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- Path: sparky!uunet!biosci!agate!ames!haven.umd.edu!darwin.sura.net!fconvx.ncifcrf.gov!fcs260c2!toms
- From: toms@fcs260c2.ncifcrf.gov (Tom Schneider)
- Newsgroups: bionet.info-theory
- Subject: Re: Animate Nature and Noise
- Keywords: info theory isothermal noise physical limit receptors
- Message-ID: <C1L6GL.93H@ncifcrf.gov>
- Date: 28 Jan 93 22:57:56 GMT
- References: <1k6igvINNeg0@shelley.u.washington.edu> <C1JHLu.IA7@ncifcrf.gov> <1k9lsvINNosr@MINERVA.CIS.YALE.EDU>
- Sender: usenet@ncifcrf.gov (C News)
- Organization: Frederick Cancer Research and Development Center
- Lines: 24
- Nntp-Posting-Host: fcs260c2.ncifcrf.gov
-
- In article <1k9lsvINNosr@MINERVA.CIS.YALE.EDU> smith-una@yale.edu (Una Smith) writes:
-
- I hope you are kidding us Una! The three phenomena you were discussing are
- quite different. Gravitational "bending" of light or matter is really that the
- space is distorted and they move "straight". The ping pong ball is held in the
- stream of air because when a ball is half out, the air travels parallel to its
- surface inside the stream and so the molecules don't hit the surface as often
- as they do on the other side of the ball. Hence there is a differential
- pressure on the two sides of the ball (just like an airplane wing) and the ball
- goes into the stream. The ball is also balanced against gravity in the
- weakening air flow. If you have never seen this phenomenon, it is really worth
- reversing your vacuum cleaner for! The optical tweezer works by a focused beam
- of light. The light is refracted by the object (it does NOT go around, it goes
- through!!). The refraction of the light requires a momentum shift of the
- photons and the particle gets the opposite reaction. The diagram would show
- that when a particle is placed at various positions relative to the focus of
- the light beam, the particle experiences a force that is always toward the
- focal point.
-
- Tom Schneider
- National Cancer Institute
- Laboratory of Mathematical Biology
- Frederick, Maryland 21702-1201
- toms@ncifcrf.gov
-