When you're out in the countryside, and you see a big explosion, it's not necessarily that mysterious. Chalk it up to a kid making homemade TNT (maybe even a future scientist), and blowing up a road sign or two.
But it's different in deep space. Earlier this year, scientists observed a bright, long-lasting flare of gamma-ray radiation, the kind of event that is usually associated with the violent death of a massive star.
Yet when researchers turned the telescopes on the site of the flare-up, they found almost nothing. No surrounding galaxy, no signs of dense gas or dust absorbing the afterglow. A little like the interstellar equivalent of the old murder mystery in a locked room.
Researchers have considerable data on this kind of gamma ray burst. The kinds of stars that produce them tend to be very massive and very short-lived. They typically don't have time to wander outside of the galaxy or gas and dust clouds where they were created.
So if this really was an exploding star, how did it come to be so far from anyplace where it should have been?
The best idea so far is that the dying star formed between two interacting galaxies, in the region known as a "tidal tail." In our local portion of the universe, about one percent of star formation happens in these areas, Cenko said.
The next step is to train the Hubble Space Telescope on the region again, and take a very long-exposure look. If a tidal tail formation is there, it's possible that Hubble will pick it up.
Otherwise, one this year's brightest flare-ups will have to remain the mystery of the explosion in the dark.
'Shot in the Dark' Star Explosion Stuns Astronomers (NASA press release)
(Image: The long tail of the so-called Tadpole Galaxy. If the current flare-up happened in such a tail, Hubble is the only instrument that could detect the surrounding formation. Credit: NASA, H. Ford, et al.)
