SPECIAL REPORT: Kohoutek: Comet of the Century

  • Share
  • Read Later

(7 of 10)

The early discovery meant that Kohoutek was not only intrinsically brighter than Halley's comet but probably quite large. Astronomer Elizabeth Roemer, of the University of Arizona, estimates that Kohoutek's nucleus is about 25 miles in diameter, far larger than most comets, probably including Halley's. Other astronomers calculate that Kohoutek weighs about 1 trillion tons. But size is not Kohoutek's only distinction. It will pass within 13 million miles of the sun. That close flyby, well within the orbit of Mercury, should make for a dazzling interaction between sun and comet. Perhaps most important of all, astronomers describe it as a "dirty" comet, one with an outer layer of dust that has probably never been stripped off by solar heating. That layer may prevent the comet from becoming as bright as originally predicted. But it also means that Kohoutek may be a "virgin," making its very first visit to the hot inner sanctum near the sun. That will give scientists an opportunity to study at close hand the structure of material that has never been heated, and thus is largely unchanged from its primordial state.

Because Kohoutek was spotted much earlier than most new comets, astronomers have had an exceptionally long lead time to prepare for a thorough examination. They are taking full advantage of the opportunity. In addition to the conventional telescopes of every size and variety that will be following the comet, NASA'S big radio telescope in the Mojave Desert will be aimed at Kohoutek in an attempt to bounce radar signals off the comet's nucleus (those echoes may tell scientists more about the size and character of the nucleus). M.I.T.'s Haystack Radio Observatory will try a similar experiment in reverse: it will study radio waves from a far-off radio source (possibly a quasar) after they pass through the comet's tail, in hopes of finding the spectral "signatures" of water or ammonia. If they succeed, the M.I.T. astronomers will have gone a long way toward confirming Whipple's icy-snowball theory.

Much work will be conducted under the aegis of NASA'S Operation Kohoutek, directed by Astronomer Stephen P. Maran. Involving hundreds of scientists and millions of dollars in hardware, the observations will be largely made from above the atmosphere, which blocks out the ultraviolet and infrared frequencies useful in gathering data about the comet's composition and structure. At least five sounding rockets and two balloons will be launched to view Kohoutek. The comet will also be chased by two highflying, instrument-crammed jets. Other information will be gathered by Copernicus, NASA'S orbiting astronomical observatory, and OSO7 (for Orbiting Solar Observatory). The Venus-and Mercury-bound Mariner 10 may be used to take high-resolution TV pictures of the comet, while either Pioneer 6 or Pioneer 8, both of which are orbiting the sun, try to determine the density of the comet's tail by probing it with radio signals.

  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6
  7. 7
  8. 8
  9. 9
  10. 10