Thursday, July 31, 2008

What I loved best about my Summer Astronomy Adventure

By C. Zaitz

I only noticed the thin air when I was either walking up a hill or getting excited.
This night I was doing both. A week from when we arrived in Arizona on a ten day “Astronomy Adventure,” a dream finally came true. I was walking up hill to an observatory, excited and breathless, ready to spend five hours shadowing astronomers and telescope operators on their jobs.

On the first night, the two astronomers whom we met were very polite and welcoming to us. My partner and I were very thrilled to be there and a little “starstruck” to be in the big leagues, which may have reassured them that we wouldn’t hamper their work. Our main guide was very talkative and funny, giving us humorous glimpses into what goes on in the dome all night long, and how he keeps himself awake when we hits the “wall” in the wee hours of the morning. The other astronomer, a young grad student, was nice enough to draw me pictures of her research on intermediate Seyfert Galaxies. These are galaxies with extremely bright cores, thought to be gigantic black holes. Her research had to do with figuring out the orientation of these galaxies, since the hot topic in AGNs or Active Galactic Nuclei galaxies is that they may be the one object behind three faces; we’ve seen them as quasars, blazars and Seyferts depending on their orientation.

The astronomers also operated the telescope, and watching them do that was also awe inspiring. Though we didn’t get to look through the instrument ( we had to bite our tongues not to call them “scopes!”) we got an excellent view into what makes a research astronomer tick. I will take that glimpse back into the classroom to enrich the picture I paint about what scientists can do for a career.

Friday, July 11, 2008

Where Are the Stars?

5/11/08 – 5/17/08
by C. Zaitz

We tend to think of the night sky as having an infinite number of stars, but in all reality we can only see one or two hundred in our local sky. This fact seems to contradict poems and prose that refer to the sky full of "countless stars." So where are all the stars?

From earth, we see the individual stars that make up the familiar constellations like Orion and Leo. Stars like Betelgeuse and Sirius are either fairly close, or really big, or both. They appear much brighter than the rest of the stars in the sky. They are so noticeable that they were granted proper names, rather than just catalogue numbers like the rest of the visible stars. But there are only a few hundred bright stars with proper names. The rest are either just too far away, too faint and unnoticeable. We see them as the blurry path in the sky called the Milky Way.

When we look up at night, nearly everything we can see is part of our galaxy. The Milky Way is home to several hundred billion stars in different stages of life and death. We only see several hundred of them when we look up at night due to light pollution from sources like civilization and the moon. On a dark, clear night away from a metropolitan area, maybe thousands of stars are visible. But where are the rest of them? Where are the other billions?

Our galaxy is a flat disk of stars with a bulge in the middle, like a flying saucer made out of sand. Each “sand grain” is a star like our sun, but there are other things in the galaxy, like clouds of gas and dust called nebulae. These clouds might be stars waiting to form, or stars that have exploded. Often when these giant clouds form stars, they form in big groups called clusters. When you put honey into a bowl of granola, the granola clumps around the honey. Imagine that gravity is the honey. Gravity causes the gas to clump and out of the clumps are born stars. Most stars that you see in the sky formed in groups, but over time they scatter. Our own sun seems to stand alone, but most likely formed in a group of stars that long ago scattered. Most of the stars in the Milky Way are too far away for us to see individually now. They are scattered throughout the galaxy, which is over 100,000 light years end to end.

Other clouds are from stars that have exploded, flinging their gas and dust back whence they came; cold, empty space. Dark clouds or nebulae block light from stars beyond them. As we look along the galaxy, along the flat disk of milky faraway stars, we can detect these dark clouds. They look like dark smoke hiding the bright stars behind them. The best time to see the dark clouds and stars of our galaxy is in the summer time. The Milky Way looks like a swath of milky light stretching from north to south overhead, but only from places where there are very few lights, or on an evening with no moon. Summer time is a good time because we often get to leave our cities and find places with fewer lights, lower populations, and a much better view of our home galaxy.
You may not see the billions of stars, but you'll get enough starlight in your eyes to appreciate our tiny place in the vast galaxy, the Milky Way.

Until next week, my friends, enjoy the view.

Saturday, July 05, 2008

Jewels in the Spring Sky

4/20/08 – 4/26/08
by C. Zaitz

If you like sparkly things, there is something in the spring sky worth looking at. We’ve been used to dashing from car to work, and back home, without so much as a quick glance skyward all winter long. But now we’re beginning to walk and jog after work, to play with the kids and the dog in the yard, and to notice the outdoors a little more. So what are we seeing in our spring sky? On spring evenings, the stars can glitter wildly as the moving air blinks and twinkles their light. Moving air causes the light from distant stars to jump around and blink on and off like Christmas lights. As pretty as it looks, it makes the image in a telescope look blurry. But when the wind dies down and the temperature rises, there are some spectacular sights to be seen. Two that I'd like to describe look like fuzzy blobs in the sky, but turn spectacular jewels through a telescope.

The first is a very famous fuzzy blotch that is very hard to see with the naked eye, but is one of the most popular destinations for telescopes and binoculars. It is called M-13, but we know it better as the Hercules Cluster. It is a giant group of stars called a globular cluster. Globular clusters are common in galaxies, but they are rebels in a sense. They don't generally ride the spiral arms of the galaxy like the rest of the stars. They can be found high above or below the plane of the Milky Way, in its halo. Spring is an excellent time to spot globular clusters, because we are looking out away from the plane of the galaxy, to the halo area where they live. The Hercules cluster is home to over a million stars, but the true beauty of the cluster comes from the fact that the stars are much closer together than stars in the rest of the galaxy. Instead of a 3 light year average separation, the stars of M13 are on average only one light year apart, making the cluster dense and very brightly sparkly. It's a trick I would use if I was a jeweler and had diamonds to set. The dense packing of stars in a globular cluster make them some of the most beautiful objects to see.

Another famous cluster seen in the spring is M44, known as the Beehive cluster. It is just in front of the sickle shape of stars that marks the head of Leo the Lion. It is one of the nearest and largest open clusters we can see, and therefore one of the brightest. You can see its fuzzy glow with the naked eye, but both clusters really shine when you view them through a telescope. Their true nature will be revealed as you begin to see the individuals making up these vast clouds of stars. Open clusters are made of young, hot, blue stars, and live in the plane of our galaxy, so they are different in appearance and make-up from globular clusters. If I were trying to match their character as a jeweler, I would select the brightest and clearest diamonds to set in a less dense, but still brilliant way.

To find these beautiful objects, it's always good to know your way around the sky. If you spend a little time in the spring with a flashlight and star map, you can see them for yourself. And who couldn't use some sparkly in their life?

Until next week, my friends, enjoy the view.

Sunday, April 06, 2008

What a Little Starlight Can Do

4/7/08 – 4/13/08
by C. Zaitz

When you look up at the night sky, you may have an emotional experience from the sheer beauty of the stars, but you are having a physical experience as well. Your eyes are taking in photons of light streaming from distant objects that are undergoing intense nuclear fusion. You gotta feel that!

I’m being playful, but the truth is, starlight packs a punch. We get a host of information from a little starlight. For example, when we see Betelgeuse in the eastward shoulder of Orion, it beams down faintly peach colored light to us. From this light we can deduce that Betelgeuse is a reddish star. Rigel, in the foot of Orion, shines bright white, almost blueish. Rigel is called a blue star. Each star has its own designer color.

The faint splash of color we detect with eyes can be amplified by a telescope. Through one, you can really tell that Betelgeuse is a red star. From that we can deduce its temperature, size, age and magnitude, since there is a relationship between all these characteristics. That’s a lot of information from a little starlight. If we had eyeballs shaped like prisms rather than marbles, we would be able to see even further into the starlight. The light would spread out into a spectrum- a rainbow of colors! Even better, we would see shadowy bars in the pretty band of color which tells us what the star is made of. It turns out that each element in nature has a fingerprint, and it shows up as dark lines in the colorful spectra of the star. The pattern identifies helium and carbon atoms as accurately as fingerprints identify people.

Once we know what the star is made of, know its color and therefore temperature and magnitude, we can reconstruct the star’s story from birth, through midlife, and even death. We know that stars like Betelgeuse are the “Elvis” stars; they burn brightest and hottest, but have short lives and die spectacular deaths. They only live millions of years, endure supernovae explosions, and end as pulsars or black holes. This will not happen to stars like our Sun. Smaller stars don’t have it in them to explode. The best they can hope for after a life of billions of years is to shed their outer layers and die a more peaceful, wasting away kind of death. Neither scenario is lucky for any planets orbiting, but both are inevitable. And all fates are written indelibly on the light we get from the star.

One even more powerful aspect to starlight is that it contains the information and history of the star from birth to death, like an endless movie. The second the star “turns on” by fusing atoms, its shines at the speed of light and on the light is a record of the star at that moment. When Betelgeuse dies its inevitable explosive death, we will have to wait the 400 plus years it will take for the light from the explosion to reach us. But it will be worth the wait. In the light from the explosion will be written the story of the creation of new elements; in the death of one star a story of future stars begins.

Until next week, my friends, enjoy the view.

Friday, March 28, 2008

Gamma Ray Bursts

3/30/08 – 4/5/08
by C. Zaitz

Even though we think of the sky as having countless stars, it turns out we can only see several hundred of them due to light pollution. In fact, our Milky Way galaxy contains several hundred billion stars. Only in very dark skies can you see anything beyond the Milky Way. Until recently, our sibling galaxies, the Triangulum and Andromeda, were the most distant objects visible to the naked eye, at a distance between two to three million light years. Recently, something even more distant was seen. Though it was only slightly brighter than the faintest stars visible to us, it was very distant, and very old, light. At a staggering seven and a half billion light years away it was still seen, if even for seconds, and if you knew where to look.

What was this fleeting image? It was a bright gamma ray burst. Gamma rays are the most energetic form of “light” or electromagnetic energy. Gamma rays are produced by all stars, but when a huge star dies, it often produces prodigious amounts of them as it collapses. Astronomers think that these gamma ray bursts we see all around us are the relics of the deaths of some of the very first stars formed in the early universe. When they die, they go out with a big flash.

The incredible thing about gamma bursts we detect is that they are all very distant, but incredibly powerful and bright, much brighter than anything known in the universe. But they are not bright in all directions. The reason they can show up looking so luminous after seven and a half billion years of travel in a stretching universe is because the energy is bundled into relatively narrow columns. The energy streams out like a beacon from a lighthouse and if earth happens to lie along its route through the universe, we will catch a glimpse of it.

Astronomers are very interested in spying gamma ray bursts because they could tell us more about the early universe. Bursts of high energy rays are very harmful to humans, so it’s providential that air stops gamma and x-rays from getting to us. But it also makes them hard to find. Currently NASA has a telescope in orbit called Swift that scans the universe for gamma ray bursts. The problem with gamma rays is that they are much more energetic than visible light waves, and they don’t give a very accurate image of what they are detecting. It’s like trying to draw a picture using a shotgun rather than a pencil. In order to pinpoint where the bursts come from, we have to coordinate space and earth telescopes. So astronomers on earth are tied into Swift’s detectors. Once the gamma rays are detected, astronomers know about it and telescopes on earth can search the same area for visible light, which sometimes accompanies the bursts. Once we find them, we can study the information the bursts give us and map them.

Even though the bursts aren’t around for long, they do give us an incredible look at our past, into a time where the universe was dominated by giant hydrogen stars and was much smaller than it is today. It’s a universe that is continually changing, and revealing itself to us a burst at a time.

Wednesday, March 19, 2008

Space Flight

3/23/08 – 3/29/08
by C. Zaitz

Do you ever look at a bird and wonder how it flies? Or even better, wonder why you can’t? I wondered that the other day watching a hawk swooping and scooping air with its wings. I remembered Icarus of ancient mythology, the man who wore wings so he could fly. The higher he went, the more his giant wings made of wax and feathers melted from the high temperature of the sun.

In modern terms, the story makes no sense at all. First, if Icarus was confined to flying in the sky, he would have gotten colder, not warmer, as he flew higher. Second, if he had actually broken free and reached escape velocity by flapping his home-made wings, he would also have escaped the means of his flight- air pressure! Birds and planes rely on moving air to stay aloft. In space, there is no air, and thus no flight by wing. But the Greeks didn’t know this, and Icarus tumbled to earth with the melted wax and feathers all akimbo, a testament to man’s hubris and the punishment for flying too high.

Nature may not have gifted us with the ability to fly, but she did endow us with giant brains to figure out how to build devices that fly. In space, we have to use different principles to get around. One elegant solution was proposed long ago by Johannes Kepler. He noticed that comet tails were pushed back away from the sun by some force, and proposed that humans could catch that “breeze” to sail the solar system. Centuries later, the idea was proven true. Pressure from photons streaming from the sun can actually accelerate a thin, lightweight material, like a solar sail, to speeds that eventually could outrun our best traditional rockets. The key to their success, however, is patience.

If our traditional rockets are hares, solar sails are the tortoises of space travel. Since they are collecting ephemeral starlight, it takes a long time to get up a full head of steam to go fast. It’s a continual acceleration, unlike traditional rockets that blast off in a hurry but eventually run out of fuel. It may take a while to get “sailing”, but once it does, it will win the race!

Due to the nature of the slow acceleration, solar sails may not be suited for certain types of space travel. But there are so many benefits to using sunlight to propel a spacecraft that there are companies involved in creating materials and designs for commercial use. Launch rockets can be much smaller and more efficient to get the sails off the ground. The sails themselves don’t need fuel other than what they get from the sun. They can be cheaper, faster, easier, and create less waste.

It turns out that solar sails would need to get pretty close to the sun to go fast enough to travel large distances quickly. Like Icarus, they would swoop near the sun, but unlike him, they can use the energy and gravity to swing back out and go flying through the solar system. Perhaps one day, in the not so distant future, our night sky will be filled with sailing ships, off to distant worlds, using the “winds” of light and the wings of modern technology to fly.

Until next week, my friends, enjoy the view.

Wednesday, March 12, 2008

Stars and Daffodils

3/16/08 –3/22/08
by C. Zaitz

Just as the snow is melting to reveal the buds in the ground and on the trees, the winter night sky is drifting into the sunset, making way for the spring stars. We can still see the pretty set of constellations that make up the Winter Circle, but as we continue our orbit, the sun will be in front of those constellations in the coming months. Let’s take a last, lingering look at them.

I will miss the mighty Orion who watches over us on our quick trips between warm car and warm house. If you wink at him, he seems to twinkle back with his saucy grin and gleaming sword, his broad shoulders marked by the stars Betelgeuse and Bellatrix. The tilt of his belt leads the eye up to his nemesis, Taurus the Bull, off his western shoulder. Taurus’ bright eye is the star Aldebaran. It has a definite reddish tinge, as if Taurus was pawing the ground with his hoof and staring Orion down with an angry, bloodshot glare.

If we slide our eyes back to Orion’s belt and continue east, we find the bright blue-tinged beacon Sirius, in the constellation Canis Major, “the big dog.” Procyon is a star in the “little dog” Canis Minor above it, and still further above are the Gemini twins, Pollux and Castor. Above and to the west shines the bright star Capella, nestled in the five-sided constellation Auriga, who rides his chariot high over the winter sky carrying kid goats in his arms. Then back down to Aldebaran, “the follower” in Arabic, who seems to be following the ever delightful and lovely “Seven Sisters” or the Pleiades across the sky. It’s a familiar and comforting tableau; a collection of images that I look forward to seeing, even if it is a brief glimpse between destinations.

Springtime brings a changing scene. The sun lingers in the sky longer, so the stars come out later each night. Leo the Lion takes center stage not long after sunset. His stars look like a backward question mark with a little triangle marking his backside. Leo has a visitor this spring, the giant ringed planet Saturn. It will be drifting through the constellation, and its orbit will take it past the brightest star in Leo called Regulus. Regulus is a form of the Latin word Rex, which means king. I can really imagine a regal, burly, golden-maned lion, lying on his belly, paws curled under, watching over us all night long. Leo used to have a bushy tail, but it has long been severed to make a small constellation with the odd name, Coma Berenices. Coma means “hair,” and the tuft, rather than being the end of Leo, became the symbol of the crowning glory of Queen Berenice, wife of Ptolemy III of Egypt. She bobbed her hair so she could offer it to the goddess Aphrodite to ensure the safe return of her husband from battle. Whether it was her husband’s skill or her coiffured offering, he did return safely, and the locks were put in the sky.

The spring equinox is on March 20tht this year, and as it approaches we can simultaneously watch the march of the constellations and the unstoppable budding growth of new life.

Until next week, my friends, enjoy the view.

Thursday, March 06, 2008

The Nature of Math

3/9/08 – 3/16/08
by C. Zaitz

I’ve done many different things to make a living, but I never thought I’d be teaching math to anyone. Frankly, I wasn’t a big fan of math classes in school, though I’ve taken my share of them to get to the “good stuff” in physics and astronomy. I found some math teachers to be in a “mathy” tower, using a “mathy” language that was hard to understand. But I needed the tools of math, like poets need a language to do their art. Without math, physics and astronomy are only descriptive. Without it, we would never have been able to pin down the age of the universe, much less balance our checking accounts. So we have to do math.

I’m teaching it only temporarily, but already I have a new appreciation for the language of mathematics. Math never wanted to be in a tower, and never wanted to be a separate language. Math permeates everything. Nature has a deep friendship with math- it uses it to design itself. Leaves, seashells, flowers and pinecones all reflect specific mathematical relationships.

Not only did nature use math in its designs, mathematical relationships have allowed us to unlock the mystery behind why the planets orbit they way they do, to understand the relationship between a star’s distance and brightness, and even to figure out how fast we are moving on the surface of our planet, earth.

I’m not saying the language of math is always easy, but it’s not always hard either. Kepler’s laws tell us that the period of a planet is related only to its distance from the sun. That’s beautiful, but it requires finding squares and cubes of numbers. Thank goodness for calculators. To figure out how bright a star is, you can use the inverse-square law. That sounds complicated, but nature says the further you are from a source of light, it gets dimmer faster than you’d think. If you are twice as far away from a star as your neighboring alien, you will experience only a quarter as much light. The cool thing is that the law works for other things, like gravity and magnetism! The math is fairly simple, but it has far reaching import.

To find our speed standing still on the surface of the earth, we need to know how fast the earth is spinning. 2 pi divided by 24 hours times the radius of the earth yields around 1,000 mph! That’s how fast the ground under our feet is moving (at the equator.) And so are we. But it takes physics to explain why we aren’t flying off the planet if we’re traveling so fast. We call it inertia- we’ve all been going that fast since we were born, and the only way we’d feel it is if the earth sped up or slowed down abruptly. Math coupled with science is the most powerful tool we humans have.

For me, the beauty of math has been about how useful it is. But the Golden Ratio is a famous relationship between ratios, and its proportions are pleasing to us. Artists have used it throughout history in famous paintings. There have been philosophers who suggest that numbers have been our connection to the eternal. But I’m not that ambitious with math. If I can just get my students to figure out how high a flagpole is by measuring its shadow and using trigonometry, I’ll be happy.

Until next week, my friends, enjoy the view.

Wednesday, February 27, 2008

Shot Down in Midair!

3/2/08 - 3/8/08
by C. Zaitz

I’m not usually picky about why people get interested in science. But when my spouse came to me excited about the fact that the US Navy had shot down one of our own satellites with an unarmed missile launched from a ship out in the middle of the ocean, I felt smug. “Oh that’s nothing” said I. “We went to the moon six times, when we had to launch incredibly huge Saturn V rockets, figure out how to slip three astronauts into orbit, plunge two of them down to the surface to play, then scoot them back into a tiny aluminum foil launch vehicle, blast them off the moon, rendezvous with the orbiting vehicle, and have them burn themselves back into a tricky return to earth, with just the right trajectory to ensure they neither would skip off the atmosphere nor burn up in re-entry. No easy feat!” He rolled his eyes.

Meanwhile, I was just being cynical, and he was right, the destruction of the satellite was pretty interesting. Launching a missile from a rocking, moving ship is no easy feat, and hitting a fast-moving target is trickier still. Shooting down satellites is a controversial affair, due to China’s demolishing of a weather satellite last year. Nations get nervous when other nations send missiles shooting into the sky. But they did it, and so did we. How? Why?

The “why” of shooting down our own satellite was apparently due to the tank of hydrazine on board. Hydrazine is a toxic substance which once gained fame as being a product of a compound called Alar which was sprayed on apples to keep them on the tree to ripen them. The fear of this substance falling to earth as a cold slush, possibly killing or injuring people within 30 feet of it, was reason enough for the US to destroy it before reentry. The satellite had died, leaving no energy to keep the hydrazine warm, and hydrazine has a freezing point above water, so the threat of it surviving reentry as a half-frozen substance was real. Some say we did it just to see if it could be done, which leads up to the “how” of hitting a satellite moving at 17,000 km/second.

Breaking up a satellite before reentry poses problems. We have a pretty good understanding of orbits and trajectories of objects, once we know their mass and velocity. But when conditions like weather are uncertain, or change rapidly, problems of math and physics become very complex. So we use guiding systems which can track infrared, or heat signals. Unfortunately the satellite was dead so it wasn’t producing much heat. When China blew up one of its spy satellites, a cloud of debris was left behind in orbit that still exists and will remain for years, creating hazards for other orbiting bodies. We needed to hit the satellite in the hydrazine tank, which upon impact, even without explosives, would smash both the missile and the satellite, the pieces of which would reenter the atmosphere and burn up within weeks. And apparently that’s what happened.

Without knowing all the military details, but knowing that we are target practicing, as are other countries, I’m kind of glad that some of us are very interested in science.

Until next week, my friends, enjoy the view.

Wednesday, February 20, 2008

Spelunking in Space

2/24/08 – 3/1/08

by C. Zaitz

The planet Mars currently has a flotilla of spacecraft either orbiting or crawling on it. Interest has always been high when it comes to Mars, due to the strange landscape and its earth-like features, as well as the fact that it may have harbored life in its history. Recently, orbiting spacecraft have found holes the size of football fields in Mars’ landscape. After careful study, speleologists (scientists who study caves) say it is most likely that the holes are cave entrances, similar to caves on earth.

The fact that Mars has caves is interesting for a couple of reasons. First, caves can be safe havens for any life that might have taken hold on the planet. Mars is a harsh place, though it is the more earth-like than other planets. Its atmosphere is much thinner than earth’s and the weather is significantly meaner as a result. The thin atmosphere allows more killing solar radiation to reach the surface of Mars, even though it is farther away from the sun than we are. If life did form on Mars, it wouldn’t last long in the sizzle of the sun’s energy.

Caves provide protection from the more dangerous forms of radiation, and can also be shelter from raging wind and dust storms that often blast across the surface. Scientists think that caves are an excellent place to look for evidence of life on Mars. But even if life never did exist on Mars, there is another reason caves interest us. We humans have lived in caves for much of our history. They are perfect protection from fierce weather and from marauding neighbors. Though we don’t expect to have to hide from Martians, we will need protection from the elements on Mars that caves afford.

Scientists wonder how the caves formed. We know what can cause caves on earth. Falling rain water absorbs carbon dioxide. Water and carbon dioxide combine into a weak form of carbonic acid. The acid eats away rocks that are made of calcium carbonate, or limestone, and caves form as rock is dissolved and carried away in underground streams. Hollow chambers are left behind.

Caves on Mars may not be limestone, however. Mars has a very different atmosphere. It is mostly carbon dioxide, not nitrogen and oxygen. 95% of the air is poison to us, but would be very useful to plants. However, it isn’t clear that Mars has the right chemistry for the karst formations and caves we find on earth. So if the caves on Mars aren’t eroded limestone, what are they?

What Mars does have is volcanoes, like those on earth. The caves may be hollow lava tubes from ancient volcanoes. If it turns out that they are, they would provide excellent shelter for future spelunkers from earth. There might be magnificent chambers with sky lights and protected rooms for equipment and living space. These volcanic mansions might provide the right environment for exploring humans to survive on the foreign planet. Work is currently being done to design and build robots that could explore the caves on Mars, These robots could not only look for signs of past life, but could pave the way for future inhabitants to move in.

If you’d like to see Mars tonight, look to your southern sky for a bright, peach-colored light among the stars.

Until next week, my friends, enjoy the view.

Wednesday, February 06, 2008

Spring on the Sun

In January, solar scientists found their first robin of the sun’s spring. It was a sun spot, a little black dot on the visible surface of the sun. This spot was somehow different from the spots that had come before and from spots still on the sun. This spot had a different magnetic polarity, and was in a different place than previous spots. The news was clear: the long awaited first sign of Solar Cycle 24 had arrived. The sun’s winter, known as “solar minimum,” was midway through and the new solar cycle had begun.

The analogy of spring can only be taken so far. The sun does go through activity level changes, just like we do in different seasons, and these changes are related to the sun’s average temperature. But the sun doesn’t have seasons, just an ongoing 11 year cycle of magnetic storm activity. It turns out that the sun’s average temperature is lower during the multi-year lull in sunspot activity, and is greatest during the peak, called solar maximum.

Like a human going through puberty, the sun face is always changing, and its most noticeable feature is the scattering of spots on its face. The spots indicate areas where the turbulent and twisted magnetic field lines are organized and the normally bright plasma of the sun is slightly cooled and darkened. They appear darker against the bright background of hotter plasma, and that is what we see as a sunspot. Sunspots form often form in pairs or groups. They have a system of polarity, just like magnets have south and north poles. They form in somewhat predictable ways throughout an entire solar cycle. One of the clues scientists have been looking for is the switch in polarity of spots that form in in either the northern or southern hemisphere of the sun. This is one of the clues that indicate the official end of cycle 23 and the beginning of the new solar cycle.

Another clue is where the spots form on the sun. New solar cycles always begin with a high-latitude, reversed polarity sunspot. Old cycle spots form near the sun's equator. New cycle spots appear higher on the sun, around 30 degrees above the sun’s equator. The new spot was high and backward, indicating cycle 24 had begun. Now the sun’s activity would grow day by day over the course of the next 4-6 years.

Though we’ve turned the corner in the sun’s growing activity, it takes years to peak. Scientists predict that the upcoming solar cycle will be quite fierce when it peaks around 2011. What that means is that we will be vulnerable to the effects of solar storms, like power grid overloads causing power outages, cell phone and other communication interruptions due to satellite malfunction, GPS malfunctioning and air traffic problems. One pretty side effect caused by excess solar particles in our atmosphere is the Northern Lights. Scientists predict this solar cycle will be famous for Northern Light displays. We‘ll have to wait for solar max to see these spectacular Auroral displays, however. Meanwhile we can enjoy the heightening daily path of the sun, and that it lingers longer as the days go by. Spring is indeed coming.

Until next week, my friends, enjoy the view.

Wednesday, January 30, 2008

Moon Dragon

2/3/08 – 2/9/08
by C. Zaitz

Michigan winters can drag on and on, but soon there will be a real “dragon” in the sky; the moon-eating dragon we know as a lunar eclipse. The word eclipse is Greek, meaning “abandoning” or “forsaking.” On February 20th, around 9pm, you will see our lovely full moon abandon us as it is “eaten” by the shadow of the earth.

Lunar eclipses may seem rare, but they actually happen twice a year. We cannot see them if they happen during the day. The moon is always full during a lunar eclipse, and full moons are always opposite the sun. As the sun sets, a full moon rises, and as the sun rises, the full moon sets. That is why we see a lovely, huge, and sometimes reddish full moon rising at sunset. The color comes from light getting scattered as it passes through the atmosphere, but the apparent size is an optical illusion, due to the moon being close to the horizon.

A lunar eclipse happens when the moon passes through the earth’s shadow. As the moon orbits the earth once a month, there will be a time when the sun, earth and moon are in a line. The moon’s orbit around us is tipped about 5° from our orbit around the sun, so usually it passes above or below our shadow cast into space. Twice a year, the orbits cross so there is a chance for a lunar eclipse, but sometimes the moon may skim only part of the shadow. There will be such an eclipse in August, but it happens during our daytime so we will not be able to see it. The February eclipse is total and happens at night. This is our eclipse.

So here are the nitty-gritty’s of this eclipse. It begins with the moon moving into a penumbral shadow at 8:43 pm on February 20th. This will be hard to see, since penumbral shadows are light. The full eclipse begins at 10:01pm, and by 10:26 the entire moon will be eclipsed. This is when you can tell what color the eclipse is. Will it be reddish, like a rising full moon sometimes is, or will it be dark grey or brown? Sunlight passing through the atmosphere is responsible for the colors of an eclipse. Even though the moon is in our shadow, some sunlight does pass through our atmosphere and falls on the moon. Depending on how much the light is scattered, the colors can range to orangey red to dark, muddy brown. The more stuff in the atmosphere, (ex. volcanic ash) the darker the eclipse.

Eclipses were often seen as bad omens, especially solar eclipses, as if the sun and moon were being eaten or destroyed by dragons. People had different methods of scaring away the moon-eating dragon, such has making loud noises or praying. The best remedy for an eclipse, though, is time. By 10:51pm the total eclipse will be over, and the moon will be completely out of the earth’s shadow by 12:09am.Hopefully the skies will be clear so we can all enjoy this special event.

Until next week, my friends, enjoy the view.

Tuesday, January 22, 2008

Messenger from Space

A space craft called Messenger was launched back in August of 2004, en route to the smallest of the planets, Mercury. Tiny and dense, closest to the sun, and with a very ancient surface, Mercury should be a planet of great interest, but has been largely ignored for most of the era of solar system exploration.

Only one other spacecraft has visited Mercury. From 1974-1975, Mariner 10 flew by and sent back the pictures of the heavily cratered planet. The data showed a hot little world, burning and freezing alternately through its day and night. The surprising thing learned by Mariner about the closest planet to the sun is that there are spots that are colder and darker than many places in the solar system. One of the reasons we’re so curious about Mercury is the fact that it may harbor ice in a deep, dark polar crater. Ice on Mercury? How could this be?

All planets spin as they orbit the sun, and usually those spins have some harmonic resonance, thanks to gravity. This means that Mercury’s spin has slowed to the point that for every two times it orbits the sun, it rotates three times. A day on Mercury lasts about 176 earth days, baking the landscape for 88 days at a time from sunrise to sunset. The polar regions are the exception; they see little sun due to Mercury’s axis being nearly upright. It is deep craters in these polar regions that may harbor ice from a long past comet collisions or outgassing from Mercury itself.

Mercury’s curious spin has also led to the discovery that it may still have a molten core. Raw eggs tend to wobble more than hard boiled ones when they spin. That’s a good way to tell which ones have been cooked. Using that same principal, scientists have used radar to learn that Mercury wobbles more than a hard-boiled planet should wobble. This is surprising since tiny Mercury has had time to cool enough to solidify in the past 5 billion years. Its core is surprisingly large, as well. It makes up about 75% of the diameter of the planet. Such a large, dense core can’t be explained by compression, as it can in the cases of earth and Venus, so astronomers are curious to find out how Mercury accumulated such a great proportion of the solar system’s heaviest elements.

The Messenger spacecraft should be able to shed some light on these questions. The Mariner data was limited and up to now we have only had pictures of one side of Mercury. New pictures of before unseen parts of Mercury are streaming in, and soon this little world will tell us more about how the solar system formed.

There are many mysteries about Mercury, some of which Messenger will try to answer. But in the meantime, we can try to spy the tiny planet in the fierce glow of the sun. The evening sky of late January still has elusive Mercury visible very low in the west after sunset. In the morning, Venus and Jupiter will be together, shining brightly in the February pre-dawn sky. On February 4th, the waning crescent moon will join the party in the eastern morning sky.

Tuesday, January 15, 2008

Oceans of Life

I love the Great Lakes, but I have a new crush- the ocean. I just returned from California and the Pacific. Over and over, like the ticking of an endless clock, waves crashed on the beach, bringing evidence of life from its depths and splaying them on the shore. The ocean seems timeless. But it wasn’t always here.

Early earth looked a lot different from the planet we know today. Scientists think that when earth first formed, there were no oceans. As the planet was forming, outgassing of the crust, along with constant meteor and comet bombardment, slowly built up the water vapor that condensed to form large bodies of water. These first oceans were not the blue beauties we are familiar with. We call earth the blue planet because of our azure skies and violet oceans, but when earth was young it had red skies and greenish-grey oceans. The thick early atmosphere was mostly carbon dioxide, and the water was a cloudy stew of water and other chemicals, with lots of salt from volcanic rock erosion and dissolving gasses from the air. Evidence suggests that this stew brought all the right ingredients together to create self-replicating matter, or life. The oldest life forms we know are found along the ancient ocean shores. Stromatolites are the fossil remnants of ancient communities of bacteria, and it seems that microbial life ruled the earth for most of its history, as far back as 3.5 billion years ago.

Now we find microbes in the violent heat and pressure of volcanic vents, and miles high in the harsh outer layers of our atmophere. Our bodies are crawling with them, and it is microbes that we search for as we send probes to other planets and moons.

The origin of microbes is not understood. Perhaps the earth supplied the right ingredients herself, or perhaps they flew in on a dirty comet from outer space. As we learn more about how life formed, we gain insight as to where to look for it in the solar system. And the evidence points to water.

We’re already crawling over the surface of Mars looking for signs of water. We find a lot of evidence for its existence, but as we drill into the rocks and look for fossils, none appear. We’ve also sent a probe to Saturn’s largest moon, Titan. The probe found no watery oceans or lakes in its quick descent and painless death on the moon’s cold, remote surface. Instead, it glimpsed rivers and streams of liquid hydrocarbons, which may be home to other, unfamiliar life forms, but nothing we can recognize.

Jupiter’s moon Europa also intrigues scientists, since it is completely enveloped in ice, has a thin surface layer of organic molecules, and may harbor an entire ocean of liquid water beneath the ice. Scientists are hard at work in Antarctica, perfecting tools that can drill through miles and miles of ice and submarines that can explore the depths. They hope to send a probe to Europa to drill beneath the ice and peer below this frozen shield. Though the mission is currently on hold at NASA, someday we will launch a vehicle to the oceans of Europa to see if they hold the promise of life. Even if they don’t, we will learn more about the incredible specialness of life here on our home planet.

Until next week, my friends, enjoy the view.

Monday, January 07, 2008

The Space Club, Part II

1/13/08 – 1/19/08
by C.Zaitz

In our current climate of economic struggles, sometimes it’s hard to see the benefits of globalization. As Michiganders see jobs flying out the proverbial window to other countries, it’s hard to welcome the change. But it may be argued that the sharing of resources may be the only way to continue human and robot space exploration, and therefore help ensure the survival of our species.

Globalization is painful. Rich countries, superpowers even, may lose some of what they have to support countries that don’t have as much. Can a country, can a people, be that altruistic? I don’t know if compassion is anywhere in Darwin’s “survival of the fittest.” I don’t know that evolving the ability to share for a common good is necessarily going to help us survive as a species, much less get us to the moon or a nearby star. Maybe that’s why we don’t see aliens in Red Cross trucks patrolling our solar system.

The ability to launch space vehicles is the first level of space exploration. The second level is sending probes to other worlds. The Soviet Union sent the first landed spacecraft explorer to Venus in 1970. Prior to that, both the US and USSR had sent flybys to Mars and Venus, some successful, some not. In the 1990’s, Japan sent a probe to the moon, and then tried to send one to Mars. The first made it, the second didn’t. India also wants to join the probe club with a program to go to the moon and Mars. They plan on launching an unmanned moon mission in April of 2008. Meanwhile, nearly two thirds of the probes sent to Mars have failed. It turns out that sending probes to space is not the easiest thing to do. With a failure rate like that, it stands to reason that sending people to space is even more dangerous. So instead of secretly “cold-warring” our space programs, maybe our nations should share our resources. But can that happen? Perhaps the space race is fueled by competition, not compassion.

Level three of the space club, sending humans into orbit, has been reached by only three countries so far: China, Russia and the United States. The Soviet Union beat everyone in 1961, when Yuri Gagarin became the first human in orbit. The US, sweating bullets, followed by shooting John Glenn into orbit in 1962. China has recently gained entry to this level of the club by blasting Yang Liwei off to space in their own launch vehicle in 2003. This is a very elite club, but not as elite as the next level.

The twelve American men that walked on the moon from 1969-1972 are the only humans to step foot on extra-terrestrial ground. Many countries have a stated interest in going to that level, but the stakes, expense and danger to human life are so much greater than the other levels of the space club that I wonder if it will happen. Intense motivation is needed: perhaps motivation like a large asteroid heading our way, or a real visit from extraterrestrials. Or perhaps just the Helium-3 that we know the moon is loaded with. Whatever it takes, cooperation and compassion, or competition, I hope we can someday enjoy the next level of space exploration: stepping foot on another planet.

Until next week, my friends, enjoy the view.