Stargazing

An Invisible Alignment

The planets Mercury, Venus, Mars, Jupiter, and Saturn all congregate near the Sun in our sky during late April and early May 2000. The Moon will join them for a couple of days. The tightest grouping of these six bodies will occur on May 5, when the Moon and planets spread across 25 degrees of sky -- a little more than the width of an outspread palm held at arm's length. The tightest grouping of the planets alone occurs on May 17, when they will span about 20 degrees.

Unfortunately, we won't see any of this because the light from the planets is overpowered by the Sun's intense glare.

Fortunately, despite the wild claims of doomsayers, this planetary "alignment" will have no effect on Earth. Our planet will not tip over, and we won't see great earthquakes or tidal waves as a result of the configuration.

It's not exactly correct to call this an "alignment." While it's true that the planets line up across our sky, they're not really in alignment; you couldn't string them like the beads on a cosmic necklace because their distances from Earth vary tremendously (from roughly 120 million to one billion miles).

Some web sites and other publications predict that the combined gravitational pull of the planets will produce catastrophic effects on Earth.

But at their great distances, the planets exert only a tiny pull on Earth. One astronomer calculated that even if the five planets were all at their closest possible distance from Earth, their combined gravitational pull would equal only about 0.01 percent of the Sun's pull on Earth. That's not nearly enough to affect us. Since the planets are all farther away, and they are not precisely aligned, their effect is even smaller.

Although it's relatively rare for so many planets to appear in such a small region of the sky, it's certainly not unprecedented. In fact, the five planets will be even more tightly bunched in September 2040. That configuration will occur farther from the Sun, so the planets will all be visible.

All five of the planets are on the "far side" of the Sun from Earth right now, and soon will cross behind the Sun: Jupiter on May 7; Mercury, May 8; Saturn, May 10; Venus, June 11; and Mars, July 1.

Jupiter and Saturn will emerge from the Sun's glare around the first of June, and will be visible in the morning sky. Mars is headed toward a morning appearance, too, but won't become visible until late summer. Mercury will put in a good showing in the evening sky in early June, with Venus popping into view as the brilliant "evening star" around the end of July.