It’s Groundhog Day!  I know…it’s hard to contain your excitement.  It’s that day each year when a mammal is held up in front of a crowd of people.  If it’s a sunny day and the groundhog cared about such things, he could see his shadow and we would have more wintery weeks ahead.  If the sun was blocked, no shadow and thus spring would arrive soon.  A bit of a strange ritual.  But it actually has roots that go back a long way.

Groundhog Day began centuries ago as a variation on Candlemas, an ancient European holiday.  According to an old English song:

If Candlemas be fair and bright,
Come, Winter, have another flight;
If Candlemas brings clouds and rain,
Go Winter, and come not again.

The early Germans appear to be the first ones to adopt the use of an animal, specifically a hedgehog in their celebration, perhaps due to animals often being able to detect weather changes and other events before humans.  Many of Pennsylvania’s earliest settlers were Germans and brought the traditions with them, adapting the similar groundhog to the role.

But then we have to wonder, what’s so special about that day that makes it the source of all these traditions?  Well, it’s actually the same reason for our celebrations of Halloween.  These are surviving Pagan holidays known as Cross-quarter Days.  They occur in the middle of a season, between the solstices and equinoxes.  February 2nd is approximately the middle point between the Winter Solstice (Dec. 21st) and the Spring Equinox (March 20th).  Think about it this way…have you ever wondered why Winter begins on Dec. 21st, but it feels like Winter well before that?  It always seems like we get the first snow of the year on Halloween…a cross-quarter day.  They were originally the markers of the beginnings of the seasons.  But, over the years, their significance was lost compared to their more astronomically important cousins and the more significant celebrations that occurred at those times.

Paying homage to "Groundhog Day" on this chilly day in February. Image from the 1993 Columbia Pictures film.

In the end though, if I were to stand outside this morning holding a rodent up and looking for its shadow, I should remember that I live in one of those weird mountain states.  Seasons seem to do whatever they feel like, fluctuating between Summer and Winter from one day to the next.

But that doesn’t make the holiday any less fun to celebrate.  Have a safe and fun Groundhog Day, Candlemas Day, Cross-quarter Day, or Wednesday…whichever you like best.

The stars of Orion make for one of the most recognizable constellations in the winter sky

Many of us can instinctively pick out Orion because of its three prominent “belt stars” arranged in a convenient line, surrounded by four more bright stars representing the character’s shoulders and knees. But its notoriety comes from other factors as well. It may have been known as a “mighty hunter” to both the Greeks but many other cultures had celebrated descriptions for this group as well. One of my favorite representations of Orion comes from the Tewa People, who referred to Orion as their Chief Long Sash. Long Sash was remembered for leading his people westward to a new land away from their enemies who were constantly raiding their villages. It’s a wonderful story about perseverance, equality and humility – highly valued traits of the Tewa Pueblo People.

The bright reddish star in Orion’s shoulder is sometimes called “Beetlejuice” (like the movie), because it’s true name is “Betelgeuse” (an ancient Arabic word that roughly translates into “Armpit of the Mighty One”!). And, Orion’s sword contains one of the most famous nebulas in the sky – The Orion Nebula, a massive cloud of dust and gas giving birth to hundreds of new stars.

We’ll present some special features of this constellation on our dome that you can’t experience on any computer screen or movie, but we’ll also show how the pattern of Orion itself can make for one of the best guideposts to the Winter sky. Selected stars in this constellation can act like “pointers” to other major stars and deep sky wonders, many visible to the naked eye or binoculars.

Get ready for a multitude of astronomical treats. From Orion to the “Dog Star,” Taurus to the “The Seven Sisters,” this is the season for celestial riches!

Tickets for this presentation are $1 at the ticket window or $2 online. Members are free.

Of the 38 Mars mission launched from Earth so far, exactly half of them arrived at Mars in operating condition.

A case in point is the Russian “Fobos/Grunt” (in English we would call it “Phobos/Soil”) mission launched last November that was intended to land on one of Mars’ moons, Phobos, scoop up some surface material, and then rocket the sample back to Earth. Total round-trip time: three years.

Sadly, just a couple of hours after launch the rocket motor that was supposed to send Fobos/Grunt from low Earth orbit to Mars failed to fire and ground controllers lost contact with the spacecraft.

Fobos/Grunt is now a derelict fourteen-ton spacecraft in a deteriorating orbit, destined to burn up in the atmosphere sometime between now and Monday.

The Fobos/Grunt Spacecraft - now just so much junk.

Most of the spacecraft’s mass is its eleven tons of fuel. True, that’s a lot of toxic chemicals, but the fuel will most likely vaporize quickly very high in the atmosphere upon reentry.

Only about three tons of actual hard metal will survive the initial 18,000 mph encounter with our atmosphere, and only about 400-500 pounds of the spacecraft is expected to survive the fiery reentry and make it all the way to Earth’s surface.

There is almost zero chance that Fobos/Grunt falling from the sky will injure anyone or cause damage. After all, three-quarters of the world is covered by oceans, so right there you see there’s only a one-in-four chance of the spacecraft even hitting land.

Earth is a big place, and humans represent a teensy-tiny portion of the surface area. The chances of a piece of Fobos/Grunt hitting a human being are on the order of one in a thousand, and the chances of you being hit are something like one in million-million.

Update: Fobos/Grunt fell harmlessly into the southern Pacific Ocean at about 10:45 MST on Sunday, January 15, about 600 miles west of Chile. See? Told ya.

This phenomenon of dead satellites in low-Earth orbit creating problems for us is the subject of Clark Planetarium’s next ATK IMAX theatre documentary film. It’s titled, appropriately enough, “Space Junk 3D.” We’ll have more information about this film later in the month.

Taurus the Bull winter constellation

The cold weather might seem like a deterrent to winter stargazing but it can actually be quite enjoyable and rewarding with just a little preparation. Before going outside, check out the locations of the objects you want to observe. That will help you find them quickly and easily. Star dome charts and star maps are readily available online, or you can get night sky software that allows you to customize the view for your location and time.

Also, remember the first rule of observing: Make yourself comfortable! Plenty of warm clothing (especially thin, warm gloves for handling cold metal binoculars or telescope eyepieces). Occasional breaks for hot cocoa (Earl Grey works for me!). A red-filtered flashlight for reading charts outside. And position your viewing spot so that bright lights are blocked by trees, buildings, etc.

Ok so now that you’re all comfy, what are your celestial rewards? The three stars of Orion’s Belt are making their appearance in the eastern sky, making for one of the best “pointers” in the winter sky. Draw them upward and to the right and you’ll find Aldebaran, the fiery orange eye of Taurus the Bull. But keep that imaginary line going still higher and you’ll find the most famous winter star cluster of all – the Pleiades (commonly known as “The Seven Sisters”). There are many legends connected to the Pleiades, but one of my favorites come from the Chippewa People called “The Seven Dancing Brothers.” We will retell this story in the show.

What are the Pleiades in actual outer space? What about Venus and Jupiter? What else is in the January sky? Come join us for “Gateway to the Stars” Saturday, Jan. 7 at 6:45 p.m. and see for yourself!

Tickets for this presentation are $1 at the ticket window or $2 online. Members are free.

Okay, so it’s not a commonly-celebrated event. Nevertheless, January 4th, 2012 is a significant date for the year, at least astronomically. Perihelion occurs on Wednesday, January 4th, 2012. This marks the time when the Earth is closest to the Sun for the year. Yes, I said closest. ‘Peri’ comes from the French for ‘near to,’ and ‘helion’ comes from the Greek for ‘Sun.’

Many people believe, mistakenly, that the Earth is farthest from the Sun in winter. However, we need to realize that when it is winter in the northern hemisphere it is summer in the southern hemisphere, and vice versa.

Earth (and every other planet) orbits the Sun in an elliptical orbit, not in a circular one. So, there will be one moment of the year when the Earth is closest to the Sun and another moment in the year when the Earth is farthest from the Sun. Those moments are known as perihelion and aphelion, respectively; and always occur around January 4th and July 4th, respectively.

Perihelion 2012

The difference in distance from the Sun between these two dates is rather small, around 5 million km, and has little noticeable effect on temperatures.

Here in Utah (and the intermountain west) we may get a brief glimpse of the beginning of the eclipse in the early morning hours. It really depends on where you live and your view of the western horizon.

The umbral phase of the eclipse begins about 5:45 am, MST; with totality beginning about 7:06 am, MST. Unfortunately, moonset is about 7:45 am, MST on a flat horizon. For the Salt Lake valley, with the Oquirrh Mountains to the west, we will miss totality, but may get a glimpse of the early stages of the eclipse.

Moonset on western horizon as eclipse begins

A total lunar eclipse occurs when the Moon passes through the shadow cast by the Earth out into space. This means that we must be at Full Moon, and the Moon must be in line with the Sun and Earth at that time.

There are no total lunar eclipses for 2012. However, we are in for two rare events next year. There is an annular solar eclipse for observers in the western US and Canada on May 20th, 2012. Even more exciting is the coming transit of Venus on June 5th/6th (depending on where you live). More on these event as we get into 2012.

On the morning of December 10, the Moon will move through Earth’s shadow producing a total lunar eclipse. For observers in Utah, the Moon will set about the time of greatest eclipse. Sharp-eyed observers should detect the Moon entering into Earth’s umbral shadow at 5:46 a.m. Look for the Moon in the west, about 20 degrees above the horizon. Totality begins at 7:06 a.m. At this time the Moon will appear about 5 degrees above the horizon and could be hidden behind mountains from some observing locations. Moonset for a flat horizon is 7:44 a.m. For the longest view of the eclipse, find an observing location with a clear horizon in the west-northwest.

Geometry of a lunar eclipse

Meteor showers occur when Earth passes through a stream of debris given off by a comet. Particles that make up this debris stream typically range in size from pebbles to sand grains. As they enter Earth’s upper atmosphere at high speeds, they vaporize 50 miles above our heads, producing the slivers of light streaking across the sky that we call a meteor or “shooting star”.

Geminid meteor shower courtesy of National Geographic

Astronomers began searching for a comet as a source of the particles. Their search was unsuccessful until 1983, when NASA’s Infra-Red Astronomy Satellite (IRAS) spotted an object, several miles across, moving in about the same orbit as the Geminid debris stream. The object was named 3200 Phaethon. Oddly, Phaetheon seems more like an asteroid. It is rocky, not icy, and has no obvious tail. If Phaethon is an asteroid, how did it produce a stream of particles? Several possible explanations have been proposed. None are completely satisfactory. The mystery continues.

On a dark, moonless night, the Geminid meteor shower can produce as many as 120 meteors per hour for observers far away from city lights. However, this year the meteor shower occurs four days after the full moon. So, moonlight from a waning gibbous moon should greatly reduce the number of visible meteors. The shower peaks on December 14 at 11 a.m. MST, so observers in Utah should look on the nights of the 13th and 14th.

During the first half of November the planets Mercury and Venus will appear close to each other in the evening sky. The challenge is seeing them. The difficulty arises from the geometric relationship between Earth’s axis tilt and its orbit at this time of year. This particular geometry results in a shallow viewing angle between the horizon and the orbital planes of planets in the evening sky (in the morning sky the angle is much larger). This means Venus and Mercury will appear low in the sky after sunset.

Finding them in the twilight so close to the horizon can be a challenge. Look for the pair in the southwest right after sunset. Binoculars can be a great help in searching for them. Venus is the brighter of the two. Mercury will appear about 2 degrees below Venus (an index finger held at arm’s length has an apparent width of about 2 degrees).

Looking southwest from Salt Lake City on November 4 at 6:10 p.m.

Other astronomical happenings in November:

We will experience a 25 hour day on Sunday, November 6 as Daylight Saving Time ends.

The Leonid meteor shower peaks on the evening of November 17, but light from a last quarter moon will interfere with the view for those observing after midnight.

Blog readers in Antarctica will have the opportunity to observe a partial solar eclipse on November 25.

I walked down the road to the trail and as I neared where I thought the entry point should be, I saw many footprints in the sand. I knew I was entering the trail a bit early, but figured that it had probably seen several groups of hikers in recent days—so I took it. After about 20 minutes of rapid hiking, I got to the edge of the cliff face. There was no way to enter the canyon from there, so I walked to my left, knowing I’d intersect the real trail and just follow it in. Three loops and an hour and ten minutes later, I stumbled across the real trail while hiking back out after having given up. I had to race to get to the proper location and get set up before the moonlight from the waning crescent moon became too intense (it never did). Since my entire hike occurred in the dark (pitch black, except for the stars), I was very thankful to eventually arrive at my destination.

Much to my surprise, the moon was too dim and too low to provide the light I needed on the canyon below—that is until I had been there for another hour. I spent that time taking one test shot after another, tweaking the alignment, and shooting again. It just never seemed to be quite right. It took so long that I then had to move my equipment to maintain the shot…and realign again. Thankfully it went better this time. I shot several singles and this shot which is a series of 5 shots stitched together. Lighting was done with the same 1,000,000 spot light, which was very tricky because some of the rocks in the shot are only about six feet away while others are fifty feet from the camera. By the time I finished, the moon had risen high enough in back of the Kiva that it was nicely lighting the entire valley. The small stringer of clouds was the only one in the sky and seemed to appear at the most inopportune time, although it did add a splash of color to the scene. Had I been able to get the shot earlier, the whole Milky Way would have appeared farther to the left. Soon after I finished, the galactic core disappeared behind the large formation to the right. Hiking out in the darkness was made slightly easier due to the scant amount of moonlight. An hour’s sleep in my car as the sun rose and it was time to head for home.

Heritage Starfest 2010 courtesy of Mark Bailey

This is a free community sponsored event that will be held primarily at the Wayne County Community Center in Bicknell, Utah.  Starfest kicks off with family activities Friday evening once it gets dark: telescope viewing, constellation tours, and night sky walks. Saturday afternoon there will be opportunities to learn about astronomy and the importance of dark skies.  Saturday evening there will be stories around the campfire and, of course, more stargazing.

Heritage Starfest 2010 courtesy of Annette Lamb

If you don’t have your own telescope you can register to use one set up by Starfest volunteers. Download a map to the event location and activities at the 2011 Heritage Starfest.