It looks like gamma-ray bursts (GRBs) just became even more inscrutable. And that’s saying something for the brightest — and potentially most destructive — known objects in the universe.
Even though it’s still a mystery just how these things work, scientists believed GRBs originated from a giant “fireball” made up of traditional matter, spewed out during black hole formation. But a recent paper in the Astrophysical Journal Letters (August 1, 2009) concludes that, for at least one GRB, this can’t be the case.
In the paper, Bing Zhang of the University of Nevada, Las Vegas, and Asaf Pe’er of the Space Telescope Science Institute in Baltimore analyzed recent data from the Fermi Gamma-ray Space Telescope and discovered none of the expected thermal emissions from GRB 080916C. Instead, they suggest it was a Poynting flux (energy spikes in electromagnetic fields) that got the GRB going.
GRBs seem to be quite rare, just a few per million years per galaxy, but that doesn’t stop them from capturing the imagination. They release as much energy in a few seconds as the Sun does in its entire lifetime. If our planet ever got caught in the line of fire, we’d probably go extinct. Fortunately, we’ve only seen GRBs in galaxies billions of light-years away.
I try not to focus on how dangerous GRBs could be, but how crazy they are. These things are so bright that last year GRB 080319B (illustrated above) was visible to the naked eye (with apparent magnitude 5.8) despite being more than 7.5 billion light-years away. 7.5 billion light-years! That means light we could have seen with our own eyes originated 7.5 billion years ago, considerably before Earth formed and roughly half the estimated age of the universe!
So let’s hope this Poynting flux idea pans out. If we can understand something so ludicrously powerful and mind-blowing, there’s no limit to what we could figure out.
Do you worry about an impending GRB? Can you think of anything crazier in the cosmos, stranger in space, or more unique in the universe? Let me know!
GRB 080319B illustration: NASA/Swift/Mary Pat Hrybyk-Keith and John Jones