Meteorite Shower: South Korea sees large meteor shower

A corner of South Korea is in the grip of a frenzied hunt for valuable space souvenirs, following a rare meteor shower there last week.

Hundreds of people have been scouring hills and rice paddies for meteorites near the southeastern city of Jinju after the shower on March 9, some of them armed with GPS devices and metal detectors, according to media reports.

A specimen of the NWA 869 chondrite (type L4-6), showing chondrules and metal flakes

"Media hype claiming that chondrites (a type of meteorite) could bring you a bonanza sparked the fever for space rocks," an official from the Cultural Heritage Administration of Korea (CHAK) told reporters.

Local greenhouse owners have put up signs warning off trespassers after the first large chunk of rock, weighing around nine kilograms (20 pounds), was found in a greenhouse near Jinju.

A second piece weighing four kilograms was found by another local resident.

Scientists confirmed that both rocks, found in the two days after the meteor shower, had come from space.

A US meteorite-hunter has been handing out business cards in the local area, asking people to sell him any shards they find, the Korea JoongAng Daily said.

Chung Hong-Won

Prime Minister Chung Hong-Won suggested the government should secure them for research or as a natural monument.

The CHAK official said the agency would designate any meteorites found as cultural assets to stop them from being taken out of South Korea.

Ownership of the meteorites remains a legally grey area because of the lack of relevant provisions in South Korean civil law, the official added.

A space rock was last found on its soil in 1943, when the Korean peninsula was under Japan's colonial rule.

Meteor showers occur when hundreds of meteors, fragments of dust and rock that burn up as they pass through the Earth's atmosphere, light up the sky in a spectacular display.

Meteorites are meteors that do not burn up completely, surviving the fall to Earth.

Hunt is on for pieces of van-sized California meteor

Wanted: fragments of a minivan-sized meteor that exploded over northern California and Nevada on Sunday morning and may well have survived to strike Earth.

Meteorites – meteors that make landfall – can provide crucial information about the chemical composition of the early solar system.

"It's like getting sample return without having to go there," says Bill Cooke of NASA's Meteoroid Environment Office at the Marshall Space Flight Centre in Huntsville, Alabama.

However, meteorites are rare. Though meteors frequently streak across the sky, they tend to burn up before reaching the ground or they land in the sea. There's reason to think the recent meteor is different.

Apart from exploding over land, it created a sonic boom, so it must have stayed intact for long enough for it to get down into the denser air low in the atmosphere – just 16 kilometres above the Earth's surface, Cooke reckons – raising the chance that some of it hit the dirt.

Sudan similarity
He estimates it was about 4 metres long, about 70 metric tonnes and packing the energy of 4 kilotonnes of TNT. "That's about one-fourth the energy of the 'Little Boy' bomb dropped on Hiroshima," he says.

That makes the rock even bigger than 2008 TC3, a meteorite which was detected before it entered the atmosphere and became the first cosmic impact to be traced from space to landfall when astronomers found its scattered fragments in Sudan in 2008.

Cooke is also hoping someone took a video of the new meteor.

Astronomers used infrasound signals – low frequency sound that travels great distances – detected at two ground-based stations to pinpoint the spots where the new meteor entered the atmosphere and then exploded. They don't yet know where the fragments went.

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Jupiter helps Halley's Comet give us more spectacular meteor displays

The dramatic appearance of Halley's comet in the night sky has been observed and recorded by astronomers since 240 BC.

Now a study shows that the orbital influences of Jupiter on the comet and the debris it leaves in its wake are responsible for periodic outbursts of activity in the Orionid meteor showers.

The results will be presented by Aswin Sekhar at the National Astronomy Meeting in Manchester on Tuesday 27th March.

Halley's comet orbits the Sun every 75-76 years on average. As its nucleus approaches the Sun, it heats up and releases gas and dust that form the spectacular tail. This outgassing leaves a trail of debris around the orbit.

When the Earth crosses Halley's path, twice per orbit, dust particles (meteoroids) burn up in the Earth’s atmosphere and we see meteor showers: the Orionids in October and the Eta Aquariids in May.

Previous research has suggested that Orionid meteoroids have at times fallen into 'resonances' with Jupiter's orbit – a numerical relationship that influences orbital behaviour.

Sekhar's new study suggests that Halley itself has been in resonances with Jupiter in the past, which in turn would increase the chances of populating resonant meteoroids in the stream.

The particles ejected during those times experience a tendency to clump together due to periodic effects from Jupiter.

Image of 2007 Orionids, showing Orion constellation in the backdrop. Credit: S. Quirk    

"This resonant behaviour of meteoroids means that Halley's debris is not uniformly distributed along its orbital path."

"When the Earth encounters one of these clumps, it experiences a much more spectacular meteor shower than usual," said Sekhar, of Armagh Observatory.

Sekhar has modelled Halley’s orbital evolution over more than 12 000 years into the past and 15 000 years into the future.

The model suggests that from 1404 BC to 690 BC, Halley was trapped in a 1:6 resonance with Jupiter (in which Halley completed one orbit for every six orbits of Jupiter around the Sun).

Later, from 240 BC to 1700 AD, the comet’s orbit had a 2:13 relationship with Jupiter’s orbit. Debris deposited during these two periods can be directly attributed to heightened activity in the Orionid meteor showers in some years.

Sekhar’s work suggests that the unusual Orionid outburst observed in 1993 was due to 2:13 resonant meteoroids ejected from Halley around 240 BC.

He predicts that the next similar display of meteors from this 2:13 resonance will be in 2070 AD.

"The real beauty of this area of science lies in the convergence of cometary physics and orbital dynamics."

"The close correlation between historical records from ancient civilisations and the predictions using modern science make it even more elegant," said Sekhar.

He added, "There are enough unsolved problems pertaining to Halley and its meteor streams to keep us occupied till the next apparition of the comet in 2061!"

Provided by Royal Astronomical Society

Antartica (ANSMET): Hundreds of Meteorites Uncovered

A gang of heavily insulated scientists has wrapped up its Antarctic expedition, with its members thawing out from the experience, but pleased to have bagged more than 300 space rocks.

They are participants in the Antarctic Search for Meteorites program, or ANSMET for short. 

Since 1976, ANSMET researchers have been recovering thousands of meteorite specimens from the East Antarctic ice sheet. 

ANSMET is funded by the Office of Polar Programs of the National Science Foundation.

According to the ANSMET website, the specimens are currently the only reliable, continuous source of new, nonmicroscopic extraterrestrial material. 

Given that there are no active planetary sample-return missions coming or going at the moment, the retrieval of meteorites is the cheapest and only guaranteed way to recover new things from worlds beyond the Earth.

Leonid Meteor Shower Peaks

Earth pays its annual visit to the Leonid meteor shower Thursday night and Friday morning; this view is at 1 a.m. looking east.

CREDIT: Starry Night Software

As the Earth moves around the sun in its annual orbit, it passes through patches of space debris left behind by comets and asteroids.

As it moves through these clouds of dust and sand-sized particles, it sweeps them up, and they are heated to incandescence by friction with the Earth's atmosphere, causing bright streaks of light in the night sky known to scientists as meteors, and to skygazers as shooting stars.

Meteors can be seen every night; these are known as sporadic meteors but when the Earth passes through a cloud of debris, it sometimes produces displays known as meteor showers.

A famous annual shower known as the Leonids is set to peak Thursday night (Nov. 17).

Unlike rain showers, meteor showers are not concentrated. Usually they mean seeing 10 or 20 meteors an hour, as opposed to the typical average of one or two.

Most of the time the Leonids are a fairly quiet shower, but every 33 years they put on a major display, known as a meteor storm.

This last happened in 1999, when more than a thousand meteors per hour were observed.

ESA: Watching the dragon spit fire - video

A Draconid meteor burns up as a fireball in the atmosphere of Earth on 8 October 2011.

2011 Perseid Meteor Shower Images

Skywatcher and photographer Nick Rose snapped this stunning view of a Perseid meteor from Millbrae, Calif., on Aug. 10, 2011 as the annual Perseid meteor shower neared its peak.

[See more amazing Perseid meteor shower photos from 2011]

Asteroids make life's raw materials

For the first time, rocks from an asteroid have been shown to power the synthesis of life's essential chemicals.

The asteroid in question fell to Earth on 28 September 1969, landing on the outskirts of the village of Murchison in Victoria, Australia. 

Tests showed it was laced with amino acids and some of the chemicals found in our genetic material.

The discovery suggested that space was not the chemically sterile place it was once thought to be, and that organic chemistry was widespread. It hinted that the molecules life needed to get started could have been produced in space, before dropping to Earth.

But how did those molecules form? Raffaele Saladino of the University of Tuscia in Viterbo, Italy, and colleagues wondered if they could have been made deep inside the asteroids from which some meteorites break off. The team knew that a simple chemical present in space, called formamide, can be transformed into many biomolecules, so they used that as their starting point.

They obtained 1 gram of the Murchison meteorite, ground it to powder and removed all the organic molecules, leaving just the mineral. They mixed this with formamide and heated it to 140°C for 48 hours. 

The reaction produced nucleic acids - essential building blocks of DNA and RNA - as well as the amino acid glycine, carboxylic acids and a precursor to sugar (Origins of Life and Evolution of Biospheres, DOI: 10.1007/s11084-011-9239-0). This suggests the meteorite's parent asteroid was a chemical factory, Saladino says.

Crucially, the compounds produced are both metabolic and genetic, covering two key parts of primitive life, says Monica Grady of the Open University in Milton Keynes, UK, who was not involved in the study. "If you can catalyse both reactions in the same place, from the same starting material, that's obviously advantageous."

The ability to produce a range of essential molecules sets the meteorite mineral apart from Earth minerals, says Mark Sephton of Imperial College London. On Earth, the formation of each biomolecule tends to be catalysed by a different mineral, meaning they end up separated and less likely to form life.

Saladino's team also found that the meteorite mineral could stabilise RNA, thought by some to have been the first genetic material. RNA reacts with water and breaks down easily. Most minerals accelerate this process, but the team found that the Murchison mineral did not. "If RNA could be synthesised [inside the asteroid], this environment would stabilise it," Saladino says.

The Perseid radiant: Meteorite Shower

Looking northeast around midnight on August 12th-13th.

The red dot is the Perseid radiant. Although Perseid meteors can appear in any part of the sky, all of their tails will point back to the radiant

The show begins at sundown when Venus, Saturn, Mars and the crescent Moon pop out of the western twilight in tight conjunction.

All four heavenly objects will fit within a circle about 10 degrees in diameter, beaming together through the dusky colors of sunset. No telescope is required to enjoy this naked-eye event.

The planets will hang together in the western sky until 10 pm or so. When they leave, following the sun below the horizon, you should stay, because that is when the Perseid meteor shower begins.

From 10 pm until dawn, meteors will flit across the starry sky in a display that's even more exciting than a planetary get-together.

The Perseid meteor shower is caused by debris from Comet Swift-Tuttle. Every 133 years the huge comet swings through the inner solar system and leaves behind a trail of dust and gravel.

When Earth passes through the debris, specks of comet-stuff hit the atmosphere at 140,000 mph and disintegrate in flashes of light. These meteors are called Perseids because they fly out of the constellation Perseus.

Swift-Tuttle's debris zone is so wide, Earth spends weeks inside it. Indeed, we are in the outskirts now, and sky watchers are already reporting a trickle of late-night Perseids.

The trickle could turn into a torrent between August 11th and 13th when Earth passes through the heart of the debris trail.

2010 is a good year for Perseids because the Moon won't be up during the midnight-to-dawn hours of greatest activity. Lunar glare can wipe out a good meteor shower, but that won't be the case this time.

As Perseus rises and the night deepens, meteor rates will increase. For sheer numbers, the best time to look is during the darkest hours before dawn on Friday morning, Aug. 13th, when most observers will see dozens of Perseids per hour.