It was a poor choice to use GRBs as an example because that is one of
the few astronomical objects for which we have acquired fundamental
understanding in the last decade plus it is complex because there is not
a unique cause for them.
>
>
> Brian Thomas wrote:
>> On Wednesday 06 February 2008 11:50:23 am Alasdair Gray wrote:
>>
>>>> Gamma-ray bursts (GRBs) are the most luminous events occurring in the universe since the Big Bang.
>>>>
Speculation. It is possible for there to be more luminous events that
we are unaware of because they are more rare. Can add "that we are
aware of at this time"
>>>> They are flashes of gamma rays emanating from seemingly random places in deep space at random times.
>>>>
It is a bit misleading to continue to say they are seemingly random.
"They are known to be events occurring in galaxies.
Several of these with durations, at the event, of > 2 sec (long-duration
GRB) have been clearly linked to high mass supernova (hypernova). The
leading candidate class for the shorter duration ones is neutron star
mergers."
>>>> The duration of a gamma-ray burst is typically a few seconds, but can range from a few milliseconds to
>>>> minutes, and the initial burst is usually followed by a longer-lived "afterglow" emitting at longer wavelengths
>>>> (X-ray, ultraviolet, optical, infrared, and radio). Gamma-ray bursts are detected by orbiting satellites
>>>> about two to three times per week, but their actual rate of occurrence is much higher because not all
>>>> bursts are pointed at Earth.
>>>>
Would change "pointed" to "beamed".
Actually the short duration bursts are not directional.
So, while I agree that in general one can cut and paste from Wikipedia
or some on-line open astronomical glossary, there are a few terms that
do need special care because of recent developments or technical
complexity. I also would not underestimate the number of times a term
has multiple meanings. That is unacceptable for us.
Ed Received on 2008-02-07Z16:12:28