Astronomy: Splendor in the Night

After sunset on Oct. 20, a strange and luminous object will rise above the western horizon and make a broad sweep across the darkening sky. Beginning as a fuzzy smear of light, it is expected to grow brighter and brighter until its 20 million-mile tail stretches put to look like a new Milky Way; then its head will appear with a light as great as the full moon. As the newly discovered Ikeya-Seki comet makes its rendezvous with the sun, it will curve high above the northern sky in one of the most spectacular celestial shows of the century.

In the U.S., Ikeya-Seki has been visible in the southeastern sky just before sunrise each morning. It has been moving toward the sun at the rate of about 2° a day. It will reach perihelion (closest point to the sun) shortly after midnight (E.D.T.) on Oct. 21; during hours of darkness, it may be visible to the naked eye. Though the comet’s tail will show up most clearly on the West Coast, Easterners may also be able to see it during the night. Then, shortly before dawn on the East Coast, the head of the comet should appear above the eastern horizon and may remain visible even after sunrise.

With 14 cameras set up around the world, the Smithsonian Astrophysical Observatory in Cambridge, Mass., will photograph every 15 minutes of the comet’s journey. NASA plans to launch sounding rockets with instruments to analyze the spectrum of the comet; the crew of Gemini 6 will attempt to take pictures of it on their mission, which is scheduled to start Oct. 25.

Unfamiliar Glow. All that intense professional activity—involving everything from rockets to careful studies with powerful telescopes—was touched off by a couple of amateur Japanese stargazers working with homemade equipment. For Kaoru Ikeya, 21, who lives in a tin-roof shanty near the eel farms on Lake Hamana, 140 miles southwest of Tokyo, this was his third comet discovery. Since his first (TIME, Jan. 25, 1963), Ikeya has advanced from a $28-a-month lathe operator to a $44-a-month ivory-key polisher in the same piano factory, but has no greater ambition than to help support his mother and his five brothers and sisters—and always to study the stars.

Two hours before every sunrise, he tiptoes out of the house, climbs a rickety bamboo ladder to his rooftop observation platform, built from driftwood, and aims his homemade telescope toward the sky. He has come to consider the stars old, familiar friends. It was only a month ago that he focused on the constellation Hydra, near whose tail he had spotted his first comet. Suddenly he spotted an unfamiliar glow. “It shone,” says Ikeya, “like a street lamp on a misty night.” All his checks confirmed what he could hardly believe: he had found another comet.

He hurried off on his bicycle to send a telegram to the Tokyo Astronomical Observatory. At the same time, it turned out, another amateur astronomer about 240 miles away in the city of Kochi had made the same discovery. Like Ikeya, Tsutomu Seki, 34, a classical-guitar instructor, had also used a simple, homemade telescope and had two previous comet discoveries to his credit.

Beyond Pluto. Though Ikeya-Seki is the fourth new comet to be discovered this year, and there are some 1,700 already on record, astronomers are still not sure exactly what comets consist of. For centuries they were objects of excitement and superstition, often feared as precursors of grave and cataclysmic events. Today some astronomers speculate that comets are the debris flung off by larger planets out beyond the earth. The most widely accepted theory holds that a vast cloud completely surrounds the solar system. According to Fred Whipple of the Smithsonian Observatory, about 4.6 billion years ago the cloud (a giant snowstorm”) began to condense into separate bodies—”dirty snowballs” of dust and ices made up of methane, ammonia and water. Some of these bodies were captured by the outer planets and fell onto them, and some fell into the sun. About 1% of them, Whipple thinks, have gone into orbit around the sun as periodic comets ranging in size from tiny bits to as much as 20 miles in diameter.

Despite their fiery appearance, comets are not actually aflame but glow mostly from fluorescence due to solar radiation. The closer they get to the sun, the brighter and larger they grow. One of the rare “sungrazing” comets, Ikeya-Seki will whip around the sun at a maximum speed of about 300 miles per second, passing within 300,000 miles of the sun’s surface. Astronomers discounted some predictions that the comet will collide with the sun. But it could be broken up by the sun’s radiation and gravitational field. If it survives its solar encounter, the comet discovered by a piano-key polisher and a guitar instructor will then disappear into the nether reaches of space—considerably beyond Pluto—and will not come hack into view for some 500 to 1,000 years.