Posted on 05/31/2004 8:42:21 PM PDT by neverdem
In Shakespeare's "Julius Caesar," the title character declares, "But I am constant as the Northern Star, of whose true fixed and resting quality there is no fellow in the firmament."
In modern astronomical terms, Caesar was saying that he was a flaky, unstable guy.
Astronomers have known for some time that Polaris, the North Star, sitting almost directly over the North Pole, is a Cepheid variable, a type of star that is caught in a cycle of bloating and collapsing because it has exhausted its hydrogen fuel.
In this unsettled state, Polaris brightens and dims every four days or so, and over time, its pulsations have been slowing, the period of oscillation lengthening eight seconds a year.
Yesterday at a meeting of the American Astronomical Society in Denver, astronomers reported that Polaris is even unsteadier than they had thought.
Even Polaris's average brightness has not remained the same, reported Dr. Edward F. Guinan of Villanova University. Measurements over the past half century show it has brightened 10 percent. When he and Scott Engle, an undergraduate, checked older records, they found more surprises.
In the 1800's, Polaris appeared to be 20 percent less bright. In the 1500's, the astronomer Tycho Brahe recorded an even dimmer value. Ptolemy of Alexandria in his star catalog of A.D. 140 listed Polaris as a third magnitude star. Magnitude is a scale devised by the Greek astronomer Hipparchus around 120 B.C. ranking stars from bright (1) to dim (6), a system still in use today.
Today, Polaris is a second magnitude star. A change of a full magnitude would mean Polaris is 2.5 times as bright as it was 2,000 years ago. "That's unusual," Dr. Guinan said. "It shouldn't be changing that fast."
Of course, maybe Ptolemy's eyesight was off. "You're using someone's judgment calls, and these aren't scientific yet," Dr. Guinan said.
Dr. Guinan and Mr. Engle also looked at the work of the Persian astronomer al-Sufi in the 10th century; he made his own observations and corrected Ptolemy's errors. Because al-Sufi also reported Polaris as third magnitude, "it makes me believe that this could be correct," Dr. Guinan said.
Meanwhile, Dr. David G. Turner of St. Mary's University in Halifax, Nova Scotia, said Polaris was much closer than had been thought. His research indicates that Polaris is 310 light-years away. The current accepted distance to Polaris is 430 light-years.
If Dr. Turner is correct, his findings offer an explanation for why Polaris appears as bright as it does. Until now, astronomers have suggested that the star possesses unusual internal pulsations that pump out additional light, but if it is nearer, that elaborate theory would be unnecessary.
Because of the wobble in Earth's spin, even the northness of Polaris is transient. Back in the time of the Egyptian pharaohs, another star, Thuban, was the North Star. Over time, as the axis tipped, Thuban moved away, and Polaris approached the pole. In Shakespeare's time, Polaris was farther from the pole than now, , but still close enough to be considered the North Star.
But Caesar, who ruled in the first century B.C., would have seen neither Thuban nor Polaris as a fixed North Star. The Shakespearean lines are an astronomical anachronism.
"He wouldn't have said that, probably," Dr. Guinan said.
PING
Always trying to blur the lines, they are, in oh so deceptive ways.
LOL
"an attack on objective truth."
Shakespeare's point is that the North Star doesn't spin like the other stars or move like the planets. That is still true even if it is changing in intensity. We can always look to the fixed star to find our direction, exactly like we can look to eternal truths in the Word of God for direction in life.
In classical times, the point on the ecliptic where the sun was at the time of the vernal equinox was in Aries; now it is in Pisces. No harm done, except to inspire some nonsense some years back about "the Age of Aquarius." Eventually there's a complete circuit; someday Thuban will again be the star closest to the North pole.
What about the title? The "North Star" ain't always gonna be Polaris. The cycle for one "rotation" of stars is about
25,000 years, and the star nearest the Earth's polar line changes about every 5000 years. I think the next star will
be Thuban in about 2500 years.
So, the Slimes can't even pick an appropriate analogy with "Constant of the North Star".
Given the general accuracy of modern day astronomy it is odd to see the NY Times reporting that scientists may have been off 120 light years on the distance to the North Star. What will they report next, that Bush actually won Florida?
I like your deduction.
Your so right the north star is just a referance point to guide you in a northern direction the magnitude of its light does not matter( a cloudy night the north star is worthless), the north star is a constant referance point a fixed point to guide your way. But like you say the NYT does not like fixed points or any other guides besides its all knowing all seeing editorial wizards behind the curtain.
Do those Cepheids finally blow up in the end? If yes, then it might be a little too close...
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