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The Milky Way's Most Recent Supernova That Nobody Saw 56

Posted by samzenpus from the didn't-see-it dept.
StartsWithABang writes: A little over 300 years ago, a supernova — a dying, ultramassive star — exploded, giving rise to such a luminous explosion that it might have shone as bright as our entire galaxy. And nobody on Earth saw it. Located in the plane of our Milky Way galaxy, the light was obscured, but thanks to a suite of great, space-based observatories (Hubble, Spitzer, and Chandra), we've been able to piece together exactly what occurred. Not only that, but observations of a light-echo, or reflected light off of the nearby gas, has allowed us to see the light from this explosion centuries later, and learn exactly how it happened.
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The Milky Way's Most Recent Supernova That Nobody Saw More

The Milky Way's Most Recent Supernova That Nobody Saw

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  • Neat-o. (Score:5, Insightful)

    by mythosaz ( 572040 ) on Monday May 11, 2015 @06:22PM (#49668839)

    Every time I see a cool space/science story, despite having been an adult for some time now, I still get an awesome sense of "wow" out of it.

    Keep on exploring the mysteries of the universe guys.

  • how would the forked-tongue know?

  • too dim (Score:1, Troll)

    by epine ( 68316 )

    If no-one could see it because it was too dim to see everywhere on earth, then we probably should describe the source object as "luminous" rather than "bright".

  • "The Milky Way's Most Recent Supernova That Nobody Saw"

    But we DID saw it! The same way we see all things...? Some delay (and reflections/"light-echo") exist even for what i see right now in the monitor... am i blind?

    • Re: (Score:1)

      by Bengie ( 1121981 )
      A super nova that out shined the entire galaxy and the only way we get to see it is via light echos that only powerful telescopes can see. So no, we didn't get to see it with our naked eyes.

  • 11,000 years ago, not 300 (Score:3, Insightful)

    by doug ( 926 ) on Monday May 11, 2015 @06:48PM (#49669027)
    TFA says it was 11,000 light years away, so it took 11,000 years for the light to get to Earth. We should have seen it 300 years ago, but the explosion was a long time before that. So the summary's opening line of "A little over 300 years ago, a supernova ... exploded" is incorrect.

    • TFA says it was 11,000 light years away, so it took 11,000 years for the light to get to Earth. We should have seen it 300 years ago, but the explosion was a long time before that. So the summary's opening line of "A little over 300 years ago, a supernova ... exploded" is incorrect.

      To a relatively stationary you 11000 ly from the source, it was about 11000 years ago.
      To the light emanating from that explosion that reached us (unnoticed), it was 300 years ago.
      The the light emanating from that explosion that reached us via reflection, it was however long ago we detected those reflections.
      Time is relative. Shit traveling near the speed of light experiences much less time than shit at non-relativistic speeds.
      HEY! Maybe that's why it's called relativity!

      • Re:11,000 years ago, not 300 (Score:5, Informative)

        by PPH ( 736903 ) on Monday May 11, 2015 @08:16PM (#49669601)

        Shit traveling near the speed of light experiences much less time than shit at non-relativistic speeds.

        I don't think relativity enters into this. In space, light travels at the speed of light. And to a photon, time means nothing.

        What we have here is a direct path length from the supernova to earth of 11,000 ly. Something went 'bang' 11,300 years ago, so we missed the first signals. But there are gas clouds and other crud floating around which reflect the pulse, making it travel longer paths. We are now seing the reflections with path lengths of 11,300 ly. And as time goes by, we will see reflections with longer and longer path lengths.

        This will (in time) be an interesting opportunity to map the structures of the gas clouds surrounding the supernova using successive images (over dozens or hundreds of years) and calculating path differences and the underlying 3D structures causing the reflections.

        • Shit traveling near the speed of light experiences much less time than shit at non-relativistic speeds.

          I don't think relativity enters into this. In space, light travels at the speed of light. And to a photon, time means nothing.

          Light travels at the speed of light, but time is relative.
          And you don't know that time means nothing to a photon. They could be sentient spacefarers for all you know.

      • Re:11,000 years ago, not 300 (Score:5, Funny)

        by thegarbz ( 1787294 ) on Tuesday May 12, 2015 @03:17AM (#49671165)

        To a relatively stationary you 11000 ly from the source, it was about 11000 years ago.
        To the light emanating from that explosion that reached us (unnoticed), it was 300 years ago.

        Time slows down when I read slashdot comments like this.

    • Re: (Score:1, Funny)

      by Anonymous Coward

      Relatively speaking you're wrong, it happened 300yrs ago -- when the light hit earth.

      Now, in absolutes; 11300yrs ago (note that 300 years ago the light hit Earth, so you have to add the years up!), a big explosion occurred and probably vaporized a few planets with species on it... So, PETA should be protesting the supernova these physicists are studying for the obliteration of several hundreds of millions of animals. Now way should these physicists be continued to misuse public funds to continue their resea

    • So the summary's opening line of "A little over 300 years ago, a supernova ... exploded" is incorrect.

      I'm glad this was modded up so that all those people who didn't see that episode with the Picard Maneuver could be brought up to speed.

    • Re:11,000 years ago, not 300 (Score:4, Insightful)

      by iMadeGhostzilla ( 1851560 ) on Tuesday May 12, 2015 @12:42AM (#49670765)

      No that is the whole point of the Relativity Theory. There is no absolute time or "God time", there are only points in timespace. 300 years ago here on Earth if you could see the photons of the explosion, you were witnessing the explosion exactly as was happening. "Now" spreads at the speed of light so when you see something, it's happening, as far as you are concerned, right now.

      • Re: (Score:2, Informative)

        by wonkey_monkey ( 2592601 )

        "Now" spreads at the speed of light so when you see something, it's happening, as far as you are concerned, right now.

        I don't think that's how a physicist would define simultaneity. There is a reference frame in which it happened as arbitrarily close to "now" (in that reference frame) as you'd like, but we're not in one of those.

        The event which produced the photons happened, as far as I'm concerned, 11,000 years ago.

        If you want to say it's happening "now," then any signal we send back in that direction will also get there "now." Except that that "now" will be 22,000 years later then the first "now," which makes no sense.

        • I think the problem is that the question "did the star really explode now or 11000 years ago?" is philosophical as it tries to go beyond the theory. The only thing that matters is that the light -- the information -- has just reached our frame of reference. (Actually 300 years ago.) "Now" only has meaning in our frame of reference.

          Simultaneity as you said is a better term, and "according to the special theory of relativity, it is impossible to say in an absolute sense that two distinct events occur at the s

          • Simultaneity as you said is a better term, and "according to the special theory of relativity, it is impossible to say in an absolute sense that two distinct events occur at the same time if those events are separated in space." So if, say, I see my alarm clock go off at say 10pm and just then see a star exploding, then the explosion and the alarm activation are happening simultaneously -- as far as I'm concerned.

            The trouble with that definition of simultaneity is that it's asymmetrical. By that definition, someone sitting at the point of the explosion would disagree that the explosion and your alarm clock going off happened at the same time - he'd have to wait 11,000 years for the light from the alarm clock going off to reach him.

            Two observers in the same frame of reference (assuming Earth and the exploding star are not moving very much relative to each other) should agree on the order and simultaneity of events -

            • You're right. I can only say that my detection of light from the exploding star and the detection of alarm clock going off have happened simultaneously. And if my alarm clock is 11,000 light years away in another direction, if I detect its light and the star's light simultaneously, I can infer that the alarm and the star went off at the "same time". At the same time for me, that is. For someone who was moving at the time, not necessarily.

              I'm still not quite convinced that I can talk about events that I can'

    • Dark Helmet: What the hell am I looking at? When does this happen in the movie?
      Colonel Sandurz: Now. You're looking at now, sir. Everything that happens now, is happening now.
      Dark Helmet: What happened to then?
      Colonel Sandurz: We passed then.
      Dark Helmet: When?
      Colonel Sandurz: Just now. We're at now now.

      and so on...
    • Came here to say this.

  • If a tree explodes in the forest...

    • Re: (Score:2)

      by jrumney ( 197329 )

      If a tree explodes in the forest...

      ...and you happen to have a mirror handy, you might just catch it's light echoes.

      • ...and you happen to have a mirror handy, you might just catch it's light echoes.

        My mirror was destroyed by extraneous apostrophe shrapnel from the exploding tree, you insensitive clod.

        • Re: (Score:2)

          by jrumney ( 197329 )
          It's is a perfectly good use of the possessive singular of it, seen throughout historical texts like the US constitution. I reject the revisionism that brought about the artificial word its so that grammer nazis can start flame wars on internet forums.
          • No. "It's" is a contraction of "it is," and "its" is possessive in a form much like the word "his." What you're rejecting is clarity in communication. Why?

            • Re: (Score:2)

              by jrumney ( 197329 )
              It's perfectly clear from context. There is no need for revisionism in the language purely for the sake of looking down on those who do not follow your rules.
              • Your write. Theirs know raisin too every extinguish between too words that seam clothes enough in how they sound.

                Why evolve a language into a form that's clearer and easier to use, right? Right! All of this revisionism is nonsense, and we should be sticking with Ye Olde English. Or better yet, a bit of Chaucer-style middle English, right? Of course, he was a revisionist bastard wasn't he! He was probably looking down on those primitive Anglo-Saxons and their "clear from context" runic vagueness. We shoul

  • 2008 wtf? (Score:5, Informative)

    by I4ko ( 695382 ) on Monday May 11, 2015 @11:41PM (#49670581)
    How is this news? The video in TFA is from 2008, check the upload date on Youtube. There must be some weird time dilation effect going on, posting 2008 news is a new low, even for ./ on nowadays.

  • Summary.... Incorrect (Score:3, Insightful)

    by aepervius ( 535155 ) on Tuesday May 12, 2015 @12:29AM (#49670725)
    Cassiopeia is 11.000 LY away. The star exploded not 300 years ago, but the explosion light reached us 300 years ago. Heck even the article says it wrongly "A supernova dating back to the 17th centuryâSâ"âSthe most recent one in our galaxyâSâ"âSwith a massive black hole left behind. 11,000 light years distant". It might be a bit pedantic, but instead of stating the star exploded 300 years ago, one should say the light of the explosion reached us 300 years ago.
    • Maybe the original light should have arrived 300 years ago (due to Earth being 11,000 LY away from source), but the reflected echo is coming to us only now (since the reflection traveled further) ?

  • "A little over 300 years ago, a supernova ...exploded."

    If it exploded 300 years ago or so then for us to know about it, it must have been within 300 light years of us, thtats a bit close for my liking

    • Depends on the reference frame you're using. Saying it exploded when the light hit us is perfectly correct, in the frame of reference of the light. It's a useful frame of reference, in that we can refer to times without bothering to determine exactly how far away the explosion was (and what frame of reference do we use for that?), and because we can specify events as they appear to us without having to subtract a large and arbitrary number.

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