Dena Herrington, age 14, of Tulsa, Okla., for her question:
WHAT ARE AQUARIDS?
No, they are not little creatures who feel at home in a watery aquarium, though in a roundabout way their name is related to the word water. Actually they are specks of dust out there in the heavens. Once each year they shed a small shower of meteors in our sky. And the Aquarids seem to fall down from the starry constellation called Aquarius, the Water Carrier.
The story of the Aquarids is for star gazers, and it goes back at least 2,000 years. It is related to Halley's razzle dazzle comet, which appears in our skies at intervals of about 77 years. Its return visits have been recorded on schedule, way back to the year 240 B.C.
Its orbit was computed in the 1600s by William Halley, who predicted that it would reappear in the year 1759. So it did, though Halley did not live to see it. We know now that it travels a long narrow orbit. One end loops around beyond the orbit of Neptune. The opposite end makes a U turn around the sun.
As it nears the sun it lights up, and the solar wind adds a long golden tail. Some of this fine comet dust is left behind as the comet whizzes on its way. The comet may change to cut directly across a point along the earth's orbit, leaving dusty fragments that may stay there for ages. When the orbiting earth reaches this point, we get a shower of mini meteors.
Actually we run into Halley's dust twice each year. And since the celestial traffic is very precise, this happens on certain dates in certain parts of the sky. On May 4, if the starry sky is very clear and free from smog, we may see a small meteor shower near the constellation Aquarius. These are called the Aquarids. Around Nov. 20, we get a larger meteor shower from the region of Orion. These are the Orinids.
Both the Aquarids and the Orinids come from dusty debris left behind by Halley's comet. When they collide with the orbiting earth, the little specks light up as they fall through the atmosphere. They burn to ashes high above the earth. But gradually the ashes seep down and of all things, these wisps from a comet's tail are added to the weight of the world.