Sun Shots

By JoAnne Hewett | October 13, 2006 7:04 am

I’m in DC for a meeting of the High Energy Physics Advisory Panel. It’s the kind of thing where you spend 2 days in a windowless room listening (and supposedly asking intelligent probing questions) to talks about the scientific merit of various projects. Actually, it can be rather interesting, but the day does get long. Which is why more speakers need to perk up the panel with graphics like this:

This is a photo of the sun. Not taken with the usual medium for viewing the sun (photons), but taken with neutrinos. Partly at night. Through the earth. It was photographed by the Super-Kamiokande experiment in Japan with 503.8 days and nights of exposure.

This photo is a few years old now, but it always brightens my heart to see it. Kinda makes it all worthwhile…

  • Stephen

    I believe MINOS has similar shots of the sun and the moon…
    Didn’t Soudan II do that too?

  • Navneeth

    Wow! Never seen this before. Thanks for posting it!

  • Anonymous

    MINOS and Soudan are not sensitive to solar neutrinos, so cannot produce this kind of plot. SNO possibly could, though.

  • nc

    Can you indicate where the visible radius of the sun falls in this picture? The sun has presumably a core where the densities are highest and most of the fusion occurs, surrounded by a convective zone of somewhat lower pressure and density.

    You haven’t even indicated what the photo is. Someone looking at it might imagine it to be a kind of X-ray photo of the sun using the neutrinos normally buzzing around the universe which get stopped by the sun’s mass!

    Clearly the neutrino picture is not an neutrino x-ray but shows where neutrinos are being generated, because the sun emits neutrinos (as shown in the link).

    It would be great if you could draw an outline of the sun’s visible size on to the illistration. I just want to know if the white area is the sun’s core where the fusion is occurring. It is not obvious where the sun’s radius is in the illustration.

    Badly labelled illustrations and figures from astronomy actually put people off, because you can’t learn a thing from them! Thanks.

  • macho

    The size of a pixel in this image is about one degree — twice the size of the visible Sun. So the Sun would be a tiny circle in the center, less than a pixel across.
    (Bob Svoboda (SuperKamiokande, LSU) created the image quite a few years ago.)
    The neutrinos are all coming from the center (core) of the Sun, (an even smaller region on the figure than the visible Sun) but our ability to extract precise directional information from the reactions that allow us to detect the neutrinos is not very good.

    So while neutrino telescopes don’t have the precision of those that collect photons, I’ve always loved this image — you can find the Sun using neutrinos, but the image is just a bit blurry.

  • N. Peter Armitage

    >Badly labelled illustrations and figures from astronomy actually put people off, >because you can’t learn a thing from them! Thanks.

    Mr. nc, (or dr. nc?) why so grumpy? It is not a figure or illustration, it is art based on the physical world.

    You learned neutrinos can pass through the earth relatively unimpeded didn’t ya? Not bad for a piece of art.

  • nc

    thanks macho! That answers the main question! 😉

    N Peter Armitage: everyone knows neutrinos are weakly interacting, the image should at least have a scale decoding the colours as intensities (even if only a relative scale). Artificial colours are fine if you tell people what they correspond to. BTW, you don’t have to be “grumpy” just because you like science! 😉

  • nc

    By relative intensities, I mean what is the difference in flux between white and red, for example. Another question springs to mind: what about the solar neutrino problem? There was an issue a few years back that neutrinos were thought by some to oscillate between different types to explain the low detection rate, so there are serious questions in this area.

    If the sun is really small in the middle of the white area, then the gradual fall in intensity around it shown by the coloured areas is interesting, because you don’t expect any scatter by the earth’s atmosphere or the detection instrument (because of the small cross section for any interaction by neutrinos). :-)

  • Rob Knop

    nc — the blurriness of the image isn’t scatter due to the Earth’s atmosphere. It represents the limitation of the spatial resolution of the detector. It’s analogous to the fact that there is some width (and structure) in images of point-sources observed with the Hubble Space Telescope.

    The brightness profile is simply the “point spread function” of the detector. It’s noting particularly deep or meaningful as far as actual astronomy goes. It is cool, though, that the Sun can be localized! Many neutrino detetors over time haven’t had any spatial resolution; they can tell you that neutrinos are there, but not where they’re coming from. (Amanda and Ice Cube will have better spatial resolution than Super-K, I think.)

    Re: Neutrino Oscillations, they have been confirmed to exist. The observational result is five or so years old now. The Solar Neutrino Problem has indeed been solved; in between the Earth and the Sun, the neutrinos emitted originally as electron neutrinos decohere in flavor, so by the time they get to the Earth you may observe an electron, mu, or tau neutrino.


  • nc

    Rob, thanks for the blurring analogy! I’ve got you! :-)

  • Louise

    From comments I heard at HEAD last week and Salamon’s comments yesterday, the Dark Energy Mission is likely to be indefinitely deferred. We remember Sean bravely warning Danger, Phil Anderson for suggesting that Dark Energy might not exist. Who is in danger now?

  • mollishka

    So, if a photograph is “made” from photons, would that make this a neutrinograph?

  • JoAnne

    Mollishka: Thanks for making me smile!

    Rob and Macho: Thanks for answering nc’s questions while I was on a cross-country flight home.

    nc: To borrow a phrase from Sean – maybe you ought to switch to decaf.

    Louise: NASA and DOE have appointed a National Academies panel to recommend whether LISA (space-based gravity wave probe), CON-X (space-based X-ray telescopes to study blackholes) or JDEM (joint dark energy mission) should be launched. NASA has the funds to do exactly *one* of these projects. The panel is just being formed now and will report a year from now.

  • Kea

    The panel is just being formed now and will report a year from now.

    A year is a long time in this game!

  • nc

    Hi JoAnne: I’m a serious caffeine addict, so sorry but no I can’t switch! I don’t smoke or drink, but my nerves go if I drop below two cups an hour. :-(

  • Craig

    Out of interest, does anybody know the source of the huge horizontal bar across the image? I assume it is to do with the detector rather than something physical, but would like to make sure.

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  • Plato

    More on name.

    Possibly from a generalized “point of view” the concept of the “Navier-Stokes equations” can be applied here?

    Maybe it is as Einstein relayed that the ancients had a “purity of thought” based on the fluidic notions of the QGP??

  • Plato

    Some do not believe the internet to be a powerful tool?

    The basis of this post is the affront to the way we see. An “affront” to the “Trouble with Physics.”

    For example, the Window on the Universe?” Some like to speak about “Glast” while others will look at JoAnnes image above. It is about the deeper perception developing(our window), and not just about the “energy” although this governs the thought processes?

    LIGO may say they are the window? And we await for compilation of the data?

  • nc

    Just found a photo of: “The moon’s shadow, as seen in muons 700m below ground at the Soudan 2 detector.”

    See also:

    Seems to go nicely with JoAnne’s neutrino photo of sun!


  • Plato

    More on Name.

    You think enough about the sun in this picture above and the deeper one’s thinking becomes in manifesting information about the “sterile neutrino” and gravity?

    While it had only been high energy valuations, what about a target of 12.7 billion years ago?

    Would this allow research of asymmetry, from GRB to account for the “sterile neutrino” manifesting as weak field gravity consideration?

    Current evidence shows that neutrinos do oscillate, which indicates that neutrinos do have mass. The Los Alamos data revealed a muon anti-neutrino cross over to an electron neutrino. This type of oscillation is difficult to explain using only the three known types of neutrinos.

  • Big Dog

    It looks like Lego building blocks. Still very cool though.

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