Trying to keep up with science is, I conclude after watching openmouthed at an air show, like flying an F-18 at 700 miles an hour just 200 feet above the ground. The landscape is coming at you so fast, I assume, that you don't dare blink, much less sneeze. My desk is a little like that streaking landscape: so much is happening in science that I don't dare look away. The weekly science journals pile up, as do the news releases delivered by mail, electronic or snail. There are Websites such as EurekAlert! to check; tip sheets; alerts from scientist friends, unofficial contributing editors and writers; and the daily papers.
Some of the news makes the front page, like the wholesale cloning of farm animals or the first steps toward growing cells that can reverse what had been irreversible damage in humans. Some of it does not make the front page, but it represents fundamental changes in the way science sees the world. Take the neutrino, for example, the "little neutral one," a subatomic particle that fills the universe and routinely passes through the entire Earth (not to mention us) without touching anything. Since its existence was first predicted and then discovered, the neutrino has been treated as if it did not have any mass.
Now comes evidence from 3,000 feet down in a zinc mine 125 miles from Tokyo that, yes, neutrinos do have mass. Not much, to be sure, but there are so many neutrinos that the sum total of their mass would be an impressive, if incomprehensible, figure.
How about antigravity, a favorite of science fiction writers for decades? Well, some such force is at work in our universe, causing it to expand faster than would be expected. Astronomers study supernovas in distant galaxies in the hope of using them as "standard candles." If such stellar explosions of particular kinds produce certain absolute luminosities, then we can judge how far away they are by how bright they appear. Applying the resultant rules of thumb to the most distant galaxies, however, astronomers found those galaxies were farther away than they should have been. Some unknown repulsive force is counteracting the gravitational field of the entire universe. Brian Schmidt, the Australian astronomer who heads one of the two teams investigating the matter, was quoted as saying: "My own reaction is somewhere between amazement and horror."
Many years ago Einstein incorporated a "cosmological constant" into the equations he used to describe gravity, together forming a theory we know as the general theory of relativity. Einstein used the constant to correct what he considered a flaw in his work; without it, the equations seemed to say, the universe would collapse under its own weight or expand forever. At the time, there was no observational evidence for such a constant, and later he called it his greatest mistake. Now it turns out he was right on the money. The unknown form of energy that is accelerating the expansion of the universe, a kind of negative gravitational force, works exactly like Einstein's makeshift constant. The discovery has been named "Breakthrough of the Year" by Science, a publication of the American Association for the Advancement of Science. It is not just a matter of distant galaxies being 10 to 15 percent farther away than our calculations had predicted. The discovery apparently means that the newly detected force may constitute more than half of the energy in the universe, which in turn means that the theorists have their work cut out for them.
Then there are stories that never see a front page. Radio astronomers announced at a meeting in Australia that they had captured images of streams of hydrogen that our home Milky Way galaxy is sucking out of two satellite galaxies, the Large and Small Magellanic Clouds (naked-eye objects in the Southern Hemisphere sky). The whole thing works like tides on Earth. Our galaxy's gravitational effect on the Magellanic Clouds is strongest on the parts closest to us. That actually pulls some of the gas away. The gravitational effect on hydrogen on the far side of the clouds is less than its effect on the main bodies of the clouds, so the main bodies are pulled away from that gas. The two clouds end up with streams of gas being left behind them and an arm reaching ahead of them, curving all the way to us here in the much larger Milky Way.
Even less attention was paid to "blinkers" on the surface of the sun, small explosions that occur sporadically on every part of the sun. A press release from the Royal Astronomical Society called them insignificant because they were small and had only one-millionth as much energy as a solar flare. Each explosion, however, is about the size of Earth. The blinkers could help explain how the sun produces the solar wind, the stream of charged particles that constantly blow outward from the sun's surface.
On the technology front, another staple of science fiction has come to life. A spacecraft called Deep Space 1 is heading out from Earth on a test flight that will take it by a small asteroid in July. It does not burn rocket fuel to create thrust. Instead, it uses electricity supplied by solar panels to strip electrons from xenon atoms, making them electrically charged particles known as ions, and then it uses more electricity to push them out of the engine so fast that they create thrust. The New York Times reported that the thrust so generated would have the force of one sheet of typing paper pressing down on your hand. The secret is time, though. That laughably small amount of thrust is expected to add 8,000 miles an hour to the velocity of Deep Space 1 by the end of the mission, currently planned for September 1999.
Now if a person had a reasonable expectation that things would slow down, that sooner or later we would have time to catch our breath, it wouldn't be so bad. Unfortunately, it looks like the future holds more of the same, only more so. A man named John Maddox was for nearly 23 years the editor of Nature, a weekly journal that publishes both original research and science news. He had first-hand knowledge of what was happening, especially in astronomy and molecular biology. He is retired (and is now Sir John) and has written a book called What Remains To Be Discovered. It is a long book, and dense, so rich that it is best approached like pâté de foie gras, to be ingested in small quantities. Maddox believes that science is not quite as far along as is sometimes thought. Some of the questions he raises, he writes, "cry out for answers. The nature of the hidden mass in apparently ordinary galaxies is a deepening embarrassment as the decades tick by. On the other hand, the search for 'missing mass' to close the Universe [make it eventually stop expanding and collapse in on itself] seems destined to be a wild-goose chase. The origin of the energetic particles in cosmic rays, a fashionable object of study three or four decades ago, remains enigmatic. The role of magnetism in the structure of galaxies and perhaps of the Universe at large is another issue that cosmology has put aside for the time being."
Maddox is less than convinced of either the Big Bang or black holes. "Observers of the heavens have been like kidnap victims seeking to learn where they are," he says, "from the chinks of light that reach them through the imperfections of their blindfolds; half a century from now, cosmologists will have a much better idea of what kind of Universe they are expected to explain." Fifty years isn't much from the universe's point of view. Without saying the M word, let's think in larger units. Think of how far astronomy has come in the past 1,000 years. (For a clue as to where some of the centers of astronomy might have been 1,000 years ago, consider how many stars have names derived from Arabic: Aldebaran, Rigel, Altair, Deneb...) So, how far will it go in the next 1,000? Or 10,000? And how fast will the F-3712 be flying?