Geologist Gregory Retallack may be correct that the release of megatons of methane helped cause the Permian extinction, but it is probable that an asteroid impact contributed too [“20,000 Microbes Under the Sea,” March]. The massive impact would have disturbed the seafloor over vast areas of the planet, which might well have triggered a methane release. As Antje Boetius’s research experience shows, looking for a single factor may make you blind to multiple factors.
CHARLES M. BARNARD
“Before the Big Bang” [February] quotes cosmologist Joel Primack as saying that it’s silly to make a production about the ekpyrotic universe theory and that he’d much rather spend his time on “the really important questions” of dark matter and dark energy. He implies that there is solid cosmological evidence for dark matter and dark energy, which there is not. The ekpyrotic universe eliminates the need for dark matter and dark energy, makes inflation unnecessary, offers an explanation for the Big Bang, offers an answer to whether our universe is a onetime fluke or one of many, and grows directly out of a physical theory that appears to reconcile all of the currently existing competing theories of high-energy physics. When you look at it this way, Primack’s dismissal begins to sound rather like “Go away and let me work on my epicycles. I’m sure if I add just one more layer, it’ll all work out.”
Greenville, North Carolina
Cosmologist Paul Steinhardt and his associates have done nothing of scientific significance. They have postulated an infinite regress of untestable universes with unknowable dimensions in an attempt to avoid a creation. Of course, the odds that any one of these universes would have just the right density to keep from collapsing on itself or expanding too rapidly for galaxies to form are still astronomical. Nor have they answered the fundamental question, “Why is there something rather than nothing?”
Letting It All Hang Out
Upon reading about Body Worlds [“Gross Anatomy,” March], I was appalled by the absolute lack of respect anatomist Gunther von Hagens has for the people these “exhibits” once were. These unfortunates deserve to be treated better than as a perpetual sideshow attraction for an abominable P. T. Barnum wannabe. While I credit Von Hagens with creating a new method of preservation that will be good for science and the study of bodies, this is one step too far.
The Revolution Will Be Tracked
Steven Johnson’s prediction of the future of consumerism, in which RFIDs track every purchase we make, is truly Orwellian [“Smart-Label Revolution,” Emerging Technology, March]. He makes it sound harmless and inevitable. Why stop at placing microchips in our consumer goods? We should all just have microchips implanted in our bodies that would automatically debit our bank accounts when we make a purchase. I suggest Mr. Johnson lead the way. Perhaps one day he will need an organ transplant or lifesaving surgery, but his insurance company will access his purchasing records and say, “We are sorry that we cannot save your life, because our records show you have consumed too much Ben & Jerry’s ice cream, bacon and eggs, and alcohol.”
Political Science Revisited
I was somewhat distressed to read in the recent letters section [Letters, March] that some subscribers are canceling their subscriptions because the magazine takes up issues having to do with politics or religion. Reporting attacks on the ability to conduct scientific research, abuses of scientific research, or the ignoring of scientific research is very important if one is to know what is taking place in the scientific community. Keep it up. Better science will result. Anyone who thinks politics is not a part of science, religion, or anything else needs more education.
“Leap Seconds” [March] has a statement I can’t believe. You say: “Earth’s rotation is erratic. Although it has lost three hours in 2,000 years, within that slowing there are random fits and starts.” Are you saying that a day in the year A.D. 1 was three hours shorter than ours?
Irmo, South Carolina
Author Karen Wright replies: Many readers wrote to us with the same question, and it’s easy to understand why they were confused. Our point was that Earth’s rotation has slowed by a total of three hours over the course of 2,000 years, for an average of 0.015 second per day: If you think of Earth’s period of rotation as a kind of clock, it would be three hours slow by now. The length of a day in A.D. 1 was shorter than ours by just a fraction of a second.
The Far Side
Having taught astronomy for nearly two decades, I read with interest Paul Taylor’s criticism of Bob Berman concerning the lopsided cratering on the moon [Letters, March]. I agree with the editors’ response, which challenges Taylor’s notion of Earth’s role in this regard. The editors conclude with the statement, “The real question is why those processes were so lopsided.” The seismographs left on the moon’s surface by the Apollo astronauts and the gravity measurements of the 1998 Lunar Prospector probe have provided enough data to explain why there are many more craters on the moon’s far side than on the near side. The crust on the far side is estimated to be thicker—about 90 miles—as compared with the roughly 40-mile crust facing Earth. This difference was probably created by Earth’s gravity, which could have pulled the heavier mantle underneath the crust toward Earth. The moon’s craters were created by meteoroids, some of which could have punctured the thin crust on the near side or created fissures through which molten lava gushed out and covered most of the craters. The craters on the thicker far side would thus have escaped obliteration.
In March’s Ask Discover [R&D]: The correct direction of Earth’s rotation is west to east. In March’s Discover Dialogue: The Caenorhabditis elegans worm has six pairs of chromosomes.