Originally posted by Megatronus
It was also very odd. When i first spotted it it seemed to be traveling up like a like a fire work them seemed to change directing and come straight
over head. It was massive And it didnt seem to break up either. It lost its tail and changed from yellowish to orange as it cooled slightly glad it
was such a clear night
As I have long been saying here on ATS, meteors, especially bright (or "fireball" class meteors), can easily play tricks on the eyes. Appearances are
often deceptive when it comes to meteors as I pointed out in this thread
What I talked about in the thread I linked to above regarding the estimation of distance also applies to direction of travel, as well as actual or
"true" velocity. These things are all quite hard for most people to judge in such cases, and even people who are experienced observers/who have
studied the subject can only make educated guesses based on a single observation in some cases.
To address what you said above about the apparently odd course it took, the apparent course/heading of a meteor depends on two important things:
Firstly the angle of entry in relation to the earth/ground.
Secondly, the position of the observer (in this case you) in relation to the meteor - Perspective
plays an important role in how we perceive
If the angle of entry is steep, a meteor will generally appear to have a very short path (especially if seen close to or directly overhead), and
usually they won't last too long since most objects are too fragile to withstand a steep entry.
If on the other hand, the object enters at a low angle, otherwise known as "grazing" the atmosphere, because of the reduced stresses and strains
associated with type of atmospheric-entry, "earthgrazing" meteors as they are called often survive for much longer than their less fortunate "high
angle" brothers and sisters. They will often last for many seconds and in some cases tens of seconds, making them both impressive and unmistakable.
Some reports have mentioned flight times in excess of 40 seconds, which would only
be possible with a meteoroid/asteroid that has a low entry
angle. The slowest meteoroids hit earth's atmosphere at speeds of around 10 km/s, so given that meteors become visible at altitudes of around 100km,
even the slowest meteoroid entering at a very steep angle would have reached the ground after just 10 seconds (if it was big enough to survive), and
we know from the reports that this was likely going much faster than 10 km/s (probably closer to 30 km/s).
If you are observing an earthgrazer from the right location on earth, so that the point at which it enters the atmosphere is over on the other side of
and obstructed by the horizon, and that meteor happens to be heading roughly in your direction, it would appear to shoot upward (AKA shooting straight
up like a firework), and then pass over head. It does not have to change direction at all to seem to do this, that is simply a trick of
For someone in another location, seeing the same meteor from a different perspective, the meteor might appear to shoot down from above - they would
have to be observing from way further back up the path of the meteor in the North.
Consider this diagram It's exaggerated, but demonstrates what is going on:
The green part of the meteor represents the start of the meteor or when it first became visible, as is often the case with fast meteors. The red lines
represent the lines of sight of the observers. The upper/outer blue ring represents the upper part of the atmosphere where meteors first become
If you are the observer (B), it will look to you like the meteor has fallen (downwards) just behind the mountain, but the observer (A) who is
observing the same meteor from a few hundred miles from your location, and over the horizon will see something completely different. He/she would see
the meteor apparently going up, and away from the horizon.
I hope that helps you (and others) understand a little more about what you saw the other night.
edit on 4-3-2012 by FireballStorm because: