E-mail this page Reader Comments (below)

By Bernie Reim Sunday, March 4, 2007

March always marks the beginning of spring for us in the Northern Hemisphere. This year the vernal equinox will happen at 8:07 p.m. Eastern Daylight Time on Tuesday, March 20.

The vernal and autumnal equinoxes are special days because those are the only two days each year that the sun rises due east and sets due west for everyone on Earth, except at the poles. During winter, the sun rises and sets south of east and west and right after the vernal equinox the sun will start rising farther and farther north of east until it reaches its northernmost point at the summer solstice, creating the longest day of the year.

The vernal equinox can also be defined as that point in the sky when the sun on the ecliptic intersects the celestial equator on an upward path. Within a few days of the equinoxes, the days and nights are of equal length for everyone on Earth, except for the poles.

The main highlight for this month will be the first total eclipse of the moon since the Red Sox finally won the World Series on Oct. 28, 2004. It will be about 100 years before there is another chance of a total lunar eclipse happening during a World Series game.

When the full Sap, Crow, or Lenten moon rises on Saturday evening, March 3 at 5:25 p.m., it will already be partially eclipsed by the Earth's shadow. The farther west you go, the less of this eclipse you will be able to see. You need to be in Europe or Africa to see this entire eclipse.

The total phase of this eclipse, when the moon is completely immersed in our shadow, starts at 5:44 p.m. and lasts until 6:58 p.m. The moon won't be completely out of our shadow until 8:50 p.m., but it will be very hard to detect our shadow on the moon after 8:12 p.m., when it leaves the umbra, or darker part of our shadow. The lighter part is called the penumbra.

Every eclipse is always very different, although the physics causing them are always the same. The exact intensity and shades of red and orange that the moon will take on is dependent on many factors, the main one being the amount of dust suspended in the upper atmosphere. The less dust, the lighter the colors. I remember a lunar eclipse in December of 1991, right after Mount Pinatubo in the Philippines erupted again, when there was so much dust in the atmosphere that the full moon completely disappeared for a while. All that dust also caused some amazing sunsets for a while, almost as good as the northern lights.

If the Earth didn't have an atmosphere to bend or refract the sunlight back onto the moon as we pass directly between the sun and the moon on the same plane, the moon would always become invisible during the umbral, or total phase of the eclipse. When you watch this lunar eclipse, think of what is really causing the incredible colors and subtle shades that you will be seeing. You will actually be witnessing the combined effect of all the simultaneous sunrises and sunsets on Earth projected onto the moon. This makes the moon seem so close that you could reach out and touch it. It is really not that far away, about 240,000 miles on the average, which is only a little over one second at the speed of light.

This lunar eclipse will be different again because it will already be partially eclipsed as it rises out of the Atlantic. Just watching a regular full moon rise over the ocean is an amazing event, because it already exhibits different shades of red and orange simply because its reflected sunlight has to pass through more of our atmosphere when it is on the horizon. That is the same thing that causes red sunrises and sunsets.

If it is clear that Saturday evening, carefully watch the eastern horizon just before the spinning earth allows us to view the moon once more. This time our only natural satellite will look like an alien planet as its dim, eerie, reddish-brown orb slowly climbs into our deepening purple-gray sky as twilight fades. It will help to see the subtle details if you use a pair of binoculars or a telescope.

You may see a faint pink band of light in the east right after sunset. That is called the Belt of Venus. Below that you will see the purplish-gray sky that you probably thought was simply the onset of night. What you are actually seeing is the shadow of the Earth projected onto our atmosphere. This only lasts for about 10 minutes and you can see this every clear night.

Saturn continues to rule the night sky, now rising a couple hours before sunset and reaching its highest point in the sky by 10 p.m. Notice that its softly glowing golden light is slowly drifting westward, in retrograde motion away from Regulus, which it will continue to do until April 19.

Venus continues to climb higher into our western evening sky. It will set 3 hours after sunset by the end of March.

Jupiter now rises around midnight in Scorpius. At magnitude minus 2, it is about 6 times brighter than Saturn. Mars rises just one and a half hours before sunrise and remains low in the eastern sky.

March 1: The moon and Saturn will be just 1 degree apart this evening.

March 3: Full moon is at 6:17 p.m. EST. A lunar eclipse happens this evening.

March 7: The moon is at apogee, or farthest from Earth today at 251,629 miles.

March 11: Last quarter moon is at 11:54 pm EDT. Daylight Savings Time starts early this year; at 2 a.m. Jupiter will be 8 degrees above and to the left of the moon this evening.

March 14: Albert Einstein was born on this day in 1879. His General Theory of Relativity, published in 1915, completely redefines gravity as simply the curvature, or topography of the fourth dimensional space-time continuum in which we all live.

March 18: New moon is at 10:43 p.m.

March 19: The moon is at perigee, or closest to the Earth at 221,845 miles.

March 20: The spring equinox is at 8:07 p.m. EDT. The slender waxing crescent moon will be just below and to the right of brilliant Venus this evening. The next evening the moon will be 12 degrees farther east along the ecliptic, placing it about the same distance above Venus.

March 22: On this day 10 years ago, Comet Hale-Bopp made its closest approach to Earth.

March 23: The first photograph of the moon was made on this day in 1840.

March 25: First quarter moon is at 2:16 pm. Comet Hyakutake made its closest approach to Earth on this day in 1996. Both of these great comets were once-in-a-lifetime events, and they happened just one year apart.

March 29: Saturn will be one degree south of the moon this evening.