First light, confirmed?

By Phil Plait | July 2, 2007 8:15 pm

Hmph. I sometimes draft up blog entries, only to have them get buried under other drafts. I originally wrote this a few months ago, but I think it’s still relevant, and it makes a point about science.

Way back in November 2005, I wrote about a Spitzer Space Telescope observation that purportedly showed light from the very first objects in the Universe.

The images were made by taking very deep exposures, then subtracting away all known light sources. What was left was a softly glowing web of light from no known source. The astronomers on the Spitzer team then said this could be the light from the very first stars. These stars were extremely massive, a hundred or more times the mass of the Sun — and up until now have been entirely theoretical.

Well, NASA has issued a press release saying the observations have been confirmed. The press release was sparse on details. It did say that the same technique has been expanded from one to five different sections of the sky, and had been done at different wavelengths, and the results still held up. That was nice, but most of the release was the same as the one a year ago!

So I called my friend who is the PR person for Spitzer, and she told me that while the results were not yet in the journals, they were online at astro-ph, a clearing house for astronomy papers. I read the papers (here is the observation paper, and here is the results paper), and feel a bit better now. The papers are brief, but do indicate the authors did due diligence, checking through their data as carefully as possible, making sure the light they were seeing wasn’t something just inside their telescope or detector. They were also able to use some simple arguments to eliminate sources like solar system objects, nearby galaxies and even relatively distant galaxies. All that’s left, they claim, are the putative First Objects.

While I do think the images show something real, I’m not convinced they are from the first stars just yet. Just because you have eliminated everything you know about except for one thing, that doesn’t mean that last thing must be what you see. There may be something unknown out there causing this. It’s maybe not terribly likely, but it’s possible. And the alternative, that they are seeing the accumulated light of thousands, millions, of first generation stars is, well, an extraordinary claim. Not a goofy one, or a crazy one — they may very well be right! — but a big enough claim that I’d like to see some independent confirmation.

I don’t think that will come until the James Webb Space Telescope is launched, sometime in the distant future (like 2013, according to the NASA site about it). These observations have to be done in the infrared (the light from these objects is heavily shifted to that wavelength) and no other ‘scope can go as deep as Spitzer right now. Unless someone thinks of a different and clever way to do this, the confirmation of these results will simply have to wait.

… although, hmmmm. When one of these stars blows up, it should make a gamma-ray burst, an intense flash of high-energy light. If one were to explode, and it were caught by the Swift satellite, then maybe we might have more evidence of these objects. Swift might do it; we’ve had a couple of bursts that for a while looked good (but turned out to be much closer than the oldest stars). It’s too much to ask that a burst appear right on top of the light Spitzer saw: the area of sky Spitzer looked at was tiny, so the odds are extremely low. But a burst with a confirmed redshift putting it at the right distance would be interesting indeed.

Science is a tough road to walk on, and sometimes the big discoveries are first just barely seen when pushing your machines to the limits. Maybe these observations will pan out, and maybe they won’t. But either way, I’m pretty sure we’ll learn something important.

CATEGORIZED UNDER: Astronomy, Cool stuff, NASA, Science

Comments (22)

  1. Remek

    Interesting intensity dispersion even that far back (if true, of course).

    Next interesting study might be to compare the charted background microwave data with this new infrared data, and see how the two compare.

  2. autumn

    “I’d like to see some independent confirmation.”

    Greatest phrase in the history of knowledge.

    You are told something amazing by those whom you respect for their knowledge in the field discussed, and your reaction is one of cautious optimism.

    Wow. I will constantly bring this post to the attention of those who parrot the idiocy that scientists accept data from other scientists uncritically. It will make no difference, but here is evidence of how science works.

  3. Joakim Rosqvist

    “Nothing can go as deep as Spitzer before 2013”, how about Herschel, (due to launch 2008)?

  4. chris

    i can imagine some how a creationist will work this into thier aganda and say this was the moment god said let there be light

    this is becoming some of the most interesting fields of study into the evolution of the cosmos. its exciting to think what else thyele find

  5. Lyle Gaulding

    Sherlock Holmes’ ‘Eliminate the impossible, and what ever remains must be the truth.’ Assumes that one can reliably know what is the impossible.

  6. Gary Ansorge

    First stars. Very Phat,,,

    Are they the at the same distribution/intensity and distance no matter which direction we look? How does our new found hyper inflation affect these old stars and their radiance?

    GAry 7

  7. unknownkadath

    Wow, Lyle, that’s very quotable.

    I’m stealin it. :)

  8. bearcub

    Actually, the entire quote is: “Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth.”

    Not that it changes the meaning (I’m not accusing you of anything Lyle), but if you’re going to steal it unknownkadath, you may as well steal the whole thing :)

    .. and yes, we still don’t a total grasp of what’s impossible out there.

  9. criticalthinker

    But…but…isn’t the Earth and the universe only 5.000 years old according to the Creationists and I hear they have a museum that proves this very fact. How can there be this conflict? I don’t want to disparage the religious nut jobs out there but I think they’re wrong and science is correct. I rest my case, Your Honour.

  10. Cosmic_Comic

    In relativity theroy, would being “first” really be all that important? And, furthermore, what would be the “last” light emitted in this local universe?

    So much data—so many questions….

  11. George

    Remarkable story! A lot of firsts are happening in our lifetime. Great going Spitzer!

  12. Floating Stars- How I wonder what you are ? Where lies the Mass and Gravity ! Where lies the Wisdom. You protect the Conscious Spirit of
    Knowledge Expansion
    The Cosmic Puzzle attracts Scientists, Philosophers
    and all mankind in several disciplines in search of divinity of the Human
    Being and Nature.
    Presently Cosmology is undergoing REVISION and BIG-BANG,
    Dark Matter,DARK ENERGY and Black-holes are all under question.
    Evolution needs to catch up with creation.
    Why not Organise East West Interaction : Cosmology World Peace
    and Search Cosmology Vedas Interlinks

  13. Buzz Parsec

    Lyle and Bearcub –

    I also thought of Sherlock Holmes while reading BA’s post. But I disagree a little bit… It’s easy (well, sometimes it’s easy) to eliminate the impossible. The hard part, I think BA is saying, is being sure that when you’re down to one thing, that you haven’t left anything out, something entirely else that you’ve forgotten to include, not one of the impossible things that you’ve already eliminated. Of course, if you eliminate all the impossible things, and nothing is left, then you *know* you’ve left something out :-)

    BTW, I’ve seen proof that since Conan Doyle, an extreme and documented irrationalist, couldn’t have invented the supreme rationalist Sherlock Holmes, Holmes must have really existed, and, perhaps, Sir Arthur was in fact the fictional character. :-)

  14. Buzz Parsec Says: “Of course, if you eliminate all the impossible things, and nothing is left, then you *know* you’ve left something out :-)”

    No, that’s when you become an atheist :)

    Seriously though, I hope that in my lifetime we’ll be able to see/detect beyond that first light..

    Happy 4th!

  15. Buzz Parsec

    Slang, I think we already have detected beyond first light. My guess would be the CMB is older than these stars, even if they are the first… The CMB is the (massively redshifted) light from the time the universe cooled below the ionization temperature of Hydrogen (~10,000 K, IIRC) and thus became transparent. Clouds that hot are much too hot to collapse into stars. I think the temperature would have to drop below a few hundred K to initiate star formation,
    which would take millions of years.

  16. forrest noble

    I believe this is just another false start based upon the false premise of the universes age, 13.7 B years– I believe, like many others, based upon the large scale structures of the universe and stellar/ galactic age analysis, the universe is much older, therefore I suggest that we never could see the first light because it has dissipated long ago. There is also a good chance that the real first light was not even contained within the observable part of the universe. This observation could be a faint glimmer of a very distant galaxy.


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