My son and I were simply breathless when a large comet(?) came zooming in fro the west. It was just after night fall. This object streaked across the sky heading east. Biggest I had ever seen! I was bright with a tail and seemed to be visible for a long time, disappearing over the eastern horizon. Does anyone know what this was? I can't narrow it down anymore than late summer, early fall. Thanks - John Wargo

It wasn't a comet. What you describe was almost certainly a meteor. A comet moves slowly and is seen over a number of nights or weeks even. If you have the proper telescope it can be seen for months.

Meteors are typically solid pieces of rock, and sometimes iron, that enter the earth's atmosphere at very high velocity and are heated up due to air friction. If they make it to earth without burning up the item is then called a meteorite. Most are small but occasionally big ones occur.

Perhaps this is what you saw. (meteorobs) Fwd: Extremely bright meteor, 03:07 MST (US) But it may have been another incident that you are referring to. While there are metor showers (that is, periods when many meteors can be expected) that occur at well documented times of the year, individual meteors occur randomly throughout the year.

This as very slow moving, did not burn up into the atmosphere, came off the western horizon and disappeared on the eastern horizon. I remember much talk about it the following day, but neither my son or I can recall. I am checking locally and have gotten some feedback... comets name soon to follow . Thanks for your quick response!

Hello John

Meteors normally burn up in the atmosphere completely. After all, they are most of the times not bigger than a grain of sand. The duration of a meteor sighting is in the order of seconds.

A meteorite is (much) bigger, and can just hit the atmosphere but miss earth itself. Doing so will heat it up so that you see it moving through the upper atmosphere. The duration of a "fly-by" meteorite sighting is in the order of (a) minute(s).

A comet highly reflects sunlight, and can be seen from far away, also while it is in our region of the solar system - but still far away from earth. Most of the time it has a long "tail" from escaping gasses, pushed away by the pressure of the solar wind. The duration of a comet sighting is in the order of weeks and months.

So from your original post I conclude that you have been one of those lucky persons who has seen a meteorite passing through our atmosphere.

Here is a link to wellknown meteorite (and meteor) sightings in 1999. Have a look there

The 2 last sightings refer to a meteorite that skimmed the atmosphere on February 2, 1999.

Definitions for the terms, meteor, meteorite and, to add one, meteoroid, may be found here. Meteorites: What is a Meteorite?

As sarnian indicates impact angles and directions as well as the resulting relative velocity to the earth will impact how bright it is and for how long the meteor lasts.

You will never see a comet "streak across the sky". The Hale-Bopp comet of 1997 looked stationary if you saw it with the naked eye. You probably saw some of the material that falls on the earth every day burning up.