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Science News, Dec 24, 1994 by Patrick Young

I'm amazed at how many people regard each new scientific report as THE TRUTH. They seem to view the latest research finding as the absolute answer. Science, however, doesn't work that way. Even the genius of Newton needed tweaking. Much as we might wish otherwise, the wisdom and truth of science advance in fits and starts, through revisions and sometimes reversals, rather than in a smooth march forward that expands human knowledge.

So findings from individual studies are best regarded as tentative. Science builds on the work of many, and what looks solid upon publication may crumble in time. Certainly, 1994 offers some examples of this. Consider:

* For more than 30 years, psychologists have held that excessive crowding brings out aggressive behavior in primates, including humans. But the largest study yet of primate crowding found a remarkably stable level of aggression across population densities (146: 20).

* Biologists usually depict cells as encased in smooth, flexible membranes that consist of a spherical, double layer of lipids. Now one researcher argues that the cell surface is cratered, pitted, and creased with deep labyrinths that fold into the cell's depths (145: 266).

* Since the late 1960s, atmospheric chemists have fretted that engine exhaust from a fleet of supersonic transports (SSTs) would damage the protective ozone layer in the stratosphere. New data suggest that such fleets would actually slow ozone destruction in the lower stratosphere, where SSTs fly, but that their exhaust would move to higher altitudes and seriously damage ozone there (146: 260).

* Sometimes science disabuses us of cherished notions. The devastating 1737 Calcutta earthquake and its 300,000 deaths never happened (145: 250). For some 3 decades, pediatricians have told parents to put their infants to sleep on their stomachs; now, they say parents should let babies sleep on their backs to help prevent sudden infant death syndrome (146: 13). And the great attractor, a vast mass toward which the Milky Way and many other nearby galaxies seem headed, apparently doesn't exist (145: 271).

Astronomers have long disagreed about the Hubble constant, which, if measured accurately, should reveal the universe's rate of expansion. I suspect researchers will argue that issue well into the 21st century, as they will the risks of electromagnetic fields, whether dinosaurs were hot-blooded, and the origins of language. Along the way, some interesting and tentative findings will emerge to intrigue and confound scientists and our readers.

Anthropology

* An Ethiopian site yielded the 4.4-million-year-old remains of a hominid dubbed Australopithecus ramidus, the oldest member of the human evolutionary family (146: 212).

* Investigators at another Ethiopian fossil site unearthed a 3-million-year-old skull, as well as other bones, that belonged to ancient human ancestors known as A. afarensis (145: 212).

* A redating of Indonesian fossils suggested that human ancestors left Africa and reached eastern Asia at least 1.8 million years ago, much earlier than previously thought (145: 150).

* An analysis of the inner ear in fossil hominids, modern humans, and chimps indicated that Homo erectus was the first human ancestor to spend all its time on the ground (145: 231).

* Research at a Siberian site raised the controversial possibility that humans inhabited northeastern Asia as many as 500,000 years ago (145: 84).

* Genetic traces of tuberculosis infection extracted from a 1,000-year-old Peruvian mummy confirmed that Europeans did not introduce the disease into the Americas (145: 181).

* Scientists announced the discovery of a Neandertal baby's remains in an Israeli cave, where the child apparently was buried around 60,000 years ago (145: 5).

* Fossil finds in China fueled a controversial

* Fossil finds in China fueled a controversial theory that primates evolved in Asia much earlier than previously thought (145: 245).

* Genetic analyses suggested adding a third chimpanzee species to the two generally accepted ones (146: 168).

Astronomy

* Tests revealed that a December 1993 repair mission successfully corrected the blurry vision of the $2 billion Hubble Space Telescope (145: 52).

* Several groups reported new measurements of the Hubble constant, which indicates the age and rate of expansion of the universe. Many of the findings, including a long-awaited set of observations by the repaired Hubble telescope, reinforced the paradox that the cosmos appears to be younger than its oldest stars (146: 232, 265, 278).

* After years of searching, astronomers reported the most compelling proof to date that a black hole exists at the center of a galaxy (145: 356).

* Radioastronomers found more evidence that two planetlike bodies orbit a star 1,300 light-years from our solar system (145: 151). Images suggest that disks of dust and gas -- the raw material of planets -- surround at least half the stars in a nearby stellar nursery (145: 391). Astronomers gathered new evidence that one or more planets orbit the star Beta Pictoris (145: 404).