PacSci Doku

What is the source of the meteors in a meteor shower?

The Answer — Comet Gunk
(Scroll down to see the solution to our puzzle.)

August is a great month to see Comet Gunk. Comets are often compared to dirty snowball. The “snow” part made up mainly of frozen water and carbon dioxide (dry ice) and small amounts of frozen methane, ammonia and other substances. The “dirt” is small rocks, many the size of grains of sand on a beach. Most comets are no bigger than Mount Rainer and they orbit the Sun. Many of them orbit in elongated paths that take them inside the orbit of Mercury (the closest planet to the Sun) and then out to the far reaches of our Solar System — to the distance of Neptune, Pluto or beyond.

When the comet nears the Sun, the comet begins to heat up. The ices turn into gas and disperse into space. The rocks continue to orbit in the same path as the comets orbits like minute planets in orbit around the Sun. When the Earth passes through orbit of the comet, these rocks entire our atmosphere, heat up the air until it glows and we see a streak of light — a meteor. Because there are so many rocks from the comet in the orbit, we see a large number of meteors over a few days — a meteor shower.

On August 12th and 13th is a great opportunity to see the Comet Gunk from Comet Swift-Tuttle — called the Perseid Meteor Shower. To see the most meteors, get as far away from city lights as you can, get in a comfortable position flat on the ground (or a comfortable lounge chair) in an open area where you can see as much of the sky as possible. Plan to stay for 15 to 20 minutes as your eyes will adapt to see fainter meteors the longer you are in the dark. To see the greatest number of meteors you should be out between midnight and dawn, since this is when the portion of the Earth you are located is moving into the direction of the Earth's orbit around the Sun. Just as the front of your car gets splattered with more insects than the back of your car while you drive down the road, the Earth will run into more meteors between midnight and noon — but of course you can't see the meteors during the day. Even if you can't be out after midnight, it should be a great light show made possible by Comet Gunk.

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