From owner-freebsd-chat@FreeBSD.ORG Tue Nov 2 19:12:58 2004 Return-Path: Delivered-To: freebsd-chat@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id C2AC916A4CE for ; Tue, 2 Nov 2004 19:12:58 +0000 (GMT) Received: from ms-smtp-04-eri0.ohiordc.rr.com (ms-smtp-04-smtplb.ohiordc.rr.com [65.24.5.138]) by mx1.FreeBSD.org (Postfix) with ESMTP id 5CFD743D2F for ; Tue, 2 Nov 2004 19:12:58 +0000 (GMT) (envelope-from marc.ramirez@bluecirclesoft.com) Received: from www.bluecirclesoft.com (cpe-024-165-114-048.cinci.rr.com [24.165.114.48])iA2JClHH013642; Tue, 2 Nov 2004 14:12:55 -0500 (EST) Received: from www.bluecirclesoft.com (localhost [127.0.0.1]) iA2JCk1f041393; Tue, 2 Nov 2004 14:12:47 -0500 (EST) (envelope-from marc.ramirez@bluecirclesoft.com) Received: from localhost (localhost [[UNIX: localhost]]) by www.bluecirclesoft.com (8.12.11/8.12.11/Submit) id iA2JCkBt041392; Tue, 2 Nov 2004 14:12:46 -0500 (EST) (envelope-from marc.ramirez@bluecirclesoft.com) X-Authentication-Warning: www.bluecirclesoft.com: mrami set sender to marc.ramirez@bluecirclesoft.com using -f From: Marc Ramirez Organization: Blue Circle Software Corp. To: Mark Murray Date: Tue, 2 Nov 2004 14:12:36 -0500 User-Agent: KMail/1.7 References: <200411021821.iA2ILI3N092806@grovel.grondar.org> In-Reply-To: <200411021821.iA2ILI3N092806@grovel.grondar.org> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart2046417.hs6hh9XWvZ"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit Message-Id: <200411021412.44009.marc.ramirez@bluecirclesoft.com> X-Virus-Scanned: Symantec AntiVirus Scan Engine cc: freebsd-chat@freebsd.org Subject: Re: Speed of light? [was Re: GPL vs BSD Licence] X-BeenThere: freebsd-chat@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Non technical items related to the community List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 02 Nov 2004 19:12:59 -0000 --nextPart2046417.hs6hh9XWvZ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline On Tuesday 02 November 2004 01:21 pm, Mark Murray wrote: > Marc Ramirez writes: > > > IANAPhysicist but, isn't the speed of light in a vacuum constant? Wel= l, > > > it may be being actively debated by cosmologists attempting to explain > > > the origins of the universe; but, VSL aside... the speed of light is > > > 2.998something x10^8 m/s in vacuum. > > > > > > Sorry, but this is chat, and I figured I ask. > > > > Yes, it is a fixed speed in a vacuum; it gets redshifted in a > > graviational field. Again, I will preface by saying I am a professional doofus and amateur=20 windbag. > Not quite. The Speed Of Light in a Vacuum Constant is constant in all > inertial frames of reference, and is exactly 299792458 m/s. In other media > (air, water etc, it may be slower than this. It is never faster. True. More precisely, the slowing of light within materials can be derived= =20 from first principles by assuming a fixed SoL, c, and factoring in the time= =20 involved in absorption/re-emission of photons by the molecules. > If the originator of the light is moving away from you, atomic spectra in > the light are shifted towards the red end of the spectrum ("redshift"). If > the originator of the light is moving towards you, atomic spectra are > blueshifted. This is called the Doppler shift. All true. > Gravity may bend light beams. More precisely, gravity is what we call the curvature of spacetime. Light= =20 always heads in the straighest possible line, but in a curved spacetime... = =20 Also, if light is emitted in an area of lower potential and is absorbed in = an=20 area of higher potential (e.g., from Sun to Earth) it will be redshifted.=20 Other way around, it will be blueshifted. If you are using the frequency of= =20 light as a clock (and you basically have no other choice), you will notice= =20 this effect as "time moving more slowly around massive bodies." Marc. =2D-=20 Marc Ramirez Blue Circle Software Corporation 513-688-1070 (main) 513-382-1270 (direct) http://www.bluecirclesoft.com http://www.mrami.com (personal) --nextPart2046417.hs6hh9XWvZ Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.6 (FreeBSD) iD8DBQBBh9wrg1EgpGw750IRAvfFAJ9BLhdLo3GHv0FQG1EPJwu5MNLYiACbBO7L GUNJ9G8uHk+WwcEJGtQCVUA= =SUDy -----END PGP SIGNATURE----- --nextPart2046417.hs6hh9XWvZ--