sábado, 29 de junho de 2013

Out and About: Meteorites find way to the prairie

Until Virgin Galactic makes good on its promise of commercial space travel, the night sky is the main conduit to the cosmos for anybody not part of an astronaut program.

For amateur astronomers such as University of Sioux Falls emeritus physics professor Wally Klawiter, “after a while, you get to understand how the planets follow the same path the sun follows.

“It’s just nice to be able to look up in the sky and know what you’re seeing. It makes you feel like you know something, and it doesn’t take long to start learning those things.”

Every now and again, though, the heavens make a more intimate connection with folks on earth. It has long been known shooting stars slashing across the darkness are meteors burning themselves up in the planet’s atmosphere. Sometimes they survive the trip, and in the early to mid-20th century, self-taught scientist and meteorite collector Harvey Nininger discovered the Great Plains was a tremendous place to find them. He recovered several hundred meteorites during his life and published more than 160 scientific papers on his collection.

Nininger died in 1986 at age 99. Now Calvin Duszynski, a fossil and crystal dealer from Calgary, Alberta, is picking up his banner. Duszynski began collecting meteorites about a dozen years ago.

“I’ve got a pretty neat collection from different parts of the world,” he says.

Like Nininger, “my goal is to contact as many farmers and ranchers as possible and educate them,” Duszynski says. “They know their properties inside and out. They know these odd-looking rocks show up from time to time, but that’s as far as they know. So they huck them into a rock pile.

“Sometimes they’re used as door stops or they’re in barns or in rock gardens.”

Duszynski has placed an advertisement in several farm and ranch magazines. “I hope somebody reads it who is sitting in his rocking chair in the middle of Montana and realizes ‘Hey, I just hucked one of those rocks this spring.’ ”

So far, Duszynski has been contacted by a farmer in Hanson County, who wishes to remain anonymous, and one in Minnesota who are willing to sell him meteorites they found. The going rate is “a couple hundred to several thousand dollars. It all depends what it is.”

Meteorites are typically dimpled like a golf ball and have either a weak or strong magnetic attraction, depending on how much iron ore they contain. The ones with the most iron “will be much heavier than any ordinary rock,” Duszynski writes in his ad.

No kidding. There have been about a dozen known meteorite finds in South Dakota from 1892 to 1990. Bruce Eichstadt found the most recent one while disking a field on his father’s farm near Wolsey.

“I don’t know how many times I disked that field before, and I never run across it. I hit that thing, and it just threw the disk plumb up in the air. I thought, ‘What in the world did I run over?’ ”

Eichstadt found a roundish rock a little larger than a basketball.

“I was going to lift it up and set it on the tip of the disk wing and haul it to the end of the field. I couldn’t lift it.

“A rock that size, you can pick it up with just a little bit of effort. I leaned in and thought, ‘Boy, this is something else.’ ”

He was able to roll it up a ramp of dirt piled up by the disk and onto the implement. By this time he was pretty sure what he had. The disk had gouged a small chip in the gray and black rock and the inside “was shiny like steel.”

Eichstadt hauled it home and tried to cut it with a hacksaw. “I tried four blades on it, and it burnt the teeth right off them blades,” he recalls.

The rock only a little larger than a basketball turned out to weigh 160 pounds.

The meteorite discovery made Eichstadt a local celebrity for a time, and the rock spent years on his porch.

“There were times you’d have to step around it,” he says. “But you’d admire it. I sure did.”

Eventually his father and brother sold it to a collector in Malta, Mont.

“He gave them quite a sum of money for it,” Eichstadt says.

The meteorite was cut in two, and half of it went to a University of Arizona researcher.

Eichstadt said he saw a picture of the meteorite among his father’s things at a nursing home about a month ago. Before that, “I hadn’t thought about it for a while.”

Eichstadt is 70 now, a semi-retired truck driver who still hauls fertilizer from North Dakota to Nebraska. When he’s out on the road at night “I notice falling stars in the distance. There’s a flicker and the light goes out. That would be a treat to see one of them hit the ground again and be able to drive to it.”

He doesn’t seem obsessed, however, by a desire to handle something from beyond earth again.

But it is taking over Duszynski’s life.

“I eat, breathe and sleep meteors now,” he admits. “I am so excited about this project.”

Source: argusleader.com

quinta-feira, 27 de junho de 2013

Mystery solved: meteorite caused Tunguska devastation

A century after, scientists have revealed that the 1908 Tunguska devastation was caused by a meteorite by identifying its microscopic remains. Why it took them so many years makes for a fascinating tale about the limits of science and how we are pushing them.

By Simon Redfern, University of Cambridge

On the morning of June 30 in 1908, a gigantic fireball devastated hundreds of square kilometres of uninhabited Siberian forest around the Tunguska river. The first scientists to investigate the impact site expected to find a meteorite, but they found nothing.

Because no traces of a meteorite were found, many scientists concluded that the culprit was a comet. Comets, which are essentially muddy ice balls, could cause such a devastation and leave no trace.

But now, 105 years later, scientists have revealed that the Tunguska devastation was indeed caused by a meteorite. A group of Ukrainian, German, and American scientists have identified its microscopic remains. Why it took them so many years makes for a fascinating tale about the limits of science and how we are pushing them.

Big ball of fire

Eyewitness reports of the Tunguska event help paint a partial picture. As the fireball streaked across the sky, a blast of heat scorched everything in its wake, to be followed by a shock wave that threw people off their feet and stripped leaves and branches from trees, laying a large forest flat. Photos reveal the extent and force of the impact, showing trees that look like bare telegraph poles, all pointing away from the impact site.

The inability to find any meteorite, however, led to a century of speculation on the origins of the blast. The Tunguska event has spawned a wealth of science fiction that has fed outrageous theories. But the main question has remained: what was it?

An icy comet would evaporate on impact, which could explain the lack of any observable evidence. But a study in the journal Planetary and Space Science provides, for the first time, evidence that the impact was not caused by a comet. Researchers collected microscopic fragments recovered from a layer of partially decayed vegetation (peat) that dates from that extraordinary summer.

Victor Kvasnytsya from the National Academy of Sciences of Ukraine and his colleagues used the latest imaging and spectroscopy techniques to identify aggregates of carbon minerals—diamond, lonsdaleite, and graphite. Lonsdaleite in particular is known to form when carbon-rich material is suddenly exposed to a shock wave created by an explosion, such as that of meteorite hitting Earth. The lonsdaleite fragments contain even smaller inclusions of iron sulphides and iron-nickel alloys, troilite and taenite, which are characteristic minerals found in space-based objects such as meteorites. The precise combination of minerals in these fragments point to a meteorite source. It is near-identical to similar minerals found in an Arizona impact.

The samples point to one thing: the Tunguska impact is the largest meteorite impact in recorded history. US researchers have estimated that the Tunguska blast could have been as much as the equivalent of a five megaton TNT explosion—hundreds of times more powerful than the Hiroshima blast. The meteorite tore apart as it entered the atmosphere at an angle, so that little of it reached the ground intact. That is why all remains are such small specks that have been fossilised in the Siberian peat.

2013 meteorite impact

We can compare the Tunguska event with the fireball seen during the impact of the Chelyabinsk meteor earlier this year. Although much less powerful than Tunguska, the Chelyabinsk event was similar. A low-angle approach broke up the body, leaving fragments that were found over the vast expanse of Eurasia. More than 1,000 people were injured, some drawn to windows by the flash of the fireball and then hit by the shock wave that followed.

The Tunguska devastation that was not investigated for 19 years, partly because of lack of resources. In contrast, the Chelyabinsk meteorite attracted immediate attention. Dashboard cameras captured the trajectory and brightness of the fireball, while CCTV networks provided fixed reference points. The US space agency NASA has now been able to identify the origins of the meteorite.

The low-frequency rumble of the Chelyabinsk event travelled twice around the globe. The datademonstrates that the energy of the impact was equivalent to a 460 kiloton (TNT) bomb, which is about 40 times the Hiroshima blast.

Simon Redfern does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.

Keywords: Tunguska event, Chelyabinsk meteor, lonsdaleite, National Academy of Sciences of Ukraine, Arizona impact, The Conversation

Source: thehindu.com

quarta-feira, 19 de junho de 2013

An Arlington Minnesota couple discovered a strange rock in one of their corn fields

A Minnesota couple found a 33-pound meteorite at their farm in Arlington, Minn.
Bruce and Nelva Lilienthal said it's unclear when the debris from outer space landed at their farm.
It's believed to be one of the largest meteorites ever found in Minnesota. Another meteorite landed at the farm about 120 years ago, they said.
Source: KSTP

segunda-feira, 17 de junho de 2013

Ancient craters on Mars may have been oases for life

Meteorite craters on ancient Mars may have been home to primordial life forms. Because hydrothermal systems host the most ancient known lineages of life on earth, many biologists think that the first organisms on this planet arose in hot springs. On earth these were largely volcanic systems, such as those that exist today in Yellowstone.

On Mars, the impact of large meteorites and asteroids may have been the main source for hydrothermal activity. The energy generated by these events melted surface rocks and heated water. Since it may have taken more than a million years for the center of a crater to cool, it would have been possible that a warm, moist environment could have lasted that long—more than enough time to give life a chance to evolve.

Recent studies of Sudbury crater in Canada and Lappjärvi crater in Finland have borne this out. Scientists Gordon Osinksi and Martin Schmieder have shown that the 155-mile-wide Canadian crater was home to hydrothermal activity for at least 1.6 million years and perhaps even longer. Smaller impacts creating craters 12 to 18 miles in width were ten times more common than Sudbury-sized impacts. They may also have been home to early life—though the lifespans of their hydrothermal activity—a few tens of thousands of years—may have been too short.

Craters like these on earth may have been the first—literal—hot spots of life on this planet. Cratering may have played a similar role for early Mars.

Source: http://io9.com

Rock Found In Amesbury Backyard Came From Space Station

Phil Green wasn’t quite sure what he had, when he noticed the unusual rock on the banks of the Merrimack River.

His yard backs up to the river and he was on one of his frequent walks, looking for arrowheads. The tide was low, leaving behind exposed mud and smooth granite. And then he noticed something that just didn’t look right.

“There she was just sitting there, sticking up like that, and I said heck what is this,” recalls as he holds a large greenish colored rock. “It just didn’t belong.”

The rock was covered in mud when Phil found it. It was hard to see the burn marks on the side. At first he thought it was a rock used to make arrowheads. Then he suspected it might be meteorite. He used a metal detector to check and found it wasn’t metallic.

He suspected it might have come from outer space. But he had no idea just how unusual it actually was.

Phil was puzzled by the strange rock so he held on to it. But before long, he placed it in the yard and forgot about it. The rock sat under a tree for six years until a friend started asking questions.

Phil’s sister in law also thought it was from space so she sent it to a friend who works for NASA. That friend confirmed the rock was special, and that it wasn’t actually a rock at all.

What Phil had found was a piece of the Russian Space Station Mir. When Mir was de-commissioned, much of it burned up as it re-entered Earth’s orbit. The rest landed in the South Pacific Ocean. Somehow, one palm-sized chunk crashed into the Merrimack River in Amesbury.

Phil, who works as a custodian at Amesbury Elementary School, has brought it in as a teaching tool.

“I had a lot of fun taking it to school and showing it to all the kids,” he says.

Now it sits in his house, next to a letter from the NASA engineer.

The “rock” that started on Earth, went to space, and came back to Amesbury, now has a place as Phil’s prized possession.

Source: CBS Boston

domingo, 2 de junho de 2013

Meteorites Treated By Different Cultures in Unique Ways

The heavens fascinates mankind for ages. They marveled at the stars and rocks falling from the sky.

Meteorites were regarded as messages from God in historic times and were considered good or bad omens depending on the culture and social environment.

1.In Switzerland, meteorites were believed to be blessed with the power of God.
2. In Chile, when one sees a meteor, he must pick up a stone.
3. A shooting star was believed by the Swabians as good luck.
4. Modern Hawaiian Japanese must open the collars of their kimono if a meteor is coming in their direction to welcome the good luck.
5. In the Philippines, a knot must be tied in a handkerchief before the light is extinguished.
6. People who believed that meteors signal ill-omen, they should say words like, “amen,” or “go away” to avert bad luck.
7. It is still considered as bad luck by some Americans when talking or pointing to a meteor.
8. One of the most notable omens was the Ensisheim stony meteorite in Alsace in 1492 and was determined as a good omen in the Holy Roman Emperor Maximillian’s war with France and the Turks.

Egyptian tombs contain meteorites, and its hieroglyphic symbol were translated as “iron from heaven.” Para’oh Tutankhamun’s burial chamber also found a dagger of meteoritic. According to Titus Livius, in 2000 B.C., when a meteorite fell near Phrygia, it was venerated by many people for years and worshiped as a divine object for 500 years in Rome.

Throughout history, meteorites have been treated by different cultures in unique ways. They been collected, divinely worshiped or fashioned into tools.

1.Romans and Greek temples enshrined rocks that had reportedly fallen from heaven.
2. In ancient Greece, meteorites were held as objects of veneration in one of the most important sites at Apollo’s temple at Delphi.
3. In the U. S., meteorites have been found at Indian graves where they were worshiped in Hopewell Mounds.
4. The shrine of Islam at Mecca holds a black stone measuring 16 by 20 cm at the wall of the Ka’ba believed to be a stone of meteoric origin.
5. Numerous other instances of meteorite worship were seen from Europe, Africa, Asia, and the Americas.

In North America, little was recognized about their synergy with the sky and since there were no written documents left, archaeologist can only theorize their meteorites use from the information they recovered. However, there is budding evidence that because of the North American Indians extensive knowledge of the celestial events, they could develop timekeeping systems. The Inca, Maya, Aztecs, and American Indians realized that they could predict seasonal changes based on the movements of the stars, sun, and moon allowing them to lay out religious ceremonies as well as planting, and harvesting.

Some archaeological sites in Mississippi River Valley were built to signal summer and winter solstice by the setting and rising of the sun. The Toltec Mounds near Little Rock, Arkansas contained adjustments for the equinox as well as the setting and rising of star Vega.

Since the 19th century, the appearance of meteorites on North American archaeological sites has already been known. Though treated by different cultures in unique ways, our modern world still venerate these objects. Whether messages from God or a signal for good or bad omen, scientists have created scientific fields devoted to the study of the science of meteoritics.

Written by: Janet Grace Ortigas

Source: guardianlv.com