Planets for Dessert
"It's going to be beautiful," says Vince Huegele, a researcher at the NASA/Marshall Space Flight Center. "And best of all, you won't need a telescope to see it, just your naked eye."
Right: Duane Hilton's rendering of the April 6 planetary get-together as seen above Bryce Canyon in Utah.
To admire the display, simply go outside after dinner on April 6 and look toward the southwest sky. Around 8 p.m. local daylight savings time the slender crescent moon will be easy to spot about 30 degrees above the horizon. The brightest nearby "star" will be Jupiter. At magnitude -2.1, the giant planet is 8 times brighter than Saturn, which glows pale yellow less than 3 degrees west of the Moon. Mars will lie a scant 1.1 degrees north of Jupiter. The red planet (magnitude 1.4) will be about 3 times fainter than Saturn (magnitude 0.3).
Jupiter, Mars, and Saturn will appear to be even closer together on April 15 when the three will fit inside a circle less than 5 degrees across. That's the most compact grouping of any 3 planets for the entire year. Nevertheless, the display on April 6 will be more beautiful thanks to the delicate crescent Moon as it passes by the trio.
When Planets Align (or "Taking Nostradamus to School")
Although the May 5 alignment won't produce a visible sky show, some people are touting the event. Why? According to doomsayers, the alignment will cause earthquakes, floods, and maybe even split our planet in two like a meat cleaver through a head of lettuce! In all fairness that sounds like an event to note on your calendar.
If these sensational claims sound familiar, it probably means you were alive 38 years ago when there was a similar celestial alignment. On February 4, 1962, the Sun, the Moon, and all the planets from Mercury to Saturn were clustered within a 17-degree area of the sky. To top it off there was a total eclipse of the Sun! Doom seemed certain to many astrologers and students of Nostradamus.
In the May 1962 issue of the Griffith Observer, astronomer Robert Richardson described the scene in Los Angeles on February 4, 1962:
Weeks beforehand we began getting inquiries [at the Griffith Observatory] from people wanting to know, "What was going to happen? What does it mean?" ... Sunday, February 4 [the crowd at the Observatory] must have been the largest since it was opened to the public in 1935. By two o'clock the road leading to and from the observatory was a solid mass of cars lined up bumper-to-bumper for half a mile. One woman was weeping so badly it was hard to understand her. She was practically on the verge of collapse. "I know it's silly to carry on this way,' she gasped between sobs, 'but I can't help myself." [ref]
Fortunately, nothing happened. There were no severe earthquakes, no devastating floods, no mass destruction. With no planet-wide disaster to spoil the day, millions of onlookers enjoyed the solar eclipse.
History shows that planetary alignments are harmless. In fact, alignments like the one in 1962 and in 2000 are fairly common. The five naked-eye planets cluster together in the sky within a circle 25 degrees or less in diameter once every 57 years, on average. The next time it will happen is September 8, 2040. The 2040 grouping will include Mercury, Venus, Mars, Jupiter, Saturn and the crescent Moon. Clustered well to the east of the Sun, the planets will stage a spectacular show at 7:30 p.m. in the evening. (Mark your calendar now!)
If planetary alignments are common and the Earth is never destroyed, why do predictions of doom seem to attend each one?
Many people believe that when planets are aligned their gravity and tidal forces are magnified, leading to extraordinary effects here on Earth. This seems reasonable. After all, "spring tides" (peak ocean tides that arise bi-monthly) occur when the Sun, the Moon and the Earth are nearly in a straight line around the times of the New Moon and Full Moon. Shouldn't even more powerful tides arise when lots of planets are lined up?
|Solar System Object||Tidal Force|
Above: In this table, adapted from the Griffith Observatory's "Planetary Alignments in 2000", the Sun exerts 1 unit of tidal force on the Earth; the Moon has a little more than twice the effect of the Sun; the other nine planets together with all their moons add only another one five-thousandth as much.
So, if you've already packed away your Y2K survival gear, don't worry. There's no planet-rending catastrophe in the offing. Like most other 5ths of May, the one in the year 2000 is a more appropriate occasion for Cinco de Mayo festivities than for disaster planning.
For lesson plans and educational activities related to planetary alignments, tune into the March 30 episode of Thursday's Classroom. There is also a version of this story for kids at NASA/Marshall's NASA Kids web site.
Planetary Alignments in 2000 - from the Griffith Observatory
Do planetary alignments cause earthquakes? - find out at badastronomy.com