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.

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.

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.

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.

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.

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.

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.