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Space Science

See a Supernova From Your Backyard 182

Posted by samzenpus
from the no-sunglasses-required dept.
hasanabbas1987 writes "Want to catch a glimpse of the closest supernova astronomers have discovered in the last 25 years? All you need to do is get yourself a small telescope or a pair of binoculars (some DSLRs would do just fine as well). Astronomers think that they may have found the supernova within hours of its initial explosion on August 24. Generally, supernovas are around 1 billion light years away but this one is only 21 million light years away. The supernova is in the Pinwheel Galaxy and you can see it within the Big Dipper."

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See a Supernova From Your Backyard

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  • by freaktheclown (826263) on Monday September 05, 2011 @01:07PM (#37309354)
    I'm pretty sure it exploded about 21 million years ago.

    If a supernova were close enough to be seen within hours of its explosion, we probably wouldn't be here.
    • Re: (Score:1, Insightful)

      by Anonymous Coward

      From our reference frame, this happened hours ago. The summary is correct. You are not.

      • by freaktheclown (826263) on Monday September 05, 2011 @01:22PM (#37309426)
        No the summary is not correct. It did not happen "hours ago" from any reference frame. Other articles written about this got it right; this one did not.
        • by Cyberax (705495)

          Speaking "it happened millions years ago" is not correct since there's no absolute reference frame.

          In our reference frame it happened days ago.

          • by quenda (644621)

            In our reference frame it happened days ago.

            Only if your reference frame includes infinite light speed. I'd like to see your maths for that one.

        • by Raenex (947668) on Monday September 05, 2011 @06:34PM (#37311278)

          It did not happen "hours ago" from any reference frame.

          Is that really true? Somebody mentioned elsewhere [slashdot.org] in this thread that:

          "Yet, no time has passed for the traveling light. Or more precisely: if an observer had followed the light emitted from the supernova at almost the speed of light, very little time would have passed in his frame of reference. So what we take as 21 million years would have been nearly instantaneous for our traveling observer."

          It seems that you can define a reference frame arbitrarily close to the speed of light at an arbitrary starting position and get the desired duration.

        • No the summary is not correct. It did not happen "hours ago" from any reference frame.

          Sure it did - in a reference frame moving from it toward us at nearly the speed of light. B-) "any" is a very strong word when you're talking about reference frames and relativity.

          However it's obvious that they're talkiing about "hours ago plus the light lag from the distance", i.e. the timescale of the obervability of the event.

      • The star that exploded is not moving at relativistic velocities in relation to us, and the non-inertial part of our and its reference frames are tiny too. It exploded 21 million years ago in our reference frame.
      • This is one of the major issues of society today.

        The stupid strongly believe they are right.

        The intelligent get modded troll...

      • From our reference frame, this happened hours ago. The summary is correct. You are not.

        It happened 21 million years ago in both the frame of reference of the solar system of the star gone nova and in the frame of reference of our solar system. We may have only just seen the evidence but we know it is 21 million light years away, so we know when it happened. I don't think distance changes one's frame of reference, I think only motion does. Two travelers in our system, one at 0.25c and the other at 0.5c have different frames due to their respective velocities, not distance from the nova.

        I wi

      • Our reference frame does not magically cause a photon to travel 21 million LY in zero time, so this did not happen hours ago for anybody. Just because information travels at the speed of light doesn't mean events don't happen before we see them. By your line of reasoning, the Big Bang just happened because photons from around that time are still hitting our detectors today.

        It's amazing how many people get this stuff wrong. I blame physicists who make it a habit to formulate anything related to relativistic

      • by SiChemist (575005)

        Ahh, but did the explosion even happen until someone OBSERVED those particles/waves emitted by the explosion?

        (Before the inevitable flames, I AM JOKING, I'm not an idiot. Well, I'm definitely joking anyway.)

    • by paiute (550198)

      I'm pretty sure it exploded about 21 million years ago.

      In the star's POV, yes. In our POV, it just exploded.

      • by pyrosine (1787666)
        You seem to be troubled here: The light from some number of hours after the star going supernova has finally reached us after 21 million years
        • by gmueckl (950314) on Monday September 05, 2011 @02:11PM (#37309690)

          Yet, no time has passed for the traveling light. Or more precisely: if an observer had followed the light emitted from the supernova at almost the speed of light, very little time would have passed in his frame of reference. So what we take as 21 million years would have been nearly instantaneous for our traveling observer. Simultaneity is a weird thing when time is relative.

          • ^^^This. If only I had mod points...
          • by lennier (44736)

            Yet, no time has passed for the traveling light.

            So how come something happens to the photon rather than nothing? How come the emission of that photon from the supernova comes "before" its absorption in the CCD detector in our telescope? There's no time for anything to happen to it, it's travelling infinitely fast in a zero-dimensional world according to the Lorentz contraction, so why should it even interact with the rest of the universe at all?

            • by wdef (1050680)

              I'd hazard a guess and say:

              From the photon's "point of view", nothing does happen to it en route. Actually there is no "en route". It's the universe that's abruptly crazy at the boundary conditions at each end.

              Also, special relativity per se doesn't know what a photon is: SR is closely related to Maxwell's equations and so thinks in waves rather than quanta, if you will. The process of a photon being emitted or absorbed is a quantum mechanical event. SR and QM have never been fully integrated into one th

    • by exploder (196936)

      There's not some cosmic clock that marks a simultaneous "now" for every point in the universe, such that the light from that supernova actually traveled for 21 million years to reach us. Simultaneity doesn't exist, independent of reference frame. In our reference frame, the supernova exploding and the light reaching us are simultaneous events. If you don't believe it, pick up a physics book--even a very watered-down pop physics book from Barnes & Noble will set you straight on this issue.

      • by rubycodez (864176)
        Except you pseudo-relativity experts don't understand we can establish our reference frame as a standard, and that the exploding star is essentially in our reference frame, as it is not in relativistic motion in relation to us, nor is it or we in huge potential well in relation to each other. It's just a real-time signal propagation lag we experience, no different than sound of firecracker two city blocks away taking a second to reach you.
        • by Cyberax (705495) on Monday September 05, 2011 @04:18PM (#37310526)

          It IS different. With a firecracker we have a flash which reaches us 'instantaneously' and then a sound which takes a few moments to reach us. Moreover, different observers with clocks synchronized to a same source would see the flash at the same time (we're ignoring relativity) so they can agree on a universal frame of reference (Earth + UTC time).

          With light it's different. We have NO other faster channel. Imagine that you have no way of knowing that firecracker has exploded except by listening to a sonic boom. And you have no faster way to communicate except by shouting.

          • by lennier (44736)

            With light it's different. We have NO other faster channel.

            Are we so sure we don't? Or did we just decide that since we hadn't measured any such channel in 1905, then there isn't?

            It seems to me that Einstein arbitrarily decided to assume that there exists no faster channel than light in order to redefine the Lorentz contraction as a spacetime effect. Which was a clever hack and made the maths simple, but isn't much of an explanation because it then leaves us with not only no answer to "so what is the physical mechanism which causes space and time between events to

            • by wdef (1050680)

              With light it's different. We have NO other faster channel.

              Are we so sure we don't? Or did we just decide that since we hadn't measured any such channel in 1905, then there isn't?

              It seems to me that Einstein arbitrarily decided to assume that there exists no faster channel than light in order to redefine the Lorentz contraction as a spacetime effect. Which was a clever hack and made the maths simple, but isn't much of an explanation because it then leaves us with not only no answer to "so what is the physical mechanism which causes space and time between events to appear to dilate as relative motion approaches C", but also makes it impossible to find an answer because it disallows asking the question - it shoves "why" under the carpet of kinematics, not dynamics. And assuming C is the maximum speed of signal propagation causes no end of trouble when you attempt to reconcile relativity with quantum mechanics.

              But we have no evidence that there is any faster channel. And the Lorentz contraction and time dilation aren't merely an illusion; these have been proven to be real.

            • by sFurbo (1361249)

              Are we so sure we don't? Or did we just decide that since we hadn't measured any such channel in 1905, then there isn't?

              Basically, from the set {faster than light communication, relativity, causality}, you can pick two. Relativity has done remarkably well in predicting what we would observe, and continues to do so. Causality seems to hold up, so the natural assumption is that no communication faster than light is possible. But it could be wrong, we could live in a non-causal universe, or the true theory behind relativity could be compatible with both.

              isn't much of an explanation because it then leaves us with not only no answer to "so what is the physical mechanism which causes space and time between events to appear to dilate as relative motion approaches C", but also makes it impossible to find an answer because it disallows asking the question - it shoves "why" under the carpet of kinematics, not dynamics.

              Isn't that what any physical hypothesis does? Explain some observation to a

            • by delt0r (999393)
              Do some GR and then tell me the math is simple. The speed of light thing being a constant was something from Maxwell equations and *experimental* evidence. Add the postulate that the laws of physics are the same in every inertial frame of reference you get SR. Add acceleration, you more or less get GR (kinda).
            • Are we so sure we don't? Or did we just decide that since we hadn't measured any such channel in 1905, then there isn't?

              Yes, because in the 106 years since Einstein's breakthrough, nobody has done any more physics. Jesus.

              It seems to me that Einstein arbitrarily decided to assume that there exists no faster channel than light in order to redefine the Lorentz contraction as a spacetime effect

              You seem very smart. Why don't you write us a book on physics and set all our sorry asses straight?

      • This is correct. From the Earth's reference frame, this supernova just occurred, and it occurred 21M LY away. As I demonstrate with an example below, it is misleading and meaningless to talk about how long ago it occurred, or in which order things occurred using any other frame of reference.

        Suppose a supernova 1000LY away had two stars near enough that the supernova had an effect on them, and one of those stars (star B) was 5 LY from the supernova and one (star C) was 15 yr from the supernova. However, star

    • No - it just exploded, but it took 21 million years for it's 'now' to arrive here.
    • by interkin3tic (1469267) on Monday September 05, 2011 @02:12PM (#37309702)
      Important lesson here: there is no "+1 pedantic" mod. On slashdot or in real life, which is why no one was too interested in making out with you new year's eve 1999 when you were telling everyone that the millennium wouldn't start until the next year.
  • Supernova fun! (Score:5, Informative)

    by Mr. Underbridge (666784) on Monday September 05, 2011 @01:10PM (#37309370)

    Just as a warning to those trying star-hunting for the first time: finding this guy can be tricky. Best thing is to get some charts from AAVSO.org. Use 2011fe as the search. Print a 15 degree chart for finding the general area from the big dipper, then 1 degree and 2 degree charts for finding the supernova.

    For now, the supernova is getting easier to find by the day - I tried last week and couldn't find it, but now it's pretty bright. However, finding the correct area can be tough because there's no obvious landmarks in the area unless your sky is dark enough to make out the face of the galaxy. And, unless you live in an exurban or rural area, it won't be. Otherwise, you'll need to rely on patterns of stars at the 1 degree scale. Otherwise, you can easily be looking at the supernova but not know which star it is.

    There are good threads over at cloudynights.com that provide helpful images and advice. Good luck all! It's really fun to know that you're looking at something that didn't exist last month (correcting for travel time of the light, of course).

    • Huge Optics Needed (Score:5, Informative)

      by Iskender (1040286) on Monday September 05, 2011 @01:32PM (#37309486)

      Another warning from another astronomy enthusiast: note that the guy in the video talks about "decent-sized" binoculars and then specifies 20x80 or 20x100.

      That 100 at the end means the lenses at the front have a diameter of ten centimetres (four inches) each! So under any normal circumstances those are considered HUGE rather than decent binoculars.

      My advice on how to see this supernova: ask someone into astronomy who has a telescope or huge binoculars. Doing the observing "from scratch" is probably a too tall order.

      • by hedwards (940851)

        I was wondering about that, because even with my 200mm lens with a 1.6x crop factor trying to take a photo of the moon is really tough to do, as it's far enough away that metering doesn't really work very well.

        This event is happening significantly further away, which makes me wonder what sort of a lens one would need in order to observe it. I'm guessing that you'd need something on the order of a 1000mm lens to get a halfway decent view. At 500mm you're getting a 5 degree view, and I'm guessing that you'd n

        • by Iskender (1040286) on Monday September 05, 2011 @02:11PM (#37309694)

          1.6x crop probably means you have a Canon DSLR. All I can say is that you should really explore the manual modes - with digital you can just try different shutter speeds until you get it right. The moon is illuminated by the sun so the settings that work in sunny daylight should work for photographing the moon too.

          Photographing stars often isn't a matter of magnification, but rather of light gathering. Only few stars are close/large enough to be imaged as disks, and that's with professional equipment - you'll never resolve a star into a disk yourself.

          Rather, stars are point sources. Everything comes from a single point, only the intensity and colour of that point varies. If you want to see fainter stars with a camera, you just need to expose longer. An 18-55 kit lens might very well be able to image this given the right other circumstances. The resolution of 500 mm would be more than enough in any case.

          In fact, the hardest problem would probably be to get low enough magnification - the sky moves all the time and therefore everything is blurred when you make the shutter speeds longer. This means you need large apertures more than you need long focal lengths, and pretty fast you need a tripod/mount that's capable of tracking the sky.

        • by ceoyoyo (59147)

          The focal length of the lens and the distance of the object has very little to do with it.

          You can't get a good picture of the moon in an automatic mode because it's very bright. Go to a manual mode, dial in 1/250 s (to start) at f8 and move around until you get a picture you like.

          Focal length isn't going to make a bit of difference when you're looking at something 21 million light years away. It's a point, no matter what. The focal length of your lens will determine whether you JUST get a point of light i

          • by hedwards (940851)

            If focal length isn't going to make a difference, then why did the astronomers recommend using binoculars that are giving that much magnification?

            And yes, it's going to be worthless for taking photos of stars, but by the same token, if you need that much magnification to see the super nova, then I'm not sure why a camera would be any different.

            • by ceoyoyo (59147)

              They recommend 20x100 binoculars. The 20 is the magnification. The 100 means 100 mm, which is the "aperture," or light gathering capability of the binoculars. I put that in quotes because I mean actual aperture, not the aperture/focal length ratio photographers usually mean when they say "aperture." Think of it (roughly) as the diameter of the main lens. The supernova is dim, so you need a fair amount of light gathering power to brighten it to where you can see it with your eyes. If you're using a cam

            • They recommended 20x80 or 25x100 binoculars. The second number is the diameter in mm of the objective (front) lens. It needs to be this big in order to collect sufficient light to make the object clearly visible to a naked eye. The first number is the magnification (crudely speaking the ratio of objective to eyepiece focal lengths). 20 is simply the common magnification in binoculars, which have fixed eyepieces, with objective lens sizes large enough to be useful.

              You'll also notice that when recommen

        • It's possible to take decent moon pictures with any camera.
          320mm equivalent is more than enough to get some serious details (craters and stuf..).
          your problem is probably some serious over-exposure, where the moon is a completely motion-blurred washed-out white disc.
          Get to Manual mode, choose f/8, 1/400s, ISO 800 and see what you get. The auto focus might have problems, so just focus close to infinity and adjust it with magnified live-view (if available).
          It works best when the moon is half lit, so that the s

  • Any danger of gamma rays? Though I suppose if my skin were to turn green, that'd be a sign that something's happening.

    • No. 25 million light years is a long way. To put it in perspective, that's 250 times the diameter of our galaxy. The fact that you need a telescope to spot it should give you a clue - it's spewing out vast amounts of radiation (or, it was, 25 million years ago), of which visible light is just part, but it's still barely visible with the naked eye. Even if it was emitting 1,000 times as much gamma radiation as visible light, it would be a negligible amount.
    • by Iskender (1040286)

      You're probably joking, but let's put it like this:

      The star Betelgeuse could go supernova tomorrow or a million years from now. It's about 600 light years distant. The consensus is that it won't pose any danger to us.

      The supernova we're discussing here, SN 2011fe, is about 20 million light years away from us. So if this supernova was 30 000 times closer to us it would most likely still be safe. =)

      • Hmm. It would be quite dangerous to us - some sorry fellow on the road and me - as I'd surely notice it driving home late in the evening and would be terribly distracted.
  • Here is a great idea for improving the economy - stimulate more R&D, research and development, more supernovas need to be found, more telescopes must be built, put the money into this, get some engineering going. Fuck wars, lets build telescopes. Build more telescopes, build more space ships. Need more engineers for this, need more scientists, need more architects, need more of everything. Build more, spend on building, stop wars and get going.
    • Re: (Score:3, Informative)

      by mikech2000 (1230790)
      Sorry but discovering interesting things about the universe offers no ROI during the next fiscal quarter.
    • Here is a great idea for improving the economy - stimulate more R&D, research and development, more supernovas need to be found, more telescopes must be built, put the money into this, get some engineering going. Fuck wars, lets build telescopes. Build more telescopes, build more space ships. Need more engineers for this, need more scientists, need more architects, need more of everything. Build more, spend on building, stop wars and get going.

      Go check how many space exploration lobbyists exist in Washington then check how many petroleum and military-tech lobbyists exist in Washington. Now try to rephrase your suggestion in terms of oil usage and military technology.

  • I'm in the southern hemisphere, you insensitive clod! ok, maybe next time.
    • by quenda (644621)

      I'm in the southern hemisphere, you insensitive clod!

      That's OK. We had front-row seats for the 1987 supernova, a mere 168,000 light-years away, and visible to the naked eye.
      The previous one brighter was in 1604.

      http://en.wikipedia.org/wiki/SN_1987A [wikipedia.org]

  • I'm always curious about these observed supernova events. How long do they last in a well-defined event? Even if not visible to the unassisted human eye at cloudless night, how long by optical telescope? How long can the more subtle beginnings and endings be seen with radar telescope and our more advanced instruments?

    Milliseconds? Minutes? Hours? Days? Months? Lifetimes? Planetary lifetimes? Depends on the supernova?

    • by mojo-raisin (223411) on Monday September 05, 2011 @05:23PM (#37310916)

      I don't know how long it lasts, but its daily intensity is being plotted here [aavso.org]. From what little I've read, it can be expected to increase like this for ~14 days from the initial explosion

      • by jmichaelg (148257) on Monday September 05, 2011 @06:34PM (#37311272) Journal
        This web page [gsu.edu] has a graph that shows the different light curves for type 1 and type 2 supernovae.

        A Type 1 supernova reaches it's peak light output around 10-15 days of the initial explosion and then exponentially decays over a period of years. As the curve is exponential, a good chunk of the luminosity is lost within a couple of months and then the loss rate tapers off somewhat.

        A type 2 supernova reaches its peak output in a few days decays, plateaus for a few months and then begins decaying again over a span of years.

        The mechanism behind a type 1 is fairly well understood but the variation in modeled and observed luminosity is greater than 2%. A paper a few years back suggested that the variation might be evidence of dark matter but subsequent modeling has shown that the 2% variation can be accounted for by where the observer happens to be relative to the explosion as the explosions aren't symmetric.

  • For Earth, it happened a week ago. Space and time aren't separable, stuff doesn't merely move through space, it moves through space-time. We can only refer to time separately when looking from a specific reference frame. Only from the space-time of the supernova did it happen 21M years ago, and we're not in that space-time. From ANY other reference, it DIDN'T happen 21M years ago, it happened less than that, or (for distances greater than 21M LY from the event) it hasn't even happened yet. Thus it's both mi

  • by AP31R0N (723649)

    Do not look at supernova with remaining good eye.

  • I remember reading about supernovae being so bright they could be observed during the day, brighter than Venus for instance.

    From History of supernova observation [wikipedia.org]

    The supernova SN 1006 appeared in the southern constellation of Lupus during the year 1006 CE. This was the brightest recorded star ever to appear in the night sky, and its presence was noted in China, Egypt, Iraq, Italy, Japan and Switzerland. It may also have been noted in France, Syria, and North America. Egyptian physician, astronomer and astro

    • And since you figured it out, why did you choose to post it rather than cancel it?

      Also, intensity decreases with the square of the distance, so brightness would be roughly 7.1K^2/21M^2 ~ 1.14E-7 the brightness, which is ~17 orders of apparent magnitude (5 orders of visual magnitude is a factor of 100).

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