Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site sunybcs.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxl!houxm!houxz!vax135!floyd!cmcl2!seismo!rochester!rocksvax!sunybcs!acscmjm From: acscmjm@sunybcs.UUCP (Mike Moroney) Newsgroups: net.physics,net.astro.expert Subject: Re: pulsing quasars and the like Message-ID: <255@sunybcs.UUCP> Date: Tue, 5-Jun-84 21:41:59 EDT Article-I.D.: sunybcs.255 Posted: Tue Jun 5 21:41:59 1984 Date-Received: Thu, 7-Jun-84 07:44:35 EDT References: <2631@ecsvax.UUCP> Organization: SUNY/Buffalo Computer Science Lines: 29 [ ]Help!!! I'm TRAPPED in a VAX 11-780!!!! >> For some time I have been reading about rapidly pulsing objects and how this >> puts an upper limit on their size. That is, since no signal can propagate >> faster than light, the period of oscillation of a body cannot be less than >> the light transit time. >>I'm confused by this... The upper limit on the size is because the pulsing objects are actually rotating, they appear to pe pulsating from Earth the same way the rotating light on a lighthouse appears to pulse on and off from a distance. THe size limit is because no object can rotate such that any portion of it exceeds the speed of light, c. For example, if an object pulses at 1 pulse per second, it has an upper limit on its size of 29602 miles radius, since if it were larger, its outer edge would rotate at > 2*pi*29602 mi/sec or 186000 mi/s or the speed of light, which is impossible. >> Or, more to the point, imagine a spherical body in space light years across. >> A signal travelling at less than c but consisting of high-frequency pulses >> travels from the center of the body >> and reaches the perimeter 'simultaneously' in all directions, causing said >> perimeter to pulsate in unison. This does not disprove the above, since the actual source is not the object light years across, but the thing in its center which is pulsing. The rest of the object is just responding to the pulses. Mike Moroney ..!rocksvax!sunybcs!acscmjm