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Monday, December 15, 2014

the spectacular Geminids meteor shower

A spectacular meteor shower lit up the skies last night with 100 shooting stars an hour as the celestial firework display reached its fiery peak.

Gazing the star-studded sky is interesting ~ an ordinary daily event for those who still live in villages – not for those of us, who live in small apartments, where every wall, ground, roof and other space is shared with people.  At city, you will have more difficulty due to ‘city light refraction’…… and on somedays you could suddenly see ‘something lighting the sky’ 0r ‘falling objects leaving a trail’. 

விண்வீழ்கல் என்பது ஒப்பீட்டளவில் சிறிய, பூமிக்கு வெளியிலிருந்து, பூமியின் மேற்பரப்பை அடையும் பொருளாகும். விண்வெளியில் இருக்கும்போது இது விண்கல் என அழைக்கப்படுகிறது.  A meteor or "shooting star" is the passage of a meteoroid  into the Earth's atmosphere, incandescent from air friction and shedding glowing material in its wake sufficiently to create a visible streak of light. Millions of meteors occur in the Earth's atmosphere daily. Most meteoroids that cause meteors are about the size of a grain of sand. Meteors may occur in showers, which arise when the Earth passes through a stream of debris left by a comet, or as "random" or "sporadic" meteors, not associated with a specific stream of space debris.  The falling objects in many traditions are held to be a bad omen.

The Geminids are a meteor shower caused by the object 3200 Phaethon, which is thought to be a Palladian asteroid with a "rock comet" orbit. This would make the Geminids, together with the Quadrantids, the only major meteor showers not originating from a comet. The meteors from this shower are slow moving, can be seen in December and usually peak around December 13–14, with the date of highest intensity being the morning of December 14. The shower is thought to be intensifying every year and recent showers have seen 120–160 meteors per hour under optimal conditions. Geminids are debris from an extinct comet called 3200 Phaethon, which was previously believed to be an asteroid, according to NASA. The meteors in this shower appear to come from a radiant in the constellation Gemini (hence the shower's name). However, they can appear almost anywhere in the night sky, and often appear yellowish in hue.

Across the globe, the Geminids show is popular and is viewed by many during mid-December, not sure whether it is so well visible over here. Pieces of gravel and dust from  "rock comet" called 3200 Phaethon shot across the sky and lit up discussion boards from NASA.gov to Twitter — for those who could tear their eyes away long enough to type.  In UK, Daily Mail reports that sky-watchers braved freezing temperatures last night to enjoy the Geminid meteor shower in clear conditions.  It was visible in both hemispheres and was spotted from Dover in Kent to Macedonia and across the whole of the US.

Geminids are classed as potentially hazardous, as they pass within 4.6 million miles of Earth, burning 24 miles away. At their height, the Geminids produce between 50 and 100 shooting stars which travel at 22 miles per second.  The report mentions of shooting stars seen streaking across the night sky just after midnight in London and past the Dover Patrol Memorial in St Margarets Bay, Kent. The best time to see the meteors was around 2am, when the point in the sky from which the meteors appear to originate - was almost overhead, next to the constellation Gemini.  NASA map depicted  how 556 fiery asteroids smashed into the Earth's atmosphere in the past two decades... but most were harmless. 'Basically it is the rocky skeleton of a comet that lost its ice after too many close encounters with the sun,' NASA said on its website. But it has an eccentric orbit that looks more like that of a comet than an asteroid and brings it well inside the orbit of Mercury, the closest planet to the Sun, every 1.4 years. Traditionally asteroids are made of rock and comets mostly of ice, but NASA describes Geminids as a type of 'rock comet'.

Another unusual feature of the Geminids is that they can shine in different colours. Mostly glowing white, they may also appear yellow, blue, green or red. Regardless of whether 3200 Phaethon is an asteroid or comet, it is classified as a 'potentially hazardous' near-Earth object (NEO). To be classified as potentially hazardous, an NEO must pass within 4.6 million miles of the Earth. At its closest upcoming approach on December 14 2093, the object will be 1,812,640 miles away - quite far enough to be safe.

Though some aspects of this newsitem was not so easily comprehensible,  the photos makes it an interesting spectre.
With regards – S. Sampathkumar

15th Dec 2014.

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