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Space Science

What Happens When Betelgeuse Explodes? 203

StartsWithABang writes: One of the great, catastrophic truths of the Universe is that everything has an expiration date. And this includes every single point of light in the entire sky. The most massive stars will die in a spectacular supernova explosion when their final stage of core fuel runs out. At only an estimated 600 light years distant, Betelgeuse is one (along with Antares) of the closest red supergiants to us, and it's estimated to have only perhaps 100,000 years until it reaches the end of its life. Here's the story on what we can expect to see (and feel) on Earth when Betelgeuse explodes.
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What Happens When Betelgeuse Explodes?

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  • I have supernova insurance

  • by Askmum ( 1038780 ) on Wednesday February 25, 2015 @02:31AM (#49125301)
    Beetlejuice, Beetlejuice, BEETLEJUICE

    Nope, nothing happened.

  • Isn't that (Score:5, Funny)

    by rossdee ( 243626 ) on Wednesday February 25, 2015 @02:33AM (#49125303)

    where Ford Prefect and Zaphod Beeblebrox come from?

    • by Scarletdown ( 886459 ) on Wednesday February 25, 2015 @02:47AM (#49125333) Journal

      It was a small planet somewhere in the vicinity of Betelgeuse. So it could have been a neighboring system. Because when talking on astronomical scales, the vicinity of a star can cover a tremendous amount of space. After all, space is big, extremely big. You wouldn't believe just how big it is...

      • by aliquis ( 678370 )

        It was a small planet somewhere in the vicinity of Betelgeuse. So it could have been a neighboring system. Because when talking on astronomical scales, the vicinity of a star can cover a tremendous amount of space. After all, space is big, extremely big. You wouldn't believe just how big it is...

        Is that when the universe is viewed in the perspective of say petunias or when it's viewed by mice?

      • After all, space is big, extremely big. You wouldn't believe just how big it is...

        That's why it's called space - because there is such a lot of it.

        (The rest of the movie where that quote came from was quite forgettable. I don't even recall it's name.)

    • Well it would be came from. Get your tenses right.

  • a little brighter (Score:5, Insightful)

    by itzly ( 3699663 ) on Wednesday February 25, 2015 @02:37AM (#49125311)

    A long winded article where the crucial information "a little brighter" is hidden between 2 pages of fluff.

    • Re:a little brighter (Score:5, Informative)

      by BlackPignouf ( 1017012 ) on Wednesday February 25, 2015 @03:28AM (#49125441)

      A bit more than "a little brighter".
      It would go from 0.5 (now) to -10 apparent magnitude. That's about 15000 times brighter.
      It would be much brighter than Venus/Jupiter/Sirius, and be visible during daytime.
      It would be about as bright as a quarter moon.

      • by itzly ( 3699663 )

        It would be about as bright as a quarter moon.

        Yes, so nothing special. 90% of the people wouldn't even notice, unless it was pointed out to them.

        • by Anonymous Coward on Wednesday February 25, 2015 @04:44AM (#49125617)

          It will have roughly the same magnitude as the quarter moon, meaning the total flux. Unlike the moon it will appear as an extremely bright pin point of light

          So saying as bright as the quarter moon greatly understates the apparent brightness.

          • by itzly ( 3699663 ) on Wednesday February 25, 2015 @04:51AM (#49125631)

            In other words, a poorly written article. Plenty of pictures, but not a single one showing a daytime sky with some clouds, a quarter moon, and an accurate representation of what the nova would look like in comparison.

      • by gsslay ( 807818 )

        And yet it takes so long to say what you summarise in four lines.

        Yes, the all the math is good to see, it's not just making this all up. But this article starts out so promising and ends abruptly just when it gets around to the interesting bit.

      • It would be about as bright as a quarter moon.

        I wonder what that means. Is the light density the same as of a quarter moon, or is the total amount of light the same? If it is the first, is this really that different for a quarter moon and a full moon?

        • I'm not sure about the 2 first questions.
          http://www.sr.bham.ac.uk/~tjp/... [bham.ac.uk] seems to suggest that apparent magnitude is based on flux (=total amount of light), and not on intensity (=light density).
          It means that the light density of Betelgeuse supernova would be much higher than the light density of the quarter moon. The total amount would be approximately the same. If I'm not mistaken, since the sun (32.7 arcminutes) is much bigger than Betelgeuse (0.056 arcseconds), Betelgeuse supernova would also have a m

          • I think you are right, it must be the flux, not the light intensity. I think the light density of the quarter moon is not that much compared to e.g. Sirius, but of course the flux is considerably larger.
            But it is hard to imagine a star with the whole flux of the quarter moon, that must be an extremely bright tiny spot, maybe like a laser.
      • by Gamasta ( 557555 )

        Thank you for the "TL;RD" comment. The article is really full of fluff, which is interesting for the layman. The facts you pointed out would have sufficed for me. Lesson learned again: DRTFA.

        Out of my head the full moon has apparent magnitude of -13, Venus is about -4.3 at its brightest. So the full moon would makes a better comparison, it would easily be visible during daytime. Nobody would have to be told it's there to notice it.

    • If that's what you concluded from the article then you may want to re-read it with more care.

    • Sigh... Once again, we get this earth-centric slant on Slashdot.

      For those folks who may see it 599.99 years before us, a little brighter may not fully capture the magnitude of it. Insensitive clods.

  • I was under impression that gamma bursts are a lot more interesting things when supernova expodes. What are the chances of it hitting Earth (they are focused, not omnidirectional ?) and how bad it would be for supernova so close to us?

    • Good questions that aren't answered in that disappointing article.

    • Even if the gamma ray burst were aimed straight at us, the exploding star would have to be within 50 light years to hurt our ozone layer (source: google).

      • by abies ( 607076 )

        Seems to depend on type of nova:
        http://news.nationalgeographic... [nationalgeographic.com]
        Here, they claim 6500 light years - but it might be for hypernova rather than supernova.

      • I doubt that the ozone layer has any influence on gamma ray bursts.
        I guess a huge deal of life on the side of the earth aiming to that burst would die. And the other side of the planet would 'colonize' the dead part later again.

        • No, the atmosphere would shield you from the gamma rays. However, a side effect of that would be the generation of massive amounts of ozone-destroying chemicals in the upper atmosphere. The subsequent lack of ozone and massive UV exposure would be the real risk, especially because almost all of our food grows in sunlight.

    • The atmosphere would boil and we'd all die. Basically.

      • by abies ( 607076 )

        This is not that obvious.
        If hypernova expode 5 LY away from us and points gamma ray burst at us, we boil away.
        If 'normal' nova expodes 10000LY away from us, then we we hardly notice that.

        Between nova, supernova and hypernova and 5, 600 and 10000LY there is a lot of difference. I was hoping for some more exact data about Betelgeuse in particular...

    • I'd suggest reading Phil Plait's Death From The Skies [amazon.com]. He goes into the details about the Earth being destroyed by supernovae, gamma ray bursts, etc.

  • Poul Anderson pointed out in a 1967 story that a supernova could have devastating electromagnetic pulse effects.

    Since then, we've found that supernova explosions are asymmetrical. There is plasma moving at very high speeds near a new neutron star's magnetic field and not in a neat way where the effects cancel out.

    How far away would you have to be in order not to have all your electronics fried?

  • I assume Betelgeuse is on a slightly different orbital trajectory around the galactic center. So, if Betelgeuse is going to explode in about 100,000 years, won't its distance to Sol have changed by then?

  • It gets as bright as a quarter full moon on a pinpoint in the sky.

    Where the feel of "what we would see (and feel)" comes into it, I have no idea.

    Long article, for simple answer, that isn't even that interesting.

    Personally, the most interesting bit was the bit about a previous supernova in the 1000's that looks like a cloud of dust now.

  • Asy Ray to write it up in his blog. Ray will be the only one of us still alive in 100,000 years.

  • Please have exploded 600 years ago!

  • We might see not much at all because Betelgeuse happens to be located almost exactly in the ecliptic plane (10 degrees or so below it), so at certain times of the year you can't see it because it's just 10 degrees away from the sun. It would really suck if the supernova occurred during those months. I think even Hubble can't observe that close to the sun, so you'd need a telescope in deep space, which we don't really have atm.
  • by PortHaven ( 242123 ) on Wednesday February 25, 2015 @09:24AM (#49126663) Homepage

    Supernova will be ~1/4 the brightness of the Luna.

    There, you can now skip to your loo and read your Kindle.

  • ... I made the assumption that it would address how such an explosion happening so close to our own solar system would likely affect this planet.

    But.... nothing. Lots there about what to see, but not a speck of text anywhere in the article that addresses what would actually happen for us.

    I already have a pretty rough idea of my own on what will happen on Earth anyways... and I suppose I went looking to the article in the hope of seeing either confirmation or denial, but I found neither. If I'm right,

  • How do we know it hasn't happened already? It could have exploded five hundred years ago, and we wouldn't know.

  • who bought...*cough* I mean "named" a star after someone at the "international star registry." What a sh*tty gift.

  • 1 ) This could've already happened.

    2 ) How long would this be visible for?

  • Worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, as bright as a quarter moon for a while, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry, worry.

    There would be considera

  • Maybe it already has exploded.

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