PURPORTED PROTOPLANET, hanging on at the lower left from a star system in Taurus, was later shown to be an unrelated background star. Each technique for finding planets has its potential for error, so astronomers must always seek independent corroboration. Image: S. TEREBEY Extrasolar Research Corp. AND NASA
PASADENA, CALIF.--"It's not even wrong" was physicist Wolfgang Pauli's famous putdown for a theory he regarded as implausible and inconsequential. For the past several years, it has been most astronomers' response to the ideas of David C. Black. The researcher from the Lunar and Planetary Institute in Houston is the most outspoken skeptic of the discovery of planets around other sunlike stars. He thinks the planets are actually misidentified stars, and he has stuck to that position despite the failure of his predictions, the weight of scientific opinion and an almost total lack of observational support. His colleagues whisper that his planet doesn't go all the way around his star.
Now, for the first time, some evidence for Black's view has emerged. At the Division for Planetary Sciences conference in Pasadena last October, veteran planet hunter George D. Gatewood of the University of Pittsburgh Allegheny Observatory presented the results of a study he conducted with Black and then graduate student Inwoo Han. They checked whether the parent stars of the purported planets swayed from side to side, the sign of a cosmic do-si-do with partners too small to be seen directly. In many cases, the team concluded, the swaying motion was strong enough that the partners must be fairly heavy--brown dwarfs or other smallish stars, it would seem. At the least, the group has stirred a debate over selection biases in the planet searches and spiced up the broader discussion over what exactly a planet is.
In the 1980s the name of David Black was practically synonymous with extrasolar planets. He was once the head of the National Aeronautics and Space Administration's search. But his reputation started to slide in 1995 when planet hunting became planet finding. None of the new worlds resembled anything in our solar system. Black took this as a sign that they weren't planets after all. Their mass distribution and orbital characteristics, he asserted, look rather like those of stars. William D. Heacox of the University of Hawaii at Hilo sympathizes with that view, but says most astronomers now think Black is clinging to outmoded ideas. If nature created odd planets, even ones with starlike orbits, so be it. Accept it and move on.
This article was originally published with the title Lost Worlds.