by Sylvain Comeau
Are black holes science or science fiction? When their existence was first theorized in the 1930s, black holes were usually dismissed as the latter. For decades, scientists were unable to accept the far-out notion of a region of space where gravity is so strong that not even light can escape its pull.
Today, the scientific reality of black holes is widely accepted, but speculation about them, and even some of the facts, still smack of science fiction, says Werner Israel, professor of Physics and Astronomy at the University of Victoria. Israel delivered the first Science College lecture for 1999/2000 last Thursday.
"It is hard to imagine a time in which black holes was not a household term. Today, you can walk into any bookstore and find books on black holes, although some of them might be in the science fiction or occult section."
Some speculation involving black holes, which are the remains of burnt-out stars, claim that they are vehicles for time travel, or gateways to other dimensions.
"I won't talk about that, but the facts about black holes are as bizarre and incredible as anyone could want," Israel said.
For example, an astronaut caught in a black hole would see "the entire future of the outer universe flashed in fast motion before his eyes; he would see the winner of all the horse races for the next 1,000 years, and more. But this information would not do him any good."
That astronaut, and other matter caught in the black hole, would be compressed to the point that "they would probably be crushed out of existence."
In an interview after his lecture, Israel readily acknowledged that much of what is known about black holes "certainly goes against our common sense. They originated as theoretical concepts, but they have since been verified through actual experiments, for example with particle accelerators, in which particles move at very nearly the speed of light. The time-travel effect in a black hole would be similar to that which would be experienced by someone travelling at the speed of light."
Rush to fill the gaps
So why do black holes lend themselves so well to wild speculations and bizarre ideas?
"There was tremendous resistance to black holes for decades. People thought these things were so absurd that they couldn't possibly exist. That only changed in the 1960s, when observations of quasars and nuclei of galaxies forced them to confront the fact that black holes really do exist, in our galaxy and others."
Independent thinkers, in both the scientific and non-scientific worlds, have rushed to fill persistent gaps in our scientific understanding.
"It is perfectly reasonable for people to indulge in these kinds of speculations; no one can either prove or disprove them because we don't have a basic mathematical theory to describe what is happening inside black holes.
"We know that something very strange is happening there, something beyond our ability to describe in detail, so we have to speculate."
One of the most outrageous theories (as opposed to speculations) about black holes is that the gravitational forces at their centre crush matter to the point that they probably cease to exist.
"Matter would be destroyed, and the protons, neutrons and atoms of the original matter would no longer exist. And we know that when black holes evaporate, what remains is pure radiation, not the original matter."
The end of the universe
That process may provide a preview of the eventual fate of the universe, and insight into its beginnings. "What happens inside a black hole is very much like the end of a universe. It is possible that the universe will eventually collapse in the form of a Big Crunch, the opposite of the Big Bang, although this is unlikely, according to current observation. It is more likely that the universe will expand forever."
Paradoxically, black holes also provide insight into the origins or our ever-expanding universe.
"The Big Bang also entailed a Big Crunch; before the Big Bang, the universe was a place where matter was compressed to infinite or near-infinite density. So the ends and beginnings of universes might be more or less the same, and black holes might teach us about both."
The next Scence College lecture will be by Dr. Louis-Eric Trudeau, Assistant Professor of Pharmacology and Psychiatry, Faculty of Medicine, Universitˇ de Montrˇal. Dr. Trudeau is a Science College graduate. He went on to do his MSc in Paris, his PhD in Montreal, and postdoctoral work in the U.S.
The title of his lecture will be "From the Synapse to Schizophrenia: Help Wanted, Inquire Within." It will be given at 8 p.m. on Thursday, November 11, in the deS¸ve Cinema, 1400 de Maisonneuve Blvd. W.