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First Evidence of Supernovae Found In Ice Cores

Posted by kdawson on from the hot-and-the-cold-of-it dept.

KentuckyFC writes "Supernovae in our part of the Milky Way ought to have a significant impact on the atmosphere. In particular, the intense gamma-ray burst would ionize oxygen and nitrogen in the mid to upper atmosphere, increasing the levels of nitrogen oxide there by an order of magnitude or so. Now a team of Japanese researchers has found the first evidence of a supernova's impact on the atmosphere in an ice core taken from Dome Fuji in Antarctica. The team examined ice that was laid down in the 11th century and found three nitrogen oxide spikes, two of which correspond to well known supernovae: one event in 1006 AD and another in 1054 AD, which was the birth of the Crab Nebula (abstract). Both were widely reported by Chinese and Arabic astronomers at the time. The third spike is unexplained, but the team suggests it may have been caused by a supernova visible only from the southern hemisphere or one that was obscured by interstellar dust."

8 of 145 comments (clear)

  1. The Crab Nebula wasn't born in 1054 AD by unassimilatible · · Score: 3, Insightful

    1054 AD, which was the birth of the Crab Nebula

    The Crab Nebula is 6,500 light years away from earth (http://en.wikipedia.org/wiki/Crab_Nebula).

    This means the birth of the Crab Nebula was in the year 5446 BC. Mankind witnessed it 6,500 years later.

    News stories on such phenomena invariably leave out this little fact, i.e., that which is witnessed by man in the sky usually happened thousands of years earlier than when he actually saw it. This makes it confusing for the average reader.

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    1. Re:The Crab Nebula wasn't born in 1054 AD by Anonymous Coward · · Score: 3, Insightful

      But isn't it more sensible when speaking in a historical tone to refer to a celestial objects birth relative to our time line and not the objects actual birth?

      I suppose it would be astute to word it in the tune of, "1054 AD, which was when man observed the Crab Nebula". This isn't accurate either as it may suggest that the Nebula could have existed prior to the observed date. ::shrug::

    2. Re:The Crab Nebula wasn't born in 1054 AD by Anonymous Coward · · Score: 5, Insightful

      You seem very confused about reference frames. There's no "fixed" time reference for the universe, so it seems perfectly reasonable to use the one on Earth where all the readers live. Sure it give jerks like you something to complain about, but the rest of us understand exactly.

    3. Re:The Crab Nebula wasn't born in 1054 AD by zappepcs · · Score: 4, Insightful

      Try: 1054 A.D. which is when man observed the birth of the Crab Nebula

      One thing I'm curious about. Does this mean that we admit freely that extra-solar events affect the climate of this planet? Anyone have a slide rule handy and some star charts or galactic weather maps? Can we calculate probable effect on current climate conditions from extra-solar events?

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    4. Re:The Crab Nebula wasn't born in 1054 AD by jmizrahi · · Score: 3, Insightful

      The whole point of relativity is that there is no such thing as absolute time. Your statement assumes that there is meaning to simultaneity, which is incorrect.

    5. Re:The Crab Nebula wasn't born in 1054 AD by techno-vampire · · Score: 4, Insightful
      This means the birth of the Crab Nebula was in the year 5446 BC. Mankind witnessed it 6,500 years later.

      AIUI, it's customary in Astronomy to ignore the time it took for the light to reach us and consider that things in the sky happen when we see them happen. Not that they're not aware of it, it's just that it makes things easier to talk about, especially to laymen. In general, people either understand about the time lag and take it for granted, or neither understand nor care.

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    6. Re:The Crab Nebula wasn't born in 1054 AD by Anonymous Coward · · Score: 4, Insightful

      Glaring error? Frankly, I thinking giving 1054 AD as the birth of the Crab Nebula is the most precise way of pinpointing that event. We could have obtained absolutely no information about the event before that date anyhow.

      Given general/special relativity, appealing to some objective background time and saying that the supernova occurred "simultaneous" to events in 5446 BC on Earth is the truly ridiculous claim on a cosmic scale. To another equally valid observer, those two events are not simultaneous, and could be in a different order.

      If our understanding of cosmology or general relativity ever fundamentally changed, it's the date of the observation that's going to actually be relevant. If your audience *is* a bunch of scientists, they're going to recognize this...

    7. Re:The Crab Nebula wasn't born in 1054 AD by Hillgiant · · Score: 3, Insightful

      You know that this is what a relativistic physicist will tell you, right?

      Depends on how fast he's moving.

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