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Our future, our universe, and other weighty topics

Monday, January 19, 2015

Bursts of the Gods?

In 2007 astronomers detected a new class of radiation signal from deep space – what are called fast radio bursts. Fast radio bursts are highly energetic but very short-lived bursts of radio energy, typically lasting less than a hundredth of a second. Fewer than twenty of these bursts have been detected. For years, all of the detections came from a single telescope in Australia, but then the Arecibo Observatory in Puerto Rico also detected such a fast radio burst.

Where are the signals coming from? A recent estimate by scientists is that the signals come from a distance that is "up to 5.5 billion light years from Earth,"  which is pretty vague.

Based on the number of fast radio bursts that have been detected, astronomers have estimated that our planet could be receiving as many as 10,000 of these radio bursts per day. What could be causing the signals? Astronomers don't know. Some astronomers speculate that the fast radio bursts could be caused by various exotic types of stellar events, such as unusual solar flares or two neutron stars colliding with each other.

There is, however, a general problem with such explanations. Most highly energetic freak events imagined as possible sources of the fast radio bursts would probably have produced other types of radiation such as gamma ray radiation, x-rays, or visible light. But no one has detected a flash of any of these types of radiation with a position in space (and time of origin) matching any of the fast radio bursts. To give an analogy, it's kind of as if you felt the ground shaking, and assumed it was something heavy falling to the ground, but you didn't hear any noise at the same time. That would throw doubt on your explanation.

Previous discoveries of the fast radio bursts came from mining old observations. But this year scientists detected a fast radio burst in “real time,” noticing it shortly after the signal arrived. The scientists alerted other observatories around the world, asking them to check the point in the sky where the signal was detected, to look for other types of radiation. The other observatories did that, but basically came up empty. This result is described in this recent paper and this news story that came out today. 

The latest fast radio burst (the time unit is milliseconds)

According to scientist Daniele Malesani, “The fact that we did not see light in other wavelengths eliminates a number of astronomical phenomena that are associated with violent events such as gamma-ray bursts from exploding stars and supernovae, which were otherwise candidates for the burst.”

In short, we seem to have no really good astrophysical explanations for the fast radio bursts. Given the fact that short radio bursts have been postulated as one means by which extraterrestrial civilizations could announce their existence, there would seem to be a very real possibility that some or many of these short radio bursts are coming from extraterrestrial civilizations.

The idea of extraterrestrial civilizations communicating by fast radio bursts may conflict with a long-standing notion of SETI, the search for extraterrestrial intelligence. I may call this idea the “Christmas gift” concept. It's the idea that one day we will be lucky enough to get from some incredibly old and advanced extraterrestrial civilization a nice, easy-to-digest radio signal designed to be understood by primitive newbie fledglings such as our species. It will be just as if they sent us a wonderful Christmas gift across the vast interstellar void (some have even imagined such a radio signal containing an “Encylopedia Galactica” written for beings of our level).

But the idea of extraterrestrial civilizations communicating by fast radio bursts suggests another possibility: that of super-advanced civilizations communicating in ways that can only be intelligible to other super-advanced civilizations, who might have no problem unraveling trillions of bits of information packed into a tiny radio burst lasting only a fraction of a second. We might determine that such signals are likely to be of intelligent origin, but then experience the frustration of having to wait for centuries until we are technologically advanced enough to decipher and unravel such super-condensed information bursts. It will be like getting a Christmas present and being told it's the greatest present ever, but also being told it will take you thirty years before you can figure out how to get the present out of the box.