We are now at "midwinter," as this time of year is known to many people. The nights are longest, the days are shortest, and, when we have clear skies, the starry hosts are beautiful. There are mighty Orion and his dog. Over there are Taurus the Bull and the Seven Sisters. The whole majesty of the winter heavens complements beautifully the other riches of the season.

But, alas, it will not last. The very celestial winter artwork that we love so much is destined to leave these skies relatively soon. But how?

Wobble is to blame. Yes, wobble. The earth is wobbling and very soon, on an astronomical time scale, our wintery constellations will be replaced with those from summer. Here is how it works.

We all know our planet rotates to give us day and night. And it revolves around the sun to give us our year. But it also wobbles. Have you ever spun a top on a table and observed it wobbling around as it spun down? The Earth does that, too. Only it takes a long time to wobble, or "precess" in astrospeak. In fact, it takes about 26,000 years to wobble around just one time!

How does this affect the constellations? Well, right now we are at the point of our orbit where we in the north are tilted most away from our sun. Hence, winter. And the stars in that night sky - when we are tilted most away - are the stars we see now.

Ok, now I need you to use your imagination. In your mind's eye, stop the Earth from going around the sun. Allow it to wobble half way round. Now we in the north are tilted towards the sun, right? It is our summer, but the constellations of Orion and Taurus and the rest of the gang are still in that future Earth's night sky. But they are now summer constellations, gone from our holiday skies!

This half wobble will take half of the 26,000 years, or 13,000 years. Then our present summer constellations will be up in winter; our winter constellations will be up in summer.

Of course we humans can reshape our malleable calendar so that the tilt-away time will always be in December and the tilt-towards time will always be in June, but there is no such manipulation of the stars. They are where they are.

So enjoy our winter constellations while you can! Over the next thousands of years they will be slowly and stealthily sneaking through other seasons thanks to our precessing planet. And before you know it, Scorpius and Sagittarius will be headlining our holiday heavens! Yikes!

The best and most meaningful holiday season to you all!

There is a famous constellation in the winter sky called Orion, the Hunter. It has some real tourist sights for the backyard astronomer. There you'll find the well-known Orion Nebula, filled with brand new baby stars. There is bright Rigel, a blue supergiant star many times bigger and more luminous than our sun. Orion's Belt is made of three extremely bright and lethal stars which are, thankfully, very far away. The famous Horsehead Nebula is located at Alnitak, the lowest of the belt stars.

But one site that stands out prominently in Orion is the great star, Betelgeuse, the bright, pinkish star located farthest to the "left" in the evening at this time of the year. Why is it that color? What's going on? And why the funny name?

The reason for the funny name is probably harder to nail down than why it is that color. Back in Medieval days, the Arabs played a huge role in naming the stars. Many of their star names are with us even today. Most all stars, for example, that start with Al- are arabic in origin, like Aldebaran, Alcor, and Alnilam.

Believe it or not, the jury is still out on the origin of the name Betelgeuse. The common myth, which may be true, is that the name derives from the arabic for something like "armpit of the giant." But since the name travelled through Europe during the Renaissance, some believe it was tweaked so often over time that the present name is corrupted beyond recognition. That may be so, but Armpit of the Giant fits Betelgeuse perfectly, in my humble opinion.

Betelgeuse is a star in the last throes of life. It is a red supergiant. What is that?

When a large star finishes its life, when it finally runs out of fuel in its core, it starts going through some funky elemental gymnastics down at its core. To make a very complicated story very short, the core of the great star gets really, really hot which expands the outer layers of the star very, very far.

How far? In the case of Betelgeuse it is believed that the star has expanded to more than 1000 times the size of our sun. If it were put in our sun's place it would swallow all the planets out to Jupiter.

When a gas expands that much its surface cools, and "cool" to a physicist means reddish in color. Hence, Betelgeuse is classified as a red supergiant. You can detect its redness in its obvious pinkish hue.

Just a little heads up: Betelgeuse is scheduled to supernova - explode in the worst way - in the next million years or so. It's far enough away that it won't do us much harm. But when it does, it will outshine all the other sites Orion has to offer - by far.

Until next time, clear skies!

For many of us Thanksgiving is already a distant memory. The football games are over, the family has departed. Our only reminders may be a few leftovers in the refrigerator.

My personal philosophy is that we should be thankful continuously - not just on one day of the year. How can we use the skies above to remind us to be thankful for what we have? Here are just a few of literally hundreds of ways.

The sun is going to rise later, set earlier, and travel lower in the skies for the next month. This may make things gloomier here, but Down Under they are enjoying the warmth of summer. However, because of Earth's ideal tilt, as we go into the new year our daytimes will begin to get longer and the sun will be higher as we head towards spring. We can be thankful for a tilt that gives us this annual hope for spring and new life, and also allows most of the planet to get a nice distribution of seasons.

Every day the sun rises in the east and sets 10-14 hours later for us over in the west. It is because of our 24-hour spin that we have this. Shorter, faster days would give us very uncomfortable winds and weather. A slower spin of the planet means obnoxiously hot daytimes and freezing cold nighttimes. We can be daily thankful for this seemingly mundane phenomenon - the rising and setting of the sun every 24 hours.

The stars in the sky are beautiful to be sure, but we can nightly be thankful that they are where they are. Our starry neighborhood, those stars nearby, are mostly invisible to the naked eye and are almost all dull, boring stars, lacking in fiery excitement. Most of the stars we see at night are terrifyingly dangerous stars but are so far away they pose little to no threat. I can be thankful for boring, invisible, nonlethal neighbors every night I look up.

We can see the sun and moon every day and be grateful for them. The sun is the ideal size, distance, color, age, composition, type, and temperament for us to enjoy life on Earth. The moon is just the right distance and composition to stabilize our tilt and length of day. They are both godsends.

The very air we are immersed in is an ideal combination of gases found as of yet nowhere else. There are many causes for this wonderful mixture but one is that our planet is just the right mass, and thus has the just-right gravity to hold on to such a mix. I am grateful for all of that.

Daily life among humans can be tough, to be sure, but the physical creation surrounding us drowns us in an ocean of reasons to be thankful - not just one day of the year, but every day.

Until next time, clear skies!

Ready to have a little fun? Here is a small quiz about what's going on in the sky in November. See how much you know, and have fun doing it!

T/F The bright beacon of a light in the west just after sundown is Jupiter.

Regular readers here will recall that Jupiter is near opposition now, over on the other side from the sun. It is the bright planet rising in the east at sundown. The big luminous beauty near the sun as it sets is actually Venus, making a return appearance after spending a while behind the sun. Watch how she climbs higher in the sky over the next months.

T/F In a few days the moon will be at Third Quarter. That means it is only about one "quarter" away from being full.

That sounds kind of right, huh? But "third quarter" means it is three quarters of its way around the Earth, with the "start" time being the New Moon, the time when the Moon is between Earth and sun. Using New Moon as a starting point - not the Full Moon - our satellite travels around the earth reaching First Quarter after a week. After another week it is on the opposite side as the sun and is now "full." A week later it is three quarters the way around the earth. One full month after it started, more accurately 29.5 days, it is back to New.

T/F The only time we can see a Leonid meteor is on the night of the shower, late night on the 17th, early morning of the 18th.

When we have a meteor shower we are passing through the debris train of a comet whose orbit intersects ours. As we pass through it, the sand-sized particles hit our atmosphere at dozens of miles per second lighting up as they vaporize. Those are the meteors we see. But it takes sometimes weeks to move through the dust train. So we can have meteors from that particular comet dust trail for a week or two before and after the official "peak." Go out tonight and you might see a Leonid meteor days before the official peak later this week.

T/F Both Neptune and Uranus are in the skies above us this month and can easily be seen with the naked eye if you know where to look.

Uranus and Neptune were discovered only after the invention of the telescope. That is a big clue as to how easy they are to see. They're not. Before the telescope, people from time immemorial only knew of the big five: Mercury, Venus, Mars, Jupiter and Saturn. Can you see the two new kids on the block, Uranus and Neptune? Sure, but you'll need at least a backyard telescope and a star chart to find them.

How did you do? No matter. If you learned something, we all passed with flying colors.

Somehow in all the turbulence of our world events and economic disasters and hectic personal lives, an annual event got passed over entirely - again. Jupiter was in opposition and no one even noticed!

It's OK. It's just a few days past and, for all intents and purposes, Jupiter is still in opposition. But what is that, and so what?

Opposition is the term astronomers give to the position of a planet when it is on the exact opposite side of the earth as the sun is. One can draw almost a straight line from sun to earth to a planet in opposition. Because of this, we can see this planet rising in the east at the same time the sun is setting in the west.

And that's exactly what will happen this evening at sunset. Go out in the early evening, soon after sunset, and observe that big bright brother of ours rising brilliantly in the east.

Another way of looking at opposition is the time we pass an outside planet on our inside lane around the sun. Two things result from this.

One is that we are now closest to that planet than ever. In Jupiter's case that means we are a mere 372 million miles away from it. For astronomers that is a wonderful thing. We now see Jupiter as up-close-and-personal as we can from Earth. It's the best time for you who own a telescope to go see Jupiter's parallel weather patterns and, if the conditions are right, the famous Great Red Spot. These are great weeks for espying the Great One.

Another more subtle phenomena that happens around opposition is called retrograde. This is a kooky backwards movement of the planet through the skies, observed by astute sky watchers since ancient times.

Normally a planet would seem to crawl ever so slowly, night after night, week after week, eastward through the background stars. But once a year the planet would slow its trek to a stop, reverse direction for a spell, then turn back again onto its normal path. This strange phenomenon was christened retrograde.

It was eventually explained as nothing more than an illusion resulting from our passing an outer planet from our closer, faster orbit. This makes it appear that the slower planet is temporarily moving backwards.

Well, Jupiter is in retrograde now. The more patient readers here may notice Jupiter over the next couple months creeping westward through the faint background stars, then switching direction once we are in the new year.

Go out tonight and catch a glimpse of the great gas giant, and if time and schedule allow for the next months, follow its dance through the stars in the skies above.