12/3/06 – 12/9/06
by C. Zaitz
We’ve all seen the dish. They have popped up like mushrooms all over the place. Even colleges and universities have them. However, some dishes that look like TV satellite dishes may actually be radio telescopes. They collect radio waves from the universe. I know that sounds funny, as if you could hear the universe on your radio, but I should clarify. Radio waves are very different from the sounds coming from your radio.
When we point big dishes up to the sky, even a satellite TV dish, we are collecting electromagnetic radiation in the form of radio waves. These are very long waves that can pass through our bodies without as much as a tingle. One wave can be as long as a city block, or as short as your shoe size. The radio station you listen to has to change electronic signals into carrier waves, which travel through the air. When these waves, which are flying all over the place harmlessly, get to the tuner in your radio, they are changed back into a signal that is amplified and modified. These signals produce vibrations on a speaker in your radio. It’s the sound pressure waves from the speaker going in and out quickly that reach your ear and your brain interprets as Mozart or Green Day. Pretty cool.
Sound waves cannot travel in space, since they need a medium (air) to vibrate in order to travel. The beauty of radio waves is that all they need is the original energy source that set them off. They can travel from one end of the universe to the other. Sure, they’ll lose some energy if they travel a long way, but we can still collect them if we have a big enough dish. That’s why we build giant radio dishes. One of the most famous ones was built in an old meteor crater in Arecibo, Puerto Rico. Nature hollowed out a big hole for us, and we stuck a dish in it and collect radio waves from all sorts of interesting objects.
Another cool thing about radio waves is that they can penetrate clouds and dust. Many other wavelengths, like much of the infrared and ultraviolet waves, as well as gamma and X-rays, are blocked by our atmosphere. But radio waves can go through clouds, even clouds of dust in space. Light can’t do that, so our picture of the universe in radio waves can sometimes be clearer than optical images. So what do we look at in radio waves?
The sun is a great producer of radio waves. In radio wavelengths, we see sunspots and solar flares that we might not see in visible light. Beyond the sun, there are stars and galaxies that produce radio waves. In fact, some objects emit more energy in radio waves than in light, so radio astronomy has opened up a new window on the universe. Galaxies that emitted strongly in the radio spectrum were the first clues to finding black holes and quasars. The Cosmic Background Radiation, the lynchpin in the theory of the Big Bang, was discovered by radio technology back in the 1960’s. Radio astronomy is still going strong today, and since radio dishes are relatively inexpensive and easy to build, even some schools and amateur astronomy clubs have them. So the next time your hear about a radio telescope, you’ll know that they are looking at, not listening to, the universe!
Until next week, my friends, enjoy the view.
Wednesday, November 29, 2006
Wednesday, November 22, 2006
How’s the Weather?
11/26/06 – 12/2/06
by C. Zaitz
It’s the time of year when people start wondering about El Nino and what kind of winter we’re going to have. When I was younger, I would roll my eyes when my parents would ask, "how's the weather." Now, because I’m six hours due west of them, it’s fun to see how long it takes our weather to get to Rochester, New York. Weather tends to move from northwest to east in the United States. What Canada brings us, we send along to them, with a little Ontario “lake effect snow” for excitement.
If we lived on the western side of Michigan, we’d get lake effect snow as well. ”Lake effect” happens as air moves over a large body of water and picks up warmth and water vapor. As the air moves onto land, it cools off. Cooler air can’t hold as much humidity as warmer air, so it precipitates out and falls as snow. Our weather in Metro Detroit has to cross the whole Michigan Mitten before it reaches us, and by then it’s had time to dry out. Our snow fall is much more reasonable than snowfall in Traverse City, since it’s the lee shore of the lakes that gets the brunt of lake effect snow, sometimes spectacularly. I remember some awesome snowstorms and school closings growing up.
Nowadays there’s talk about El Nino. Simply put, it’s a combination of ocean and air changes that effect climate in a far-reaching area. If the Pacific Ocean has a higher than normal near-surface temperature for an extended period of time, it causes climate changes not only across North America, but around the globe. The combination of the warmer ocean along with changes it produces in air currents cause circulation to change, trade winds to alter, and weather reflects the changes.
The west coast may get more rain, and the Midwest can be drier during an El Nino period. But in Michigan, we get a milder winter. I’m not complaining. By now you’ve probably guessed I’m not a fan of snow, storms, or clouds. After growing up with lake effect snow and bad sinuses, I long for hot, dry and sunny. I’d be happy if I never had to blow my nose again. But it seems with El Nino and the effects of global warming, Michigan just might be the place to be. Folks in California may be under water, along with the east coast. The Midwest will be on fire, but in Michigan, we’re sitting pretty. Michigan may be the new Georgia.
I don’t mean to make light of a serious situation, but the more we learn about the earth’s climate systems, the more we should be ready for changes. We have already seen rising global temperatures over the past decade, and carbon dioxide levels in the atmosphere currently surpass any we’ve seen in the last 650,000 years. If a lot of volcanoes happen to erupt in the next decades, we’re sunk! It won’t be a giant asteroid that does us in, it will be our proclivity for spouting CO2 into the air. Google “Venus” if you want to see what happens next.
Speaking of Venus, she’s going to make her return to the evening twilight in December, so keep your eyes peeled for her bright orb to appear near the sunset as the month wears on.
Until next week, my friends, enjoy the view.
by C. Zaitz
It’s the time of year when people start wondering about El Nino and what kind of winter we’re going to have. When I was younger, I would roll my eyes when my parents would ask, "how's the weather." Now, because I’m six hours due west of them, it’s fun to see how long it takes our weather to get to Rochester, New York. Weather tends to move from northwest to east in the United States. What Canada brings us, we send along to them, with a little Ontario “lake effect snow” for excitement.
If we lived on the western side of Michigan, we’d get lake effect snow as well. ”Lake effect” happens as air moves over a large body of water and picks up warmth and water vapor. As the air moves onto land, it cools off. Cooler air can’t hold as much humidity as warmer air, so it precipitates out and falls as snow. Our weather in Metro Detroit has to cross the whole Michigan Mitten before it reaches us, and by then it’s had time to dry out. Our snow fall is much more reasonable than snowfall in Traverse City, since it’s the lee shore of the lakes that gets the brunt of lake effect snow, sometimes spectacularly. I remember some awesome snowstorms and school closings growing up.
Nowadays there’s talk about El Nino. Simply put, it’s a combination of ocean and air changes that effect climate in a far-reaching area. If the Pacific Ocean has a higher than normal near-surface temperature for an extended period of time, it causes climate changes not only across North America, but around the globe. The combination of the warmer ocean along with changes it produces in air currents cause circulation to change, trade winds to alter, and weather reflects the changes.
The west coast may get more rain, and the Midwest can be drier during an El Nino period. But in Michigan, we get a milder winter. I’m not complaining. By now you’ve probably guessed I’m not a fan of snow, storms, or clouds. After growing up with lake effect snow and bad sinuses, I long for hot, dry and sunny. I’d be happy if I never had to blow my nose again. But it seems with El Nino and the effects of global warming, Michigan just might be the place to be. Folks in California may be under water, along with the east coast. The Midwest will be on fire, but in Michigan, we’re sitting pretty. Michigan may be the new Georgia.
I don’t mean to make light of a serious situation, but the more we learn about the earth’s climate systems, the more we should be ready for changes. We have already seen rising global temperatures over the past decade, and carbon dioxide levels in the atmosphere currently surpass any we’ve seen in the last 650,000 years. If a lot of volcanoes happen to erupt in the next decades, we’re sunk! It won’t be a giant asteroid that does us in, it will be our proclivity for spouting CO2 into the air. Google “Venus” if you want to see what happens next.
Speaking of Venus, she’s going to make her return to the evening twilight in December, so keep your eyes peeled for her bright orb to appear near the sunset as the month wears on.
Until next week, my friends, enjoy the view.
Wednesday, November 15, 2006
In the Twinkle of a Star
11/19/06 – 11/26/06
by C. Zaitz
Have you ever wondered why the stars twinkle? We all know the song by heart, but it never really tells us why they twinkle, twinkle. The song wonders what they are, the little twinkling stars. I don’t want to ruin the song for anyone, but there are answers to both questions.
We don’t have to go very far to study a star. There’s one about 8 minutes away (going at the speed of light, of course). Traveling 70 mph, it would take us 1,328,571 hours, or 55,357 days, or 152 years!
Luckily we don’t have to go there. We can collect information from the sun just by standing outside with a telescope or other device to collect its light. The information we gather tells us the story of the Sun. It’s a middle-aged star, fusing hydrogen atoms in its core to produce enough energy and light to keep its planets warm and cozy. Well, not all its planets, just the lucky closer ones.
All stars are giant collections of atoms, mostly hydrogen. Stars are so mammoth that the great pressures near their centers allow for normally repulsive forces to be overcome and for atoms to fuse into new elements like oxygen and carbon. In fact, without the stars’ atom-fusing abilities, we’d have been a pretty boring universe of hydrogen and helium with a sprinkling of lithium for spice. No mercury, gold or silver. They came later, from stars.
So when you look up at the stars, you can think of them as giant element-producing ovens, getting very hot from churning out planet-making elements like silicon and nitrogen, stuff that ends up as sand and air. Think of that next time you’re on the beach, looking at the pretty sunset. It all came from some star, ancestor to our own sun.
While we’re at the beach, we can also figure out why stars twinkle. Just look into the water. See how the pebbles on the bottom seem to jump and hop around as the waves wash over them? The water is the medium that the light must travel through to get to our eyes. Light likes to go straight in a vacuum, but will change speed or direction in thicker stuff, like air or water, especially if they are moving. The water at the beach is moving a lot, so the pebbles seem to jump around madly. The air is also moving and therefore “bending” light, but not as much, since it is much less dense than water.
However, there is much more air above us than below us. There is a veritable ocean of air above us, and we must look through this “ocean” to see the stars. The starlight may have been traveling in the vacuum of space for millions of years, steady and true, all the way to earth. But when it gets to our atmosphere, it gets jostled, nudged and pushed around by moving air currents. By the time we get to see it, starlight can be jumping around like a drop of water on a hot frying pan. In winter, the atmosphere is often more turbulent, so you will see lots of twinkling and winking of starlight. It’s annoying in a telescope, but can be very pretty to the naked eye. So while you’re humming the song, you can enjoy the very distant stars twinkling and making someone a new beach!
Until next week, my friends, enjoy the view.
by C. Zaitz
Have you ever wondered why the stars twinkle? We all know the song by heart, but it never really tells us why they twinkle, twinkle. The song wonders what they are, the little twinkling stars. I don’t want to ruin the song for anyone, but there are answers to both questions.
We don’t have to go very far to study a star. There’s one about 8 minutes away (going at the speed of light, of course). Traveling 70 mph, it would take us 1,328,571 hours, or 55,357 days, or 152 years!
Luckily we don’t have to go there. We can collect information from the sun just by standing outside with a telescope or other device to collect its light. The information we gather tells us the story of the Sun. It’s a middle-aged star, fusing hydrogen atoms in its core to produce enough energy and light to keep its planets warm and cozy. Well, not all its planets, just the lucky closer ones.
All stars are giant collections of atoms, mostly hydrogen. Stars are so mammoth that the great pressures near their centers allow for normally repulsive forces to be overcome and for atoms to fuse into new elements like oxygen and carbon. In fact, without the stars’ atom-fusing abilities, we’d have been a pretty boring universe of hydrogen and helium with a sprinkling of lithium for spice. No mercury, gold or silver. They came later, from stars.
So when you look up at the stars, you can think of them as giant element-producing ovens, getting very hot from churning out planet-making elements like silicon and nitrogen, stuff that ends up as sand and air. Think of that next time you’re on the beach, looking at the pretty sunset. It all came from some star, ancestor to our own sun.
While we’re at the beach, we can also figure out why stars twinkle. Just look into the water. See how the pebbles on the bottom seem to jump and hop around as the waves wash over them? The water is the medium that the light must travel through to get to our eyes. Light likes to go straight in a vacuum, but will change speed or direction in thicker stuff, like air or water, especially if they are moving. The water at the beach is moving a lot, so the pebbles seem to jump around madly. The air is also moving and therefore “bending” light, but not as much, since it is much less dense than water.
However, there is much more air above us than below us. There is a veritable ocean of air above us, and we must look through this “ocean” to see the stars. The starlight may have been traveling in the vacuum of space for millions of years, steady and true, all the way to earth. But when it gets to our atmosphere, it gets jostled, nudged and pushed around by moving air currents. By the time we get to see it, starlight can be jumping around like a drop of water on a hot frying pan. In winter, the atmosphere is often more turbulent, so you will see lots of twinkling and winking of starlight. It’s annoying in a telescope, but can be very pretty to the naked eye. So while you’re humming the song, you can enjoy the very distant stars twinkling and making someone a new beach!
Until next week, my friends, enjoy the view.
Wednesday, November 01, 2006
Games People Play
11/5/06 – 11/11/06
by C. Zaitz
I was out on a night hike last week with one of my classes. We did not use flashlights, but there was a half moon fading in and out of stratocumulus clouds. The focus of the evening was on screech owls, so the moon was just a big sky-flashlight. Unfortunately, the owls were not in the mood to return the melodic and persistent calls of our interpreter. We did hear the rumbles from the constant parade of planes flying into Metro Airport and the distant snarls of a raccoon squabble, but otherwise it was a pretty quiet and uneventful tramp.
So to amuse myself, I played a game which I call, “identify the star without any other reference but the moon.” Over the course of the walk, one or two stars at a time would shine through the clouds. My rules were that I had to figure out which star I was looking at out of the thousands of possibilities, with no constellation patterns to help, and no directions other than my knowledge of the time of night and the position of the moon.
Could you do it? Where would you start? I saw a bright star pretty high up in the sky. I thought of the brightest stars that are up after sunset in the autumn. There are less than a dozen, but they are scattered over the sky. I needed to know where I was looking, and though our path was constantly changing and twisting, I had a compass in the sky - the moon.
I saw half a moon in the sky. My first clue: half a moon seen in the early evening must mean a first quarter moon, waxing. I knew that its shiny side was facing the sun, and though the sun had already gone down, the moon was still pointing to it. I couldn’t see the glow from sunset due to the trees, but if I bisected the bright side of the moon, the line that I drew would point to the sun. Where that line met the horizon would be pretty close to west, since in the autumn the sun sets nearly due west. It’s not precise, but close enough for my game.
Once I knew that the bright star was high up in the west, I had arrived in the ballpark. I knew that my choices would be from the bright stars setting in the early evening, probably one from the Summer Triangle. Most likely Vega, the brightest of the three stars of the triangle. At this point it was a gut feeling, because it also might have been Deneb, but it just “felt” like Vega. Of course, when the clouds cleared enough for me to catch a glimpse of Deneb, I knew I was right. I sat under a cloud of smug for at least 30 seconds, until I went on to a different part of the sky. By the end of the tramp, the whole constellation of Pegasus was visible and so ended my game. Too easy!
Later I thought about how it might not have been such a game for people through history who were lost in the woods. I also remembered how eerie it can be in the dark with strange sounds and naught but the moon to illuminate your way. I was glad I had made friends with the sky a long time ago.
Until next week, my friends, enjoy the view.
by C. Zaitz
I was out on a night hike last week with one of my classes. We did not use flashlights, but there was a half moon fading in and out of stratocumulus clouds. The focus of the evening was on screech owls, so the moon was just a big sky-flashlight. Unfortunately, the owls were not in the mood to return the melodic and persistent calls of our interpreter. We did hear the rumbles from the constant parade of planes flying into Metro Airport and the distant snarls of a raccoon squabble, but otherwise it was a pretty quiet and uneventful tramp.
So to amuse myself, I played a game which I call, “identify the star without any other reference but the moon.” Over the course of the walk, one or two stars at a time would shine through the clouds. My rules were that I had to figure out which star I was looking at out of the thousands of possibilities, with no constellation patterns to help, and no directions other than my knowledge of the time of night and the position of the moon.
Could you do it? Where would you start? I saw a bright star pretty high up in the sky. I thought of the brightest stars that are up after sunset in the autumn. There are less than a dozen, but they are scattered over the sky. I needed to know where I was looking, and though our path was constantly changing and twisting, I had a compass in the sky - the moon.
I saw half a moon in the sky. My first clue: half a moon seen in the early evening must mean a first quarter moon, waxing. I knew that its shiny side was facing the sun, and though the sun had already gone down, the moon was still pointing to it. I couldn’t see the glow from sunset due to the trees, but if I bisected the bright side of the moon, the line that I drew would point to the sun. Where that line met the horizon would be pretty close to west, since in the autumn the sun sets nearly due west. It’s not precise, but close enough for my game.
Once I knew that the bright star was high up in the west, I had arrived in the ballpark. I knew that my choices would be from the bright stars setting in the early evening, probably one from the Summer Triangle. Most likely Vega, the brightest of the three stars of the triangle. At this point it was a gut feeling, because it also might have been Deneb, but it just “felt” like Vega. Of course, when the clouds cleared enough for me to catch a glimpse of Deneb, I knew I was right. I sat under a cloud of smug for at least 30 seconds, until I went on to a different part of the sky. By the end of the tramp, the whole constellation of Pegasus was visible and so ended my game. Too easy!
Later I thought about how it might not have been such a game for people through history who were lost in the woods. I also remembered how eerie it can be in the dark with strange sounds and naught but the moon to illuminate your way. I was glad I had made friends with the sky a long time ago.
Until next week, my friends, enjoy the view.
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