This Week's Amazing Sky: Ever See a Fireball?

Photo Credit
NASA
Bob Berman
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This week offers dark moonless skies. Perfect for meteors! We've all seen them streak across the heavens. But did you know that....

You always see more after midnight, when you're on the forward-facing part of Earth

  • You see more from August through early January than any other month
  • You never see the meteoroid itselfjust the glowing air surrounding it
  • Most are the size of apple seeds

Some of these facts seem counterintuitive. After all, a reader recently reported seeing one come down over a neighbor's backyard. Well, yes, they can seem that way. In truth, they either burn to dust or else slow down enough to stop glowing when 60 miles up. So all are between 60 and 120 miles away from you. On this moonless week, if you live away from bright city lights, you'll see six each hour between midnight and dawn.

Perseid Fireball from 2013. Credit:  www.willgater.com

What's in a Name?

 

Out in space, the tiny invisible bits of ice, stone, or metal -- debris from asteroid or comets -- are called meteoroids. When they hit the atmosphere and become visible, they're meteors, or shooting stars, or falling stars.

A rare super-bright one that casts shadows is called a fireball. And if it explodes into glowing pieces, you've been lucky enough to see a bolide.