Have you noticed that the Leonid Meteor Shower has been a subject of discussion at the APOD 5 times in 2 weeks?
This is a not-to-be-missed event. Check back in the APODs to find a webcam if your weather doesn't cooperate.
So how do we see sand-grain-sized particles burning up in the atmosphere miles up? Speed has a lot to do with it. Leonid meteors are some of the fastest; they can enter our atmosphere at speeds of 160,000 miles an hour. At these speeds, the light emitted from collision with air molecules is quite striking. Color can range from red to white to blue and even green. Watch out for larger meteors - fireballs are a sight to see!
Got camera? Some meteors leave a trail of glowing gas for several minutes!
See the Leonids 2001 Meteor Gallery for amazing photos!
If you have meteor-related questions, this site might have the answers:
American Association of Amateur Astronomers: About Meteors and Meteor Showers. Enjoy!
That would be of an object travelling in the opposite direction than earth. Earth's speed plus the asteroid's speed plus gravitational effects = 160,000 mph maximum.