After  midnight, the only meteoroids escaping collision are those ahead of the  Earth and moving in the same direction with velocities exceeding 18.5  miles per second (30 kilometers per second). All others we will either  overtake or meet head-on.
But  before midnight, when we are on the back side, the only meteoroids we  encounter are those with velocities high enough to overtake the Earth.  Therefore, on average, morning meteors appear brighter and faster than  those we see in the evening.
And  because the Leonids are moving along in their orbit around the sun in a  direction opposite to that of Earth, they slam into our atmosphere  nearly head-on, resulting in the fastest meteor velocities possible: 45  miles per second (72 kms).  Such speeds tend to produce bright meteors,  which leave those aforementioned long-lasting streaks or trains in their  wake.
Also,  as Leo is beginning to climb the eastern sky near and before midnight,  there is a small chance of perhaps catching sight of an "Earth-grazing"  meteor.
Earth-grazers  are long, bright shooting stars that streak overhead from near to even  just below the horizon. Earth-grazers are distinctive because they  follow a path nearly parallel to our atmosphere.  
 
 
No comments:
Post a Comment