Tuesday, August 3, 2010

the latest science "news"

From the New York Times:


Rumors in Astrophysics Spread at Light Speed

[SPACE QUEST Technicians readied one of the telescope mirrors used in NASA's Kepler planet-finding mission.]

Ball Aerospace
SPACE QUEST Technicians readied one of the telescope mirrors used in NASA's Kepler planet-finding mission.

Published: August 03, 2010

Dimitar Sasselov, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics, lit up the Internet last month with a statement that would stir the soul of anyone who ever dreamed of finding life or another home in the stars.

Brandishing data from NASA's Kepler planet-finding satellite, during a talk at TED Global 2010 in Oxford on July 16, Dr. Sasselov said the mission had discovered 140 Earthlike planets in a small patch of sky in the constellation Cygnus that Kepler has been surveying for the last year and a half.

"The next step after Kepler will be to study the atmospheres of the planets and see if we can find any signs of life," he said.

Last week, Dr. Sasselov was busy eating his words. In a series of messages posted on the Kepler Web site Dr. Sasselov acknowledged that should have said "Earth-sized," meaning a rocky body less than three times the diameter of our own planet, rather than "Earthlike," with its connotations of oxygenated vistas of blue and green. He was speaking in geophysics jargon, he explained.

And he should have called them "candidates" instead of planets.

"The Kepler mission is designed to discover Earth-sized planets but it has not yet discovered any; at this time we have found only planet candidates," he wrote.

In other words: keep on moving, nothing to see here.

I've heard that a lot lately. Call it the two-sigma blues. Two-sigma is mathematical jargon for a measurement or discovery of some kind that sticks up high enough above the random noise to be interesting but not high enough to really mean anything conclusive. For the record, the criterion for a genuine discovery is known as five-sigma, suggesting there is less than one chance in roughly 3 million that it is wrong. Two sigma, leaving a 2.5 percent chance of being wrong, is just high enough to jangle the nerves, however, and all of ours have been jangled enough.

Only three weeks ago, rumors went flashing around all the way to Gawker that researchers at Fermilab in Illinois had discovered the Higgs boson, a celebrated particle that is alleged to imbue other particles with mass. The rumored effect was far less than the five-sigma gold standard that would change the world. And when the Fermilab physicists reported on their work in Paris last week, there was still no trace of the long-sought Higgs.

Scientists at particle accelerators don't have all the fun. Last winter, physicists worked themselves up into a state of "serious hysteria," in the words of one physicist, over rumors that an experiment at the bottom of an old iron mine in Minnesota had detected the purported sea of subatomic particles known as dark matter, which is thought to make up 25 percent of creation.

Physicists all over the world tuned into balky Webcasts in December to hear scientists from the team, called the Cryogenic Dark Matter Search, give a pair of simultaneous talks at Stanford and Fermilab, and this newspaper held its front page, only to hear that the experiment had detected only two particles, only one more than they would have expected to find by chance.

We all went to bed that night in the same world in which we had woken up.

One culprit here is the Web, which was invented to foster better communication among physicists in the first place, but has proved equally adept at spreading disinformation. But another, it seems to me, is the desire for some fundamental discovery about the nature of the universe - the yearning to wake up in a new world - and a growing feeling among astronomers and physicists that we are in fact creeping up on enormous changes with the advent of things like the Large Hadron Collider outside Geneva and the Kepler spacecraft.

I can't say what the discovery of dark matter or the final hunting down of the Higgs boson would do for the average person, except to paraphrase Michael Faraday, the 19th-century English chemist who discovered the basic laws of electromagnetism. When asked the same question about electricity, he said that someday it would be taxable. Nothing seemed further from everyday reality once upon a time than Einstein's general theory of relativity, the warped space-time theory of gravity, but now it is at the heart of the GPS system, without which we are increasingly incapable of navigating the sea or even the sidewalks.

The biggest benefit from answering these questions - what is the universe made of, or where does mass come from - might be better questions. Cosmologists have spent the last century asking how and when the universe began and will end or how many kinds of particles and forces are needed to make it tick, but maybe we should wonder why it is we feel the need to think in terms of beginnings and endings or particles at all.

As for planets, I no longer expect to see boots on Mars before I die, but I do expect to know where there is a habitable, really Earthlike planet or planets, thanks to Kepler and the missions that are to succeed it. If such planets exist within a few light-years of here, I can imagine pressure building to send a probe, a robot presumably, to investigate. It would be a trip that would take ages and would be for the ages.

There is a deadline of sorts for Kepler in the form of a conference in December. By then, said William J. Borucki, Kepler's leader, the team hopes to have moved a bunch of those candidate planets to the confirmed list. They will not be habitable, he warned, noting that that would require water, which would require an orbit a moderate distance from their star that takes a year or so to go around. With only 43 days' worth of data to analyze yet, only planets with tighter, faster and hotter orbits will have shown up.

"They'll be smaller, but they will be hot," Mr. Borucki said.

But Kepler has three more years to find a habitable planet. The real point of Dr. Sasselov's talk was that we are approaching a Copernican moment, in which astronomy and biology could combine to tell us something new about our place in the universe.

I know that science does not exist just to fulfill my science-fiction fantasies, but still I wish that things would speed up, and the ratio of discovery to hopeful noise would go up.

Hardly a week goes by, for example, that I don't hear some kind of rumor that, if true, would rock the Universe As We Know It. Recently I heard a rumor that another dark matter experiment, which I won't name, had seen an interesting signal. I contacted the physicist involved. He said the results were preliminary and he had nothing to say.

Smart guy. Very.