Powerful Blast Confuses Astronomers

eldavojohn writes "Astronomers are still speculating as to what could have caused an abnormally strong five millisecond burst to be detected six years ago when it completely saturated their recording equipment. From the article: 'The burst was so bright that at the time it was first recorded it was dismissed as man-made radio interference. It put out a huge amount of power (10exp33 Joules), equivalent to a large (2000MW) power station running for two billion billion years.'"

Comments

Re:Due diligence

[p0tat03]

I admit I didn't RTFA - but if this was an actual reading, shouldn't it have been recorded by *multiple* sensors that are spaced very far apart? What are the odds that all the sky-facing sensors caught the same misreading at the same time? If it's just a single (or a group of local) sensors, then it's probably nothing.

Re:Due diligence

[History's Coming To]

I'm inclined to agree. A one-off freak occurrence is usually Somebody Else's Fault. Plenty of astronomical events put out this level of energy, but very rarely for such a short length of time.

Re:Due diligence

[Anonymous Coward]

The above poster is correct. If you hear a burst of static on the radio, you might just as easily suspect the radio has a loose wire as you would suspect a distant source of interference.

However, if you pick up Beethoven's 5th Symphony, the odds of it being the loose wire making and breaking contact in exactly the right pattern are incredibly low...to the point you'd be insane if your top theory wasn't a distant transmitter broadcasting the symphony.

That's a little extreme of an analogy, but in this case there is also an order to the noise that highly suggests a real signal. Of course, there's orderly forms of interference, too, but most of those can be eliminated by comparing them with the signal.

I don't understand the comment on the rate. If they've only observed one, they can't make any guesses about the rate. The fact that we saw one looking at only a small portion of the sky suggests the rate is reasonably high, but we don't know how much dumb chance was involved.

As for what it is, it sounds like they may have ruled out this idea, but I was wondering if it might actually be a much more distant gamma-ray burst that's been red-shifted all the way to radio wavelengths.

Re:Due diligence

[NeutronCowboy]

I'm inclined to agree. There are very few violent events in Astrophysics that last exactly 5 ms. Even if it's true that the cosmos is vast, and that it is not very likely that someone else was looking at the same exact patch (more like fraction of a pinhead) in the sky at the same exact time, I believe something else should have picked up something. A pure radio radio signal that completely saturates equipment for exactly 5ms? I expect neutrino showers, x-ray waves, visible light - anything, something - to go along with, precede or follow it. Events of that magnitude are messy, and they leave other traces behind.

There are two possibilities here:
- Someone got too excited with their data processing software. Some of that stuff was written in the 70s and is held together with spit, duct tape and undergrad students who have never before seen a Fortran77 program, and probably never will again. I don't trust weird stuff that only shows up after heavy duty data processing.
- Someone picked up a not-so-local radio signal. The atmosphere can do weird things to radio waves.

Or some aliens were messing around with their cell phones again. In any case, I'll file this under "Postprocessing is a bitch".

Radar chirp

[G4from128k]

Perhaps the signal was manmade. And if the signal saturated the detector, then it's even harder to judge the waveform and deduce what caused it. TFA says the frequency shifted during the pulse. That's not uncommon in the pulses used in radar which may been on a passing plane or satellite. Even if the frequency bands are different, the harmonic effect means that a strong source of one frequency may appear as a weak source of a different frequency. Either that, or someone made microwave popcorn on a lonely night and wouldn't confess.

Of course, I've not seen the data and IANARA.

Re:Radar chirp

[patchvonbraun]

The article mentions that they were doing pulsar surveys, which means that the signal arrived over a number of channels, but the pulses
    showed dispersion. Radar signals won't display that kind of behaviour, as far as I know.

If it was at Parkes, it was likely at 326 or 408Mhz.

I run a small radio observatory, and I see large spikes from time to time. It's very likely that 99.9% of them
    are local interference, distant thunderstorm activity, etc. But it's generally acknowledged in the Radio Astronomy
    community, that there *are* unexplained transient phenomenon that are observed from time to time.

Some Pulsars, for example, occasionally emit "super pulses" that are usually orders-of-magnitude stronger than
    the average pulses.

GRBs are also associated with radio afterglow, which can account for some small fraction of the observed
    transient phenomenon.

One of the projects I'd like to do is to have different radio telescopes watching the same portion of sky, but
    separated by enough distance that local RFI isn't a factor. Any transient pulses that arrive at all of the
    telescopes are very likely to have originated from "out there".

Re:Due diligence

[Cassius Corodes]

Well how about breaking with tradition and reading the article for once. :(

I am no astronomer but from the article it looks like the problem was that it was a very short burst (5ms) and you needed to be looking at the right place to see it. I presume that current telescopes don't sample at that low rate so they might have missed it or there were looking at different parts of the sky. Also it was totally Baba Gunusha.

Re:What's an "athiest"?

[KeensMustard]

Is that a label which cultists apply to those who refuse to join their cult? I think you'll find it's a label that certain cultists apply to themselves.