Geminid fireball falling Earthward. (Source: NASA)
By Glenn A. Walsh
Reporting for SpaceWatchtower
The most intense meteor shower of the year, the Geminids, peaks this-coming weekend: officially the peak is Friday night / Saturday morning, 2013 December 14 at 1:00 a.m. EST (6:00 Coordinated Universal Time). Particularly in good years when Moon light does not hamper viewing, 100 to 120 meteors per hour can be seen. However, some people believe this meteor shower is intensifying, as 120 to 160 meteors have been seen, under optimal conditions, during this meteor shower in recent years.
Due to the intensity of the Geminid Meteor Shower, some meteors can be seen Thursday through Monday nights. Of course, the number of meteors that can be seen is less on nights other than the Friday night / Saturday morning peak.
Clear skies are always a must for meteor viewing, something not always available in late Autumn and early Winter skies. And, it is always best to get away from city lights, for the chance to see the dimmer meteors.
As always, the best viewing for a meteor shower is between local midnight and local dawn, when the Earth is rotating into the meteor shower. However, a nearly Full Moon (waxing gibbous, with 93 per cent of the Moon's surface illuminated by the Sun) will hinder meteor viewing until the Moon sets (Moon set in Pittsburgh for December 14: 4:54 a.m. EST). Dawn begins at Civil Twilight (for Pittsburgh: 7:05 a.m. EST with sunrise at 7:35 a.m. EST), which means there should be about two hours when the Moon and the Sun would not interfere with watching for Geminid meteors.
The Geminids are so named because most meteors appear to radiate from the Constellation Gemini the Twins (apparent meteor shower radiant), a constellation which becomes more prominent as the Winter season approaches in Earth's Northern Hemisphere. However, during any meteor shower, meteors can appear in any part of the sky at any time.
Telescopes and binoculars are of little use for finding meteors. Such optical devices restrict the field-of-view, thus that you could easily miss a lot of meteors, and the chance that you could observe a meteor with a telescope or binoculars is not very good. The best way to look for meteors is to lie down on the ground, in an area with an unobstructed view of most of the sky. Then, just keep scanning throughout the sky until you see a meteor.
While most meteor showers occur at a time when Earth's orbit coincides with a trail of debris from a comet, this is not the case for the Geminids. Amazingly, the most intense meteor shower of the year seems to come from a strange rocky object identified as Asteroid 3200 Phaethon, what some scientists call a "rock comet." Discovered by NASA's Infrared Astronomical Satellite (IRAS) in 1983, 3200 Phaethon has an eccentric orbit which brings it inside the orbit of Mercury every 1.4 years.
Even though this asteroid is regularly blasted with solar heat when it nears the Sun, scientists using NASA satellite data have concluded that the debris falling-off of the asteroid due to this heating could not have caused the amount of debris found in the debris trail which comprises the Geminid Meteor Shower. The amount of debris which scientists recorded as having fallen-off of this asteroid during a recent encounter with the Sun is too low.
Some researchers believe that 5-kilometer Phaethon may have been chipped-off of one of the largest asteroids in the Solar System, 2 Pallas (which is 544 kilometers in diameter). Could some past planetary collision, which caused Phaethon to break-off from Pallas, have caused the debris trail now known as the Geminid Meteor Shower? Scientists who have studied this possible scenario say no. They say that the Geminid meteoroids were created much closer to the Sun, not in the Asteroid Belt.
Hence, the explanation for the intensity of the Geminid Meteor Shower remains a mystery to scientists.
So, bundle-up this weekend and hope for clear skies to see the most intense meteor shower of the year, apparently caused by an astronomical anomaly.
More on the Geminid Meteor Shower ---
Link 1 >>> http://science.nasa.gov/science-news/science-at-nasa/2010/06dec_geminids/
Link 2 >>> http://en.wikipedia.org/wiki/Geminids
Source: Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of the Zeiss.
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