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(meteorobs) Fireball meteors

Prasad wrote:

>I am a new member to this list. When I read the above post, I am
>reminded of a very bright trail that I saw along with James Kevin Ty on
>the night of June 13/14 at about 9:00 pm local time (13:00 UTC). We were
>at the PAGASA Observatory (the Philippine Meterological Organisation)
>roof, setting up our telescopes for the night. The trail was very broad
>and ended with a big burst. No sound was heard. The trail was seen for a
>few minutes after the event. It was this event that triggered me to join
>the meteorobs list.
>
>I wonder if anyone can put me wise on what I saw? Was it a metor or
>something else?

Hello Prasad and welcome to the list!

It looks like what you saw was a bright meteor or fireball.
It is possible to see very bright meteors, sometimes even 
brighter than Venus at any time of the night but these are rare. 
Most meteors are as bright as an average naked eye star.
You are much more likely to see a fireball meteor during
a good shower like the Perseids (August 12) or the 
Geminids (December 13). The Leonids (November 17) for this and
the next few years *might* produce a better than average display
with a number of fireballs. 

Most fireballs, even the bright ones will burn out quickly and
last only a second or two. Occasionnaly, they may last longer
and produce a long trail travelling a good portion of the sky.
Most fireballs, especially those moving fast will leave a
vapourous wake or train behind that can last between a couple
seconds to sometimes many minutes! Occasionnaly, color can be
seen in bright meteors. 

Sounds associated with meteors happen very rarely. Only the very
brightest fireballs might produce a distant sonic boom minutes
after the sighting. Even much rarer is the possibility of sounds
heard *with* the appearance of the meteor. This could be caused
by meteor sound being transmitted with nearby overhead wires
or other metal objects. There has been some debate whether
this is really possible.    

The big burst you saw at the end is called a terminal flash.
As the meteor travelled in the atmosphere, it disintegrated
rapidly, exploded and fragmented at the end, making the bright 
flash. Chances are it totally vaporized very high in the atmosphere.

A flash can cause people to think that the meteor "fell"
and "crashed" not too far, but it is often an illusion with
the observers percepton. No one can immediately tell where
a meteorite could have fell by seeing a fireball. Many 
observations from different people at different locations and 
precise calculations of trajectories, angles and speeds are needed 
to do this. And even so, there is no garantee. Even a very bright 
and spectacular fireball will (or might) produce only a few 
small scattered pieces on the ground (or more often in the ocean). 
Only a tiny fraction of all meteorites on earth are recovered. 
Without good knowledge, one can easily walk over meteorites
thinking they are normal earth rocks! 

Clear skies!


  
  


                                  .    .    . .
Pierre Martin                    . . *  . *  .  .
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Ottawa Valley Observers Group    .  .  .  .   . .
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Ottawa, Ontario, CAN                / / .   . .  .
home:  p.martin@cyberusdot ca         / /   / . . .  .
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