By KEAY DAVIDSON
San Francisco Chronicle
August 25, 2005
But is our new knowledge as reliable as it appears? Maybe not, if one believes a few doubters.
If one judged solely by the newspaper headlines, or by what schoolchildren are taught in science classes, one might think that scientists unanimously agree on the details of the Big Bang theory of cosmic origins; on the reality of a mysterious force called dark energy, which is allegedly driving the universe to expand faster over time; and on the existence of many other things that might, in fact, be mirages - or, at least, more poorly understood than orthodox researchers acknowledge.
Behind the headlines, though, a handful of iconoclastic scientists question important details of such accepted knowledge. If history is any guide, most of these iconoclasts will fail to convince their colleagues that they're on the wrong path. In all likelihood, the doubters' objections are bound for the historical dustbin, the final resting place of the forgotten errors of yesteryear - for example, the belief in an Earth-centered cosmos, or the 19th century notion that bumps on people's heads revealed their personalities.
Yet in rare cases, iconoclastic scientists prove to be right - sometimes spectacularly so. In the early 20th century, most geologists scoffed when German scientist Alfred Wegener proposed that continents move about, like bumper cars at an amusement park. Nowadays, the idea of continental drift is familiar to every schoolchild.
Is the science of cosmology in the same position that geology was circa 1900 - due for a big overhaul?
Cosmology - the study of the origins, nature, evolution and fate of our cosmos - has been a respected and well-populated science for almost four decades. Popular books tell the sagas of its triumphs - how, for instance, in the mid-1960s, two scientists working on a New Jersey communications antenna accidentally discovered faint cosmic radiation that poured from the sky. Later, that cosmic background radiation was identified as the leftover "glow" of the Big Bang, a sort of super-explosion that spawned not only space but also time itself about 13 billion years ago.
But that isn't the whole story of the Big Bang theory. The thesis has evolved radically since the 1960s, and scientists continue to argue over crucial details.
Recent months have brought a surge of iconoclastic studies in cosmology. They include:
- Doubt about present formulations of the Big Bang hypothesis. This month, a major problem in the mainstream Big Bang hypothesis is reported by two physicists at the University of Alabama at Huntsville. According to the Aug. 1 issue of the prestigious Astrophysical Journal, Professor Richard Lieu and research associate Jonathan Mittaz analyzed measurements of the cosmic background radiation made by a space satellite, the Wilkinson Microwave Anisotropy Probe, a few years ago.
For more than a decade, scientists have known that the radiation is pockmarked with cooler-than-normal spots. Most scientists regard these spots as places where gravity tugged together primordial matter shortly after the Big Bang, forming seeds of the first galaxies, which are stellar swarms akin to our Milky Way.
However, Lieu and Mittaz are disturbed that in the Wilkinson satellite's map of celestial radiation, the cool spots - which caused an international sensation when first reported in 1992 - are suspiciously similar in size to one another. They believe the size variations should be much greater, partly because so-called gravitational lensing - the gravitational bending of light by unseen matter in the universe, which distorts the shapes of celestial objects - should greatly distort the spots' size. That's especially true because the spots are presumed to be so far away, billions of light years distant, on the edge of cosmos.
The lack of such distortion suggests a far-out possibility: Maybe the cool spots aren't nearly as far away as assumed. For this and other complex reasons, they propose the possibility that an overhaul of the standard model of the Big Bang is needed.
"Could it be that although the radiation itself is from far away, some of these cool spot structures are caused by nearby physical processes and aren't really remnants of the universe's creation?" Lieu asked in a statement issued by the University of Alabama. "There is certainly plenty of room for unknowns."
- Doubt that a puzzling and so-far-unseen dark energy is causing the universe to expand faster and faster over time. When first reported in the 1990s, this discovery was recognized as one of the most counterintuitive developments in the history of astronomy. Previously, astrophysicists had assumed the universe was expanding but would either expand increasingly slowly with time or collapse back upon itself like a ruined souffle.
The leading doubter is Edward "Rocky" Kolb, director of the Fermilab Particle Astrophysics Center near Chicago. In March, in a paper that he published with three colleagues in Italy and Canada, Kolb offered an alternate explanation for the ever-accelerating cosmic expansion, one that employs existing theories of physics rather than the new, unknown physics that is presumed to lurk behind dark energy.
This spring, when Science magazine asked him if dark energy is an illusion, Kolb dryly replied: "I'm not willing to bet my life on it yet. I would bet my collaborators' lives, though."
- Doubt about neutron stars. Are some of them impostors? First discovered by their electromagnetic pulses in the 1960s - by scientists who initially suspected the signals might come from "bug-eyed monsters" or BEMs in an alien civilization - neutron stars, some of which are pulsars, are among the strangest cosmic phenomena. In theory, they consist largely or totally of extremely compacted neutrons. Whereas our sun is almost 900,000 miles wide, a neutron star might be as compact as San Francisco. (The three main building blocks of atoms are protons, electrons and neutrons, which are, respectively, positively, negatively and neutrally charged particles.)
However, some purported neutron stars might be impostors. That is, they could consist substantially of matter other than neutrons, but have other properties that allow them to masquerade as neutron stars, say physicists at Washington University at St. Louis, Los Alamos National Laboratory in New Mexico, and Jefferson National Laboratory in Newport News, Va.
"Most people agree that these stars have a surface layer of nuclear matter (mostly neutrons), but no one knows what is in the middle," said one of the scientists, physicist Mark Alford of Washington University, in an e-mail to The Chronicle. Conceivably, the core of a purported neutron star "might be something more exotic such as quark matter," in other words, a "hybrid star" that is substantially composed of even smaller particles called quarks.
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