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Prince
2002-May-15, 09:25 PM
Does anyone still hold that Gamma Ray Bursters occur within the "Solar" System as some thought 10 years ago?

http://www.ledger-enquirer.com/mld/ledgerenquirer/news/local/3251673.htm

DoctorDon
2002-May-16, 12:36 AM
No.

ljbrs
2002-May-16, 02:08 AM
Ditto. No.

ljbrs

_________________
*Nothing is more damaging to a new truth than an old error.* Goethe

<font size=-1>[ This Message was edited by: ljbrs on 2002-05-15 22:08 ]</font>

Firefox
2002-May-16, 02:22 AM
Not only no, but he** no. What brought up the subject of Solar System-based bursts?


-Adam

Jigsaw
2002-May-16, 03:17 AM
What brought it on? Dunno exactly, but I'm guessing that somebody at MIT sent out a press release on some GRB or other, and it was a slow news day, and "CAROLE RUTLAND" had nothing else to do, so her editor tossed the press release over to her and told her, "Write this up."

http://space.mit.edu/HETE/mission_status.html
http://space.mit.edu/HETE/Bursts/
http://space.mit.edu/HETE/Bursts/summaries.html

The website's latest update on the "Status" page was May 13, 2002, so I'm guessing that something exciting (relatively speaking) happened last week, and somebody sent out a press release. Anybody know more about it than I do, wanna go through the website and see what happened last week?

roidspop
2002-May-16, 05:10 AM
Setting aside "real" gamma ray bursters, which seem to be supernovas, can anyone here help me answer a question I've had for a long time: what would the final, explosive decay of a 'primordial' black hole look like if it happened within about 1000 AU of us? It seems that there would be a rather slow ramp-up (probably invisible to us), with a very sharp peak in UV, Xray, Gamma, and a clean cutoff. Pretty distinct from a burster. So, could we detect an event like this and have we any candidates?

Azpod
2002-May-16, 05:16 AM
On 2002-05-16 01:10, roidspop wrote:
Setting aside "real" gamma ray bursters, which seem to be supernovas, can anyone here help me answer a question I've had for a long time: what would the final, explosive decay of a 'primordial' black hole look like if it happened within about 1000 AU of us? It seems that there would be a rather slow ramp-up (probably invisible to us), with a very sharp peak in UV, Xray, Gamma, and a clean cutoff. Pretty distinct from a burster. So, could we detect an event like this and have we any candidates?


My best guess would be a shower of quarks, not unlike what you'd see in a particle accelerator.

Accoring to the people who are trying to create a primordial BH in the lab, such BHs are being created & destroyed all the time in the ionosphere when particularly energetic cosmic rays collide with the Earth's upper atmosphere.

And no, we haven't detected any shower of particles much such black holes. The quarks decay much too quickly to be detectable at a distance.

roidspop
2002-May-16, 04:10 PM
It was my understanding (altogether too likely flawed) that the energy yield from such a decay would have been on the order of megatons; these aren't the low-mass variety of black holes such as may be created in colliders or cosmic ray interactions. If particle pairs are being produced, it seems unlikely that 100% of the energy liberated during the event would be absorbed by this mechanism. So, the question remains; could we detect such a burst and what would it look like?

Prince
2002-May-16, 06:16 PM
Are the bursters still viewed as being isotropically distributed? Does this have geocentric implications?
http://www.science-frontiers.com/sf095/sf095g15.htm

How do they know whether these bursters are near or far?
http://www.science-frontiers.com/sf095/sf095g15.htm

DoctorDon
2002-May-16, 08:02 PM
On 2002-05-16 14:16, Prince wrote:
"Are the bursters still viewed as being isotropically distributed?"

Yes. Both the short and long populations of bursts show no devations from isotropy to well less than a percent, last I heard.

"Does this have geocentric implications?"

No.

"How do they know whether these bursters are near or far?"

Because BATSE had the ability to tell where bursts were coming from to at least 10 degrees or so, and these bursts were always coming from the earth (the earth's diameter is something like 130 degrees from a low-earth orbit). You'll note in the article that they point out that the bursts are coming from areas where there are strong electrical storms.

BATSE had eight detectors, one on each vertex of the "cube" of the satellite body. Therefore, for any random direction in space, some subset of those detectors would be able to see in that direction. The others would be blocked by the satellite itself. By combining the brightness curves for the burst in the three or four detectors that recorded it, you can correlate where the burst came from.

Hope that helps,

Don

2002-May-17, 04:05 PM
On 2002-05-16 16:02, DoctorDon wrote:
On 2002-05-16 14:16, Prince wrote:
"Are the bursters still viewed as being isotropically distributed?"

Yes. Both the short and long populations of bursts show no devations from isotropy to well less than a percent, last I heard.

"Does this have geocentric implications?"

No.

from my experiance i would say yes to geocentric
as i saw it {when Rumple of GUG} (General Unit of Gravity)
Rum = Max then GUG = 0 {vanishes}
when an existing GUG vanishes it center
no longer exists and a new centrilist center
become central. [there EXISTS a very Violent
moment as the one center vanishes and the other becomes
the only example I can give is a CRASH
two cars with two centers CRASH & there
center are no longer central? its not a very good example

Prince
2002-May-17, 07:19 PM
Science Frontiers no 83 1992 suggested that the bursters are very close, consistent with the failure to find cosmological redshifts in their spectra: close, possible a few 100 light-hours away, arranged in a spherical halo around the solar system. Has this been refuted since?

DoctorDon
2002-May-17, 07:54 PM
On 2002-05-17 15:19, Prince wrote:
Science Frontiers no 83 1992 suggested that the bursters are very close, consistent with the failure to find cosmological redshifts in their spectra... Has this been refuted since?


Odd that such a claim would be made in 1992, when no (optical) spectra had been observed at all from GRBs (you can't measure redshifts from the high-energy spectra available to that date: not enough resolution to resolve lines). You'd think they would know that absence of evidence is not evidence of absence.

Anyway, the first GRB optical spectra were taken in May of 1997, showing cosmological redshifts and thus clinching the argument that had been made before based on isotropy and inhomogenaiety that the bursts are coming from cosmological distances. Since 1997, dozens of cosmological redshifts have been measured, ranging from around 0.6 to 4.0 or so, with one interesting exception at 0.0085. So, yes, any 1992 claim is highly likely to be out of date.

Don