You could, but you'll never get it there in time. The moment of the Gettysburg Address is a nearly spherical---though slightly distorted---manifold expanding through space-time. Since that moment is traveling away at the speed of light, it's exactly on the light cone that originated on November 19, 1863 (and Earth's position in space at that time.)
Catching up to that boundary would require some tricky engineering... usually involving massive, rotating, infinitely long cylinders. These are hard to procure, and likely to break your mirror. On the other hand, you could start a project today to station a mirror one light year away so you could reflect on events from two years past. In a less tongue-in-cheek scenario, we are seeing "light echoes" from supernova SN1987A. This is where light from the supernova that was initial emitted away from us either gets reflected by gas clouds, or excites the clouds into emitting their own light, which then comes back to us years after the event. So, light from SN1987A itself that travelled directly got here in, well, 1987. But light that went a 10 light years in the other direction, then got reflected back, is just reaching us now. This is giving us a fantastic "flash bulb" illumination of the nebular gas around the supernova. Similar light echoes can be observed in the Large Magellanic Cloud that probably originated from a supernova that occurred around 600 years ago. Cheers, -Michael Nygard On Sep 4, 2008, at 3:41 PM, Frank Wimberly wrote: > Makes me wonder...if there were a large mirror 71.5 light years away > could > we, in principle, with a powerful enough telescope, witness, say, the > Gettysburg Address? > > Frank > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > On Behalf > Of Kenneth Lloyd > Sent: Thursday, September 04, 2008 12:40 PM > To: [EMAIL PROTECTED]; 'The Friday Morning Applied Complexity > Coffee Group' > Subject: Re: [FRIAM] Young but distant gallaxies > > Nick, > > Things that are further away are older (GR). It's just that the light > coming from them has taken so long to get here. > > Ken > >> -----Original Message----- >> From: [EMAIL PROTECTED] >> [mailto:[EMAIL PROTECTED] On Behalf Of Nicholas Thompson >> Sent: Thursday, September 04, 2008 10:09 AM >> To: [email protected] >> Subject: [FRIAM] Young but distant gallaxies >> >> Dumb question for you cosmologists to chew over: >> >> How can they be so far away and yet so young? Or, to put it >> even dumber, >> are there parts of the Universe that are so far away that >> they havent happened yet? >> >> I guess this is a question about scales of distance vis a vis >> scales of time. >> >> Nick >> >> Nicholas S. Thompson >> Emeritus Professor of Psychology and Ethology, Clark >> University ([EMAIL PROTECTED]) >> >> >> >> >>> _______________________________________________ >>> Friam mailing list >>> [email protected] >>> http://redfish.com/mailman/listinfo/friam_redfish.com >>> >>> >>> End of Friam Digest, Vol 63, Issue 3 >>> ************************************ >> >> >> ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org
