posted on Apr, 28 2009 @ 01:19 PM
Republican08 is correct.
Here's my standard response to this question, which comes up quite allot:
People often mistake meteors for UFOs or planes about to crash - meteors have a strange knack for playing tricks on unsuspecting eyes. The brain has
trouble interpreting the size, distance and therefore the actual speed of a light source/object in the sky with no/few visual cues, so it makes up the
missing information. This is the basic principal of an optical illusion, and the nature meteors (brief and bright) makes them ideal candidates.
This page explains in a bit more detail about why meteors can appear to be closer to the ground (or
the observer) than they actually are.
This diagram should help you visualize what is going on:
Basically, the lower down in the sky (or closer to the horizon) a meteor appears to be, the further away it probably is. In the exceptional cases
where this is not the case, and a meteor is still luminous, and less than 1km away from you, unless you're within diving distance of a bunker, that
would probably be the last thing you ever saw.
In 1908, what is thought to be a fragment of a comet exploded somewhere between 5 and 10 km above
Tunguska, devastating
an estimated 2150 square km and
knocking down 80 million trees!
Here's a guide I wrote listing the characteristics of meteors:
Seen a swift/very swift moving light (colored or white) in the sky?
As for the green color, that comes from the excitation of atmospheric oxygen (it glows green) when a meteor slams into air molecules, ionizing them,
and causing the atoms to emit photons. Oxygen, when it is excited, emits photons at a specific wavelength, which we perceive as green.
Related links:
green shooting stars