P3D stereos of the sky from satellites

[Peter Abrahams <telscope@xxxxxxxxxx>]

I noticed a very interesting use of stereo in a January _Science_ (there
are 4 issues, but the copier cut off the date).  
Ultra high energy cosmic rays (UHECRs) are an unusual type of cosmic ray
that carry more energy than can be explained (they must be from nearby
sources, or the microwave background radiation would reduce their energy
levels, but no known nearby source can generate them).  Very few have been
detected.  UHECRs carry 10^20 electron volts, 100 million times the energy
of any particle on earth, and were first detected in 1966.  
A recent NASA conference at U. Maryland (Dec. 97), concerned a proposed
'Orbiting Wide Angle Light Collector (OWL) twin satellite program, to be
launched in 2010.  "Each of the two OWL satellites would contain about 10
square meters of photodetectors for observing the tracks of ultraviolet
fluorescence generated by cosmic rays streaming through the atmosphere.
They would provide a stereoscopic view of about 1 million square km of the
atmosphere at a time and observe perhaps 500 to 1000 UHECR showers per
year..." Currently, about one shower a year is observed (a shower of
secondary particles created when energetic particles (including UHECRs) hit
the atmosphere.  
Other proposals to observe UHECR showers have been discussed.  These
projects are almost certainly going to result in fundamental advances in
physics.

I thought that the idea of a stereo image of cosmic ray tracks (maybe
similar to lightning), from above, was interesting enough to share.  There
was no mention of the 'baseline' between the satellites, but the idea is to
pinpoint the coordinates of the source by observing the path through the
atmosphere.   
_______________________________________
Peter Abrahams   telscope@xxxxxxxxxx
the history of the telescope, the microscope,
    and the prism binocular


------------------------------