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Very deep M6.7 earthquake under Flores Sea, Indonesia
A very deep earthquake registered by the BMKG as M6.7 hit under the Flores Sea, Indonesia at 15:35 UTC on August 17, 2018. The agency is reporting a depth of 559 km (347 miles). USGS is reporting M6.5 at a depth of 538.7 km (334 miles). EMSC is reporting M6.1 at a depth of 546 km (339 miles). This earthquake can have a low humanitarian impact based on the magnitude and the affected population and their vulnerability. According to the USGS, the epicenter was located 109.3 km (67.9 miles) NNW of Kampungbajo, 120 km (74.5 miles) N of Labuan Bajo (population 188 724), 150.3 km (93.4 miles) NNW of Ruteng (population 34 569) and 167 km (103.8 miles) NE of Bima (population 66 970), Indonesia. The quake had no tsunami potential, BMKG said. There are about 3 000 people living within 100 km (62 miles). Some 26 659 000 people are estimated to have felt weak shaking. The USGS issued a green alert for shaking-related fatalities and economic los…

A ROCK COMET APPROACHES EARTH

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A ROCK COMET APPROACHES EARTH: You've heard of comets. But have you ever heard of a rock comet? They exist, and a big one is approaching Earth this week. 3200 Phaethon will fly past our planet on Dec. 16th only 10 million km away. Measuring 5 km in diameter, this strange object is large enough for amateur astronomers to photograph through backyard telescopes. A few nights ago, the Astronomy Club of the Sing Yin Secondary School in Hong Kong video-recorded 3200 Phaethon's approach using a 4-inch refractor:

"We observed 3200 Phaethon from the basketball court of our school campus," the club reports. "Our school is located close to the city center where the visual limiting magnitude is about 2 to 3. Despite the glare, we were able to record the motion of this object." (For others who wish to do this, Bob King of Sky & Telescope has written an excellent set of observing tips.)
3200 Phaethon is the source of the annual Gemini meteor shower, which is also coming this week. Sky watchers can see dozens of Geminids per hour on Dec. 13th and 14th as gravelly bits of the rock comet disintegrate in Earth's upper atmosphere. The best time to look is during the dark hours before sunrise when Gemini is high in the sky.
"This is 3200 Phaethon's closest encounter with Earth until December of 2093, when it will come to within 1.8 million miles," notes Bill Cooke of NASA's Meteoroid Environment Office. Despite the proximity of the rock comet, he doesn't expect to see any extra Geminids this year. "It would take at least another revolution around the sun before new material from this flyby could encounter Earth - probably longer."
A "rock comet" is an asteroid that comes very close to the sun--so close that solar heating scorches plumes of dust right off its stony surface. 3200 Phaethon comes extremely close to the sun, only 0.14 AU away, less than half the distance of Mercury, making it so hot that lead could flow like water across its sun-blasted surface. Astronomers believe that 3200 Phaethon might occasionally grow a comet-like tail of gravelly debris--raw material for the Geminid meteor shower. Indeed, NASA STEREO-A spacecraft may have seen this happening in 2010. There is much to learn about 32900 Phaethon, which is why NASA radars will be pinging it as it passes by. Stay tuned for updates.

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