John Plaxton (guest) 07 Nov 2009 04:20
This is about science, not a movie!!
Although I have not read Patrick Geryl’s book, he might be right about the earth’s True North and True South poles changing places, although in the MacLean’s article the sentence “… The globe will start rotating in the opposite direction making the sun seem to rise in the west, …” is incorrect. The globe keeps rotating in the same direction.
Astronomically, try this.
Ensuring that the South Pole is at the top, place a globe of the earth (or a large ball) in a bowl or candy dish on top and in the centre of a “Lazy Susan”. Somewhere near the equator (middle of ball) mark the letter E on the left side and the letter W on the right side. Also draw an arrow straight up, pointing to the South Pole. Position a flashlight to shine on the globe.
Rotate the Lazy Susan a couple of times from left to right. Note that the W moves into the light before the E does.
(By definition, the sun rises in the east and therefore W is east of E.)
NOW, raise the globe and turn it upside down, ensuring the North Pole at the top, then lower it back into the bowl.
Rotate the Lazy Susan a couple of times from left to right, as before. Note that now the E moves into the light before the W does. In other words, for someone now living on the globe between E and W, now the sun rises in the East but it used to rise in the (W)est. Similarly, now the sun sets in the West but it used to set in the (E)ast.
By always rotating the globe in the same direction, but turning it upside down, reverses where the sun appears to rise and set.
By today's standard, using today's CommonSense, understanding "today, everyone knows that" means that ancient, educated historians who reported on astronomical events had no idea about what they were writing. Is that a fair assumption? Were they writing fiction?
After all, consider how accurate the Mayan Calendar is (never mind about the meaning of its last date, if any), based on observation and knowledge that existed before telescopes and computers were invented.
Is Stonehenge really an accurate astronomical tool?
I have heard that the Chinese Calander is also very accurate, and that it too ends near the end of 2012. I haven't made time to find out if that is true. I wonder if they knew the difference between an eclipse and an unusual solar event?
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It has been recorded that some ancient Chinese once saw the sun rise, sink and rise again within a few of hours. They experienced a “dual Dawn.”
It has been recorded that ancient people witnessed that the sun and the moon stopped moving (presumably from East to West) for several hours during a huge battle in an area near Jericho, Israel.
It has been recorded that ancient people in Mexico experienced a night that lasted considerably longer than twice as normally expected.
The Greeks have a myth about the sun that changed its location within the zodiac within one longish day.
The painting of a night sky inside one of the Egyptian pyramids is upside down, by today’s standard of normal astronomical behavior.
Could all these historical astronomical events have happened at the same time? Could they all be explained by a spinning earth taking a few hours to turn upside down? Probably!
I did that in DOS 5 using the program 'Visible Universe' on a EGA screen twenty years ago, but the graphical printouts on a B&W dot matrix printer were difficult to understand. I couldn't convince anyone.
Asking your students, friends and fellow astronomists to research those historical facts and try to build a modern astronomical simulation would make a VERY interesting school project.
(Sterallium 0.9 and 0.10.2 does allow scripting to create your own simulation, but I don't know the programming language. If you know of any other astronomical programs that allow someone to write scripts, please let me know.)
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Ok, let’s discuss a different physical science, paleomagnetism.
Assume that the earth’s magnetic field always points in the same direction (that is, it is fixed-in-space) with the North Magnetic Pole being above the globe and the South Magnetic Pole being below the “Lazy Susan”.
Before the globe was turned up side down, the head of the arrow pointed to the fixed-in-space North Magnetic Pole. If the arrow were to represent a piece of cooling volcanic rock, that rock would have become like a bar magnet with the North Magnetic Pole pointing up.
After the globe turned upside down the rock, represented by the arrow, would also be turned upside down. Remember, now the globe’s North Pole is aligned with the fixed-in-space North Magnetic Pole. But now the rock is upside down with its North Magnetic Pole pointing to the globe’s South Pole.
Someone who did not realize the globe had turned upside down, would have no choice but to assume that the magnetic field that was recorded in the rock had flipped since the rock was magnetized; the North Magnetic Pole and South Magnetic Pole have exchanged places. This is a very logical conclusion based on a 'false' assumption, which is that the global earth cannot be turned upside down.
