Wednesday, October 25, 2006

Music of the Spheres

10/29/06 – 11/4/06
C. Zaitz

It’s noisy out there in the solar system. The Moon is ringing like a giant basalt bell. Meteors and asteroids (and human-made spaceships) striking our cosmic companion cause its rigid mass to jiggle in waves that could be translated into sound, and if there was some air or other medium to bring those sound waves to our ears, we could hear the Moon ringing.

The Sun is also making noise, though from a very different cause. The end result is the same; both objects are oscillating in such a way that if we could hear the waves at those frequencies, we would hear them both “humming” like the high voltage lines that supply our homes with electricity. There are several websites that house the sounds of the sun as audio files. If you like watching snowy channels on TV, maybe you’d be interested in hearing the sun. Otherwise, I think it may be more interesting to note that if you were standing near the sun, you wouldn’t hear a thing. You’d also be vaporized.

Sound comes to our ear drums in pressure waves, transmitted through the air around us. Think of holding a slinky between your hands on a table, pushing your right hand toward and away from your left. You’ve made a wave formed by compressing and stretching the slinky, which is how a sound wave moves. Light waves are more like the sinusoidal wave you can make with the slinky if you move your right hand toward and away from your body. It’s a snake-like wave with crests and valleys. Light can travel through a vacuum like space, because it propagates itself. But sound needs a medium. That’s why we often say that there is no sound in space, because there is no air to transmit the sound waves.

However, that doesn’t mean that crafty humans can’t devise ways to “hear” all the energy waves in space. In fact, we are so clever at adapting information to our senses that we have been able to “see” and “hear” phenomenon like the ringing of the moon or the boiling of the sun. We play with the electromagnetic spectrum to see the universe in wavelengths beyond even what a snake or butterfly can see, and we stretch or compress the frequencies of space to hear beyond the range of even the perkiest Border Collie.

It’s true that the sound of the sun isn’t as exciting as Beethoven’s 9th, but we still get a lot of valuable information about the sun’s interior by watching and hearing it jiggle and vibrate. There’s a lot about the sun that we need to understand, so we keep our “ears on” when it comes to the sun. We also listen to empty space for any sign of non-natural activity, but so far, no alien top 40 lists have been heard in the frequencies we’re tuned into.

While you are listening to the sounds of space, don’t forget to look for comet Swan in the evening sky after sunset. Look to the west. If you see a bright star with a bit of an orange-y hue, you have spotted Arcturus. Look up from there for a little fuzzy spot. It’s possible you may see it even without a telescope or binoculars, but it’s always better to have a little optical help.

Until next week, my friends, enjoy the view!

Solar sounds can be heard at:
Sounds of space:

Wednesday, October 18, 2006

Simple Pleasures

10/22 - 10/28

C. Zaitz

Fall is the time of year when we often feel most rushed. Work, school, and family can drain us, while the weather reminds us that harshness is coming. It’s easy to feel overwhelmed, and to let stress get the better of us. But I notice that every glimpse of the sky I get, whether it’s on the way to let the dog out in the morning, or just coming home after 10 hours of school at night, gives me a rush of peace. I know that’s a strange phrase, “rush of peace,” but I don’t know how else to describe it.

Do you ever get that? In our stressful daily lives, it’s rare that we get to take a deep breath and be in the moment. Maybe a glimpse of something bigger and more beautiful than the blocked up freeway under construction at 9pm on a Tuesday gives me a temporary disconnect from the stress. To me that’s invaluable.

So I thought about how the sky can give us pleasure. Even our light-polluted night skies can remind us that there are wonderful things more amazing than any bizarre behavior we experience in our daily lives. Here’s a few beautiful, refreshing things to think about when we catch a glimpse of the sky as we go about our busy lives.

First of all, it’s interesting and not coincidental that blue is a color that tends to calm us, and that the daytime sky is blue. I think looking at a clear daytime sky gives us a better chance for having a good day. Not all planets have a blue sky. Mars comes the closest, but its thin and dusty atmosphere cannot give any potential Martians the deep blues and violets of a clear fall day here on Earth. Rusty red, pinkish-grey and pale grey-blue skies have been “seen” by the robots we’ve sent to Mars. The ruddy colors come from dust storms, not a pretty sunset, so there is little chance for calm in Martian skies. Venus is a washout. Its thick, harsh atmosphere would burn and crush us before we could even open our eyes to look at the sky. We’re lucky to have such a pretty sky, and since we are equipped to enjoy it, let us!

What about the moon? Seeing the bright moon in the sky can remind us that even though things change, even as the moon waxes and wanes, she still calmly orbits, shines with the sun’s light, and follows the inevitable laws of nature. That can be comforting. It’s probable that without the moon, there may have ever been life on our planet. Thanks, moon!

And the stars, the glorious stars. They live and die in such long cycles that our lifetimes are naught but a puff of wind in a hurricane. They are basically element-fusing machines, and we can owe our existence to their efforts. The long dead star that gave birth to our own solar system can be seen all around us in the gold, silver and lead that were all created in a supernova explosion. Our 4.5 billion year old solar system is a baby compared with the universe, which is about 13.7 billion years old. So as much as we feel that there is no time, the truth is that there is plenty of time to enjoy our lives, even if it’s in a “rush of peace.”

Until next week, my friends, enjoy the view!

Wednesday, October 11, 2006

Comet SWAN

10/17/06 – 10/23/06
by C. Zaitz

There’s a comet in the sky, and its name is SWAN. It’s time to dust off those binoculars and point them halfway between the bowl of the Big Dipper and the bright star Arcturus in the evening sky. If you want to find Arcturus, you can trace an arc off the handle of the Dipper and “arc to Arcturus.” Both Arcturus and the Big Dipper will be skimming the horizon, so if you happen to sport tall trees or a roof to the north, you might not spot the comet.

Many of us remember the comets of 1996-7, Hyakutake and Hale-Bopp. They were fabulous and awe-inspiring. I was living in Yonkers, NY at the time, and remember lying on the hood of my car in the chill Westchester air, feeling the warmth of the engine and seeing the comet streaking its enormous glowing tail across the sky. You might remember where you were when you saw the comets, too. It’s rare to have two such beautiful naked-eye comets in the sky within a year. Comet SWAN is not in the same league with those comets, but it’s always interesting to spot one in the sky.

It’s not hard to make a “comet.” We can start with something to represent the nucleus, or the heart of the comet. Spectral analysis has identified major ingredients in comets: Water, ammonia, organic molecules, and silicates. For silicates, we can use sand, dirt, or my favorite: kitty litter. Then add a little ammonia. A good squirt or two of Windex will do. For the organic molecules use whatever is handy; Karo syrup, sugar, or a leftover can of Coke. Pour all those ingredients together and what do you get? A mess, and a very warm comet. We forgot the ice! Comets are cold. They live in the outer regions of the solar system, so far from the sun that they have remained relatively untouched, unmelted and unsullied for the lifetime of the solar system, some 4.5 billion years.

So to make a comet, it’s handy to have a tank of liquid carbon dioxide. You could use regular ice, or you could get a chunk of dry ice from a local supplier, but the beauty of the pressurized tank of liquid CO2 is when it shoots out the nozzle, the pressure is released, it expands rapidly and gets very cold. It becomes dry ice snow, which is easier to play with than a chunk of dry ice. You can grab handfuls of it (wearing thick gloves, of course!) and smush it into your comet. A little water for sticking and mixing purposes, and you’ve got a pretty, dirty, cold and steamy comet. As it melts, the dry ice sublimates to gas and makes a bit of a comet tail. Perfect!

When you look at comet SWAN through binoculars, you will see a bright nucleus and perhaps the fuzzy tail. The comet has just journeyed around the sun, so its tail is prominent. By the way, comet SWAN is not just another pretty bird in the sky. Its name comes from the Solar Wind ANisotropy experiment which first discovered it. We’ve noticed that instead of being the same everywhere (isotropic) the wind behaves more like a plasma ball- the kind you see in a novelty store, with filaments and structure. You can think of the comet’s tail being swept back by that solar wind as you peer at it in the night sky.

Until next week, my friends, enjoy the view!

Wednesday, October 04, 2006

Hot Pockets

10/10 - 10/16
by C. Zaitz

It was just announced that two Americans, John Mather and George Smoot, won the 2006 Nobel Prize in Physics. They were doing their part to confirm the theory that the universe began in a wild, hot expansion that started from nearly nothing and ended up as the present gigantic universe we see today.

It’s been known since the 1920s is that the universe is expanding. Before that, we had the idea that the universe was a steady state place, where nothing really changed. But Edwin Hubble noticed that galaxies were rushing away from the Milky Way, and the farther away they were, the faster they were going. Either that meant that we were the center of the universe, or that the space between galaxies was growing. Since there was no reason to suppose the Milky Way was at the center of everything, we went with the second idea. We named the great expansion the Big Bang, and scientists got busy trying to find evidence of it. We looked and looked, but we couldn’t see the remnants of the Big Bang. Finally, in the 1960s, some one heard it.

It wasn’t very loud; it was just a bit of noise. Noise heard in a radio receiver meant for earthly communications. The noise couldn’t be accounted for from a terrestrial source, so eventually the sky was blamed. What the radio dish was picking up was the echo of a long ago, tremendous expansion of space and time. It sounded like mere static, but it was the ancient birth-scream of our universe, now spread out, tired and sore after a 13.7 billion year journey.

It was called the Cosmic Microwave Background Radiation, or the CMBR. Its discovery launched a whole cascade of modern cosmology, complete with satellites like COBE, the Cosmic Background Explorer. COBE was sent to map and probe the CMBR. Looking at the background radiation was like looking at the very young universe when it was about 3,000 degrees. In 1992, COBE measured the current temperature of the radiation. Over the past 13.7 billion years, it has cooled down to a mere 2.7 degrees above absolute zero. Even at that lowly temperature, we can read that radiation like a book. And it’s a pretty interesting story.

Interesting because what the scientists working on COBE found was small anisotropies in the CMBR. An anisotropy is a little weirdness. Little pockets of slightly hotter, slightly cooler areas in the CMBR to the tune of a hundredth of a thousandth of a degree. But even this small difference means something. We have long been wondering about galaxy formation. Star and planet birth is pretty well understood, but the formation of giant galaxies has been puzzling. These “hot pockets” may be a key to how they formed. Things get fascinating when we look at the anisotropies of the CMBR. Could they be frozen sound waves or harmonics from the beginning of the universe? Further studies from recent satellites like WMAP have given us a wealth of detail about the CMBR, and it has led us to the idea that the universe is not only expanding, but speeding up its expansion, for reasons known only to the universe as of yet. But we are hard on its heels, and in future years I predict more work on hot pockets in the CMBR and more discoveries about the origins of the universe. It’s an exciting time for all of us who wonder about the cosmos.

Until next week, my friends, enjoy the view!