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Sat, 01 Oct 2016
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Comets


Fireball 5

Meteor over Srinagar mistaken for missile attack

© Express Photo by Shuaib Masoodi
The falling meteorite in Srinagar on Thursday.
Panic struck the people of Srinagar as a falling meteorite was confused for a missile, hours after India confirmed conducting surgical strikes along the border in Pakistan. Onlookers in the Jammu and Kashmir capital took the 'missile' as a retaliation in the aftermath of the border tension.

The Indian Army on Thursday organised surgical strikes targeting seven terror launch pads across the LoC overnight in which heliborne and ground forces were used. Addressing a press conference, DGMO Lt Gen Ranbir Singh said India inflicted "significant casualties" on terrorists and those who are trying to support them.

This is latest in the string of offensives India has launched against Pakistan since four attackers killed 19 soldiers in Jammu and Kashmir's Uri when they targetted the rear office of an Indian Army infantry installation on September 18. India has resorted to several diplomatic measures and vowed to internationally isolate Pakistan ever since.

Comet 2

'Lost' comet of 1915 may have been rediscovered

© YouTube/Planetary Astronomy
C/2016 R3 Borisov.
Scientists working with the Slooh observatories were able to take an image of Comet C/2016 R3, which was discovered by Russian astronomer Gennady Borisov on September 11, 2016. Since then, the comet has been too close to the sun to observe well, but Borisov and his peers think the celestial body might be one that was misplaced a century ago.

Comet C/2016 R3 was discovered by Gennady Borisov, an employee at Sternberg Astronomical Institute in Moscow, on September 11 this year. Earlier, Borisov spotted and catalogued four comets and one asteroid. He is working with observers using the Slooh global robotic observatory network.

Borisov together with Slooh member Bernd Luetkenhoener and Slooh astronomer Paul Cox have demonstrated that Comet C/2016 R3 is moving towards the sun and will reach its perihelion on October 12.

Telescope

China launches world's largest FAST radio telescope: 500 meters in diameter

© Stringer / Reuters
A 500-metre (1,640-ft.) aperture spherical telescope (FAST) is seen at the final stage of construction, among the mountains in Pingtang county, Guizhou province, China
The biggest radio telescope located in China's Guizhou Province is now operational. Featuring a reflector the size of 30 football pitches, it took five years and $180 million to construct. Called the Five-hundred-meter Aperture Spherical Telescope's (FAST), the telescope is located in a karst valley in Pingtang County, a mountainous area in southwest China.

Some 8,000 local residents were relocated to ensure a 5km radio silence zone around the facility. About $269 million were allocated to pay compensations to the villagers. The name FAST referrers to the main structure of the gigantic instrument, which has 4,450 triangular 11-meter panels and measures 500 meters in diameter. For comparison, the Arecibo Observatory in Puerto Rico, which held the title of world's largest radio telescope before FAST, has a 305-meter dish.

Comment: It would take a full 40 minutes for the average person to walk around the telescope.
See also:


Fireball 2

Meteor fireball shoots across Eastern Canada and US night sky

© Facebook/Mont-Mégantic provincial park
This meteor was seen as far west as Toronto and as far east as Edmundston, N.B., according to the American Meteor Society.
Skywatchers across Eastern Canada and the U.S. spotted an unexpected treat last night, as a meteor streaked across the sky.

The phenomenon was captured by a camera atop Quebec's Mont-Mégantic provincial park, about 80 kilometres east of Sherbrooke, Que., around 9:40 p.m. Wednesday.

Sébastien Giguère, scientific co-ordinator at the Mont-Mégantic Astrolab, confirmed Thursday morning that the fireball was indeed a meteor.

A meteor, also called a shooting star, is the light emitted from a meteoroid or an asteroid as it enters the atmosphere.

Meteors like ones seen during Perseid meteor showers are caused by particles that are the same size as a grain of sand or rice, Giguère explained. The bigger the particle, the bigger the meteor.

Last night's meteor was probably caused by something the size of a big rock, Giguère said.

"Hundreds of tonnes of meteorites fall through the sky every day," he said on Radio-Canada's C'est pas trop tôt. "But yesterday, it was nice out and [the meteor] was centred on southern Quebec. That happens once every one or two years, so it's not totally rare, but it doesn't happen every day."

Vicky Boldo, a resident of Sainte-Catherine-de-Hatley Que., said she saw the "spectacular sight" while sitting in her hot tub last night.

"It passed directly over us and lit the yard up like a football field — it seemed to be just up over our heads beyond the trees," she said in an email.


Info

5 new 'Neptune trojans' discovered

© Lin et al., 2016
The spatial distribution of all PS1 detected Trojans. The solid triangles are the newly discovered Neptune Trojans, and open triangles are the known ones detected by PS1. The positions of Neptune Trojans correspond to their first detections of PS1. The blue circles show the locations of Neptune from 2010 to 2013, and the crosses show the corresponding Lagrange points. Notice that the Galactic Center (GC) overlapped with L5 during 2010 to 2012.
An international team of astronomers led by Hsing-Wen Lin of the National Central University in Taiwan has detected five new so-called "Neptune trojans" - minor bodies sharing the same orbit as the planet Neptune. The discovery was made by the Pan-STARRS 1 (PS1) survey and is described in a paper published Sept. 15 on arXiv.org.

The PS1 survey, which utilizes the first Pan-STARRS (Panoramic Survey Telescope and Rapid Response System) telescope in Hawaii, designated PS1, is one of the best tools to search for Neptune trojans. The survey, lasting from May 2010 to May 2014, has made a strong contribution to knowledge of the solar system's minor bodies due to its very wide survey area and its optimized cadence for searching moving objects.

"PS1 survey has a very wide survey area that is deep enough to cover a large part of the Neptune trojan cloud. PS1 currently is the only one with the capability to detect several Neptune trojans in a single survey," Lin told Phys.org.

The researchers found four new L4 trojans, meaning that they orbit Neptune's L4 Lagrangian point 60 degrees ahead of Neptune; they also found one L5 trojan - orbiting the L5 region 60 degrees behind the planet. The newly detected objects have sizes ranging from 100 to 200 kilometers in diameter.

What drew the attention of the astronomers is the fact that the new L5 trojan is dynamically more unstable than the other four, indicating that it could be temporarily captured into the Neptune trojan cloud.

Fireball 2

30 tonne meteorite discovered in Argentina

© Compacto Nea
Scientists have discovered a meteorite weighing over 30 tonnes in northern Argentina. The meteorite was found in the town of Gancedo, 1,085 km north of capital Buenos Aires, Mario Vesconi, president of the Astronomy Association of Chaco, said on Monday.

"While we hoped for weights above what had been registered, we did not expect it to exceed 30 tons," Vesconi said, adding that "the size and weight surprised us", Xinhua news agency reported.

"It was in Campo del Cielo, where a shower of metallic meteorites fell around 4,000 years ago," Vesconi added.

The meteorite will be weighed again to ensure an accurate measurement.

The largest meteorite ever found is called Hoba, weighing 66 tonnes in Namibia, Africa.


Fireball 4

Meteor sighting reported across Virginia

Richmond — Numerous viewers reached out to WTVR CBS 6 after reporting seeing something strange in the sky Thursday evening.

David Livingston said he was stopped at an intersection in the West End around 6 p.m. when he saw a bright light in the southwest sky.

"It was very bright and green and possibly made it all the way to the ground," Livingston said.

Rhonda Sams from Cartersville also saw something she believed was a meteor or possibly space debris.

"My husband, son, and I were looking south toward Cumberland County and Route 60. It could have actually fell in Amelia County," Sams wrote. "Don't know what it was but it was bright and burning."

K. Learning said she was driving on I-95 south near the Doswell exit around 6 p.m. when she saw something bright in the sky.

"There was what looked like a ball of fire seen going at a rapid speed," Learning said. "The direction it was seen going was southwest."

Christy Dalton was driving on Route 288 when she reported seeing something "fall out of the sky."

‎Brian Hobbs‎ also reported seeing the bright light.

"There was a long smoke trail left behind that dissipated very slowly," Hobbs‎ wrote. "Really a neat thing to see."

Fireball 5

Asteroid 2016 RB1 to flyby Earth at 0.1 Lunar Distance on September 7

The asteroid 2016 RB1 was discovered (at ~ magnitude +19) on 2016, September 05 by Mt. Lemmon Survey (MPC code G96) with a 1.5-m reflector + 10K CCD.

Asteroid 2016 RB1 has an estimated size of 7.3 m - 16 m (based on the object's absolute magnitude H=27.8) and it will have a close approach with Earth at about 0.1 LD (Lunar Distances = ~384,000 kilometers) or 0.0003 AU (1 AU = ~150 million kilometers) on 2016, September 7 at 17:20UT and it will reach a peak magnitude of about +12.3. Radio astronomers will try to observe it as 2016 RB1 could be a really strong radar target during its close approach.

I performed some follow-up measurements of this object on 2016, September 07.6, remotely from the Q62 iTelescope network (Siding Spring, Australia) through a 0.4-m f/3.5 reflector + CCD. Below you can see our image taken with the asteroid at about magnitude +13 and moving at ~ 503 "/min. At the moment of its close approach on Sep 07, around 17UT, 2016 RB1 will move at ~ 2716 "/min (or about 45.2 deg/hour). The asteroid is trailed in the image due to its fast speed. Click on the image below to see a bigger version. (North is up, East is to the left).
© Remanzacco Blogspot

Fireball 2

Man says meteorite hit lone pear on tree in Massachusetts

© Metrowest Daily News
Framingham - First a late hard freeze robbed Steven Lovewell's Asian pear tree of most of its blossoms. Then the summer drought wiped out all but one lonely pear ripening on his tree. The final blow came swiftly and loudly - from a meteorite.

Lovewell, who lives on Grant Street, said he was awakened by a loud whooshing noise about 3 a.m. Tuesday. Later that morning he found his one Asian pear fruit on the ground with what he believes is a meteorite embedded in its flesh. The dark rocky object, about the size of a peach pit, protruded about halfway from the fruit.

Lovewell said he has been interested in astronomy and rocket science since he was a kid. He plans to reach out to the McAuliffe Center at Framingham State University to try and confirm his belief that his last Asian pear was knocked from the tree by an extraterrestrial object. In the meantime, the pear and meteorite are chilling in his freezer for safe keeping.

Comet 2

Giant comets pose a much greater hazard to life than asteroids

© The Daily Galaxy
A decade ago, Stephen Hawking warned that one of the major factors in the possible scarcity of intelligent life in our galaxy is the high probability of an asteroid or comet colliding with inhabited planets. This past December, a team of astronomers from Armagh Observatory and the University of Buckingham reported that the discovery of hundreds of giant comets in the outer planetary system over the last two decades means that these objects pose a much greater hazard to life than asteroids.

Giant comets, termed centaurs, move on unstable orbits crossing the paths of the massive outer planets Jupiter, Saturn, Uranus and Neptune. The planetary gravitational fields can occasionally deflect these objects in towards the Earth. Centaurs are typically 50 to 100 kilometer across, or larger, and a single such body contains more mass than the entire population of Earth-crossing asteroids found to date.

Because they are so distant from the Earth, Centaurs appear as pinpricks of light in even the largest telescopes. Saturn's 200-km moon Phoebe, depicted in this image, seems likely to be a Centaur that was captured by that planet's gravity at some time in the past. Until spacecraft are sent to visit other Centaurs, our best idea of what they look like comes from images like this one, obtained by the Cassini space probe orbiting Saturn. NASA's New Horizons spacecraft, having flown past Pluto six months ago, has been targeted to conduct an approach to a 45-km wide trans-Neptunian object at the end of 2018.

Calculations of the rate at which centaurs enter the inner solar system indicate that one will be deflected onto a path crossing the Earth's orbit about once every 40,000 to 100,000 years. Whilst in near-Earth space they are expected to disintegrate into dust and larger fragments, flooding the inner solar system with cometary debris and making impacts on our planet inevitable.

Known severe upsets of the terrestrial environment and interruptions in the progress of ancient civilisations, together with our growing knowledge of interplanetary matter in near-Earth space, indicate the arrival of a centaur around 30,000 years ago. This giant comet would have strewn the inner planetary system with debris ranging in size from dust all the way up to lumps several kilometres across.

Specific episodes of environmental upheaval around 10,800 BCE and 2,300 BCE, identified by geologists and palaeontologists, are also consistent with this new understanding of cometary populations. Some of the greatest mass extinctions in the distant past, for example the death of the dinosaurs 65 million years ago, may similarly be associated with this giant comet hypothesis.