Word: cloudly
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Dates: during 1980-1989
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Galvanized by this radical proposal, researchers are hunting for an agent that could explain the apparent clockwork regularity of the celestial barrages. Some suggest that a companion star to the sun periodically comes close enough to nudge comets gravitationally out of their natural habitat--a cloud of comets that circles the sun far beyond the orbit of Pluto--sending them hurtling toward earth. Others assign that role to Planet X, while some insist that the slow, bobbing ride of the sun and its planets around the Milky Way galaxy is responsible. Whatever the details, declares Paleontologist J. John Sepkoski...
Sniffing a connection, Rampino and a Goddard colleague, Astrophysicist Richard Stothers, among others, proposed an ingenious way that the oscillating journey might trigger bombardments on earth. Whenever the sun passes through the Milky Way plane, they suggested, the swirls of dust it encounters would gravitationally disrupt the Oort cloud, a vast bubble of comets that scientists believe surrounds the solar system at a distance of up to 10 trillion miles from the sun. Like a lazy fruit picker shaking plums from a tree, the dust would send showers of comets falling toward the sun. Some comets would collide with...
...solar system's asteroid belt. Trouble was, he conceded, he could not come up with a convincing orbit for the companion. Suddenly the Dutch-born Hut interrupted him with an alternative suggestion: Why not make the companion star travel through the thickest part of the comet-filled Oort cloud, rather than the asteroid belt? Muller immediately saw that the problems he had had with asteroids disappeared when he substituted comets as the culprits. As he recalls, "We wrote the first draft of our paper that...
...binary stars. Because it has not been identified in the four centuries since astronomers began using telescopes, it must be very small and dim, perhaps a red dwarf with one-third the mass and only one one-thousandth the brilliance of the sun. When it passed through the Oort cloud, it would dislodge a billion or more comets. Muller, searching for an appropriate name for the lethal companion, considered several. But the one that stuck was Nemesis, the Greek goddess who punishes the proud...
...gigantic an orbit had never been recorded for two companion stars, and with good reason. If the sun and its presumed partner were actually three light-years (18 trillion miles) apart, they said, the gravitational attraction between them would be so feeble that a passing star or dust cloud would have bumped Nemesis out of orbit long ago, certainly before it could come back through the Oort cloud a dozen times. Says Shoemaker, who has been something of an impartial judge in the periodicity controversy: "I give this idea less than a 1% chance of being correct...