Some Christmas Solstice-Searching*

The Calendar >

It's official: winter is here. We have just observed the winter solstice, a date which has both deep astronomical and cultural meaning.

Of course, winter doesn't just show up on that day; ask anyone back East and they'll tell you winter arrived a while ago and with a vengeance. In fact, by the reckoning of some, the winter solstice really marks a time more appropriately christened Midwinter.

The science-minded people will want to know what scientific significance this day could possibly have. Allow me.

Regular readers here will recall that the tilt of the earth is no insignificant thing. It gives us great climate, the seasons, and livable average temperatures --- a comfy life, to put it another way. And it's the major player here at solstice, as well. The solstice marks the day that we in North America are tilted most away from the sun in our annual trek around Old Sol.

Being tilted away of course means less of the daily sun and all those things that go with it. We experience the least amount of daylight, the lowest trek of the sun across the sky, the most oblique angle of sunlight. The sun is literally "in your face" all day long even though the "day" is short.

An observer on Earth who has been keeping tabs on the sun for the last months will have noticed the sun lowering its daily path through the sky. The solstice marks the day when it goes no lower. In fact "solstice" is from the Greek for "the stopping of the sun."

From this day on the sun will still rise in the east, but a little more northerly each day. It will traverse the heavens higher, and sink more northerly in the west. This seemingly insignificant, slow change has a profound effect on life. The daytimes get longer, the sun shines higher in the sky, and the temperatures eventually begin to rise again. There is a sense of renewal and rebirth. Spring is not far off.

 

Click here to view a QuickTime movie of the sun crossing the whole sky at Winter Solstice (888K).

This whole phenomenon was in no way missed by the ancients. One is hard-pressed to find a culture anywhere on either side of the equator that doesn't celebrate the solstice in some way.

Many ancient European peoples who had no cold, clinical knowledge of the composition of the sun or the orbits and tilts of the planets revered the sun as a god or a representative of a god. It was a mysterious life-giving celestial body, and they honored and worshipped it as such.

As the sun traveled lower through the sky during fall and finally hit bottom on solstice, they would observe annual religious rituals to please the sun god. They would then celebrate, seeing that the sun would indeed return to light the sky, and feast in anticipation that spring would come again.

A lot of the traditional things we see during this time are related to the old celebrations of the solstice, from trees to lights to Yule logs to mistletoe. But perhaps one of the most significant modern-day celebrations is directly related to the time of the solstice, if not for the same exact reason.

In AD 274, the Roman Emperor Aurelian stuck another festival into the midwinter season, one borrowed from the Syrians, when he declared the 25th of December as Dies Naralis Invicti Solis, the Birthday of the Unconquered Sun, another reference to the victory of a sun god over the impending darkness.

When Emperor Constantine converted to Christianity in the next century there was a push to eliminate the more pagan holidays and replace them with Christian ones. What better day to replace the Birthday of the Unconquered Sun, thought they, than the Birthday of the Unconquered Son, Jesus Christ?

To the Christians, the birth of the Son of God represented the beginning of the passage from darkness into light, the beginning of the end of the cold spiritual winter, the promise of new life growing out of virtual death. So declaring December 25th as the celebration of the birthday of Jesus required no stretch of the imagination.

But the old ways are hard to part with, and many still insisted on keeping some of the old pagan traditions, like those mentioned above, many of which are still celebrated today during the Christmas season.

So, yes, the winter solstice is an astronomical technicality for our civilized society, but it is also a reminder that motions in the heavens can profoundly affect our lives on the planet.

May this solstice season be a time when the marvelous Light conquers the cold darkness in our own lives. Someone say amen!

Have a great Christmas!

Mark Ritter is on a well-deserved Christmas break but normally teaches astronomy at Temecula Valley High School and can be reached at mritter@firstlightastro.com.

* (Editor's Note: The headline is meant to sound like "soul-searching" but ended up sort of not sounding like that at all. Apologies for a sub-par headline.)

Posted by Administrator at 2002.12.21 02:11 PM | Comments (0)

A Start for Winter Skywatching

Observing >

December is a special month for astronomers. Not, certainly, because of the cold temperatures and poor weather. It's special for the length of the days, or more precisely, the length of the nights.

We are now in a part of our orbit where we are tilted away from the sun and thus enjoy longer nighttimes and fewer hours of daylight. This greatly pleases astronomers. You, too, can benefit from the extra darkness.

In the skies this dark month are two of the most aesthetically pleasing lights in the Solar System --- Jupiter and Saturn. And thanks in part to the extended darkness they are both up at reasonable, pre-midnight hours for your viewing pleasure. Saturn is first up. It rises around sunset and crawls up the sky until at midnight it is almost directly overhead.

If you can find Orion, you can easily find Saturn. Find Orion's Belt, the three pretty stars all in a row in the southeastern skies in the early evening. Just to their left are his two bright shoulders. And to the left of his shoulders shining like the point of a grand triangle is golden Saturn.

Grab even a lower power telescope and check out Saturn's beautiful ring system. When you're finished being awed, take a look a Jupiter.

The Great One doesn't rise in the east until the 9 o'clock hour and doesn't really get into a good position to view through a scope until a couple hours later. But if you have the time and scope, he's worth a look.

Around Mighty Jove ride the four Galilean satellites, first discovered by Galileo more than three centuries ago and twinkling still like four little stars around a parent.

While you're absorbing the beauty of the stellar scenery, take a look just below Orion's Belt at a famous fuzzy area, the Orion Nebula, a very busy stellar maternity ward. Here stars are being birthed left and right. An older family of child stars is just above the whole Orion constellation, the well-known Pleiades star cluster.

Now for those of you up for an astronomical challenge, I challenge you to find a red beast of a star near the Pleiades. This star is as bright as almost 6000 suns, and over 200 times bigger! Should be easy to find, right? Sorta.

This giant is also over 65 light years away. That's about 350 trillion miles if you're planning a trip. That great distance means a great dimming of its light. But it is still prominent and still reddish in color. Can you find it?

Like its neighbors, the Pleiades, it is in the constellation Taurus the Bull. Find the lone, bright pinkish star between Orion and the Pleiades.

That is our star, Aldebaran, the red eye of the Bull. It is giant and red precisely because it's at that stage of its life called --- surprise! --- the Red Giant stage.

Red Giants are stars gasping their last breaths. They have used up their hydrogen fuel and are now desperately burning other elements in an attempt to beat back the inward crush of gravity.

Alas! Gravity will beat Aldebaran in the end. Go see it now because in several million years there will be no Aldebaran.

That's just a start for winter skywatching, friends. Peering around with binoculars you can see dozens of other beauties --- star clusters and nebulae and binary systems.

Commit yourself now to take advantage of our extended darkness and get to know the glorious winter skies.

Mark Ritter has helpful star charts to help you find these objects at http://firstlightastro.com and can be reached at mritter@firstlightastro.com

Posted by Administrator at 2002.12. 7 02:15 PM | Comments (0)