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Comets: From Doomsayers to Delights (Part 1)

Comets >

There are two long-haired types headed our way. They go by the code names C/2001 Q4 and C/2002 T7. If you know where to look you can see them now, with a little help. By next month just about everyone on Earth should be able to see the two. Had enough of these apocalyptic riddles?

I'm talking about comets, those rare and beautiful solar system objects, predictable to an extreme in their orbits, but very impulsive as to how they will actually present themselves.

We have two debutantes headed our way in late April and May. The big question is: Will this spring's gossamered guests power through the skies, graced by millions-of-miles-long tails, or will they be tiny, dim, disappointing fuzzballs?

In the coming weeks here we'll look at the historical role of comets as portents of ruin, where they come from and why they do the things they do, and the details of our latest two mentioned above and what to look for as they pass by.

In order to understand the importance of comets in history you'll have to put yourself back in ancient times. To most of our ancestors the sky was a thing of steadiness and relative calm. The stars kept their positions in the sky year after year after year. The planets, of course, were known to be the wanderers. But even their movements were relatively predictable.

The reliability of the sky was so well trusted one could set his or her watch by it. As a matter of fact, social, religious, and agricultural calendars were set by the movements of the trusted heavens.

So imagine the trepidation when one of these rogues would suddenly come flying by. Here they are, showing up whenever they want, coming from and leaving into whatever direction they choose. They never go by with the same steady motion through the sky, oh no! They come in slowly, speed up as they fly through the starry background, only to slow again ... and then disappear!

Since many people believed the skies were where the Deity or deities resided, many saw comets as messages from above. And almost exclusively it was bad news that was being sent.

Whether one was Chinese, Babylonian, Greek, or Roman, comets meant the death of a king, an impending war, famine, or the end of a dynasty. They were (cue dramatic music) Portents of Doom!

Not everyone saw them as starry harbingers of disaster, even if they couldn't figure out exactly what they were. The philosopher Aristotle had his spin on these strange visitors. The Universe According to Aristotle portrayed the universe as perfection. All the different heavenly objects traveled through the perfect heavens with perfect motions.

So how did Aristotle explain the creepiness of comets? They were an atmospheric phenomenon, not a heavenly one! They were literally in the blue skies above our head. This view was held for another 2000 years until Edmund Halley put a final nail in old ultra-influential Aristotle's coffin.

Halley was a contemporary and friend of Isaac Newton in the late 17th century. Newton had recently shown that there were laws governing the motions of the universe. Might comets just be solar system bodies, no better or worse than planets and moons? Could Newton's laws be used to predict whether a comet might actually return?

Looking back at historical records Halley discovered that the comet of 1682 had some unique characteristics, making it slightly unusual even by comet standards. Looking back farther he saw that the comet of 1607 and one way back in 1531 were also very similar to the 1682 comet. Hmmmm ...

Was it too much to expect that all three might be the same animal? Using Newton's laws of motion and putting his reputation on the line, Halley predicted the return of that comet "about the end of the year 1758, or the beginning of the next."

Lo and behold! On Christmas Day 1758, a farmer in Dresden first spotted the returning comet. It has returned several times since, the latest visit being in 1986.

Newton's laws stood the test, Aristotle was finally laid to rest, and the now famous comet was named Halley's Comet. Comets, it turned out, were just another group in the family of the sun, and like the other bodies were subject to ordinary laws of motion. But what were they? Where were they coming from? And why the tail?

Tune in next time as we continue our look into comets and what makes them tick.

Mark Ritter teaches astronomy at Temecula Valley High School and can be reached at mritter@firstlightastro.com.

Posted by Administrator at 2004.04.18 12:38 PM | Comments (0)

The Weekdays' Heavenly Names

The Calendar >

This week you have the rare chance of actually seeing the days of the week in the skies. That doesn't make sense, does it? Let me explain ...

To the ancients there were seven heavenly bodies other than the stars, seven "wanderers" or "planets": the Sun, the moon, Mercury, Venus, Mars, Jupiter, and Saturn. The other planets we know --- Uranus, Neptune, and Pluto --- were beyond their ability to espy.

All represented deity and each ruled a day of the week. Although other cultures shared in the shaping of all this, it is specifically the Johnny-come-lately seven-day-week of the Romans that ended up as the main foundation of our modern naming of the days. But we'll see here also how the Germanic languages built on that foundation. Ready?

Sunday
The most obvious day of the week named after a celestial object is the first day of the week, Sunday, the day of the sun. Of course, one can see that heavenly body on any clear day.

Monday
On Monday evening, go out and take a look at the nearly fully lit orb rising in the east. That heavenly body is, obviously, the Moon for which Monday is named. In Latin the day was "dies Lunae," the day of Luna the moon goddess. That Latin name is still seen today in the French word for Monday, "lundi."

Tuesday
On Tuesday you might want to go out and look at Mars. It is that pale pinkish dot just a hand width above Venus, which itself is now the brightest object in the western evening sky. Mars, as discussed here recently, ruled the third day of the week, called "dies Martis" to the Romans. In Italian, another Romance language, it is still seen in their day name "martedì." But the Germanic peoples, who substituted their own Norse gods to fill their adopted Roman calendar week, named the day for their war god, Tyr, who most closely resembled Mars. In Anglo-Saxon he was Tiw. Thence we get our own "Tuesday."

Wednesday
Now the next planet will be a challenge to see. On Wednesday you can look to the western horizon after sunset, late in the 7 o'clock hour. If you are patient you may catch a glimpse of tiny Mercury. It is the wee white dot near horizon, just a little north of due west. In Latin this midweek day was "dies Mercurii," the day of Mercury, and the source of the Spanish "miércoles." But how did we get the name Wednesday from Mercury? Via another Germanic connection, that's how! Woden was the highest deity in the Teutonic menagerie of gods. His characteristics included swiftness and a wide range of travel, not unlike the Roman god Mercury. So "dies Mercurii" was rechristened "Wodnes daeg." And from that our "Wednesday."

Thursday
Thursday night venture out and see one of the brightest objects in the sky. Jupiter, our largest planet, rises in the eastern sky after sunset and rules the late night after Venus sets. In Roman mythology Jupiter --- or Jove --- had a quiver-full of traits and powers. One of Jove's titles was ruler of the storm. We all learned of Jupiter's Germanic god-equivalent back in elementary school --- Thor. It is no challenge to see Thor's name in our Thursday. And, by Jove, neither does it take a degree in philology to see Jove's name in the Spanish Thursday, jueves.

Friday
On Friday step outside after sunset and take no more than a second to find the brightest object in the early evening western sky. That is, of course, Venus, our nearest planetary neighbor. We can still spot Venus' name in the Italian for Friday --- venerdì. But how is our name "Friday" anything like "Venus"? Back to the Germanic peoples ... Woden had a wife named Frigg. She was also the goddess of fertility, as was Venus to the Romans. So the Roman's "dies Veneris," the day of Venus, became the Anglo-Saxon "Frig daeg," which became our "Friday."

Saturday
We'll end our week of names on an easy one. Go out Saturday evening and find Venus and Jupiter. About a third of the way from Venus to Jupiter you'll find the bright yellowish dot, Saturn, a favorite of astronomers everywhere. It takes zero imagination to see that Saturday is Saturn's day. Ironically, our English name is like the Latin for once, whereas the Spanish for Saturday is "sabado," after the day of rest.

If you want to know more about the connections between the night sky and cultures world wide, a wonderful and exhaustive book on the subject is E. C. Krupp's Beyond the Blue Horizon.

Have a great "week!" The word "week," to no one's surprise, comes from the Teutonic word "wice" ... Whoa! Sorry, got carried away there.

Mark Ritter teaches astronomy at Temecula Valley High School and can be reached at mritter@firstlightastro.com.

Posted by Administrator at 2004.04. 3 12:40 PM | Comments (0)



Looking for something?	« March 2004 \| Main \| May 2004 » Comets: From Doomsayers to Delights (Part 1) Comets > There are two long-haired types headed our way. They go by the code names C/2001 Q4 and C/2002 T7. If you know where to look you can see them now, with a little help. By next month just about everyone on Earth should be able to see the two. Had enough of these apocalyptic riddles? I'm talking about comets, those rare and beautiful solar system objects, predictable to an extreme in their orbits, but very impulsive as to how they will actually present themselves. We have two debutantes headed our way in late April and May. The big question is: Will this spring's gossamered guests power through the skies, graced by millions-of-miles-long tails, or will they be tiny, dim, disappointing fuzzballs? In the coming weeks here we'll look at the historical role of comets as portents of ruin, where they come from and why they do the things they do, and the details of our latest two mentioned above and what to look for as they pass by. In order to understand the importance of comets in history you'll have to put yourself back in ancient times. To most of our ancestors the sky was a thing of steadiness and relative calm. The stars kept their positions in the sky year after year after year. The planets, of course, were known to be the wanderers. But even their movements were relatively predictable. The reliability of the sky was so well trusted one could set his or her watch by it. As a matter of fact, social, religious, and agricultural calendars were set by the movements of the trusted heavens. So imagine the trepidation when one of these rogues would suddenly come flying by. Here they are, showing up whenever they want, coming from and leaving into whatever direction they choose. They never go by with the same steady motion through the sky, oh no! They come in slowly, speed up as they fly through the starry background, only to slow again ... and then disappear! Since many people believed the skies were where the Deity or deities resided, many saw comets as messages from above. And almost exclusively it was bad news that was being sent. Whether one was Chinese, Babylonian, Greek, or Roman, comets meant the death of a king, an impending war, famine, or the end of a dynasty. They were (cue dramatic music) Portents of Doom! Not everyone saw them as starry harbingers of disaster, even if they couldn't figure out exactly what they were. The philosopher Aristotle had his spin on these strange visitors. The Universe According to Aristotle portrayed the universe as perfection. All the different heavenly objects traveled through the perfect heavens with perfect motions. So how did Aristotle explain the creepiness of comets? They were an atmospheric phenomenon, not a heavenly one! They were literally in the blue skies above our head. This view was held for another 2000 years until Edmund Halley put a final nail in old ultra-influential Aristotle's coffin. Halley was a contemporary and friend of Isaac Newton in the late 17th century. Newton had recently shown that there were laws governing the motions of the universe. Might comets just be solar system bodies, no better or worse than planets and moons? Could Newton's laws be used to predict whether a comet might actually return? Looking back at historical records Halley discovered that the comet of 1682 had some unique characteristics, making it slightly unusual even by comet standards. Looking back farther he saw that the comet of 1607 and one way back in 1531 were also very similar to the 1682 comet. Hmmmm ... Was it too much to expect that all three might be the same animal? Using Newton's laws of motion and putting his reputation on the line, Halley predicted the return of that comet "about the end of the year 1758, or the beginning of the next." Lo and behold! On Christmas Day 1758, a farmer in Dresden first spotted the returning comet. It has returned several times since, the latest visit being in 1986. Newton's laws stood the test, Aristotle was finally laid to rest, and the now famous comet was named Halley's Comet. Comets, it turned out, were just another group in the family of the sun, and like the other bodies were subject to ordinary laws of motion. But what were they? Where were they coming from? And why the tail? Tune in next time as we continue our look into comets and what makes them tick. Mark Ritter teaches astronomy at Temecula Valley High School and can be reached at mritter@firstlightastro.com. Posted by Administrator at 2004.04.18 12:38 PM \| Comments (0) The Weekdays' Heavenly Names The Calendar > This week you have the rare chance of actually seeing the days of the week in the skies. That doesn't make sense, does it? Let me explain ... To the ancients there were seven heavenly bodies other than the stars, seven "wanderers" or "planets": the Sun, the moon, Mercury, Venus, Mars, Jupiter, and Saturn. The other planets we know --- Uranus, Neptune, and Pluto --- were beyond their ability to espy. All represented deity and each ruled a day of the week. Although other cultures shared in the shaping of all this, it is specifically the Johnny-come-lately seven-day-week of the Romans that ended up as the main foundation of our modern naming of the days. But we'll see here also how the Germanic languages built on that foundation. Ready? Sunday The most obvious day of the week named after a celestial object is the first day of the week, Sunday, the day of the sun. Of course, one can see that heavenly body on any clear day. Monday On Monday evening, go out and take a look at the nearly fully lit orb rising in the east. That heavenly body is, obviously, the Moon for which Monday is named. In Latin the day was "dies Lunae," the day of Luna the moon goddess. That Latin name is still seen today in the French word for Monday, "lundi." Tuesday On Tuesday you might want to go out and look at Mars. It is that pale pinkish dot just a hand width above Venus, which itself is now the brightest object in the western evening sky. Mars, as discussed here recently, ruled the third day of the week, called "dies Martis" to the Romans. In Italian, another Romance language, it is still seen in their day name "martedì." But the Germanic peoples, who substituted their own Norse gods to fill their adopted Roman calendar week, named the day for their war god, Tyr, who most closely resembled Mars. In Anglo-Saxon he was Tiw. Thence we get our own "Tuesday." Wednesday Now the next planet will be a challenge to see. On Wednesday you can look to the western horizon after sunset, late in the 7 o'clock hour. If you are patient you may catch a glimpse of tiny Mercury. It is the wee white dot near horizon, just a little north of due west. In Latin this midweek day was "dies Mercurii," the day of Mercury, and the source of the Spanish "miércoles." But how did we get the name Wednesday from Mercury? Via another Germanic connection, that's how! Woden was the highest deity in the Teutonic menagerie of gods. His characteristics included swiftness and a wide range of travel, not unlike the Roman god Mercury. So "dies Mercurii" was rechristened "Wodnes daeg." And from that our "Wednesday." Thursday Thursday night venture out and see one of the brightest objects in the sky. Jupiter, our largest planet, rises in the eastern sky after sunset and rules the late night after Venus sets. In Roman mythology Jupiter --- or Jove --- had a quiver-full of traits and powers. One of Jove's titles was ruler of the storm. We all learned of Jupiter's Germanic god-equivalent back in elementary school --- Thor. It is no challenge to see Thor's name in our Thursday. And, by Jove, neither does it take a degree in philology to see Jove's name in the Spanish Thursday, jueves. Friday On Friday step outside after sunset and take no more than a second to find the brightest object in the early evening western sky. That is, of course, Venus, our nearest planetary neighbor. We can still spot Venus' name in the Italian for Friday --- venerdì. But how is our name "Friday" anything like "Venus"? Back to the Germanic peoples ... Woden had a wife named Frigg. She was also the goddess of fertility, as was Venus to the Romans. So the Roman's "dies Veneris," the day of Venus, became the Anglo-Saxon "Frig daeg," which became our "Friday." Saturday We'll end our week of names on an easy one. Go out Saturday evening and find Venus and Jupiter. About a third of the way from Venus to Jupiter you'll find the bright yellowish dot, Saturn, a favorite of astronomers everywhere. It takes zero imagination to see that Saturday is Saturn's day. Ironically, our English name is like the Latin for once, whereas the Spanish for Saturday is "sabado," after the day of rest. If you want to know more about the connections between the night sky and cultures world wide, a wonderful and exhaustive book on the subject is E. C. Krupp's Beyond the Blue Horizon. Have a great "week!" The word "week," to no one's surprise, comes from the Teutonic word "wice" ... Whoa! Sorry, got carried away there. Mark Ritter teaches astronomy at Temecula Valley High School and can be reached at mritter@firstlightastro.com. Posted by Administrator at 2004.04. 3 12:40 PM \| Comments (0)
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