Have you ever seen a big fireball whizzing across the night sky? I bet, if you have, you gasped out loud at this amazing sight. I have!
I have seen many very bright meteors speed across the sky, mostly because I am out under the night sky a lot, doing observing or astrophotography. You can't see them if you are not outside.
I have seen many meteors clutter up my astrophotos. Since I usually stack many images together to make a final image, I usually dump the ones with meteor trails across them. Satellite images almost always appear in a series of night sky photos -- but that is another story.
Those big fireballs really aren't that big. They are relatively small bits of stone or iron, usually about ¼ to ½ inch across. Of course, some are bigger, and some reach Earth's surface, but this is rare. Meteors have come to Earth weighing more than a ton. These are usually "irons" that survive the high temperatures they undergo as they traverse the atmosphere. These kinds of meteors are usually a compound of iron and nickel, alloyed together long ago during the solar system's formation.
Some meteors are pushed near to Earth by distant collisions between asteroids, mainly concentrated in a belt between Mars and Jupiter. Most, however, are debris from old comets that have repeatedly rounded the sun, melted off all their frozen gases, and only little pebbles are left.
In August -- indeed, the middle of every August -- on the night of the 12th and morning of the 13th, there may be the best meteor shower of the year. This shower is called the Perseids. The so-called Perseids have their name because they appear in the sky near the Perseus constellation. Of course, the stars in Perseus are enormous distances from Earth, but the meteors enter the Earth's atmosphere only miles from Earth's surface.
The Perseid meteors are cometary debris in orbit around the sun. Each year, Earth passes through this debris in mid-August. Earth runs into these meteors just as an automobile moving through the rain hits the raindrops. The meteors are moving at thousands of miles per hour and friction from Earth's atmosphere heats them hot enough to burn out high up.
If you want to see this shower, your best chance is to be outside, looking toward the northeast, at midnight or later. There will be a 10% moon that night, but it will set early in the evening. Your biggest obstacle to seeing meteors may be the weather.
The weather has been a real barrier to seeing the night sky clearly for many weeks. This cloudy and rainy weather could block the meteors from view in August. But, as my father often said, "You can't catch fish unless you have a line in the water."
So, get out there and see if you can see a good meteor shower. I know I will be out, camera mounted on a tripod, taking 30-second exposures to see if I can get a meteor trail on my camera chip. If I capture a good image, you will see it. Good luck!
David Cater is a former faculty member of JBU. Email him at [email protected]. Opinions expressed are those of the author.