(meteorobs) Imagining ourselves following a vehicle along a dusty road...

[Watt, Alex]

Why thank you both! That is a very useful diagram. 
 
Alex
 
 
>>
 
>Hi Alex, 

>Just to illustrate what Nikola said, have a look at an illustration: 
> <http://www.spmn.uji.es/ESP/radiant.gif>
http://www.spmn.uji.es/ESP/radiant.gif 

>The big yellow arrows illustrate how the parallel meteors are being 
>projected differently onto the observer's sky (perspective effect...) 

>Geert 



At 11:50 20-2-2006, you wrote: 

>At 11:28 20.02.06, you wrote: 

>>Hello all, I am a new member of the mailing list, and I have a
question 

>>which has built up in my mind and which I wondered if I might empty
into 

>>your gracious inboxes, with permission. 

>> 

>>Its about radiants. Now as I understand it, meteor showers are the 

>>product of the intersection of our spherical earth with a somewhat 

>>cylindrical region of comet/asteroid debris. This being the case, how
is 

>>it that meteors appear to radiate from a single point in the sky? I 

>>would have imagined that they would appear from along a path in the
sky 

>>that is traced out by the length of the debris trail. The only time I 

>>would expect meteors to come from a single point at any one time would


>>be if the path of the comet/asteroid was very similar to that taken by


>>the earths orbit, then it would appear like we were following a jet's 

>>vapour trail through the sky, or a vehicle along a dusty track, which
in 

>>each case would produce a 'radiant' or source of material which was a 

>>single point. 

> 

>It's very simple.. just an effect of perspective. You can find it well 

>explained in every book about meteor astronomy. 

>Shortly, it's just like a long railroad: railroad is parallel, but it 

>seems to you that it radiates from one point far on the horizon. 

>Similarly, orbits of the meteors of the same shower will be parallel to


>each other, but they seem to radiate from one point in the sky, just 

>because their orbits are parallel. 

>Nikola 

>--- 


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