Adopey.128
net.space
utcsrgv!utzoo!decvax!ucbvax!ihnss!mhtsa!rabbit!npois!harpo!chico!duke!unc!dopey.smb
Wed Mar  3 19:56:10 1982
superluminal quasars
Here's the basis for my question about quasars moving faster than light,
from the August 22, 1981 issue of Science News:

       Just a few months ago, only four quasars with components moving
       apart at apparent velocities faster than the speed of light had
       been identified.  Now... there are six.

       ... Each of the six has at least one pair of components
       separating at velocities that, from our vantage point, appear to
       be faster than light.  The apparent expansion velocities are all
       in the range of 3 to 10 times the speed of light, with the exact
       numbers depending on which assumed value of the Hubble
       constant... is used.

       ... When astronomers refer to "superluminal expansion", they
       don't necessarily mean the components involved actually are
       separating from each other at faster than the speed of light.
       Built into the phrase... is the idea ... "as it appears from
       earth."  The leading explanation... calls on a geometric
       situation in which a relativistic jet from the quasar is moving
       out from the core at a small angle to our line of sight to the
       core.  During any given period since light left the jet on its
       route towards us, the jet itself has moved almost the same
       distance toward us as well.  The light from its second position
       therefore reaches us only a short time after the light from its
       first position.

       ... Most astronomers assume this to be what is responsible for
       the measurements of superluminal expansions, although there is
       plenty of uneasiness over the requirement of having the fairly
       special line-of-sight orientation....  Six of twelve, or half,
       the appropriately analyzed quasars have shown it, a troublingly
       high frequency.  However, the twelve are not random samples,
       but highly selective samples, and that might help explain away
       the difficulty.

Now -- does anyone have any later information on this?  (I note in
passing that we seem to have yet another situation where special
alignments are involved, as in the red shift/blue shift discussion.)

-----------------------------------------------------------------
gopher://quux.org/ conversion by John Goerzen <[email protected]>
of http://communication.ucsd.edu/A-News/


This Usenet Oldnews Archive
article may be copied and distributed freely, provided:

1. There is no money collected for the text(s) of the articles.

2. The following notice remains appended to each copy:

The Usenet Oldnews Archive: Compilation Copyright (C) 1981, 1996
Bruce Jones, Henry Spencer, David Wiseman.