http://antwrp.gsfc.nasa.gov/apod/ap090105.html
http://apod.nasa.gov/apod/ap090202.html
L(uli)N ANTI-TAIL
__ {anagram}
NITAL-(lui)-LATIN
_____ lui : he, him (French, Italian)
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http://antwrp.gsfc.nasa.gov/apod/ap040422.html
http://antwrp.gsfc.nasa.gov/apod/ap980220.html
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<<In Inuit legend, the narwhal's tusk was created when a woman with a harpoon rope tied around her waist was dragged into the ocean after the harpoon had struck a large narwhal. She was transformed into a narwhal herself, and her hair twisted around in the water until it became the characteristic spiral narwhal tusk.
Some medieval Europeans believed narwhal tusks to be the horns from the legendary unicorn. The tusks were used to make cups that were thought to negate any poison that may have been slipped into the drink. During the 16th century, Queen Elizabeth received a carved and bejeweled narwhal tusk for £10,000—the cost of a castle. Herman Melville wrote a section on the narwhal in Moby Dick. In it, he claims that a narwhal tusk hung for "a long period" in Windsor Castle after Sir Martin Frobisher had given it to Queen Bess.>>
Comet Arend-Roland photographed on April 25, 1957.
The prominent anti-tail extending from the coma appears to precede the comet, though it actually trails from behind.
<<Basically, there are two types of [comet] tails, the Type I ion, or gas, tail, and the Type II dust tail. The ion tail is typically bluish, and it is carried almost straight outward away from the Sun by the solar wind. But, the dust tail is a bit more complicated. It is pushed outward by light pressure. When the dust shed by outgassing of the nucleus of the comet, it forms a cloud around the nucleus. Most people don’t realize it, but light can actually push on things. So, the light from the Sun is able to push the tiny dust grains outward. But, these dust grains are still orbiting the Sun. So, a push outward causes them to be pushed into farther orbits. The farther an orbit is from the Sun, the slower it moves. So, these dust grains lag ever so slightly behind the nucleus of the comet. The farther they are pushed, the more they lag, so the tail gently sweeps backward, though still largely pointing away from the Sun. The result is a bifurcated tail, one bluish Type I and one yellowish Type II.
But photographs are inherently two dimensional. The tail is curved in three dimensions. So, projecting this onto a two dimensional photograph, taken from the perspective of the Earth, not the Sun or some observer external to the Solar System, can often do some strange things. For example, in 1957, Comet Arend-Roland passed near the Sun, and the dust tail curved so much that it swung around behind the head of the comet, as seen from Earth. Though the tail was most definitely curving away from the Sun, from the perspective of the Earth, you could see the back end of it appear to swing around onto the other side of the head and appear as a spike pointing towards the Sun as seen in this photograph from the Armagh Observatory. We call this sunward appearing spike an antitail. Not all comets show an antitail, only those who happen to be just the right position for the orbital geometries to give this perspective. The tail definitely is not pointing sunward. It just seems to be from our perspective.>>
but still :)ing.
