[meteorite-list] Fw: Comet 17P (Holmes) Visible Event !

[Chris Peterson]

The size of the comet core is largely irrelevant. What matters is the 
size of the coma, since that's what is reflecting the light. And an 
active comet can easily have a coma many times larger than Mars. In 
reality, active comets are amongst the largest objects in the Solar 
System, even though their cores are amongst the smallest.

Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com


----- Original Message ----- 
From: "mexicodoug" <mexicodoug at aol.com>
To: <meteorite-list at meteoritecentral.com>
Sent: Wednesday, October 24, 2007 3:20 PM
Subject: Re: [meteorite-list] Fw: Comet 17P (Holmes) Visible Event !


> Hi Again Listees,
>
> With regards to Comet 17P (Holmes) estimated at under 3.5 Km in 
> diameter, and being twice as far from the Earth as the planet Mars:
>
> How could it be one sixteenth as bright as Mars and an easy object in 
> the night sky with an almost Full Moon?  No doubt it has a lot of ice 
> crystals or something white and reflective.  A rought thought says 
> that in absolute terms it is one fourth the brightness of Mars if they 
> were at the same distance from us!  This is because we perceive only 
> 1/4 of the light intensity due to the doubling of distance,
>
> It is it is hard to avoid the temptation of thinking this tiny body is 
> of relatively pristine material now confined to the Asteroid belt, but 
> before, from the Outer Solar System, and may, for once, given Jupiter 
> his dues, have been affected by a relatively close pass to the inner 
> Solar System, with Venus, Earth and Mars all aligned this month to 
> exert their gravitational attraction together.  Not to mention all of 
> the scientists and collectors who would will material to Earth.
>
> The comet is over 40% further away from Earth as it is from Mars at 
> the moment, so I hope the guys with their hands on the controls of the 
> Mars rovers take a break and look up for us at MidSolnight, and that 
> the Deep Impact Crew is already into emergency overdrive to make the 
> comparison they will be held accountable for, now that there is a 
> second chance :-)...
>
> Best Skies and great health,
> Doug