(meteorobs) Meteorobs day and night time meteors

stange stange34 at sbcglobal.net
Sat Jul 19 14:50:18 EDT 2008


Putting aside the visible portions of the spectrum referred to,

Most lab black body sources are temperature controlled precisely for 
specific IR radiation wavelengths & used in infra-red detection systems 
military & domestic research.

Conversely, the wavelength of the IR propogation from a meteor or bolide 
should yield its surface temperature at any point in time of its flight. I 
do not know if those measures are actually used to calculate the very high 
temperatures they arrive at in meteor/bolide articles.

I once worked in an IR systems lab a very long time ago. YCS

----- Original Message ----- 
From: "Chris Peterson" <clp at alumni.caltech.edu>
To: "Global Meteor Observing Forum" <meteorobs at meteorobs.org>
Sent: 2008/07/19 08:05
Subject: Re: (meteorobs) Meteorobs day and night time meteors


> I'd say that for all practical purposes, there's no difference between a
> daytime and nighttime meteor of any given magnitude. Very little of the
> meteor's light comes from gas emission lines. The light is simply the
> blackbody emission of a hot object, and the meteor temperature is the same
> day or night.
>
> There might be a slight difference in the trail characteristics due to the
> phenomenon you describe. But how would you tell? Any ionized gas emission 
> in
> the trail is going to be invisible in the day, regardless of the meteor
> magnitude. I don't think you can ever see any component of a meteor trail 
> in
> the day except for smoke and dust.
>
> Of course, when you talk about "brilliance" the question gets tricky, 
> since
> you are now bringing in issues of perception. There's no doubt that a -6
> magnitude meteor seen at night will be perceived as much brighter than 
> a -6
> magnitude meteor seen in the day, even though a camera would easily show
> that they have the same intensity.
>
> Chris
>
> *****************************************
> Chris L Peterson
> Cloudbait Observatory
> http://www.cloudbait.com
>
>
> ----- Original Message ----- 
> From: "drobnock" <drobnock at penn.com>
> To: <meteorobs at meteorobs.org>
> Sent: Saturday, July 19, 2008 7:49 AM
> Subject: (meteorobs) Meteorobs day and night time meteors
>
>
>> Question for the group.
>>
>> If it were possible to see a - 6 magnitude fireball with the same
>> brilliance in the day time as at night,  would the same amount of energy
>> be needed to ionize the gas around a meteor to be a visual -6
>> meteor?     Consider that the same fireball in question is viewed both
>> in the day and  at night. The meteor being viewed  is of the same
>> composition, speed entering the atmosphere, trajectory, and  mass. The
>> same fire ball in all factors.
>>
>> There is  event  known as the "dark effect"  that occurs with certain
>> inert gasses - neon being one of them is electrically excited. It is
>> known that a neon glow tube requires less energy to excite the gas in
>> the tube if the tube is exposed to sun light as being started in the
>> dark.
>>
>> Other gases may have similar characteristics.
>>
>> Consider for the question that most of our atmosphere is made up of
>> nitrogen(78% by volume) and  oxygen (21% by volume). The remaining 1% of
>> the atmospheric gases are known as trace gases because they are present
>> in such small concentrations.  This question is considering that the
>> most abundant  trace gases are argon (approximately 1% by volume).
>> Others include  neon, helium, krypton and xenon may exhibit the "dark
>> effect" when ionized.
>>
>> Those observing meteors by radar, is there a  quantitative difference in
>> the density of the trail for night and day time meteors?
>>
>> Thanks for any comments.
>>
>> George John Drobnock
>
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