The binary stars of Alpha Centauri, as seen from Saturn

Earlier this week, we learned that there is (most likely) at least one planet orbiting the star Alpha Centauri B. If you want to get really in-depth on this discovery, how it was made, and what it means, you should be reading Paul Gilster's Centauri Dreams blog.

I wanted to highlight this image, specifically, in order to quote some particularly evocative writing that Gilster posted yesterday. Cue the stirring music:

When planet-hunter Greg Laughlin (UC-Santa Cruz) took his turn at the recent press conference announcing the Alpha Centauri B findings, he used the occasion to make a unique visual comparison. One image showed the planet Saturn over the limb of the Moon. Think of this as the Galilean baseline, for when Galileo went to work on the heavens with his first telescope, the Moon was visually close at hand and Saturn a mysterious, blurry object with apparent side-lobes.

Laughlin contrasted that with [this image], showing the Alpha Centauri stars as viewed from Saturn, a spectacular vista including the planet and the tantalizing stellar neighbors beyond. Four hundred years after Galileo, we thus define what we can do — a probe of Saturn — and we have the image of a much more distant destination we’d like to know a lot more about. The findings of the Geneva team take us a giant step in that direction, revealing a small world of roughly Earth mass in a tight three-day orbit around a star a little smaller and a little more orange than the Sun. What comes next is truly interesting, both for what is implied and for what we are capable of doing.

Read the rest of this post, which explains what happens next with the research and why astronomers will be focusing their planet-hunting efforts on Alpha Centauri B.


  1. Inspiration drove me to mash up the Cassini team’s image with Stanek’s as two simple HD desktop wallpapers:

    Someone with talent could do better,  though I did try to honor the source images by ensuring the non-space pixels of both images remained unaltered.

  2. We have seen people our ancestors would not believe.

    I just hope they are not lost like tears in the rain.

  3. A truly amazing image! I don’t recall ever seeing the stars of Alpha Centauri separately before.

    The importance of this discovery can hardly be overstated: because there appear to be more multiple star systems than single star systems, now that we have found an Earth-sized planet in a binary system right next door to us Drake’s equation virtually guarantees life elsewhere in the universe. That might still be a bit optimistic, but the odds have skewed hugely in favor of it.

  4. Important additional factoid, Maggie:
    Centauri may actually be a trinary system, consisting of Alpha Centauri A, Alpha Centauri B and red-dwarf Proxima Centauri, too dim to see here but is the nearest known star to Sol.

    Currently, Proxima is 0.2 light-years from the Alpha Centauri twins, but it hasn’t yet been positively confirmed if it’s gravitationally bound, or if it’s just “passing through”, so to speak.  Although at that distance, it’s surely generating quite a stir in that Oort Cloud.
    Think about this:  two suns and an impressive swarm of eccentric-orbit, first-time comets (HUGE tails).  Wouldn’t wanna be there, but send an unmanned probe and beam back some uncompressed digital postcards… please?

  5. Does anyone know why only those 2 stars are visible? I would have thought that if the camera’s lens was open enough to sufficiently capture the light of these twin suns, then it seems like there would be so many other stars visible as well.

  6. It’s beautiful, and shows humanity’s march of technology.  First, spotting the planets and differentiating them from stars.  Then, a few hundred years later, actually visiting the planets.  Then, differentiating distant planets from their stars… and… eventually in a few hundred years or maybe another hundred years… visiting those planets on other stars…  It’s a beautiful thing.

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