Planetary alignment labeled harmless
Robert Frost might have seen this coming: Some say the world will end in fire on Friday, some say in ice.
That day, Earth and five other planets will roughly line up with the sun and moon. Doomsayers have predicted that the gravitational pull of this alignment could cause drastic consequences on Earth - from massive earthquakes and resulting fires to shifting polar icecaps.
But never fear. Astronomers point out that planets simply don't have enough gravitational pull, on either Earth or the sun, to cause such poetic predicaments. So books like 5/5/2000 - Ice: The Ultimate Disaster won't have much more shelf life.
"What's going to happen on May 5 will be the same thing that happens on May 5 of any other year," says Phil Plait, a Maryland astronomer who runs the badastronomy.com Web site. People will live, people will die, there may be an earthquake or some weird weather - but it won't have anything to do with the celestial alignment, he says.
Moreover, skygazers won't even be able to enjoy the show. Four planets will be so close to the line-of-sight to the sun that they will be drowned in its glare, like a firefly outshined by a searchlight. Only Mars will be visible, glowing with the moon just above the west-northwestern horizon in the hour after sunset.
Planetary alignments are not that rare, and civilization has survived many before, says Don Olson, an astronomer at Southwest Texas State University in San Marcos. In February 1962, for example, five planets joined Earth, the sun and the moon in an even closer alignment than Friday's. Humanity survived, Dr. Olson points out.
The doomsday predictions for Friday generally invoke one of two scenarios. In one, the gravitational pull on Earth causes its poles to shift position, triggering earthquakes, volcanic eruptions and other natural disasters. In the other scenario, gravity raises unusually high tides on the surface of the sun, possibly leading to solar flares or other activity that could harm Earth. This second option is put forth by Richard Noone in his 5/5/2000 book.
But the planets have too weak an effect on both Earth and the sun to cause any such disaster, astronomers say.
"The total combined gravity of the planets on the Earth is roughly 1 percent of the moon's gravity," says Dr. Plait. The planets' tug just can't compare to monthly changes in the moon's gravitational pull, which is what causes tides on Earth.
As for the sun, Dr. Olson has calculated whether unusual tides might arise on its surface because of the planetary alignment. They won't, he reports in the May issue of Sky & Telescope magazine.
On Friday, and for several days after, the tidal forces on the sun will be somewhat stronger than usual, Dr. Olson discovered. But the forces won't be nearly as strong as they have been in the past, when various planetary positions created an even stronger tidal tug. In November 1703, May 1941, and January 1990, he calculated, tidal forces were significantly stronger than they will be this month.
"Since we survived those years, I make the prediction that we will survive the next one," says Dr. Olson.