Discovery of dark energy nabs Nobel Prize for three astronomers

By Phil Plait | October 4, 2011 11:52 am

I am very pleased to write that the Nobel Prize for physics this year has been awarded to three astronomers for their discovery of dark energy — a still-mysterious phenomenon that is causing the expansion of the Universe to accelerate.

Saul Perlmutter, Brian Schmidt, and Adam Riess are sharing the award. Back in 1998, Saul and Brian headed up two rival teams trying to observe very distant exploding stars, hoping they would yield better numbers for how fast the Universe expanded. Adam was on Brian’s team, and led the work on finding a way to try to understand the behavior of the supernovae. To everyone’s surprise, the data indicated the Universe was not just expanding, but expanding faster every day — it was accelerating.

Something must be pushing on the very fabric of space itself, causing it to expand ever-faster. We don’t now what it is, exactly, but we call it dark energy, and over the past 12 years, more and more observations have piled up showing that this stuff really is out there.

If you want background info on all this, see the Related Posts section below; there are plenty of links to articles I’ve written on this topic. The folks at Hubble also created a video describing dark energy and what it means for the Universe.

This is very exciting for lots of reasons. First, of course, it’s nice to see an astronomical topic win what is considered the top prize in science. Second, because I predicted it would years ago (not that this was all that difficult to see coming!). And third, for personal reasons, because I know all three of these men. I worked with Brian and Adam back in the day; the project Brian headed up to observe distant supernovae was part of a project using Hubble to observe supernovae in general, and I worked on a different aspect of it. Adam and I were both grad students at the time; after I got my PhD I went to work on a different Hubble project, and Adam stayed with the team, cracked the supernova code, and now has a Nobel Prize.

I suspect that was the right move for him.

Saul, too, is an acquaintance; I first met him at a talk he gave in 1999, and he was also on a panel I moderated for Discover Magazine in California a couple of years ago.

All three of these men have worked for a long, long time on this problem, essentially devoting their lives to it. It’s very, very nice to see that pay off. It’s richly deserved!

Related posts:

The Universe is expanding at 73.8 +/- 2.4 km/sec/megaparsec! So there.
News: dark energy stunts your growth
The Universe is expanding at 74.2 km/sec/Mpc
Hitting the gas
The Universal expansion revisited
What astronomers do
AAS Post #6: The cosmological not-so-constant

CATEGORIZED UNDER: Astronomy, Cool stuff

Comments (47)

  1. I can just imagine Zach making some sort of a comic with a ginger astronomer doing a pelvic thrust or some other gesture at some physicists telling them to eat his shorst. Or something equally highbrow. 😀

    Well done to all, and congratulations. The City Hall in Stockholm is a cool place, and I always loved seeing the peagantry around the award ceremony.

  2. Brian Powell

    I’d be careful with this….the prize was awarded for discovering the accelerated expansion of the universe — not dark energy! Importantly, the *cause* of the accelerated expansion is still unknown, and remains an active area of current research. Sure, dark energy is one explanation, as is a cosmological constant or modified gravity.

  3. DigitalAxis

    Adam and I were both grad students at the time; after I got my PhD I went to work on a different Hubble project, and Adam stayed with the team, cracked the supernova code, and now has a Nobel Prize.

    Yeah, but your blog is probably a lot more entertaining than his.

  4. Chris

    I wonder if this is the first Nobel Prize for discovering something but having no idea what it is.

  5. Congratulations to the three astronomers for the excelent work!!

    I hope one day we will have a new category in the Nobels: “Nobel Prive for Bad Astronomy!” First winner: Phil Plait

  6. Tom (H. Type)

    (3) Chris: Obama won a Nobel Peace price…

  7. J. Rich

    @3 not withstanding the comment by greatest modern day comedian @6, I’d say Penzias & Wilson:

  8. Jose

    There was an article a few weeks ago in that mentioned a theory that the Universe Expansion might be an illusion based on our location in the universe and how we might be a separate entity or bubble expanding while the Universe as a whole is actually decelerating. I don’t know if this idea has enough evidence to hold up, but based on this news I guess there is more evidence that the Universe is indeed expanding than of this “illusion” idea, but still we may need to look into it.

  9. Rahul

    How is this discovery different/improved from that of Edwin Hubble and others who followed in his footsteps? Was he not the first to notice, study and realise the universe was expanding based on red-shift and other methods?

    I just want to understand what these authors have done differently or better than Hubble. I understand they used supernova to measure more accurately but is that all or is there more to this?

  10. Marc

    Note that on the same day, the European Space Agency selected a new mission, Euclid, to be launched in 2019 to address exactly the question raised by this discovery: what is the nature of “dark energy”… The two events are disconnected, but it’s fascinating to see them happening on the same day. Actually I wonder how ESA could have justified not selecting Euclid on the day the nobel prize is awared to the discovery of the re-acceleration of the Universe’s expansion. If you want to know a bit more on Euclid, here is the link to ESA’s press release.

  11. Robin

    Excellent. To look at the list of people who’ve won Nobel Prizes in physics and to look at the arc of scientific discovery over that interval…..Oy, it’s a beautiful, wondrous thing.

    A one time state motto for Ohio was “The Heart of It All,” but we all know, in reality, physics is the heart of it all. Physics…….and Salma Hayek.

  12. jack21222

    I’m quite happy to see a Nobel prize coming to Baltimore. Congrats, Dr. Riess and the others!

  13. johnthompson

    As Brian Powell said @#2, the prize wasn’t won for dark energy, it was won for discovering that the expansion of the universe is accelerating. The NEXT (and second) Noble prize in optical astronomy could go (or might already have gone) to the four people on the first two exoplanet papers, except for that pesky Nobel three-body problem.

  14. Daniel J. Andrews

    I would love to know how many Nobel prize winners do some kind of funky dance in the privacy of their own homes after hearing the news they’ve won. I know I get pretty excited over a new Sir Attenborough documentary–think I’d throw out my back if I won the Nobel prize (not that there’s any imminent danger to my back….)

  15. Pete Jackson

    And you also worked on another Nobel-prize winning experiment, namely COBE.

  16. Daniel J. Andrews

    For Nobel trivia buffs, this was also the first time the prize has been awarded to a dead scientist.

  17. Orozco

    @Rahul (#9) A few other (#2, #13) have pointed this out, but not directly to you, so here goes: While Hubble discovered that the universe is expanding, this prize was for the discovery that not only is the universe is expanding, but the rate at which it is expanding is going up.

  18. Julie

    And Sheldon Cooper is denied his prize yet again. 😉

  19. Rahul

    @Orozco Thanks.

    However, Hubble and others did realise it wasn’t just expanding, but in fact the universe was accelerating. So how is this new discovery really new? Or do I have it completely wrong, that Hubble et al. discovered expansion but not acceleration of the expansion?

    This is what I get from NASA’s website:
    Hubble, the telescope, also helped discover that not only is the universe expanding, the expansion is accelerating. The mysterious force causing this acceleration is dubbed dark energy.

    Is this comment related to the three people being awarded the NP or did other people already have this figured out earlier? Again, if the latter, what is new in the paper who are to achieve this high recognition?

  20. Rahul

    Never mind, I found my answer! :-)

    The discovery was made a decade ago by these very three people that are now being recognised.

  21. Crux Australis

    So, how quickly the the expansion rate increasing? What’s the rate of change of the Hubble constant?

  22. Chris

    Phil is hoping to win the Ig Nobel Prize :-)

  23. CB

    @ Rahul:

    Yeah, Hubble recognized that the universe was expanding, but not that it was accelerating. That’s why, up until the observations that resulted in this prize, it was an open question whether the fate of the universe was to eventually collapse, reach a steady state, or to expand forever, depending on the amount of mass-energy in the universe and thus its overall geometry. However even in the last case the rate of expansion was still expected to decrease, asymptotically approaching zero.

  24. Ashish

    @ Rahul
    Are u mixing discoveries of Edwin Hubble and Hubble Telescope ?

    Edwin Hubble found that the universe was expanding.
    Hubble Telescope found the Universe expansion rate is accelerating.

  25. Is this the ‘discovery of dark energy’ or a discovery of one of the effects of dark energy?
    Either way, it is seriously cool to answer one of the biggest questions to face astronomy ever. Well done fellows!

  26. crf

    I predict Astronomers will win next year’s prize as well, for exoplanets.
    Christian Marois, Gordon Walker and one other?

  27. SLC

    This finding was totally unexpected, just as the result of the Michelson/Morley experiment was totally unexpected more then 120 years ago in the 19th century. The notion that dark energy, whatever it is, makes up 75% of the gravitating matter (albeit repulsive) in the universe is mind boggling.

  28. MadScientist

    I was at Brian’s workplace yesterday but I didn’t see him there – nor did anyone tell me he had been nominated (no one would have known at the time that he had got the award). I’ll have to find time for another trip up the mountain …

    By the way, if you enjoyed the beautiful Oddie telescope when you were at Mt. Stromlo, the telescope (and I’m told the mount and clockwork drive) had been faithfully reproduced. Although the loss of the then rarely-used 74-inch telescope and the 50-inch Melbourne (among others) was quite tragic, the Oddie was just such a beautiful work of art and everyone loved it – I can’t wait for Oddie-II to go into a dome and see it in action.

  29. Adrian

    “I am very pleased to write that the Nobel Prize for physics this year has been awarded to three astronomers for their discovery of dark energy ”

    I know “dark energy” is cool, but unless you have evidence this is NOT the cosmological constant, there is no reason to promote new (fundamental?) fields to solve the “mystery” of this problem – Occam’s razor.

    Are you a scientist, or do you work in PR? :-)

    I’m not saying that it is the cosmological constant, but most of the arguments against it are theoretical problams rather than empircal.

  30. Chris

    I teach a gen chem class and in the first class I told them the makeup of the universe and that 96% we have no idea what it is. It’s also kind of funny that most of the elements (ignoring hydrogen and helium) make up <0.04% of the universe. We are an impurity. Looking back it's amazing that 10 years ago when I was sitting in those seats we didn't even know 96% was missing. Amazing times we are living in.

  31. Peter B

    Yay for Canberra! (Brian Schmidt works at the Australian National University here.)

  32. Timbo

    Wasn’t there supposed to be 4, but one of them died a few days ago?

  33. RwFlynn

    Thanks to you I knew exactly what a Type Ia nova was when this story was mentioned on The New Scientist website.
    /my $.2

  34. db26

    We are all just dust in the wind, dude (or dust in the vacuum in this case).

  35. “I know “dark energy” is cool, but unless you have evidence this is NOT the cosmological constant, there is no reason to promote new (fundamental?) fields to solve the “mystery” of this problem – Occam’s razor.”

    Exactly. As Sean Carroll pointed out, essentially everything has energy and lots of things are dark. “Dark energy” is just a stupid “marketing” term which is all style and no substance, all presentation and no content, something from a spin doctor or an add agency. Scientists should promote understanding the universe, not trying to sound cool.

    As to whether we need a deeper understanding of “what” the cosmological constant “is”: do we need a deeper understanding of what gravitation “is”, i.e. “why” it exists, or is it enough that GR describes it well?

    Nobel originally specified “invention or discovery”, so there is no problem that all the details are not understood. In fact, discoveries which are difficult to understand are more interesting.

    Note also that Hubble came to believe that the expansion of the universe was not real, though of course he discovered the relation between apparent magnitude and redshift.

  36. Keith Hall

    I’ve just finished reading “The 4 Percent Universe: Dark Matter, Dark Energy, and the Race to Discover the Rest of Reality” by Richard Panek which covers the work that these guys did. Well worth it. Here’s the link. or

  37. Nigel Depledge

    The BA said:

    Adam and I were both grad students at the time; after I got my PhD I went to work on a different Hubble project, and Adam stayed with the team, cracked the supernova code, and now has a Nobel Prize.

    I suspect that was the right move for him.

    Hah! But does he have his own TV show? I think not!

  38. Ray

    If the universe is expanding, what is it expanding into? In order to expand, there has to be something there, right?

  39. Dunc

    I know “dark energy” is cool, but unless you have evidence this is NOT the cosmological constant, there is no reason to promote new (fundamental?) fields to solve the “mystery” of this problem – Occam’s razor.

    “Cosmological constant” is also just a fancy term for “we don’t know”, only one that smuggles in an additional unfounded assumption – namely that it’s constant. We don’t know if it’s constant or not. All we know is that the rate of expansion currently seems to be increasing, when viewed from here. We have absolutely no idea why, so it doesn’t really make much difference what name you use to paper over that absence of knowledge – although it’s probably better if it doesn’t include any extra assumptions about the thing that we don’t know anything about.

  40. Messier Tidy Upper

    This has been huge news today here in Australia especially with the Aussie astrophysicist connection via Brian Schmidt. See, for instance, the coverage here :


    Plus this :

    via Lateline ion the new ALMA array that featured onthe same show. Great news! :-)

  41. @Ray (#37) you would think so, but that isn’t really the case. The space itself (between any two points is expanding. As we understand it, it’s not expanding into anything because the expansion isn’t happening in the same way as we see a balloon expanding or anything traditional that way.

    Maybe these two links will help with some of the confusion:

    This is a very good question which is not at all easy to give a satisfactory answer to! The first time I tried to write an answer to this, we got so many follow-up questions from people who were still confused that I decided to try to answer it again, this time much more comprehensively. The long explanation is below. However, if you just want a short answer, I’ll say this: if the universe is infinitely big, then the answer is simply that it isn’t expanding into anything; instead, what is happening is that every region of the universe, every distance between every pair of galaxies, is being “stretched”, but the overall size of the universe was infinitely big to begin with and continues to remain infinitely big as time goes on, so the universe’s size doesn’t change, and therefore it doesn’t expand into anything. If, on the other hand, the universe has a finite size, then it may be legitimate to claim that there is something “outside of the universe” that the universe is expanding into. However, because we are, by definition, stuck within the space that makes up our universe and have no way to observe anything outside of it, this ceases to be a question that can be answered scientifically. So the answer in that case is that we really don’t know what, if anything, the universe is expanding into.


  42. Lisa

    @Daniel J. Andrews I’ll bet they did, indeed, do their own private happy dances! But Adam also reflected on the old saying about much of life not really changing – he still has to take out the trash at home!

  43. Jenny from the block

    “It’s very, very nice to see that pay off.”

    Wasn’t the pay-off the actual discovery of accelerating expansion? It’s probably nice to get an award and some money, but I’d hope most scientists are driven by a desire for knowledge, not prizes.

  44. Keith Bowden

    1 The universe is expanding at an ever-increasing rate.
    2 The universe has always been expanding at a faster rate.
    3 The universe is 6000 years old and due to rapid expansion only appears to be around 14 billion.*

    Sorry Phil, I just beat you to the Ig Nobel Prize**! :)

    *Okay, anyone not realizing it… #3 is a joke.
    **Follow-up to #22 Chris’ joke.

  45. alex

    curious how will it turn to ice is there a boundery that it will eventually gather to to condense and cant go any further

  46. flip

    Thanks Larian @41. That explanation of the universe expanding is really helpful. I’ve never heard it explained like that (everything inside is being stretched, not the universe itself) before.


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