The aftermath of supernovae… in Antarctica

It’s pretty amazing, all the things that get caught up in the Antarctic ice. It’s a prime hunting ground for meteorites, for one thing. The infamous ALH 84001 with its supposed martian microfossils was found in Antarctica. As was the tiny MM04, a rock which is probably older than planet Earth! But it’s not just rocks that get trapped in the Antarctic ice. Supernovae that lit up the night sky a thousand years ago have also left their marks.

Quite recently, a group of Japanese scientists spent some time in Antarctica looking for evidence of past supernovae. Specifically, supernovae which were seen in the years 1006 and 1054 (the latter of which caused the famous Crab Nebula). Both of these supernovae were recorded by astronomers at the time across the globe (particularly the Japanese, Chinese, European and Arabic astronomers). The team took ice core samples, and found large amounts of nitrogen oxides at times corresponding to 1006 and 1054. Curiously, there was another spike a while after 1054, the cause of which is still a mystery! If there was a third supernova that century, then for some reason no records of it exist.

A nearby supernova leaves its mark on Earth by drastically altering the atmosphere. A blast of gamma rays hitting the upper atmosphere will hit molecules of nitrogen and oxygen and rip them to shreds. Those fragmented molecules will then rapidly react, forming nitrogen oxides. The same thing happens in lightning bolts and even sunlight causes some nitrogen oxide to form, but only light from a supernova could cause such huge amounts all at once. This is the first time such evidence of past supernovae has been found in an ice core!

As well as the supernovae, the researchers got quite a haul of data — including finding increased levels of sulfate corresponding to volcanic eruptions across the globe, and a variation in background nitrogen oxide corresponding to the 11 year solar cycle.

It’s really quite amazing what gets recorded in the Antarctic ice!

(click to embiggen)

Sources: arXiv blog, arXiv

About Invader Xan

Molecular astrophysicist, usually found writing frenziedly, staring at the sky, or drinking mojitos.
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7 Responses to The aftermath of supernovae… in Antarctica

  1. Anonymous says:

    Re: Anyone can do this
    Very nice. Thank you very much for the link!

  2. invaderxan says:

    Re: Mysterious supernova
    The biggest question, though, would be where exactly the remnant is. At under 1000 years old, it should be easily observable somewhere in the sky.
    The only possibility I know of which seems to fit could be G350.1-0.3. It’s believed that it wasn’t observed due to dust obscuring its light, although gamma rays could mostly pass straight through a dust cloud without much scattering. Mind you, it’s a bit more distant. Over twice as far away as the crab…

  3. Anonymous says:

    Mysterious supernova
    An undetected supernova could very easily have occurred in the south, it is: Near the south pole! Nobody would have recorded it, but the remnants might be still found…

  4. invaderxan says:

    Seemingly, there’s a very good chance that’s precisely what happened. I think the authors even suggest the possibility.
    To my knowledge, there were no civillisations in the Southern Hemisphere around the 11th century who kept astronomical records. Unless I’m mistaken, the Mayans were in decline at the time, and the Inca Civillisation didn’t appear until a few hundred years later — though I hasten to add that I’m by no means an expert on the matter!

  5. Curiously, there was another spike a while after 1054, the cause of which is still a mystery! If there was a third supernova that century, for some reason, no records of it exist.
    I wonder if it could’ve occurred in the southern sky? All the ancient astronomical records we have are by northern-hemisphere peoples, such as the Chinese, so if it were too far south, it wouldn’t’ve been visible to those cultures.

  6. invaderxan says:

    Re: Supernova on ice
    Isn’t it cool? :)
    (Erm… no pun intended).
    Some even believe that nearby supernovae could even have been behind a couple of Earth’s mass extinctions

  7. Anonymous says:

    Supernova on ice
    It’s amazing what can be found in the ice, but I never thought of a supernova leaving traces. As always I learn something new which makes it an even better day :-)

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