Wednesday, February 16, 2011
Friday, February 11, 2011
Avian Quickening
I once described the four Celtic cross-quarter days in an earlier posting—those times of year when the Celts saw measurable seasonal change and held festivals and appealed to their gods to watch over them. These four events meant more to those ancient people than our modern calendrical milestones, because they lived so close to the land and the cross-quarter days more closely related to events on the ground.
One cross-quarter day that we heartily greet is Imbolc—which falls half way between winter solstice and spring equinox—during the first week of February. Imbolc brings the true passing of winter, as the dark season begins to yield to increasing sunlight. For the month or so before Imbolc the day length increases a miserly minute each day—a difference that anyone is unlikely to notice. Winter seems to have settled in and is disinclined to move on. But right after Imbolc the day length grows by about three minutes each day. That becomes noticeable!
Animals and plants notice too. They may not be able to peer into the future or read a calendar and anticipate the arrival of spring as we do, but evolution has taught them to prepare for change. Tree buds swell, underground seeds begin to sprout, and mammals begin to lactate (Imbolc means “in milk). Our Celtic ancestors were attuned to the signs as well. They celebrated the goddess Brighde (pronounced “Breed”) at this time—a lady who reigned over birth, healing, inspiration, nature, and their precious livestock. They even cleaned the winter’s accumulation of trash from their dwellings in honor of Brighde. Is this the origins of our spring-cleaning?
It’s around Imbolc time that we hear the year’s first real bird calls in our neighborhood—not the brief, almost accidental bursts of sound that an isolated bird will emit on a cold winter day, but a true song to spring. Just as we know that the swelling buds will bring leaves and blossoms before long, we know that more bird songs will soon fill the air.
We know Imbolc is here and have learned what to expect in the quickening of nature at this time of year, but what’s stimulating the birds? Is it the increasing light that cues them? It can’t be a warming of the air—it’s still as cold as it was a few weeks ago. They can’t read a calendar (at least not the human kind). What might be stirring inside their wee breasts? A little testosterone? The sheer joy of spring that instinct somehow brings?
They’re not as yet ready to divulge their secret—or maybe they are, but we just don’t understand their language. Maybe I’m once again looking too hard for reasons. Regardless of what’s going on, we love to hear these early bursts of song. For us it’s a better sign that winter is coming to a conclusion, than trying to catch a groundhog being startled by his shadow.
One cross-quarter day that we heartily greet is Imbolc—which falls half way between winter solstice and spring equinox—during the first week of February. Imbolc brings the true passing of winter, as the dark season begins to yield to increasing sunlight. For the month or so before Imbolc the day length increases a miserly minute each day—a difference that anyone is unlikely to notice. Winter seems to have settled in and is disinclined to move on. But right after Imbolc the day length grows by about three minutes each day. That becomes noticeable!
Animals and plants notice too. They may not be able to peer into the future or read a calendar and anticipate the arrival of spring as we do, but evolution has taught them to prepare for change. Tree buds swell, underground seeds begin to sprout, and mammals begin to lactate (Imbolc means “in milk). Our Celtic ancestors were attuned to the signs as well. They celebrated the goddess Brighde (pronounced “Breed”) at this time—a lady who reigned over birth, healing, inspiration, nature, and their precious livestock. They even cleaned the winter’s accumulation of trash from their dwellings in honor of Brighde. Is this the origins of our spring-cleaning?
It’s around Imbolc time that we hear the year’s first real bird calls in our neighborhood—not the brief, almost accidental bursts of sound that an isolated bird will emit on a cold winter day, but a true song to spring. Just as we know that the swelling buds will bring leaves and blossoms before long, we know that more bird songs will soon fill the air.
We know Imbolc is here and have learned what to expect in the quickening of nature at this time of year, but what’s stimulating the birds? Is it the increasing light that cues them? It can’t be a warming of the air—it’s still as cold as it was a few weeks ago. They can’t read a calendar (at least not the human kind). What might be stirring inside their wee breasts? A little testosterone? The sheer joy of spring that instinct somehow brings?
They’re not as yet ready to divulge their secret—or maybe they are, but we just don’t understand their language. Maybe I’m once again looking too hard for reasons. Regardless of what’s going on, we love to hear these early bursts of song. For us it’s a better sign that winter is coming to a conclusion, than trying to catch a groundhog being startled by his shadow.
Tuesday, February 8, 2011
Sunday, February 6, 2011
Goldilocks Globe—Part 2
[News flash! It was just announced by NASA on 2 February that the Kepler Space Telescope has discovered 1235 candidate exo-planets as of that date! Of those, some 68 are Earth size! NASA will be further examining these candidates over the next few months, to see which may really be planets. How timely! On to Goldilocks.]
A few months ago a so-called “Goldilocks” planet was found. It got tagged with the name Goldilocks, because its star had two previously-discovered planets that were either too hot or too cold to support life. But a little more analysis of the data revealed a smaller in-between planet, dubbed Goldilocks, and officially given the moniker “Gliese 581 g.” It’s far enough away from its star to be able to have water, rather than either ice (it’s too cold) or steam (it’s too hot). Furthermore, it’s not much larger than Earth, so even its gravity and atmosphere could be like ours. Gliese 581 g is the first planet that we have located that just might support life as we know it! It’s caused quite a buzz in the astronomical community.
Planet Gliese 581 g is orbiting a star some 20 light years (that’s about 120 trillion miles) away. The star itself is named Gliese 581 a—which is a naming system that gives stars and their planets a numerical moniker. This star is quite different from our sun—it’s a red dwarf, it’s about one-third the size of the sun, it’s much older, and it’s a little over half the temperature. That may seem to describe an unusual star, but red dwarfs (which are too dim to see with the human naked eye) constitute as many as 90% of all the many billions of stars in our Milky Way galaxy. So they’re very common, and if life really does exist out there (astronomers get more confident every day that we’re not alone), it likely is orbiting a red dwarf star.
So what more do we know about this Goldilocks Gliese 581 g? It’s probably a rocky planet (like Earth) with enough mass to hold onto an atmosphere, if it has one. It is about 1.5-2 times the size of Earth, so its gravity wouldn’t be so large as to crush life forms similar to Earth’s. Its orbital period (its year) is very short—only about 37 Earth days—because it’s very close to its little, cool star. That brings about the fascinating result that the planet would be tidally locked to its star (like our Moon is to Earth), so it presents just one face to the star. That means that its perpetually daylight face stays boiling hot, while its permanent night face is freezing cold.
So how could it foster life or have liquid water? Because the zone between night and day (Goldilocks’s “twilight zone”) could be just the right temperature for life. In fact, if the planet has an atmosphere, that twilight zone could be quite wide, due to winds blowing around and spreading out the habitable zone.
It would be a wild experience to stand on Gliese 581 g and gaze at its sun. Rather than appear yellow-white, it’d be orange-red. It would appear about twice the size of our sun (since it’s closer), but it would never roam across the sky. Just as if you were to stand on the Moon and watch Earth constantly hovering in the same spot, day after day, year after year, the star Gliese 581 a would be stuck in the same place, and it would remain near the horizon.
Goldilocks has astronomers pretty excited, but mostly its discovery is leading them to expect to locate more habitable planets soon. The race is on! Kepler is continuing to find more planets around neighboring stars (1235 and counting!). We are beginning to document the fact that planetary systems are quite common in our galaxy. Couple this fact with the robustness of life that we’re also discovering right here on Earth, and the probability of life existing on planets other than Earth grows ever higher. Just a couple of decades ago the question “Are we alone?” had to be answered with a high degree of speculation and doubt. It’s beginning to appear, however, that the answer might well be “Not at all.”
A few months ago a so-called “Goldilocks” planet was found. It got tagged with the name Goldilocks, because its star had two previously-discovered planets that were either too hot or too cold to support life. But a little more analysis of the data revealed a smaller in-between planet, dubbed Goldilocks, and officially given the moniker “Gliese 581 g.” It’s far enough away from its star to be able to have water, rather than either ice (it’s too cold) or steam (it’s too hot). Furthermore, it’s not much larger than Earth, so even its gravity and atmosphere could be like ours. Gliese 581 g is the first planet that we have located that just might support life as we know it! It’s caused quite a buzz in the astronomical community.
Planet Gliese 581 g is orbiting a star some 20 light years (that’s about 120 trillion miles) away. The star itself is named Gliese 581 a—which is a naming system that gives stars and their planets a numerical moniker. This star is quite different from our sun—it’s a red dwarf, it’s about one-third the size of the sun, it’s much older, and it’s a little over half the temperature. That may seem to describe an unusual star, but red dwarfs (which are too dim to see with the human naked eye) constitute as many as 90% of all the many billions of stars in our Milky Way galaxy. So they’re very common, and if life really does exist out there (astronomers get more confident every day that we’re not alone), it likely is orbiting a red dwarf star.
So what more do we know about this Goldilocks Gliese 581 g? It’s probably a rocky planet (like Earth) with enough mass to hold onto an atmosphere, if it has one. It is about 1.5-2 times the size of Earth, so its gravity wouldn’t be so large as to crush life forms similar to Earth’s. Its orbital period (its year) is very short—only about 37 Earth days—because it’s very close to its little, cool star. That brings about the fascinating result that the planet would be tidally locked to its star (like our Moon is to Earth), so it presents just one face to the star. That means that its perpetually daylight face stays boiling hot, while its permanent night face is freezing cold.
So how could it foster life or have liquid water? Because the zone between night and day (Goldilocks’s “twilight zone”) could be just the right temperature for life. In fact, if the planet has an atmosphere, that twilight zone could be quite wide, due to winds blowing around and spreading out the habitable zone.
It would be a wild experience to stand on Gliese 581 g and gaze at its sun. Rather than appear yellow-white, it’d be orange-red. It would appear about twice the size of our sun (since it’s closer), but it would never roam across the sky. Just as if you were to stand on the Moon and watch Earth constantly hovering in the same spot, day after day, year after year, the star Gliese 581 a would be stuck in the same place, and it would remain near the horizon.
Goldilocks has astronomers pretty excited, but mostly its discovery is leading them to expect to locate more habitable planets soon. The race is on! Kepler is continuing to find more planets around neighboring stars (1235 and counting!). We are beginning to document the fact that planetary systems are quite common in our galaxy. Couple this fact with the robustness of life that we’re also discovering right here on Earth, and the probability of life existing on planets other than Earth grows ever higher. Just a couple of decades ago the question “Are we alone?” had to be answered with a high degree of speculation and doubt. It’s beginning to appear, however, that the answer might well be “Not at all.”
Thursday, February 3, 2011
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