APOD: Teimareh Petroglyphs and Star Trails (2012 Jul 12)

[APOD Robot]

Teimareh Petroglyphs and Star Trails

Explanation: Engraved in rock, these ancient petroglyphs are abundant in the Teimareh valley, located in the Zagros Mountains of central Iran. They likely tell a tale of hunters and animals found in the middle eastern valley 6,000 years ago or more, etched by artists in a prehistoric age. In the night sky above are star trails etched by the rotation of planet Earth during the long composite exposure made with a modern digital camera. On the left, the center of the star trail arcs is the North Celestial Pole (NCP), the extension of Earth's axis into space, with Polaris, the North Star, leaving the bright, short, stubby trail closest to the NCP. But when these petroglyphs were carved, Polaris would have made a long arc through the night. Since the Earth's rotation axis precesses like a wobbling top, 6,000 years ago the NCP was near the border of the constellations Draco and Ursa Major, some 30 degrees from its current location in planet Earth's sky.

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[BikerMike]

What??!! No moronic discussion that petroglyphs do not belong on APOD? Goodness, gracious me, the carpers must have gone off to another galaxy! Good riddance!

[Remmos]

Has anyone Really looked at the Petroglyphs at the Bottom Right in the Picture? I enlarged this picture, and it shows what appears to be a u.f.o. with landing gear.
There appear to be 2 objects with landing gear one circular and the other a long horizontal shape!

[Guest]

What??!! No moronic discussion that petroglyphs do not belong on APOD? Goodness, gracious me, the carpers must have gone off to another galaxy! Good riddance!

You should be able to take criticism without resorting to personal abuse. This has scientific interest although more strictly paleontology.

Has anyone Really looked at the Petroglyphs at the Bottom Right in the Picture? I enlarged this picture, and it shows what appears to be a u.f.o. with landing gear.
There appear to be 2 objects with landing gear one circular and the other a long horizontal shape!

Those are probably turtles.

[Indigo_Sunrise]

You should be able to take criticism without resorting to personal abuse. This has scientific interest although more strictly paleontology.

And you should be able to recognize sarcasm.
Also, the study of ancient drawings is not called paleontology - isn't that the study of fossilized organisms? Maybe you meant archeology.

[orin stepanek]

I thought it looked like a couple of the figures might have been scratched out; but than it also looks like maybe dry weeds and grass is in the cracks of the rocks instead.

[rstevenson]

Has anyone Really looked at the Petroglyphs at the Bottom Right in the Picture? I enlarged this picture, and it shows what appears to be a u.f.o. with landing gear.
There appear to be 2 objects with landing gear one circular and the other a long horizontal shape!

Those are probably turtles.

Turtles, turtles, all the way down.

Rob

[neufer]

Has anyone Really looked at the Petroglyphs at the Bottom Right in the Picture? I enlarged this picture, and it shows what appears to be a u.f.o. with landing gear.
There appear to be 2 objects with landing gear one circular and the other a long horizontal shape!

Those are probably turtles.

Turtles, turtles, all the way down.

• Until you hit Glyptodons.

<<A winter night above the prehistoric site of Teimareh in central Iran. There are over 20,000 engraved images in the valley which put the region among the world's most populated petroglyph sites, still largely undiscovered. In this view a unique panel of over 150 pictures is remotely located in the Zagros mountains. There are signs of the first era of horse riding in the Middle East (~ 6000 years ago) and some other pictures are from late Paleolithic (12000 years ago). But few of them might be even surprisingly older. They show animals which became extinct in this region by the ice age, including Smilodon (saber-toothed tiger) and a kind of large armadillos known as Glyptodon.>>

[b][color=#0000FF]Glyptodon measured over 3.3 m in length and weighted up to 2 tons. It was covered by a protective shell composed of more than 1,000 2.5 cm-thick bony plates, called osteoderms or scutes. Each species of glyptodont had its own unique osteoderm pattern and shell type. With this protection they were armored like turtles. Unlike most turtles, glyptodonts could not withdraw their heads, but instead had a bony cap on the top of their skull. Even the tail of Glyptodon had a ring of bones for protection. Such a massive shell needed considerable support, evidenced by features such as fused vertebrae, short but massive limbs, and a broad shoulder girdle.[/color][/b]

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<<Glyptodon (Greek for "grooved or carved tooth") was a large, armored mammal of the family Glyptodontidae, a relative of armadillos that lived during the Pleistocene epoch. It was roughly the same size and weight as a Volkswagen Beetle, though flatter in shape. With its rounded, bony shell and squat limbs, it superficially resembled turtles, and the much earlier dinosaurian ankylosaur, as an example of the convergent evolution of unrelated lineages into similar forms. Glyptodon is believed to have been an herbivore, grazing on grasses and other plants found near rivers and small bodies of water.

Glyptodon is part of the superorder of placental mammals known as Xenarthra. This clade of mammals also includes anteaters, tree sloths, armadillos, and extinct ground sloths and pampatheres. Glyptodon originated in South America. A related genus, Glyptotherium, reached the southern region of the modern USA about 2.5 million years ago as a result of the Great American Interchange, a set of migrations that occurred after North and South America were connected by the rising of the volcanic Isthmus of Panama. They became extinct about 10,000 years ago. The native human population in their range is believed to have hunted them and used the shells of dead animals as shelters in inclement weather.

The nasal passage was reduced with heavy muscle attachments for some unknown purpose. Some have speculated that the muscle attachments were for a proboscis, or trunk, much like that of a tapir or elephant. Most animals with a trunk, however, have nasal bones receding back on the skull, and glyptodonts do not have this feature. The lower jaws were very deep and helped support massive chewing muscles to help chew the coarse fibrous plants that can be found along river and lake banks.>>

[owlice]

Turtles, turtles, all the way down.

Rob

HA! Thanks, Rob, for the new sig line!

neufer, those Glyptodons are pretty darn cute.

[Moonlady]

Rob, the Turtle-Bus picture is cute! Take a slow-motion ride!

Glyptodons are like the mediavel armours, many protection but heavy and unflexibel, no wonder they did not survive

All the petroglphys around the world are always stunning! I wonder if and what would I engraved in rocks?!

[Indigo_Sunrise]

Turtles, turtles, all the way down.

Rob

[Chris Peterson]

Has anyone Really looked at the Petroglyphs at the Bottom Right in the Picture? I enlarged this picture, and it shows what appears to be a u.f.o. with landing gear.
There appear to be 2 objects with landing gear one circular and the other a long horizontal shape!

I believe you might be confusing "UFOs", which are things seen in the sky which can't be identified (and which are common), with "flying saucers", fictional staples of (mostly bad) science fiction movies from the 1950s and 1960s.

[plazz]

Is anyone else confused by the apparent presence of Glyptodon, a N. and S. American animal, in Iran?

[Remmos]

I agree that it could be a turtle, but How come they depicted it with 6 Legs. Also the so called horizontal turtle is the Flattest turtle I have ever seen, it looks more like a table than a turtle.

[BikerMike]

Oh Lordy! I spoke to soon!

With thanks to INDIGO_SUNRISE!

[Chris Peterson]

I agree that it could be a turtle, but How come they depicted it with 6 Legs. Also the so called horizontal turtle is the Flattest turtle I have ever seen, it looks more like a table than a turtle.

Looks like a beetle or other bug to me.

[emc]

One of the coolest things about art is that every single person can have a unique perception.

[Chris Peterson]

One of the coolest things about art is that every single person can have a unique perception.

And it's all the more extreme when we, with our current views of things, try to interpret the art (if, indeed, it was intended as art) of people living thousands of years ago.

[Mactavish]

I agree that it could be a turtle, but How come they depicted it with 6 Legs. Also the so called horizontal turtle is the Flattest turtle I have ever seen, it looks more like a table than a turtle.

Looks like a beetle or other bug to me.

Clearly a hexatestudine.

[quigley]

What happens when the Earth's spin slows down to the point that a top would fall over?

[neufer]

What happens when the Earth's spin slows down to the point that a top would fall over?

[b][color=#0000FF]Geomagnetic polarity during the late Cenozoic Era. Dark areas denote periods where the polarity matches today's polarity, light areas denote periods where that polarity is reversed.[/color][/b]

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<<A geomagnetic reversal is a change in the Earth's magnetic field such that the positions of magnetic north and magnetic south are interchanged. The Earth's field has alternated between periods of normal polarity, in which the direction of the field was the same as the present direction, and reverse polarity, in which the field was the opposite. These periods are called chrons. The time spans of chrons are randomly distributed with most being between 0.1 and 1 million years with an average of 450,000 years. Most reversals are estimated to take between 1,000 and 10,000 years. The latest one, the Brunhes–Matuyama reversal, occurred 780,000 years ago. Brief disruptions that do not result in reversal are called geomagnetic excursions.

Not long after the first geomagnetic polarity time scales were produced, scientists began exploring the possibility that reversals could be linked to extinctions. Most such proposals rest on the assumption that the Earth's field has much lower intensity during reversals. Possibly the first such hypothesis was that high energy particles trapped in the Van Allen radiation belt could be liberated and bombard the Earth. Detailed calculations confirm that, if the Earth's dipole field disappeared entirely (leaving the quadrupole and higher components), most of the atmosphere could be reached by high energy particles. However, the atmosphere would stop them. Instead there would be secondary radiation of ¹⁰Be or ³⁶Cl from collisions of cosmic rays with the atmosphere. There is evidence that this occurs both during secular variation and during reversals.

Another hypothesis by McCormac and Evans assumes that the Earth's field would disappear entirely during reversals. They argue that the atmosphere of Mars may have been eroded away by the solar wind because it had no magnetic field to protect it. They predict that ions would be stripped away from Earth's atmosphere above 100 km. However, the evidence from paleointensity measurements is that the magnetic field does not disappear. Based on paleointensity data for the last 800,000 years, the magnetopause is still estimated to be at about 3 Earth radii during the Brunhes-Matuyama reversal. Even if the magnetic field disappeared, the solar wind may induce a sufficient magnetic field in the Earth's ionosphere to shield the surface from energetic particles.

Hypotheses have also been advanced linking reversals to mass extinctions. Many such arguments were based on an apparent periodicity in the rate of reversals; more careful analyses show that the reversal record is not periodic. It may be, however, that the ends of superchrons have caused vigorous convection leading to widespread volcanism, and that the subsequent airborne ash caused extinctions.

Tests of correlations between extinctions and reversals are difficult for a number of reasons. Larger animals are too scarce in the fossil record for good statistics, so paleontologists have analyzed microfossil extinctions. Even microfossil data can be unreliable if there are hiatuses in the fossil record. It can appear that the extinction occurs at the end of a polarity interval when the rest of that polarity interval was simply eroded away. Statistical analysis shows no evidence for a correlation between reversals and extinctions.>>