ALPHA CENTAURI HAS A PLANET!

By Phil Plait | October 16, 2012 4:45 pm

Huge news! Astronomers have announced they have found a planet orbiting one of the stars making up the most famous star in the sky: Alpha Centauri, the closest star system to our own! At 4.3 light years distant, this is far and away the closest exoplanet known… and of course, it has to be.

Alpha Centauri is a triple-star system, composed of a binary star, two stars much like the Sun – one slightly larger and hotter, called Alpha Centauri A, and the other slightly smaller and cooler, called Alpha Centauri B – orbited themselves by a red dwarf (called Proxima Centauri) much farther out.

The planet orbits close in to Alpha Cen B, and is technically called Alpha Centauri Bb – planets have lower case letters assigned to them, starting at b. Its mass is only 1.13 times the Earth’s mass, making this one of the lower mass planets yet found! But don’t get your hopes up of visiting it – its period is only 3.24 days, meaning it must be only about 6 million kilometers (less than 4 million miles) from its star. Even though Alpha Cen B is a bit cooler than the Sun, this still means the planet is baking hot, far too hot to sustain any kind of life as we know it, or even liquid water.

Still. Holy crap! A planet for Alpha Cen. Wow.

The reason this is a big deal is twofold. For one, Alpha Cen is the closest star system in the sky. Because of that it’s very bright, and well studied. Planets searches have looked there for decades, and in fact for a while it was thought the dinky red dwarf Proxima might have a planet. Those earlier findings have been shown to be wrong, though. If it has a planet, it’s too small or too far out from the star (or both) to detect it easily.

The other reason this is important is that the signal from the planet is incredibly weak. It was found through its gravity. As it orbits Alpha Cen B, the planet tugs on the star, like two children holding hands and swinging each other around. This sets up a very small but detectable Doppler shift in the starlight. The more massive the planet is, the harder it tugs on the star, and the bigger the signal (making it easier to detect). Also, the closer in a planet is, the larger the signal is… and you get the added benefit of a short orbital period, so you don’t have to observe as long to see the cycle of the Doppler shift.

In this case, the planet is low mass but very close in. The Doppler shift in the starlight amounts to a mere half meter per second – slower than walking speed! When I read that I was stunned; that low of a signal is incredibly hard to detect. Heck, the star’s rotation is three times that big. But looking at the paper, it’s pretty convincing. They did a fantastic job teasing that out of the noise.

The graph displayed shows the effect of the planet on the star. RV means "radial velocity", the speed toward and away from us as the star gets tugged by the planet. The x-axis is time, measured in units of the period of the planet (in other words, where it reads as 1 that means 3.24 days). The dots look like they’re just scattered around, but when you average them together – say, taking all the dots in a one hour time period – you get the red dots shown (the vertical lines are the error bars). The signal then pops right out, and you can see the tell-tale sine wave of a planet pulling its star.

Amazing.

This is incredibly exciting to me! A few years ago, when I worked on Hubble, I looked into using it to search for planets around Alpha Cen. I worked out some simulations to see if we could detect anything, and at best we could see a Jupiter-sized planet orbiting far enough out that its faint light wouldn’t be blasted out by the star itself. It was deemed too risky an observation (too low a chance of payoff) so we didn’t get time on the telescope to make it. We’d never have seen this planet anyway; looking for a planet reflecting its star’s light is very different than looking for the Doppler shift. Obviously!

Also, c’mon. This is Alpha Centauri! Famed and fabled in a thousand science fiction stories. It’s where the Robinson family was supposed to go in "Lost in Space". It’s where Zefram Cochrane lived in "Star Trek". It’s where the Fithp came from in Footfall. Because the system is bright and close, and the stars so close to being like our own Sun, they’re an obvious place to put aliens. Plus, you get the exotic locale of a binary star plus the red dwarf thrown in on top. It’s perfect!

So I, and a lot of people like me, grew up hoping against hope we’d find a planet around one of these stars someday.

And here we are.

My very, very sincere and gracious thanks to the team that made these observations. Even if this planet is cooked to within an inch of its life, this is still literally a fantasy come true.

And it reinforces my own thinking that we are very close to finding a planet with the same mass as Earth at just the right distance from its star to have liquid water, and therefore, potentially life. We are finding planets the right mass but at the wrong place, and at the right place but with the wrong mass.

But we’re zeroing in on Terra Nova, folks, and statistically speaking there should be millions of them in the galaxy. It’s only a matter of time before we find the first one.

Image credits: ESO/L. Calçada; ESO/Digitized Sky Survey 2 (Davide De Martin)


Related Posts:

Exoplanet in a triple star system smack dab in the habitable zone
A nearby star may have more planets than we do!
Saturn and the nearest star
Theoretically, Alpha Centauri should have planets

CATEGORIZED UNDER: Astronomy, Pretty pictures, Top Post

Comments (180)

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  1. So is there a chance there could be another planet further out?

    At the very least, knowing that one planet is there might encourage future generations to travel to Alpha Centauri. It would be more likely if it was in the habitable zone though.

  2. Leonidas

    The sheer magnificence of this!! I’m jumping up and down with joy! I don’t care if it’s a hot, hellish world. It’s a planet around B Centauri and with an Earth-like mass! How friggin’ awesome is that?! Could there be more planets further out?

  3. Eric

    Another reason to travel across the void. I hope we can get there soon!

    Soon = My Lifetime. Perhaps the next 40 – 50 years.

  4. Andrew Brown

    Wow!!

    Time to fire up the Jupiter 2 :-)

  5. Eric TF Bat

    Just make sure you check for planning charts and demolition orders at the local planning office on Alpha Centauri, or we’re likely to have a nasty surprise.

  6. Robert Wildman

    Fortunately, it must be too hot for Mind Worms

  7. Do you have a link to the paper or team’s announcement?

  8. andy

    I guess the question we’re all asking now is, since Alpha Centauri Bb is sort of like a larger and more extreme version of Mercury, does it have craters that look like Cookie Monster?

  9. This is exciting news! It means (for one thing) that it will be worth building tools to look for and study planets around Alpha Centauri.

  10. Justin Higinbotham

    Wow, this is simply so cool/incredible. Like you say at the end, it is only a matter of time before we discover a planet suitable to life. I would say that that within the next few years, or decades, we’ll find planets that have atmospheres created by life, where we can say with 99% certainty that we’ve found life elsewhere in the universe. Every day, as I check out this site or browse the internet in general, some little part of me waits in anticipation for that momentous event!

  11. Jim

    When does it get a proper name rather than just a designator?

  12. Paul Buckley

    You mean “find the second one”.

  13. Why do they start exoplanet labelling with “b”?

  14. gameshowhost

    Man. I hope it’s inhabited by really hot chicks.

  15. Frost Bite

    Question: If this process used to find planets were used by a intelligent race in a solar system looking at ours, how many planets would they be able to detect?

  16. Jason Loxton

    Honestly, Phil, this is a bit embarrassing. Everyone knows that Alpha Centuri *HAD* an Earth-sized planet, Cybertron, but it was thrown out of orbit and now wanders the Galaxy. Tsk, tsk. http://tfwiki.net/w2/images2/7/76/Alphacentauri.jpg

  17. If hypothetically it were tidally locked, could it host life on the dark side?

  18. Laury

    What are the chances that one planet means possibly more? Is that a good indicator or just no way to tell?

  19. saphroneth

    @14 IIRC the primary for the planet is the implied a component. If there was a planet around Alpha Centauri A, it would be Alpha Centauri Ab.

  20. Betcha nickel there is more than one.

  21. Chris

    @14 Josh
    The “a” is reserved for the host star

    @15 gameshowhost
    I hear they are tall, blue and have tails :-D

    I wonder if there is a planet at an Earth like distance if we could see it using an IR telescope.

  22. Kappy

    @Josh:

    The star is considered a, in this case it’s a bit confusing as the star is binary. To use a better example, let’s take Gleise 581 which has become quite popular. Gleise 581 a would be the start itself, while Gleise 581 b through Gleise 581 f would be the planets in a 6 planet solution (it’s still disputed whether or not all 6 planets exist).

    -kap

  23. Uite

    Looks like a good reason to revive Project Longshot!

  24. If they don’t name this planet “Chiron” it will be a travesty. http://en.wikipedia.org/wiki/Sid_Meier's_Alpha_Centauri

  25. lepton

    Unbelievable!!!! Simply in tears!!!!

  26. Nick

    Now we just need to go there. We’ll fracture into 7 groups and each will take off based on their respective ideologies. I’m betting on the university of planet of course, though maybe the peacekeepers. The gaians also make a good show. Morgan industries, the believers, the human hive and the spartans will fall to superior technology in time. The mind worms will be somewhat annoying, but proper terraforming and good defensive planning, along with environmental safeguards will keep them manageable. Mostly the key is to just plant a ton of forests, while tech rushing for the tree farm and hybrid forest tech. The aliens will eventually show up, but we should have achieved transcendence by then.
    Unfortunately for that to work, we’d have to currently be going for a science victory, and that just doesn’t seem to be happening.

    This is great news. The percentage of stars with planets gets closer and closer to 100.

    Now if only gog.com would put up alien crossfire for download

  27. Jess Tauber

    Even if its too hot NOW to inhabit, if we’re smart enough to get there we’re smart enough to put a nice Venetian (Venusian?) blind between it and ist star. Then we just sit tight and wait for things to cool off (the blind will need maintenance). Use graphene, which is cheap and light, you don’t need much to make the blind, and you can modify it to only allow the light wavelengths you want through, and in the intensity mix you need. For industrial power you can leave holes for on-planet collectors. Or to keep your enemies in line.

  28. David

    This is great news for the robots that will replace humans, that will eventually travel there and see these planets.

  29. Jeff Dahn

    Fantastic news. It’s a shame that D.D. Harriman is no longer with us.

  30. Sam H

    There was a model that came out several years ago now that predicted planets in stable orbits in this sytem, with the possibility that they could be in the HZ (more likely for the smaller star).

    AND NOW THE THING I HAVE WAITED FOR FOR SO LONG HAS FINALLY HAPPENED :D

    The likelihood that there is another, now that we’ve found one, I would say is rather high. And if it lies in the HZ- then all interstellar missions for the forseeable future have a target. Hopefully they’ll name it Gaia Centauri or something of the like (especially if they were to find a living environment – then all my dreams would come true) :)

    ;ALSKJDF;ALSDHG;KLALSHDG;LJALJSGDL;KJASHDG;ALSJKDF;LASD;LGHALKJDSGH

    ^Sorry I’m just so damn happy right now :D :D :D

  31. Superluminously wonderfully marvellous news! :D

    Even if it is more like Kepler 10b or Corot 7b than Earth or even Mercury i.e. a Mustafar class super hostile superheated world.

    I expected and hoped that Alpha Centauri would have planets for a long time – now finally its confirmed. I really hope its not the only one and there’s more to come – round all three of this systems stars. Can’t wait to find out more. 8)

    @25. Erik Veland : “If they don’t name this planet “Chiron” it will be a travesty.”

    Sadly, the name Chiron is already in use for an asteroid /Comet orbiting in the outer solar system – it was the first “centaur’ class body ever discovered in the mid 1970’s. So I really doubt they’ll name this planet after it. (See link in name here.)

    Although Hydra is both a constellation and a Plutonian moon and there’s an asteroid Ganymed (not a typo!) as well as Jovian moon Ganymede so I guess you never know! ;-)

  32. Messier Tidy Upper

    See also :

    http://www.abc.net.au/science/articles/2012/10/17/3612356.htm

    Which adds the cautionary note :

    “I still have my doubts,” Hatzes (astronomer Artie Hatzes, from Thuringian State Observatory in Tautenburg, Germany – Ed. ) adds. “Even though there is clearly a signal in the data at 3.26 days, the nature of this is still open to debate.”

    More data – and more sensitive instruments – will nail down whether the planet actually exists or not, and if it has any siblings.

    Sorry tobe a slightly damp blanket with that. :-(

    Hopefully it’ll turn up a few better siblings in a system ranked highest for hosting a habitable world in Stephen Dole’s Habitable Planets For man study back in the 1970’s-60’s :

    http://www.rand.org/pubs/commercial_books/CB179-1.html

    See also :

    http://en.wikipedia.org/wiki/1036_Ganymed

    For asteroid

  33. This is so frakking cool. We should go.

  34. alfaniner

    They should name the planet “Jupiter II”.

  35. @ ^ alfaniner : What and get it confused with the name of an old rocket and the archaic name for one of the Jovian moons – I think Europa? ;-)

    FWIW, my naming suggestion,is using some of the alternative proper star names used for Alpha Centauri – eg. Rigil Kentauros, Toliman and Bungula. :-)

    (See link in name to Kaler’s Stars for at least the best known of those.)

    For instance, first planet found could be Toliman, next Bungula then Rigil Kentauros. Then perhaps Alpha Centauri’s name in other cultures e.g. Maori, Australian Indigenous peoples, Pacific islanders, Zulus, San (Kalahari “bushman”) and so on? I think that would be a good way of recognising history, other cultures and more.

    Although I wouldn’t mind some SF references either! Thinking of which, what, no one has yet mentioned the Centauri from Babylon-5!? Perhaps we should call it simply Centauri Prime? ;-)

  36. Minos

    Alpha Centauri Bb – pronounced “Alpha Centauri B-flat”?

  37. ggm

    We MUST built two ships ASAP ! The Jupiter 2, and the Enterprise NCC1701

  38. See :

    http://en.wikipedia.org/wiki/Centauri_(Babylon_5)#Homeworld

    Plus :

    http://en.wikipedia.org/wiki/Hydra_(moon)

    For the Plutonian moon & :

    http://en.wikipedia.org/wiki/Hydra_(constellation)

    for the eponymous, earlier named constellation.

    ‘Spose, yeah, if there’s a Hydra and a Hydra there can be a Chiron and a Chiron – also matches well with mythological Centaurs and the lumina (brightest star) of the Centaur constellation. ;-)

  39. @37. Minos : “Alpha Centauri Bb – pronounced “Alpha Centauri B-flat”?”

    But what if it turns out to be mountainous – it could have jagged diamond peaks with asphelt “snow” if its a carbon world like 55 Cancris e (see link in name) – or has a lava sea that’s really choppy stirred by storms of fountaining fire and tsunamis of molten tar? It might not be flat at all! Would we have to rename it B-sharp? ;-)

  40. realta fuar

    The importance of this is in the level of precision reached, more so than it happens to be Alpha Centauri B (after all, the Alpha Cen system is only about 6 light years closer than Epsilon Eri which also hosts a planet). The fact that it IS in the Alpha Cen system just gives it a “world record” feel, that makes it special. Haven’t been able to see the original paper since the site is so busy.

  41. Pete Jackson

    The distance between Alpha Centauri A and B varies from about 10 to 40 A.U. So if we use a rule of thumb that planets around components of a binary star can have stable orbits if they are within roughly 10% or less of the separation between the two stars, then indeed, component B could definitely have a planet with a stable orbit within its habitable zone. So, keep looking guys!

  42. The only reaction I had to this was “SQUEEEEEEEEEEEEEEEEE!” I think that sums up my excitement at this amazing discovery.

  43. Rollory

    ” planets have lower case letters assigned to them, starting at b”

    According to Star Control 2, a video game from 1992, the correct way to denote planets is with Roman numerals. It is moons that have letters. So this would be Alpha Centauri B I. If it had a moon, that would be Alpha Centari B I-a.

    The astronomy world had better get its act in gear and adopt this much better system. Video games – is there anything they can’t do?

  44. nafhan

    Awesome. Hope there are some of a similar size just a little further out (maybe at 150 millionish km).

    I also like that you mention Footfall. Great book.

  45. MrGrinch

    START BUILDING MARATHON

  46. Michael

    Great news! Was it discovered by Debra Fischer and company?

  47. mathmanprime

    The radial velocities shown are binned in units of 0.05 in phase, which is about 4 hours (though the observations were not taken in 4 hour groups), not the 1 hour stated in the post.
    I’m a little surprised that Debra Fischer’s group didn’t make this discovery first, as the observational program reported in the Nature paper isn’t THAT intense, only averaging about 1/2 hour per night. The world beating precision of HARPS must have won out.
    Oh, 0.5 m/s is about 1 mph (as stated in one of the press releases and easily worked out) which is about the speed of a maybe crawling, not a grown-up walking! 1 m/s is a pretty slow walking speed, unless you’re climbing a mountain…..

  48. OtherRob

    I knew I left a planet around here somewhere…

  49. Nemo

    I dunno about Alpha Centauri being the most famous star in the sky… I mean, you can’t even see it from the northern hemisphere. What about Sirius? Polaris?

    But most famous in SF, yeah, maybe (because it’s closest).

  50. andy

    Phil, great article! Thanks for explaining the method used to discover this planet: using periodic fluctuations in the red shift of a star. Could this method be as useful when a star has multiple planets orbiting it? Say a half dozen? That periodic red shift would be hard to detect from noise considering each planet would tug at the star over different periods.

  51. ceramicfundamentalist

    my god, if this is verified it’s probably the most monumental astronomical observation since galileo’s observation of io, europa, ganymede and callisto. and i’m glad i read it here second (saw it somewhere else, came here for verification).

    however, if i have to see the word “literally” abused in another post on this blog i will have to literally stop reading it forever. literally. phil, you are an intelligent man, please please stop relying on this exhausted trope for emphasis. i love you and all, but i literally can’t take it anymore. literally.

  52. You forgot to mention Douglas Adams’ “little furry creatures from Alpha Centauri.” :-)

  53. Randy Owens

    One caveat about getting too excited about hopes of finding such a world in the habitable zone. Like Phil said, it’s quite remarkable that they managed to tease out a 0.5 m/s signal. But, for a similar mass in the habitable zone, the signal would probably be something like 400-500 times weaker. (I believe that it would go as an inverse square; correct me if I’m wrong.) So, not easy at all. I wouldn’t be surprised if such a planet, if it exists, were found by direct observation with a telescope, before anyone managed to find it this same way. Not that that’s easy, either!

    ETA: Oh, and because you have to find the change in that signal over the course of a year or so, instead of three days and change. So, even more challenge there.
    ETA^2: Found a number for B’s HZ, so now, I’d say the signal might be only 250-300 times weaker.

  54. andy

    55 Cancris e

    As a 2nd declension masculine noun, cancer forms a genitive ending in -i. In this case it declines like ager rather than puer, so the genitive is cancri.

    Genitives ending with -is are for 3rd declension nouns.

  55. @ ^ andy : Hmm .. Don’t think that’s how they spelt it in ‘Collins Guide to Stars and Planets’ among a few other sources but okay. Have seen that version and always thought it was a typo but you may be right.

    @15. gameshowhost : “Man. I hope it’s inhabited by really hot chicks.”

    Given the distance from the star and consequent planetary temperature any chicks there would be hot alright! ;-)

  56. TheMessiah

    False:
    Planets don’t necessarily have to orbit starts. So there could be a closer one than Alpha Centauri.

  57. Giovanni
  58. Reidh

    And yet Once Again the the Conventional Theory of the Evolution of the Solar System goes into the crapper.

  59. Chip

    Very exciting news. Due to the similarities between both Alpha and Beta Centauri and our Sun in terms of types of star and metals, it seems reasonable that there could be additional planets within the system.

  60. dessy

    Great to see the development of the technology involved in this area. It will be great to see where this will go in the next few years, and what else will be found – now we just need the direct observations!

  61. Whoa! This is incredible news! I’m looking forward to learning more about any development in the next few decades. Keep us posted, Science!

  62. Andrea

    I suddenly feel an urgent need of playing Sid Meier’s Alpha Centauri! *_* Wonderful news!

  63. Steve

    Ahh, the Fithp. My favorite. They understood surrender. Too bad the humans didn’t. And A FRIKKIN PLANET THERE! All of the Whoo! And all of the Hooo!

  64. Thin_icE

    I don’t want to be that guy, as I do respect Bad Astronomy, and have been an avid reader for many years now, but there should be some mention of the team itself, I mean, european researchers deserve some credit too.

  65. anonymous coward

    @16 Frost Bite: None
    @19 Laury: Yes

  66. heng

    we are indeed living in interesting times!
    made my day, thanks phil for sharing!!!

  67. prianikoff

    “…a binary star, two stars much like the Sun”

    Alpha Centauri A is similar to our sun.
    But B has only 50% of its luminosity and emits more X rays.
    The orbital stabilities of planets circling such a binary star system would also differ from those in our solar system.
    A hypothetical planet in its Goldilocks zone might only have a stable orbit for 250 million years. This would significantly reduce the chances of complex life evolving there.
    On the other hand, if the nearest star outside of our solar system has at least one planet, they must be even more common than we once believed.

  68. Chris

    So now that we know it has a planet could we point Hubble at it and see it?

  69. Mirza10

    @52. Brian Says:
    “You forgot to mention Douglas Adams’ “little furry creatures from Alpha Centauri.”

    I scrolled down to say that. Also 5. Eric TF Bat made a very cheeky reference that went unnoticed. Sad.

  70. Nigel Depledge

    Rollory (45) said:

    Video games – is there anything they can’t do?

    The washing up?

  71. ctj

    one thing that always bugs me when people talk about whether a planet is in a star’s “habitable zone” is that frankly, we really don’t know enough even to say what what our own sun’s habitable zone is. we don’t understand enough about atmospheric density and composition to define the zone.

  72. Nigel Depledge

    Reidh (56) said:

    And yet Once Again the the Conventional Theory of the Evolution of the Solar System goes into the crapper.

    How so, Mr or Ms Wet Blanket?

    And why so many initial capitals?

  73. Nigel Depledge

    @ Chris (61) –

    Probably not. Even if Hubble could see the planet against the very-nearby glare of the star, the angular separation between the star and the planet will be very small indeed.

    Let’s see, the small-angle approximation is D = x*d/206265, where D is the linear size and d is the distance and x is the angular size in arcseconds (the numeral is a fudge-factor to convert from radians into arcseconds).

    If the distance between the star and planet is 6 million km, and the distance from us to Alpha Cen is 4.3 ly (and a light year is 9.4607 * 10^12 km), this gives:

    6,000,000 = x * ((4.068 * 10^13)/206,265)

    or

    x = (6,000,000 * 206,265)/(4.068 * 10^13)

    or

    x = 0.03 arcseconds

    IIUC, Hubble’s telescope has a resolution of 0.05 arcseconds under ideal conditions. Thus, even if the star and planet were the same brightness, Hubble could not resolve them as separate onjects.

  74. For more information on detecting extrasolar planets, delivered in audio format, consider the titanium physicists podcast, episode 7

    http://titaniumphysicists.brachiolopemedia.com/2012/01/22/episode-7-extrasolar-planets-with-ryan-north/

    … although we defer to the mighty bad astronomy blog when it comes to all things novel and astronomical.

  75. Why is it huge news? Why the capital letters? It would be surprising if it had no planets. It seems that every new planet is touted as the biggest thing since sliced bread. What’s the point?

  76. Pete Jackson

    @53 Randy: The pertinent equation, for planets of equal mass and varying distance from the primary star, is centripetal force = gravitational force. That is, v**2/r = G/r**2, where v is the velocity. This solves to v being proportional to the inverse square root of r. So, the velocity wobble of the primary for a planet of equal mass in the habitable zone would be about one third, or about 0.15 m/sec. What makes the detection really difficult, however, is that the period (P**2 = r**3) will be many months rather than a few days. That means many fewer periods in your dataset, making it much harder to find the weak signal.

  77. Drasail2

    Unmentioned in your article is the position of the ecliptic plane of Alpha Centauri B relative to earth. Is this the reason kepler-probe-type occlusion observations have failed to detect transient dips in starlight? Folks here want to fly there but what we really need are bigger better planet hunting space telescopes.

  78. nightfend

    Come on people, the planet is still over 4 light years away. That will take hundreds if not thousands of years of travel time for a probe to get there. Guess what, we have no technology that could survive that long to even make the journey. Not to mention that the likelyhood of the same stable government being around to receive the signal after the probe arrives there is doubtful as well. Face facts, the human race will live and die in this solar system. Interstellar distances are just too great.

  79. Chris

    @Nijel(66)

    Could the James Web Telescope see it?

  80. Venster

    The JUPITER 2 will soon be on its way!

  81. It would have been much harder to find this planet, but its residents’ silly hairstyles really made it stick out.

  82. Alaric

    Yay!!! Now, they need to name it “Nessus” or something- I know they don’t usually give exoplanets actual names, but come on! This is Alpha Centauri! It’s our stellar neighbor!

    (I appologize if someone’s already made this suggestion- I’m so excited I had to post before reading the comments.)

  83. g99

    I thought the most famous star in the sky was the Sun.

  84. @46 Rollory:
    There’s a good reason not to name things like that. Star Control 2 and other things like it name the planets I, II, III… in order of distance from the star. But for new exoplanets we don’t know how many there are in the system, so what numeral it should get. So b, c, d… in order of discovery makes more sense.

    This is suprising news to me, at least! It’s not the first planet in a binary, but still, Alpha Centauri is a closer pair with an extra star to perturb things. I would have bet against finding much there.

  85. abadidea

    Nigel Depledge #64 (who clearly is up on the astronomy thing): I was told a few years ago in school that it used to be thought that planets were quite rare, but now that it is dawning on us that they are quite common, we need to revisit our models for how solar systems form; not a wet blanket at all?

    Phillip Helbig #67: the point is that we are in the midst of a revolution of understanding about the nature of our universe. No biggie

  86. phdnk

    Wow!
    This planet enables us to search for others – if there is anything else in the system, it will affect the planet’s period and we will notice.

  87. Frost Bite

    @69 Someone finally answered. Though my guess was 1 or 2. Only Jupiter and Saturn, the rest would be over-shadowed by the gravitational pull of the giants. It’s my understanding of Accretion Theory that almost every star would have more than just one or two planets, and the larger the mass of the star at creation would have a larger accretion disk for more planets to form out of. Can someone set me straight on this perception?

  88. PsyberDave

    Huge news indeed. I’m suiting up now.

  89. This is great. A s we get better propulsion, we have a nearby target to study an exoplanet with probes and stuff.

  90. James Evans

    OK, rambling, speculative ignorance time…

    So, since we see solar systems noticeably different from our own (many planets with tight orbits and short periods, super-Earths, hot-Jupiters, etc.) out near/at/beyond the 1,000+ light-year range, and we now know our closest neighbor has a planet much like our own (broiling temps, yes, agreed…but probably no hot-Jupiters in closer to the star), does that suggest something unique about how planets and solar systems formed in our little cosmological ZIP code? To phrase the question more pointedly, should any future Kepler/Terrestrial Planet Finder type missions worry less about the type of suns they are pointed at, and more about what region of the galaxy?

    Exciting stuff, regardless of whatever silly presumptions I’m making when asking this question.

  91. Dang it!

    I’ve been toying with a science fiction story off-and-on for the last thirty years, which features aliens from Alpha Centauri. Now everybody’s going to think I chose Alpha Centauri just to be “trendy.”

  92. vel

    I would love to know how a planet could stand the forces involved at orbiting a star in 3.4 days at a radius of evidently around 4.3 million miles. This would be, I think, traveling at 1,144,559 miles an hour.

  93. anonymous coward

    @103 No, you’re absolutely right. Sorry, I was thinking about the inner terrestrial planets but Jupiter induces a solar radial velocity of about 12.5 m/s over a period of 12 years and Saturn about 2.75 m/s over 29.5 years so these two should be detectable provided the hypothetical extraterrestrial have enough patience but not the rest of the planets.

  94. Chris Winter

    “Also, c’mon. This is Alpha Centauri! Famed and fabled in a thousand science fiction stories. It’s where the Robinson family was supposed to go in “Lost in Space”. It’s where Zefram Cochrane lived in “Star Trek”. It’s where the Fithp came from in Footfall. Because the system is bright and close, and the stars so close to being like our own Sun, they’re an obvious place to put aliens. Plus, you get the exotic locale of a binary star plus the red dwarf thrown in on top. It’s perfect!”

    Also it’s where the aliens came from who left the Great Volume of Knowledge on Mars in Encounter with Tiber by Buzz Aldrin and John Barnes.

  95. Awesome! Superluminous! Additional adjective here! This is the sort of thing that really gets the imagination gears cranking…

    Question: Presumably, the radial velocity method makes it more difficult to detect terrestrial planets further out from the primary. Is it possible at all to use this method to detect an earth-sized planet in a “goldilocks zone” orbit? And if not, are there other methods that could find such a planet, if it exists?

    @24 Uite: Looks like a good reason to revive Project Longshot!

    That was my first thought too! :D

  96. I also love that Phil mentioned the Fithp. Honestly, there are probably many dozens of sci-fi stories involving Alpha Cen. Still, Larry Niven really has a way with creating compelling aliens.

    @28 Jess Tauber: Even if its too hot NOW to inhabit, if we’re smart enough to get there we’re smart enough to put a nice Venetian (Venusian?) blind between it and ist star. Then we just sit tight and wait for things to cool off (the blind will need maintenance). Use graphene, which is cheap and light, you don’t need much to make the blind, and you can modify it to only allow the light wavelengths you want through, and in the intensity mix you need. For industrial power you can leave holes for on-planet collectors. Or to keep your enemies in line.

    I like the way you think :) Still, I don’t think this would work. Perhaps on a planet with an orbit like Mercury’s it would, but this one is so much closer. For one thing, I’m not sure if a stable L1 orbit is possible with such a close orbit to the primary. Also, I’d be concerned that the irradiation would be such that the “sunshade” would heat up to the point where it’d still radiate too much heat for the planet to be habitable.

    @18 Vid the Kid: If hypothetically it were tidally locked, could it host life on the dark side?

    Well, you’d want some sort of atmosphere to distribute heat so that the dark side wouldn’t be too cold. Too much, though, and it’d still be too hot on the dark side. Then you have the problem of photoevaporation of the atmosphere, which could happen even if the planet has a magnetic field, with such high temperatures. And there’s the fact that you wouldn’t have photosynthetic organisms at the base of the food chain. I suppose you could have some sort of subsurface ocean capped with ice where organisms live off energy from hydrothermal vents, like some people hope might conceivably be the case with Europa… That’d be weird, eh? :) Larry Niven wrote one of his earliest stories about the “coldest place in the solar system” which (spoiler alert) was later revealed to be the “dark side” of Mercury. This was back before it was known that Mercury isn’t tidally locked, but in a 3:2 orbit/rotation resonance. A planet this close to its star, though, would almost certainly be tidally locked.

  97. amphiox

    Question: Presumably, the radial velocity method makes it more difficult to detect terrestrial planets further out from the primary. Is it possible at all to use this method to detect an earth-sized planet in a “goldilocks zone” orbit? And if not, are there other methods that could find such a planet, if it exists?

    I believe this question was in fact, answered indirectly. This planet is at the very edge of possible detection by current techniques. I think it was reported that a planet in AlphaCenB’s habitable zone that was 4 earth masses would produce a doppler wobble of the same size and detectability, and that it would take at least 8 to 10 years of continuous observation to confirm it.

    This would mean that no, an earth sized planet in the habitable zone, at least around AlphaCenB (perhaps other stars may have orbital configurations that are less noisy and easier to observe?), would not be detectable with our current technology. We would need to improve our sensitivity by a factor of 4.

  98. mike burkhart

    “I’m a little green man from Alpha Centauri nice place you aught to visit it sometime” (from a Star Trek episode Kirk to an Air Force interagator) Good News, now for two big questions 1 How many more planets are orbiting Alpha Centauri ? 2 Do any have life on them ? just think if there is a planet with life especaly intelegent life they are our next door neighbors.

  99. amphiox

    A hypothetical planet in its Goldilocks zone might only have a stable orbit for 250 million years. This would significantly reduce the chances of complex life evolving there.

    All the better! It means that we humans would be able to make use of such a planet with less concern for pre-existing native life (both practically and ethically).

  100. amphiox

    @103 No, you’re absolutely right. Sorry, I was thinking about the inner terrestrial planets but Jupiter induces a solar radial velocity of about 12.5 m/s over a period of 12 years and Saturn about 2.75 m/s over 29.5 years so these two should be detectable provided the hypothetical extraterrestrial have enough patience but not the rest of the planets.

    It would mean I think at least 36 years of observation for Jupiter and almost 90 years for Saturn, and that is assuming that the precision of their instruments is enough that they don’t need additional observations to iron out statistical noise.

    If we thus factor in time of observation, and the logistics required to set up and keep funding such continuous observations as part of the “process” and not just the technical aspects of making the observation, then for Saturn it would be a definite no, and Jupiter at best a borderline maybe.

  101. realta fuar

    The phase diagram shown is binned in units of 0.05 phase, which is about 4 hours, not the one hour stated. As stated in the press release, 0.5 m/sec is right about 1 mph, more like the speed of a baby crawling than a grown-up walking! I’m a little surprised that Debra Fischer’s group wasn’t the first the find this, as the Geneva group’s observing program wasn’t THAT intense, in absolute terms (averaging only about 30 minutes of observing time a night). The world beating precision of the HARPS spectrograph must have been the deciding factor.

  102. Benelson

    @1 Yes, it is entirely possible. And the fact that it is a near Earth-mass planet is particularly encouraging. “Hot Jupiters” were one of the first populations of exoplanets discovered, since they created the greatest Doppler signal. However, as time went on, very rarely did people find Hot Jupiter systems that contain multiple planets. Hot Jupiters are lonely. From a planet formation standpoint, this might make sense. Current formation theories suggest Hot Jupiters can’t form where we currently see them. They must have migrated from much further out, beyond the “snow line”. If there happened to be multiple planets in that system as the massive planet was migrating inward, the gravitational chaos probably ejected whatever resided inside. But the discovery of an Earth-mass planet (and no other strong Doppler signals other than the binary) so close to its host star means the system is much more flexible to contain more planets.

  103. @MrGrinch
    I do believe that the Marathon is to be sent to Tau Ceti, not Alpha Centauri. Patience. :-)

  104. shunt1

    This report provided the links to their raw data. That is all that I have ever asked for.

    I will probably spend the next few months to fully study what was published

  105. Eagerly awaiting the day when a series of deep-thrust telescopic probes conclusively establishes the existence of a habitable planet there….

  106. Jess Tauber

    re 90- nightfend, sir: why does practically no-one mention a self-bootstrapping quantum probe? You can create nano-scale components and use a massive system of in-line accelerators to get them up to good percentages of the speed of light. You make the number of components very large, with massive redundancy. They use particle emission to stay collimated in an an interstellar beam, and to decelerate using each other and electromagnetic force as anchors in concentric layers (only the innermost will get to the target with anything like a coherent spatiotemporal patterning). Then they self-assemble into your final probe, go into orbit, land, or say hi to the locals (later I assume we can construct armies for invasion of DNA sequences that can hijack the indigenous). We could be at Alpha C in a couple of decades (or anywhere else in the neighborhood).

  107. Kevin

    This news (and news release) on the 16th of October is a funny coincidence. I had put in my DVD of Lost in Space this evening, and the Jupiter 2 launched on October 16, 1997.

  108. “Phillip Helbig #67: the point is that we are in the midst of a revolution of understanding about the nature of our universe. No biggie”

    Revolution? No, not with regard to exoplanets. Good science? Yes. Interesting? Yes. Revolution? No.

  109. Dave Empey

    @53 ceramicfundamentalist, I don’t understand your issue. Why would you think this is not literally a fantasy come true for Phil?

  110. Zephyr

    @115 Joseph G,
    Exactly what I guessed, most if not all these planets that are orbiting very close to its parent star must have their orbit locked by tidal forces (i.e., their rotation synchronized rotation with the revolution around the star) except for those that have recently that orbit. Granted, there’s no way we can verify this trait with the current technology.
    Another characteristic that we can infer is the existence of an extreme geologic activity due to tidal heating from friction generated within the interior of the planet as it is pulled by the parent star likewise it occurs in Io, the innermost Galilean moon that orbits around Jupiter.
    Also, as in the case of Io, if there’s atmosphere it is probably very thin and variable.

  111. Jan

    Wow, this is great news! Wonder if mankind might try to push that planet a bit away to cool it down… :)

  112. davem

    Surely the significance of this discovery is not that some Sci-Fi fantasy has been fulfilled, but that, in the search for planets, we find that our next door neighbour also has planets. This implies that maybe EVERY Sun-like star has planets, and the search for an Earth-like planet will be so much easier than we originally thought.

  113. Academician Prokhor Zakharov

    Very good, very good.

  114. Nigel Depledge

    Chris (92) said:

    @Nijel(66)

    Could the James Web Telescope see it?

    Well, first, my name’s Nigel.

    Second, that’s an interesting question.

    In principle, my gut feelingh is yes, because, although the JWST works mostly at longer wavelengths than Hubble, it has a primary mirror that is 2.7 times the diameter of Hubble’s (6.5 m vs 2.4 m).

    Applying my wikipedia-fu . . . .

    The approximation for angular resolution of a telescope is :

    R = ([lambda]/D)

    where R is the angular resolution in radians, [lambda] is the wavelength of light and D is the diameter of the objective.

    Looking at wikipedia’s entry for the JWST, we find that it operates from 0.6 to 28 microns (µm), so let’s work this out for two wavelengths – 1 and 10 µm.

    For 1 µm:

    [lambda]/D = 10^-6 / 6.5 = 1.538 * 10^-7

    Converting from radians into arcseconds, we get a resolution of 0.03 arcseconds, so JWST might just resolve the gap, assuming that its detector is not overwhelmed by the light from the star.

    For 10 µm, the resolution is 0.3 arcseconds, so it would not be able to resolve the star and the planet in the near- to mid- IR, which is where it is designed to operate.

  115. “Surely the significance of this discovery is not that some Sci-Fi fantasy has been fulfilled, but that, in the search for planets, we find that our next door neighbour also has planets. This implies that maybe EVERY Sun-like star has planets, and the search for an Earth-like planet will be so much easier than we originally thought.”

    OK, but even so, big deal. It would be a surprise if there were no Earth-like planets. What is the significance of finding an Earth-like planet?

  116. Nigel Depledge

    Abadidea (99) said:

    Nigel Depledge #64 (who clearly is up on the astronomy thing):

    Heh. I fooled you with my wikipedia-fu!

    I was told a few years ago in school that it used to be thought that planets were quite rare, but now that it is dawning on us that they are quite common, we need to revisit our models for how solar systems form;

    It has been known for some time that our early models of how our solar system formed were over-simplistic, because the more people looked into the details, the harder it got to end up with the solar system we actually have.

    However, IIUC, our models never attempted any prediction about how likely planetary systems actually are, nor that they had to resemble our own. Up until the early ’90s, we had a sample size of 1.

    As it happens, our models of how planetary systems form are being revised using the data coming from planet-hunting surveys, but I’m not sure this (by itself) is either a surprise or a big deal to anyone.

    not a wet blanket at all?

    That part of my comment was more about the tone of the previous commenter’s post (#61 as it is now). Reidh’s comment comes across as, at best, morose or, at worst, snide and derisory.

  117. Nigel Depledge

    James Evans (106) said:

    . . . does that suggest something unique about how planets and solar systems formed in our little cosmological ZIP code?

    No.

    As far as we can tell, there is no reason to suppose that Alpha Cen and Sol formed anywhere near each other. Bear in mind that Sol itself has orbited the galaxy probably about 23 times since it formed.

  118. Nigel Depledge

    Realta fuar (120) said:

    As stated in the press release, 0.5 m/sec is right about 1 mph, more like the speed of a baby crawling than a grown-up walking!

    Eh? When was the last time babies crawled that slowly? Before he learned to walk, my little boy got up a fair turn of speed just crawling.

  119. Tim Gaede

    The two primary stars of the Alpha Centauri system tilt at an angle of only eleven degrees from Earth’s perspective. So, there’s a reasonable chance that the new planet could be seen transiting the star and a proposal has already been sent to the Hubble team to check.

    By the way, only 1.8% of the Earth’s surface is within eleven degrees of the north or south pole. That should give you some idea how lucky we are. Aren’t the distribution of the orientations of the neighborhood stellar systems random?

    Centauri Dreams

  120. ND

    Given the current technology, what is the fastest probe we can send to fly-by alpha centauri? Not to go into orbit, but to just send a camera and a few instruments to fly through the system?

    I was thinking of a combination of chemical rockets and ion engines. Assemble a multi-stage rocket in orbit which would be used to give a quick initial speed to the probe. I would think a large rocket similar to the Proton or Ariene 5 firing from Earth orbit would gain quite a bit of speed. All the probes we’ve sent to the planets left earth orbit thanks to a small dedicated rocket motor.

    The probe itself would be ion powered which would add to the initial speed gained by the chemical rocket.

    I’m sure this is most likely a naive exercise in rocket science, but the idea is to send a probe screaming out of our solar system at the fastest velocity possible with today’s technology.

    I guess the other issue is even if it’s possible, would we be able to receive radio transmission from a probe at the distance of alpha centauri?

    Nuclear power would definitely need to be involved. Which could potentially make the probe very heavy.

  121. James Evans

    @Phillip Helbig:

    OK, but even so, big deal. It would be a surprise if there were no Earth-like planets. What is the significance of finding an Earth-like planet?

    Well, phrased like that, not much. However, I personally feel this characterization cheapens the discovery. It isn’t just any old Earth-like planet that’s been found, but rather the first Earth-mass planet that orbits a Sun-like star, and it just so happens to be our closest neighbor. Stepping back and taking in the larger picture, I think you have to allow that astronomers and space enthusiasts are going to get excited when news like that first comes round. And perhaps rightly so.

    Due to the flood of exoplanet candidates/confirmations, I can appreciate where you are coming from, Philip, and to some extent I agree with you. Detections like this one are inevitable, and most likely will become routine in the coming years. Taking things a bit further, given the fact that the universe is one big, ubiquitous, prebiotic soup, as dispassionate, reasoned knowledge-seekers, we should expect to find life out there soon enough, and not succumb to the shock or thrill of that discovery either, especially since NOT finding life (if we are honest about the conditions we observe) would be the more surprising outcome. But maybe that’s being too cool for school, and at least immediately after the initial verification we can partake in some fairly harmless exuberance and celebration.

  122. amphiox

    re 131;

    I do agree that it is more evolutionary than revolutionary.

    We really overuse the word revolution too much. Everyone these days seems to want to be living through a revolution. We’re always looking for a revolution to live through, and call every interesting thing a revolution! (Have we forgotten that “may you live in interesting times” is actually and ancient oriental curse?)

  123. Tim Gaede

    A quick followup to my post that is (at this time) still awaiting moderation:
    Nevermind about the orientations of the star systems’ spin. That doesn’t really matter as the positions of the stars in the sky are random. So we are indeed lucky that we are within eleven degrees of seeing the orbits of stars A and B edge-on.

    Anyway, I’m curious about the prospects of a human-habitable planet further out from star B. The tidal influence of star B may be significant, though. At Earth’s equivalent distance from B, 0.71 AU, the tidal influence of B would be as great as our Sun on Venus, which has a very slow rotation. In order to have the same tidal influence of the Sun on the Earth, such a planet would need to be about 0.968 AU away from B and the blackbody equilibrium temperature would be 85% that of Earth.

  124. @116 Amphiox: I believe this question was in fact, answered indirectly. This planet is at the very edge of possible detection by current techniques. I think it was reported that a planet in AlphaCenB’s habitable zone that was 4 earth masses would produce a doppler wobble of the same size and detectability, and that it would take at least 8 to 10 years of continuous observation to confirm it.
    This would mean that no, an earth sized planet in the habitable zone, at least around AlphaCenB (perhaps other stars may have orbital configurations that are less noisy and easier to observe?), would not be detectable with our current technology. We would need to improve our sensitivity by a factor of 4.

    Thanks. I’ll be keeping my fingers crossed, then. Who knows, they might resurrect the Terrestrial Planet Finder or a similar mission. Hey, it could happen.

    @147 ND: Given the current technology, what is the fastest probe we can send to fly-by alpha centauri? Not to go into orbit, but to just send a camera and a few instruments to fly through the system?

    For info on this evolving area of research, look up Project Longshot, Project Daedalus, and Project Icarus. The first was a speculative exercise imagining a probe powered by pulsed inertial confinement fusion (lasers imploding and fusing He3 fuel pellets) which would accelerate to about 7% of C, then decelerate and enter orbit around Alpha Cen. The trip would take about 100 years. The second one, Daedalus, was a much more realistic and intensively researched project that also used pulsed fusion propulsion but didn’t bother with the deceleration step, entering the target star system (Barnard’s star, for some reason) at 12% of the speed of light. That’s one fast fly-by! It’d eject numerous sub-probes to get as much info about the system as possible during the short viewing window. This mission was projected to last about 50 years. The third, Project Icarus, is ongoing right now and is sort of a modern reboot of Daedalus, examining the problem with modern technology (Daedalus was undertaken back in the late 70s) and going into even more detail regarding exactly how this mission could be launched and what engineering obstacles remain to be overcome.
    It’s worth noting that the amount of He3 fuel needed for such a mission would greatly outstrip the amount that can be gathered on Earth, so even if we had the probe built already, we’d still need to develop Helium-3 mining infrastructure in space. Still, it’s exciting and inspiring to know that even now, humans are working on making such things reality :)

  125. James Evans

    @Nigel Depledge:

    James Evans (106) said:

    . . . does that suggest something unique about how planets and solar systems formed in our little cosmological ZIP code?

    No.

    As far as we can tell, there is no reason to suppose that Alpha Cen and Sol formed anywhere near each other. Bear in mind that Sol itself has orbited the galaxy probably about 23 times since it formed.

    Excellent clarification. Thank you for that, Nigel. And being that I’ve watched spiral galaxy formation simulations, and have been pretty stunned by the duration of the violent chaos/accretion, I should have known this.

  126. Ranger Jim

    Back when I was a youngun’, in the days of Hollerith cards and Fortran, there was something called the “Three Body Problem,” which was assumed to be pretty damn well unsolvable by any computer which was available to (and affordable by) Universities.

    I haven’t worked in programming (other than graphics) in quite a few decades, so I’m asking – in this instance (at least) has anyone done a 3-body analysis on this newly discovered planet, and if so, could it *ever* spend some time in the Habitable “Goldilocks” Zone?

  127. Matt B.

    The period of the orbit tells you the planet’s distance (knowing the star’s mass), and the magnitude of the Doppler shift tells you the speed of the star due to the planet’s orbit, but only in the radial direction (from Earth’s perspective). There is almost certainly a proper component of this speed (since no one has detected dimming of the star), so the planet’s combination of mass and orbital obliquity (relative to the normal of Earth’s POV) is ultimately what the Doppler shift indicates. You could get the same result from a more-tilted more-massive planet or a less-tilted less-massive planet.

    So how do they eliminate the degree of freedom relating the orbital tilt to the planet’s mass, to get to the point where they can say it’s 1.13 times Earth’s?

  128. @154 Matt B.:
    They didn’t. There is an annoying amount of confusion in science reporting between mass and minimum mass, and even things like exoplanet.eu used to mix them up. The paper, though, makes it clear 1.13 Earths is only the minimum.

    On the plus side, though, assuming a random inclination we can still expect a relatively small planet compared to most others.

  129. Captain KQA 11-222

    The first thing I wanted to do was grab the phone to tell Fleet Commander KQA 11-111 about the discovery of our home world but as I reached for the handset, I remembered that he was gone. Sometimes it’s a crock being 77 years old and having the most exciting things happen with the old star fleet gang gone. Oh, to be 17 again.

  130. Robert C

    Aw…POOH!! Just another place we could never walk on……there are NO shortages of these!! And…again…how in hell are we to get there?? In our minds…easy. In anything else….well dream on.

  131. andy

    OK, but even so, big deal. It would be a surprise if there were no Earth-like planets. What is the significance of finding an Earth-like planet?

    Actually it wouldn’t have been too much of a surprise if there were no planets. We really don’t have a particularly good handle on planet formation in close binaries, apparently the discs in such systems dissipate really fast, and for the most part are accretion-hostile (the binary induces high relative velocities between particles leading to destructive collisions rather than accretion). Before this discovery the only planets known in systems similar to Alpha Centauri were massive gas giants (Gamma Cephei Ab, etc), so the possibility was still open that such systems could only produce massive planets by gravitational instability, and such planets have already been ruled out.

  132. Just to be clear, I am worried about over-hyping something; this is usually not good in the long run.

  133. Koichi Ito

    It looklike planet orbiting Alpha Centauri B must be like giant hot Io (Innermost large moon of Jupiter). This make Alpha Centauri Bb hot and volcanic planet.

  134. SunnyD

    I hope this discovery will open us up to more possibilities of planets existing in “uninhabitable” environments and even expand our requirements for life existing, perhaps.

  135. marvintheparanoidandroid

    Need to reach Alpha Centauri B? Easy, in five steps:

    1) Get the Heart of Gold, go on board.
    2) Tell Eddie where do you want to go. Again, and again. Be patient.
    3) Warning: Do Not Ask For A Cup Of Tea To Any Electronic Device.
    4) Hit the Infinite Improbability Drive button.. done. In a mere nothingth of a second!
    5) Well, as a side effect, strange things could happen. Don’t panic.

    See you to Milliways, for a couple of Pan Galactic Gargle Blasters togheter!

  136. Nurseclaire

    I always have to smile when I hear the phrase “we’ve found a planet similar to Earth that might be able to sustain life.” To this I must ask:

    What has led you to believe that life, which evolved elsewhere, was in need of a planet similar to ours?

    Why would those beings require the same resources we do?

    Why limit our search to include only criteria that meets our own needs to sustain life?

    It is ridiculous to believe that life could only evolve exactly like we have, not to mention a rather self-important view on the universe. How close minded are we really? There is zero evidence to show that life could not evolve under very different circumstances than we have. Open your minds people! Consider a realm of ALL POSSIBILITY!

  137. @151. Joseph G :

    The second one, Daedalus, was a much more realistic and intensively researched project that also used pulsed fusion propulsion but didn’t bother with the deceleration step, entering the target star system (Barnard’s star, for some reason) at 12% of the speed of light.

    Pretty sure that was back when Barnard’s Star was – we now know wrongly – thought to have a Jupiter like planet or two orbiting it based on claims that were later revealed to be instrument error.

    An article linked to my name here – ‘Bad News, Space Fans: Barnard’s Star—One of Our Sun’s Closest Neighbors—Is Barren’ by Ross Andersen – has more info on that and the lack of exoplanets found so far round the second nearest star system to our Sun. In a nutshell from there :

    .. a group of researchers led by UC Berkeley’s Jieun Choi delivered the fatal blow to his data, when they revealed the results of 248 precise Doppler measurements that were designed to examine the star for wobbles indicative of planets around it. The measurements, taken over a period of 25 years, led to a depressing conclusion: “the habitable zone around Barnard’s star appears to be devoid of roughly Earth-mass planets or larger . . . [p]revious claims of planets around the star by van de Kamp are strongly refuted.”

    BTW. Wikipedia now has an separate page for Alpha Cen Bb too.

    Oh & on more suggestion – perhaps since it is “bb’ we could name it “Gun” or “King” after the respective air rifle and Blues singer respectively! ;-)

  138. Tom

    We better have a telescope pointing somewhere in the vicinity of Betelgeuse!

  139. @171 MTU: Pretty sure that was back when Barnard’s Star was – we now know wrongly – thought to have a Jupiter like planet or two orbiting it based on claims that were later revealed to be instrument error.
    An article linked to my name here – ‘Bad News, Space Fans: Barnard’s Star—One of Our Sun’s Closest Neighbors—Is Barren’ by Ross Andersen – has more info on that and the lack of exoplanets found so far round the second nearest star system to our Sun. In a nutshell from there :
    .. a group of researchers led by UC Berkeley’s Jieun Choi delivered the fatal blow to his data, when they revealed the results of 248 precise Doppler measurements that were designed to examine the star for wobbles indicative of planets around it. The measurements, taken over a period of 25 years, led to a depressing conclusion: “the habitable zone around Barnard’s star appears to be devoid of roughly Earth-mass planets or larger . . . [p]revious claims of planets around the star by van de Kamp are strongly refuted.”

    Interesting! I hadn’t even heard about exoplanet candidates orbiting Barnard’s star. Of course, as such a nearby star, I do hope they keep looking as the technology is improved – even a sub-Earth mass planet would be interesting. Imagine a Mars-like planet in the habitable zone, for instance!

    Oh & on more suggestion – perhaps since it is “bb’ we could name it “Gun” or “King” after the respective air rifle and Blues singer respectively!
    Hah! I love “King”. As an aspiring guitarist myself, I can personally think of no musician more deserving of his own planet (even if it is a rather hot and likely not-blue-at-all one) :D

  140. Nigel Depledge

    Nurseclaire (168) said:

    What has led you to believe that life, which evolved elsewhere, was in need of a planet similar to ours?

    What do you mean by “life”?

    Certainly life as we know it requires conditions like those we find on Earth.

    How do you propose we recognise – and search for – life as we don’t know it?

    Why would those beings require the same resources we do?

    Simple. Entities that we would recognise as living require certain resources (energy, raw material) and are constrained by the same laws of chemistry as we are.

    Why limit our search to include only criteria that meets our own needs to sustain life?

    Because this way we can define things to seek out that will be fairly sure indicators of the presence of life. We know that, for example, the presence of molecular oxygen is a likely indicator of life, but it’s not a certain one, because there exist other processes that can give rise to molecular oxygen in the atmosphere.

    It is ridiculous to believe that life could only evolve exactly like we have, not to mention a rather self-important view on the universe.

    Well, true, but do you have any evidence that anyone is actually behaving in this way?

    How close minded are we really?

    Did you mean closed-minded?

    There is zero evidence to show that life could not evolve under very different circumstances than we have.

    True, but so what?

    As I intimated earlier, how would we go about recognising and seeking life that isn’t as we know it?

    Open your minds people! Consider a realm of ALL POSSIBILITY!

    And perhaps you need to recognise two things:

    First, scientists are indeed speculating about outlandish and bizarre forms of life, ones that use biochemistry different from that we know on Earth.

    Second, the surest way to find life Out There is to find conditions that resemble those that we know can sustain life. On Earth, wherever life is even marginally possible, we find living things. Therefore, if we can find places elsewhere where we know life to be possible, we can go about identifying if it exists there as we might expect.

    This would tell us about more than just whether or not life exists in one other place. If we find a place where the conditions are favourable for life as we know it, but we don’t find any life there, that in itself tells us something more generally about how likely life is in other places. If we do find life there, it tells us that life is at least likely wherever it is possible.

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