If light, why not radio?
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From: Jeff Cunningham on 17 Apr 2010 09:18 On 4/16/10 12:53 PM, Clay wrote: > I like the way the article acts like light twisting and moving small > particles is a new idea. Astronomers have known about light's effect > on moving particles (e.g., forcing a comet's tail to point away from > the sun.) for a very long time... Sorry for nitpicking, but isn't that an effect of the solar wind, i.e. a stream of charged particles, not light? -Jeff
From: Jerry Avins on 17 Apr 2010 13:35 On 4/17/2010 9:18 AM, Jeff Cunningham wrote: > On 4/16/10 12:53 PM, Clay wrote: >> I like the way the article acts like light twisting and moving small >> particles is a new idea. Astronomers have known about light's effect >> on moving particles (e.g., forcing a comet's tail to point away from >> the sun.) for a very long time... > > Sorry for nitpicking, but isn't that an effect of the solar wind, i.e. a > stream of charged particles, not light? Solar wind too, but photons have momentum. Reflections (which entail a change of direction) exert a force. Jerry -- "It does me no injury for my neighbor to say there are 20 gods, or no God. It neither picks my pocket nor breaks my leg." Thomas Jefferson to the Virginia House of Delegates in 1776. ���������������������������������������������������������������������
From: glen herrmannsfeldt on 17 Apr 2010 20:41 Jeff Cunningham <jcc(a)sover.net> wrote: > On 4/16/10 12:53 PM, Clay wrote: >> I like the way the article acts like light twisting and moving small >> particles is a new idea. Astronomers have known about light's effect >> on moving particles (e.g., forcing a comet's tail to point away from >> the sun.) for a very long time... > Sorry for nitpicking, but isn't that an effect of the solar wind, > i.e. a stream of charged particles, not light? I think so, but light does have momentum so it could be light. It might also be from vapor given off when the ice particles warm up from sunlight. That would happen more on the sunny side, again supplying momentum to the particles. -- glen
From: Clay on 19 Apr 2010 10:49
On Apr 17, 8:41 pm, glen herrmannsfeldt <g...(a)ugcs.caltech.edu> wrote: > Jeff Cunningham <j...(a)sover.net> wrote: > > On 4/16/10 12:53 PM, Clay wrote: > >> I like the way the article acts like light twisting and moving small > >> particles is a new idea. Astronomers have known about light's effect > >> on moving particles (e.g., forcing a comet's tail to point away from > >> the sun.) for a very long time... > > Sorry for nitpicking, but isn't that an effect of the solar wind, > > i.e. a stream of charged particles, not light? > > I think so, but light does have momentum so it could be light. > It might also be from vapor given off when the ice particles > warm up from sunlight. That would happen more on the sunny > side, again supplying momentum to the particles. > > -- glen It has to do with heating and reradiation. Thus the 4th power law of Stefen-Boltzmann plays strongly. This can and does get asteroids rotating. Clay |