In case you were worrying that life on Earth would be wiped out by a catastrophic burst of gamma rays, rest easy. It turns out that our galaxy may not be a very good source of gamma ray bursts. I found this particularly interesting given recent speculation that gamma rays bursts might have triggered mass extinctions in the past. (News article here, original paper here.) The bursts are clearly catastrophic, but probably not close enough to Earth to cause much trouble.
- Log in to post comments
More like this
Last week, the brightest gamma-ray burst ever was observed. (See here.) I wanted to know what it was that caused this bright explosion that, despite it being at redshift z=0.94 (or about 7.5 billion light years away), it was visible on Earth with the naked eye!
Well, a scientific paper was written…
"Standing down on this one" - was the first line of the email I read at about 7 am this morning as I rolled over and grabbed my phone, having had about 4 hours of sleep.
After staying up past 2 am to run some numbers, we would, after all, not be submitting a request for Director's Discretionary…
A large part of my affection for science comes from the thrill of terror I get when a particularly insane piece of science news hits the presses. When an article begins with a sentence like, "there is something strange in the cosmic neighborhood," or "all the black holes found so far in our…
Cold Fusion was first reported in 1989. The original experiment was supposed to have produced extra heat that could not be explained wiht chemistry or electronics, so naturally, fusion was considered. Contrary to popular belief, that original experiment has been replicated successfully. The…
Actually, the "original" paper was quite a few years earlier than the one that you cite: http://xxx.lanl.gov/abs/astro-ph/9501019.
This makes the 'great silence', aka the Fermi Paradox, ever more intriguing.
One explanation for the fact that the galaxy isn't swarming with LGMs is that our galaxy is very inhospitable to life. Periodic bursters are a nice way to sterilize chunks of the galaxy, and thus they help explain the paradox. Another historic explanation was that earth-like planets are rare.
We now think earth-like planets may be not terribly rare. Today we learn that bursters may not be all that common. These modify terms in the old Drake equation, meaning there's more pressure on something else to explain our solitude.
Personally, I favor the explanation that the period of time that any technologic culture is interested in exploration and expansion is very short. (That is, biological imperatives never persist).
The usual explanation is that all technological civilizations turn into gray goo ... :-).
With respect to John's comments....even if our galaxy had millions of life-bearing planets...the likelihood of technology is still very small. Life would have to evolve into multi-cellular forms....then an intelligence would have to evolve in a creature that is also capable of manipulating its environment. In our case, agriculture was a pre-requisite to advanced technology....yet agriculture also encourages religious development that is often very anti-intellectual. Once the religious [anti-intellectual] hurdle is overcome....then as you say.....how long does the technology last? Ours is dependant on cheap and abundant sources of energy....and how long will that last for us?
My favorite explanation to the Fermi Paradox is that interstellar travel is hard. Civilizations might only do it if 1) they can, and 2) when they have to. It isn't clear that we can, and it will be some time before we have to. It might be easier to siphon off some mass from the Sun to extend it's life span. In any case, there may not have been enough time for anyone to have to do interstellar migration. The space Arc is going to have to be huge, unless all we send is information. A robot ship could terraform some planet, build all the life forms from scratch...
... and then there is the argument in "Rare Earth", which I commend to everyone.