Adopey.137 net.space utcsrgv!utzoo!decvax!duke!unc!dopey.smb Mon Mar 8 18:13:56 1982 Superluminal quasars Another question comes back to me: if quasars are large (on the order of lightmonths or larger -- not unreasonable if they're some sort of proto-galaxy, in which case they'd be far larger) -- how can they change luminosity as quickly as has been reported? Some sort of time contraction by the time the light reaches us? Also, what are the limitations on Very Long Baseline Interferometry? The case I cited earlier, of apparent superluminal expansion of several quasars, was detected by VLBI, which means it can be used to determine at least relative measurements of objects at vast distances. But it can't be used to determine absolute distances, or we wouldn't be wondering so much about the value of the Hubble constant. Anyone have any details they can supply? ----------------------------------------------------------------- gopher://quux.org/ conversion by John Goerzen 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.