolve that system almost as well as we could by sending a probe?

    Mars, Jupiter, Saturn, Titan, Venus, the sun, etc… there’s been a lot of exciting imagery and other data sent back from these places in my lifetime, and surely much more to come. But how cool would it be to get the same type of data from almost 5 light-years away?

    1. People have come up with ion-drive engines, nuclear engines, solar sails.  It’ll be another few decades before we can combine the best of them into a sub-light drive system to get a probe to Centauri in a reasonable time.

      1. I think the nuclear part makes it a non-starter unless a source of material can be found and exploited on the moon, Mars or in the asteroid belt.

        Remember when they launched Cassini, a lot of people freaked out, perhaps not without reason even though it turned out fine, over 72 pounds of plutonium fuel.

        Longshot, according to Wikipedia, would have had 264 metric tonnes of fuel, not plutonium-based but still radioactive. I don’t think anyone will ever try to get that kind of radioactive payload off the ground, no matter how safely it can be packaged. If nuclear is part of the mix, it will have to be built in space from materials sourced in space.

      2. If we had launched that probe in the 1980’s, when it arrived it would still be made of 1980’s technology.

        It would only be a useful probe if it was smart enough to arrive, look around, identify planets, and zoom in for some close-ups.  Also, it needs to send those photos back, and with any foreseeable technology, the best option is to BRING them back – which means a round trip.

        Also, I did the math once and I think I came up with 250 years for a constant 1G acceleration – which is, of course, far far beyond any foreseeable technology.

          1. With a crewless probe, of course, there’s no particular reason to stick to the 1G acceleration rate (or even the deceleration, if it’s a fly-by mission).  Then again, even achieving such an acceleration over a prolonged period is no doubt challenge enough!

  8. Everyone here seems stuck on the math/distance; you’re missing the point – This is Awesome! It’s a shame though that none of us will ever venture there.. :(

    1. Lots of things are awesome. Doesn’t mean they’re good for people as individuals or as a species. Setting off a nuke is pretty awesome (as a planet we’ve done it 2053 times!), but at worst it vaporizes cities and at best it poisons remote regions of the planets for eons to come and wastes untold resources in the name of ideological proxy warfare.

      The returns are too little, the costs too high. We have more pressing business on our own world – literally matters of life and death that concern millions and millions of people.

      1. Interstellar exploration (and eventual colonisation) is a matter of life and death for seven billion (and counting) people, and the rest of life as we know it.Dealing with the staggering problems which beset us here and now is critical, but that shouldn’t mean that we should turn our backs to the stars.

  9. If everyone can get over the need to correct Maggie’s math for a minute, and just take in what this means instead…

    1) This puts an exo-planet within our grasp, if we ever develop power & propulsion systems capable of driving a spacecraft interstellar distances at large fractions of the speed of light
    2) It outlines that planets can form in pretty much any type of system.
    3) It’s just damned cool.

    1. Agreed on the second and third points, but the first point contains a colossal IF in it.

      What real likelihood is there that we ever find a way to travel at large fractions of the speed of light? To say that this puts an exo-planet in our grasp is staggeringly premature.

      1. Over a long enough time scale, ANYTHING happening becomes pretty damn likely. So yes, I would say that there is a very real likelyhood that we will come up with very fast methods of transportation indeed, particularly when it becomes something that we need to do (i.e. if the Earth becomes inhospitable) rather than something that would just be pretty cool.

  10. Wow, do all of you really have to chime in on the distance thing?  I think she gets it…

    Thank you for the article!  I didn’t realize we could send a probe and be there in as little as a hundred years using advances on current tech.  

  11. A breeder reactor in space could produce more fissile marterial than it consumes. Fissile material could be packaged in such a way that, if there were a rocket explosion on the way up, it would be cobtained in a capsule and land in the ocean intact for recovery. So there are engineering ways to produce as much fissile material in space as we need.

    1. Spoken like someone who believes the media, politicians and the general public have a reasonable grasp of science and engineering.

      I’m sure that if anyone seriously proposed to launch a breeder reactor into space, the words “nuclear reactor” would be enough to set off a frenzy of doomsaying. It would never get as far as the launchpad, no matter how beautiful the engineering safeguards. Fear and ignorance would carry the day.

    1. We do already know the timeline – it’s not an eternal “5-10 years out” thing here. Zefram Cochrane makes his first successful warp flight in 2063. NASA could probably do it earlier, but WWIII gets in the way.

      I am not sure why I feel that a geektastic discussion of Star Trek history is more relevant than correcting Maggie’s math, but I do. In case anyone didn’t understand the reference, Zefram Cochrane eventually settles on an Alpha Centauri colony (among the first interstellar colonists from earth) after inventing the warp drive.

      1. Don’t forget first contact with the Vulcans! That’s the most interesting part. I mean, honestly – meeting another sapient species that not only is humanoid, but also by strange coincidence named themselves after ancient earth mythology? AND they speak English? That’s proof of a god, right there!

  12. But we should go and visit just in case the local planning office there has any plans on display (in a locked filing cabinet in a disused toilet with a sign saying “Beware of the space-leopard”) about creating a hyperspace bypass…

  13. Why don’t you guys support the petition to rename it then? http://www.change.org/petitions/international-astronomical-union-iau-rename-alpha-centauri-bb-to-something-more-inspiring

    1.  Ooh! I know! Call it “Tantalus”! Always seemingly within reach, but never actually obtainable!

  14. Harness an icy rock.
    Throw ice into GUT drive.
    Accelerate to halfway point.
    Turn around.
    Decelerate from halfway point.
    Take pictures and email home.
    Round trip for pictures could be 30 years if we get the damn drive to work. Hell, it could be 10 years round if we dropped some cash on the research into miniature black holes.

  15. Ah, but the real question is which faction of humanity will join with the native planet mind to become a god?

    On a more serious note I find this incredibly cool. I hope one day in the not extremely distant future we’ll at least be able to send probes to the closest star systems. How do their rocks and dirt compare to ours? Do any of these potential planets have weather systems like us (or even like the gas giants/ Titan)? Do they have tectonic plate movement? How strong are their magnetic fields? So many things to find out about…

  16. Zefram Cochrane?  I’m thinking Trevize, Pelorat, Bliss and Bander making their way to New Earth in Asimov’s “Foundation And Earth”.

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