(meteorobs) Meteoroid streams and the Moon

Chris Steyaert csteyaert at gmail.com
Sun Nov 30 15:14:42 EST 2008


At 20:54 30/11/2008, meteoreye at comcast.net wrote:
>The moon blocks so small an area (~ 1/2 degree diameter)

The Moon blocks her diameter projected on to the Earth, 3400 km, 
assuming the radiant is a perfect point (= meteors are perfectly parallel).

 >And for meteoroids that just miss, I suspect (though do not know) 
that the result would be to focus the paths on the earth.

Indeed, similar to the zenith attraction. But the mass of the Moon is 
rather low.

So I think it can happen for streams with low ecliptic latitude.

Somebody will have to quantify it before we know for sure ;-)


         Thanks,

         Chris


>I'm not sure it makes much difference. And for meteoroids that just 
>miss, I suspect (though do not know) that the result would be to 
>focus the paths on the earth.
>
>A teeny shield is not much of a shield :)
>
>Wayne
>
>-------------- Original message --------------
>From: Chris Steyaert <csteyaert at gmail.com>
>
> > David, All,
> >
> >
> > >I favour the second answer, but am not sure...
> >
> > Me too ;-)
> >
> > The geocentric velocity (speed and radiant position) is the vector
> > sum of velocity of the Earth and that of the stream. Also to be
> > considered is the travel time of the meteoroids from the distance of
> > the Moon to the Earth (magnitude of an hour).
> >
> > The question could be put differently: does the Moon occasionally
> > shield places on Earth from a stream? I think it can: a bit like the
> > the path of a total solar eclipse moving over the Earth.
> >
> >
> >
> > Regards,
> >
> > Chris
> >
> >
> >
> > At 10:53 30/11/2008, David Entwistle wrote:
> > >Following up on a question from 2006 09 22...
> > >
> > >On 14th December 2008 the almost full Moon will pass within a few
> > >degrees of the active Geminid radiant. Does this mean that the Geminid
> > >meteoroids that reach Earth, as visible meteors, have passed through the
> > >vicinity of the Moon on their way here? Or, is the alignment of the
> > >Moon and radiant just an optical effect and the meteoroids don't get
> > >anywhere near the Moon, on their way to Earth?
> > >
> > >I favour the second answer, but am not sure...
> > >--
> > >David Entwistle




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