Sunday, November 29, 2009
Wednesday, November 25, 2009
Leftover Crickets
Crickets are both extremely common critters and extremely accomplished songsters. There are hundreds of species found everywhere in North America. That’s the common part. Males are the singers. They have highly-specialized forewings that contain both a scraper and a file on each wing. This primitive “bow and string” instrument not only produces the song, but at the same time amplifies and broadcasts it. That’s the accomplished part.
The cricket’s song is seasonally heard well before—and long after—their musical cousins the grasshoppers, katydids, and cicadas. It is now late November, well after the other singers have fallen silent. But a couple rugged, dogged crickets persist. They seem to have found warm niches near the house that have allowed them to cozy down and extend their season. Surely by now their chances of reproduction via song is nil, yet they persevere.
Years ago a clever entomologist made note of the regular pulsations of the cricket’s song. On warm summer nights they pulse rapidly but slow down when cool fall nights arrive. In fact, an approximate “cricket thermometer” was discovered. If you count the number of pulses in 13 seconds and add 40, you come close to the Fahrenheit temperature. Thus on a 70-degree summer’s eve, you’d find yourself counting some 30 pulses in a 13-second period, or 2-3 pulses per second.
So how about these chilly November nights when I hear a dogged cricket singing? The other evening I found it easy to count the slow beats of a cricket’s song. He was sluggishly emitting a pulse every half-dozen seconds or so—telling me that the temperature was in the low 40s—pretty close to what my manmade thermometer read. I found myself musing about what he’d do when the temperature dropped below 40. Would he try to retract some of the chirps he’d produced, back in July?
Some folks consider the cricket’s song to be melodic and enchanting. Others view it as grating and tedious. One’s reaction seems to be in the ear of the observer. I see Mr. Cricket as some of both but mostly a resolute dude.
The cricket’s song is seasonally heard well before—and long after—their musical cousins the grasshoppers, katydids, and cicadas. It is now late November, well after the other singers have fallen silent. But a couple rugged, dogged crickets persist. They seem to have found warm niches near the house that have allowed them to cozy down and extend their season. Surely by now their chances of reproduction via song is nil, yet they persevere.
Years ago a clever entomologist made note of the regular pulsations of the cricket’s song. On warm summer nights they pulse rapidly but slow down when cool fall nights arrive. In fact, an approximate “cricket thermometer” was discovered. If you count the number of pulses in 13 seconds and add 40, you come close to the Fahrenheit temperature. Thus on a 70-degree summer’s eve, you’d find yourself counting some 30 pulses in a 13-second period, or 2-3 pulses per second.
So how about these chilly November nights when I hear a dogged cricket singing? The other evening I found it easy to count the slow beats of a cricket’s song. He was sluggishly emitting a pulse every half-dozen seconds or so—telling me that the temperature was in the low 40s—pretty close to what my manmade thermometer read. I found myself musing about what he’d do when the temperature dropped below 40. Would he try to retract some of the chirps he’d produced, back in July?
Some folks consider the cricket’s song to be melodic and enchanting. Others view it as grating and tedious. One’s reaction seems to be in the ear of the observer. I see Mr. Cricket as some of both but mostly a resolute dude.
Saturday, November 21, 2009
Tuesday, November 17, 2009
Earth-centered Confusions—Part 2
The third night sky object—the most charming and dramatic one—is the moon. When it’s overhead on a clear night it commands our attention like nothing else. We’re all familiar with the moon’s various phases during the lunar month. Paeans have been written and sung about the full moon and its influence on the moods of people—as well as wolves.
But understanding the moon’s journey—its location in and path across the sky—is far more complicated than either the sun or stars. Not only does the Earth rotate beneath it, but it is the only heavenly body that circles us. The Earth may have been demoted, as far as its place in the cosmos goes, but we retain the moon as our exclusive satellite. So when we follow the moon’s journey across our sky, we’re seeing the composite pattern of its monthly revolution around us and our daily rotation under it.
And the moon’s cyclical periods are neither simple nor match those of the Earth. The lunar month is some 29.5 Earth days long and there are 12.4 lunar months in an Earth year. They’re out of sync with each other, so events do not repeat themselves in a regular manner. As a result, you may get a straightforward track of the moon across the sky during a given night, but its location shifts quite a bit the next night. For example, tonight at 9:00 it may be directly overhead, but each subsequent night it shifts a substantial amount eastward. In a week it’ll be near the eastern horizon at 9:00, and then completely gone from the night sky the following week.
But there’s more. The moon’s orbital plane is at a slight angle to the ecliptic and it wobbles up and down a bit. That waver completes a cycle every 18.61 years. One needs a thorough knowledge of these wobbles in order to predict when lunar and solar eclipses will occur. There’s still more: The moon’s orbit about the Earth is not a perfect circle; it is egg shaped. So it’s closer to us at times (at perigee, when it’s also a little larger) and farther at other times (at apogee, when it’s a little smaller).
It makes my mind swoon to try to comprehend all these variations. I am humbled by the ancients who had the time and inclination to take note of all these lunar complexities and accurately predict their periodic occurrences in such exquisite observatories as Stonehenge and similar monuments.
The last and most complex of all the heavenly objects are the planets. Their behaviors are truly bizarre. If you mentally elevate yourself to a place high above the plane of the solar system, the orbits of the planets around the sun can be seen to be simple near-circles. From an Earth-centered perspective, however, the planets (Greek word for wanderer) trace weird paths across our sky. Although they may behave themselves nightly—arcing across the sky like the stars—their positions relative to those background stars wander in an almost inebriated manner, over a period of weeks or months.
Jupiter may be seen to slowly migrate westward, over a period of weeks, and then abruptly swing back to the east. It may next head west again and then dive below the western horizon, disappearing from the night sky, to reappear in the pre-dawn sky, now towards the east! In fact, these pop-up appearances of the planets—now at night in the west, now at dawn in the east—were so unaccountable that the ancients did not even recognize their reappearance as the same planet.
Only with a mixture of modern astronomy (handily found on web sites) and a little prehistoric sky monitoring can I follow the planets in their mysterious travels across the sky.
I am doing my best to comprehend the paths taken by heavenly bodies across my sky. It’s almost beyond me. I try to soak it all up from a combination of direct observation and reading books. I could do this for another few decades and still not quite approach the proficiency of my forebears. I often wish I had one of them by my side, passing on her clan’s wisdom.
But understanding the moon’s journey—its location in and path across the sky—is far more complicated than either the sun or stars. Not only does the Earth rotate beneath it, but it is the only heavenly body that circles us. The Earth may have been demoted, as far as its place in the cosmos goes, but we retain the moon as our exclusive satellite. So when we follow the moon’s journey across our sky, we’re seeing the composite pattern of its monthly revolution around us and our daily rotation under it.
And the moon’s cyclical periods are neither simple nor match those of the Earth. The lunar month is some 29.5 Earth days long and there are 12.4 lunar months in an Earth year. They’re out of sync with each other, so events do not repeat themselves in a regular manner. As a result, you may get a straightforward track of the moon across the sky during a given night, but its location shifts quite a bit the next night. For example, tonight at 9:00 it may be directly overhead, but each subsequent night it shifts a substantial amount eastward. In a week it’ll be near the eastern horizon at 9:00, and then completely gone from the night sky the following week.
But there’s more. The moon’s orbital plane is at a slight angle to the ecliptic and it wobbles up and down a bit. That waver completes a cycle every 18.61 years. One needs a thorough knowledge of these wobbles in order to predict when lunar and solar eclipses will occur. There’s still more: The moon’s orbit about the Earth is not a perfect circle; it is egg shaped. So it’s closer to us at times (at perigee, when it’s also a little larger) and farther at other times (at apogee, when it’s a little smaller).
It makes my mind swoon to try to comprehend all these variations. I am humbled by the ancients who had the time and inclination to take note of all these lunar complexities and accurately predict their periodic occurrences in such exquisite observatories as Stonehenge and similar monuments.
The last and most complex of all the heavenly objects are the planets. Their behaviors are truly bizarre. If you mentally elevate yourself to a place high above the plane of the solar system, the orbits of the planets around the sun can be seen to be simple near-circles. From an Earth-centered perspective, however, the planets (Greek word for wanderer) trace weird paths across our sky. Although they may behave themselves nightly—arcing across the sky like the stars—their positions relative to those background stars wander in an almost inebriated manner, over a period of weeks or months.
Jupiter may be seen to slowly migrate westward, over a period of weeks, and then abruptly swing back to the east. It may next head west again and then dive below the western horizon, disappearing from the night sky, to reappear in the pre-dawn sky, now towards the east! In fact, these pop-up appearances of the planets—now at night in the west, now at dawn in the east—were so unaccountable that the ancients did not even recognize their reappearance as the same planet.
Only with a mixture of modern astronomy (handily found on web sites) and a little prehistoric sky monitoring can I follow the planets in their mysterious travels across the sky.
I am doing my best to comprehend the paths taken by heavenly bodies across my sky. It’s almost beyond me. I try to soak it all up from a combination of direct observation and reading books. I could do this for another few decades and still not quite approach the proficiency of my forebears. I often wish I had one of them by my side, passing on her clan’s wisdom.
Saturday, November 14, 2009
Thursday, November 12, 2009
Earth-centered Confusions—Part 1
I have written before (12/27/08 and 1/16/09) on the fact that, although we no longer view the heavens as revolving around a fixed Earth, it’s still how we directly experience the motion of celestial objects. Our precious little planet—once thought to be the center of the cosmos—was long ago displaced from its exalted position. In fact, it was exactly 400 years ago that Galileo, peering through his first telescope, provided the first solid evidence that the Earth moves; it revolves, rotates, spins through space.
Here are two irrefutable reasons why our current understanding of the non-Earth-centered cosmic arrangement is valid: (1) it’s far simpler than the old viewpoint and (2) we send space vehicles off to Saturn and it’s out there exactly where we expect it to be. These two results are at the core of the scientific principle: if it’s simpler, it’s probably closer to the truth (that’s how Nature works) and if it stands up under repeated trials (Mars and the moon are also where they are supposed to be), it gains credence.
The more I watch the sky—particularly in the midst of my reveries while reposing in the outdoor tub—the more intimately acquainted I become with its denizens. I see repeated and familiar sights; I pick up on the cycles and patterns of the march of heavenly bodies across my night (and day) sky. I get better at predicting how things will appear tomorrow or next week, as all the objects shift with respect to one another and to the horizons.
But my experience—despite my knowledge of astronomy and our real place in the cosmos—is from that Earth-centered perspective. And if I’m going to develop anything approaching the familiarity that the ancients did, I need to cultivate my Earth-centered understanding. There are a half-dozen or so types of objects floating across my sky. Each one has its peculiar path that it follows; each one behaves according to its own fashion. Most all of them pretty much follow an imaginary arc across the sky: the ecliptic, the path that the sun pursues each day. At our latitude it’s an arc that emerges from the eastern horizon, traverses the sky a little south of directly overhead, and dives below the western horizon.
The sun—the first object I’ll describe—traces the simplest path of all the celestial bodies. It rises in the east each morning, arcs across the sky on that ecliptic, and sets in the west. The peak of that arc (at noon) is high in the sky in the summer and lower (toward the south) in winter. Therefore, summer days are longer, because the sun has a longer path to tread. The sun’s diurnal journey sets the stage for all other heavenly bodies.
The second simplest set of objects to follow a daily path across the sky is the stars. The pattern of their motion is only a little more complicated than the sun. The stars trace a nighttime path that’s pretty much the same as the sun’s daytime route. Those stars that fall on the ecliptic—those that belong to the zodiacal constellations—do indeed follow the sun’s path. All stars rotate about the North Star, which appears never to change its position in the sky.
But the stars also exhibit an additional kind of motion—beyond the sun’s simplicity. For example, at noon the sun has attained its zenith and will return to that same spot each day. The star I see at its zenith at midnight tonight, however, will have moved a wee bit westward tomorrow night. That shift (about one degree) is imperceptible on a night-to-night basis, but over a month’s time that star (and all of its celestial companions) will have moved a good distance, like the creeping hands of a clock. In three month’s time that star that was at its zenith at midnight will now be seen down by the western horizon, about to set. Six months from now it will be directly underneath me—washed out by the noontime sun. Rest assured, a year from now I’ll find that it once again is perched directly overhead at midnight. By then, of course, my planet Earth will have completed one year’s revolution around the sun.
Next time: the third, the most romantic, and very complex night sky object.
Here are two irrefutable reasons why our current understanding of the non-Earth-centered cosmic arrangement is valid: (1) it’s far simpler than the old viewpoint and (2) we send space vehicles off to Saturn and it’s out there exactly where we expect it to be. These two results are at the core of the scientific principle: if it’s simpler, it’s probably closer to the truth (that’s how Nature works) and if it stands up under repeated trials (Mars and the moon are also where they are supposed to be), it gains credence.
The more I watch the sky—particularly in the midst of my reveries while reposing in the outdoor tub—the more intimately acquainted I become with its denizens. I see repeated and familiar sights; I pick up on the cycles and patterns of the march of heavenly bodies across my night (and day) sky. I get better at predicting how things will appear tomorrow or next week, as all the objects shift with respect to one another and to the horizons.
But my experience—despite my knowledge of astronomy and our real place in the cosmos—is from that Earth-centered perspective. And if I’m going to develop anything approaching the familiarity that the ancients did, I need to cultivate my Earth-centered understanding. There are a half-dozen or so types of objects floating across my sky. Each one has its peculiar path that it follows; each one behaves according to its own fashion. Most all of them pretty much follow an imaginary arc across the sky: the ecliptic, the path that the sun pursues each day. At our latitude it’s an arc that emerges from the eastern horizon, traverses the sky a little south of directly overhead, and dives below the western horizon.
The sun—the first object I’ll describe—traces the simplest path of all the celestial bodies. It rises in the east each morning, arcs across the sky on that ecliptic, and sets in the west. The peak of that arc (at noon) is high in the sky in the summer and lower (toward the south) in winter. Therefore, summer days are longer, because the sun has a longer path to tread. The sun’s diurnal journey sets the stage for all other heavenly bodies.
The second simplest set of objects to follow a daily path across the sky is the stars. The pattern of their motion is only a little more complicated than the sun. The stars trace a nighttime path that’s pretty much the same as the sun’s daytime route. Those stars that fall on the ecliptic—those that belong to the zodiacal constellations—do indeed follow the sun’s path. All stars rotate about the North Star, which appears never to change its position in the sky.
But the stars also exhibit an additional kind of motion—beyond the sun’s simplicity. For example, at noon the sun has attained its zenith and will return to that same spot each day. The star I see at its zenith at midnight tonight, however, will have moved a wee bit westward tomorrow night. That shift (about one degree) is imperceptible on a night-to-night basis, but over a month’s time that star (and all of its celestial companions) will have moved a good distance, like the creeping hands of a clock. In three month’s time that star that was at its zenith at midnight will now be seen down by the western horizon, about to set. Six months from now it will be directly underneath me—washed out by the noontime sun. Rest assured, a year from now I’ll find that it once again is perched directly overhead at midnight. By then, of course, my planet Earth will have completed one year’s revolution around the sun.
Next time: the third, the most romantic, and very complex night sky object.
Monday, November 9, 2009
Wednesday, November 4, 2009
Cultural or Personal?
I am an inveterate watcher of things—be they nature, animals, or people. Furthermore, being a hermit, I lean towards the introverted end of the personality spectrum, so I’m more likely to watch people than join in their activities. Becoming a fly on the wall comes naturally to me. I’m also easily drawn to sitting at length and watching some intriguing activity of a bug or other critter.
This propensity to become immersed in watching often draws me deeply into an activity or event that I come upon. Hmmmm, what’s going on here? What is that creature doing? Why does he do it that way? I wonder what will happen next. My curiosity gets piqued. My imagination can go on a binge. It’s fun.
When I observe humans, I often find myself speculating whether the behavior I see stems from a cultural or from a personal attribute. General behaviors often originate from one’s culture. For example, people in the Middle East are warmly hospitable to visitors. People in Latin America highly value family connections. I have enjoyed traveling to other countries and watching the novel (to me) practices and traditions of diverse people—especially those surrounding food and holiday happenings.
From within my own culture I become very familiar with my people’s common (i.e., cultural) behaviors. In fact, the customs of our own culture can become quite invisible to us. (For example, I didn’t particularly notice how the typical American dresses until I once spent a month in fashionable northern Italy and returned home, to get jolted by the appearance of relatively casual-to-sloppy looking Americans.) Being familiar with my own culture, when I see one of my people acting uniquely or differently, I can guess that it’s probably a personal thing. That guy over there just did something unusual; it must be an individual eccentricity of his. Hmmmm, I wonder why he did that. What in his background may have led to that? Maybe I’ll strike up a conversation and see if I can find out.
But when I’m in a foreign culture and I observe someone doing something that appears unusual, I have little idea whether it’s a cultural or a personal thing. I’m fascinated. The mystery draws me in. There’s so much to learn about these folks.
Of course, one needs to be cautious and not jump to conclusions about these novel observations, since stereotyping can arise when I decide that what I see is a cultural thing, when in fact it may be personal. I don’t want to conclude, for example, that all Russians are well mannered, just because I saw one behave politely; or that all Californians are child abusers, just because I saw one slap his kid.
This propensity to become immersed in watching often draws me deeply into an activity or event that I come upon. Hmmmm, what’s going on here? What is that creature doing? Why does he do it that way? I wonder what will happen next. My curiosity gets piqued. My imagination can go on a binge. It’s fun.
When I observe humans, I often find myself speculating whether the behavior I see stems from a cultural or from a personal attribute. General behaviors often originate from one’s culture. For example, people in the Middle East are warmly hospitable to visitors. People in Latin America highly value family connections. I have enjoyed traveling to other countries and watching the novel (to me) practices and traditions of diverse people—especially those surrounding food and holiday happenings.
From within my own culture I become very familiar with my people’s common (i.e., cultural) behaviors. In fact, the customs of our own culture can become quite invisible to us. (For example, I didn’t particularly notice how the typical American dresses until I once spent a month in fashionable northern Italy and returned home, to get jolted by the appearance of relatively casual-to-sloppy looking Americans.) Being familiar with my own culture, when I see one of my people acting uniquely or differently, I can guess that it’s probably a personal thing. That guy over there just did something unusual; it must be an individual eccentricity of his. Hmmmm, I wonder why he did that. What in his background may have led to that? Maybe I’ll strike up a conversation and see if I can find out.
But when I’m in a foreign culture and I observe someone doing something that appears unusual, I have little idea whether it’s a cultural or a personal thing. I’m fascinated. The mystery draws me in. There’s so much to learn about these folks.
Of course, one needs to be cautious and not jump to conclusions about these novel observations, since stereotyping can arise when I decide that what I see is a cultural thing, when in fact it may be personal. I don’t want to conclude, for example, that all Russians are well mannered, just because I saw one behave politely; or that all Californians are child abusers, just because I saw one slap his kid.
Monday, November 2, 2009
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