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Scientists use lasers to simulate shock effects of meteorite impact on silica

Meteor Crater in Arizona
© National Map Seamless Server/USGS
Meteor Crater in Arizona, formed by a meteorite impact 50,000 years ago, contains bits of a hard, compressed form of silica called stishovite. Researchers precisely measured the rapid transformation of a fused silica glass into stishovite using SLAC's X-ray laser, the Linac Coherent Light Source.
Scientists used high-power laser beams at the Department of Energy's SLAC National Accelerator Laboratory to simulate the shock effects of a meteorite impact in silica, one of the most abundant materials in the Earth's crust. They observed, for the first time, its shockingly fast transformation into the mineral stishovite - a rare, extremely hard and dense form of silica.

You can scoop up bits of stishovite at the scene of meteorite impacts, such as a 50,000-year-old meteor crater in Arizona that measures about 3/4-mile across and about 570 feet deep. A similar form also exists naturally at the extreme pressures of the Earth's mantle, hundreds of miles below ground.

The Speed of Stishovite

In the experiment at SLAC, researchers used lasers to create a shock wave in samples of silica glass. The heat and compression of this shock wave caused tiny crystals, or "grains," of stishovite to grow within just a few nanoseconds, or billionths of a second. This speed defies predictions that the changes take tens or even hundreds of times longer.

"The beauty here is that the quality of the data enabled us to make a measurement that gives us entirely new insight into the mechanism for this transformation," said Arianna Gleason, who led the experiment at SLAC's Linac Coherent Light Source (LCLS) X-ray laser, a DOE Office of Science User Facility. The work was published in the Sept. 4 issue of Nature Communications.

"Figuring out how atoms rearrange themselves in this material is important, and to our great surprise, what we expected to be a slower process is really rapid," said Gleason, who was a postdoctoral researcher at SLAC and Stanford University at the time of the 2012 experiment and is now a postdoctoral fellow at Los Alamos National Laboratory. "That was not known before. LCLS gave us access to this ultrashort timescale combined with the capability to generate a shockwave, which is unique."

Question

Mysterious 'boom' stuns residents of a town in Gloucester, UK

Kingsholm, Gloucester

A mysterious explosion shook Kingsholm, Gloucester
on September 9 2015.
A super loud bang brought residents in Malvern Road in Gloucester from their homes last night (September 9) leaving families stunned.

The deep boom was significant enough to prise Kingsholm people from their sofas during peak television viewing time.

Residents gingerly opened front doors to peer out into the street - expecting to see a trail of destruction, bomb crater, tail of an aircraft, damage to vehicles, the front of a neighbour's house missing or the remnants and shrapnel of someone's boiler.

What greeted them came as another shock - the same peaceful scene of parked cars, twitching curtains and hedgehogs scuttling for cover.

Comment: Such loud booms with no identifiable source could in all likelihood be overhead explosions caused by meteor fireballs, or other seismic interactions brought about from our changing cosmic climate. See also:

Sott Exclusive: Meteor fireball explodes over eastern Turkey, sending shower of meteorites to the ground


Fireball 5

Unique twin meteorite impacts found in Sweden

Sweden Impact Event
© Don Dixon/Erik Sturkell/University of Gothenburg
Illustration of a twin meteorite impact that resulted in a unique double crater in Sweden.
Twin craters in a county in Sweden have been found to be the remnants of ancient simultaneous meteorite collisions that took place about 460 million years ago, say University of Gothenburg researchers. The impacts, one very large and the other about a tenth of the size, were found in the Swedish county of Jämtland. These were not the only meteorites that landed on Earth during this time.

"Around 470 million years ago, two large asteroids collided in the asteroid belt between Mars and Jupiter, and many fragments were thrown off in new orbits. Many of these crashed on Earth, such as these two in Jämtland," Erik Sturkell, professor in the University of Gothenburg's Department of Earth Sciences, said in a news release.

During this period, Jämtland was under about 500 meters of water in that area. The impact forced the surrounding water away for a short time, during which the craters were completely dry. Sturkell explained that when the water rushed back in, it brought meteorite fragments with it and caused large sea waves. Double impacts are very unusual, and this is the first one that has been proved to land on Earth.

Fireball 2

Meteor seen entering Oman atmosphere; explosions heard

Image
© Shutterstock
Meteor like unidentified object did enter the Sultanate's atmosphere on Wednesday night, however it is not clear whether it landed in Oman or not, according to Saleh Al Shidhani from the Oman Astronomical Society, Locals in Wilayat of Yanqul in Al Dhahira Governorate reported that they witnessed Meteor like object and also heard the crash.

Speaking to Times of Oman, Saleh Al Shidhani from the Oman Astronomical Society, said, "Based on the information we have gathered currently, we can't confirm whether it was a meteorite or not."

"We are also not sure whether it landed in Sultanate, but it definitely passed through the atmosphere. But we don't know where it landed exactly," he further added, saying that the object passed through Al Dhahira Governorate and probably continued to the United Arab Emirates.

"The villagers had conflicting stories where some of them said they had heard the explosion when others denied it. We will send a team to that region and question the witnesses and investigate the matter," said Al Shidhani.

Comment: See also this other recent report: Sott Exclusive: Meteor fireball explodes over eastern Turkey, sending shower of meteorites to the ground


Fireball 2

Meteor filmed by Washington Monument camera

Image
© NASA Meteor Watch Facebook
A bright meteor was seen shooting through the sky Tuesday night and a camera located on the Washington Monument captured its movement.
A bright fireball streaking across the sky Tuesday night was captured on camera from the Washington Monument.

According to NASA's Meteor Watch, the fireball was seen in Virginia, Maryland, Pennsylvania, North Carolina and West Virginia around 9:27 p.m. It moved east to west and appeared to be orange, according to witness reports on the American Meteor Society's website.

An "Earthcam" on the Washington Monument captured the meteor's race through the sky.

According to the American Meteor Society, fireballs are very bright meteors, about as bright as Venus in the morning and evening skies.

About 10 to 15 meteorites fall to Earth each day, but sightings are rare since streaking fireballs often fall over the ocean, or during daylight hours when they can't be seen.

Fireball 2

Photographer captures fireball against the Northern Lights in Finland

Image
© MARKUS KIILI
Photographer Markus Kiili was lucky enough to capture this stunning photo
The incredible images show a bright white line hurtling through the green and blue sky, in a rare moment which was visible for just a few seconds.

Photographer Markus Kiili was fortunate enough to not only witness the beautiful event - but also capture it on TWO cameras.

The 40-year-old cameraman was shooting a time-lapse video in Lapland, Finland, with two cameras last night when he witnessed the stunning sky.

Fireball

Massive meteor fireball witnessed in Thailand, explosions heard

Fireball over Thailand
© Porjai Jaturongkhakun / YouTube
A massive fireball, believed to be a meteorite, has fallen on Thailand. Awestruck commuters witnessed the spectacle, describing a green and orange glow, as it took a nosedive toward Earth.

The event took place during the morning rush hour at about 8:45am local time in Bangkok, although the meteor did not make an audible sound as it struck the ground.


Fireball 4

Over fifty reports of fireball visible over English Channel

The American Meteor Society and the International Meteor Association received over 50 reports so far about a fireball event over the English Channel on August 30th 2015 around 19:30UT. Observers from as far center of France reported seeing a bright light in the sky. Below is a heat map of the witness reports.
Image
The preliminary estimated trajectory plotted from the witness reports shows the meteor was traveling from the south east to the north west and ended its (visible) flight few miles south of Brighton, UK.
Image

Fireball 5

Researchers use lasers to manipulate spin of 'asteroid' in simulated experiment

Image
© UC Santa Barbara/Vimeo
Researchers have honed laser technology to be able to slow, stop, and reverse the rotation of an asteroid-like target in a simulated space environment. The findings could potentially help deflect Earth-bound asteroids in the event of a major-impact threat.TagsEducation, SciTech, Science,Space

The DE-STAR (Directed Energy System for Targeting of Asteroids and exploRation) can, among other uses, stop the rotation of a spinning asteroid, according to small-scale, graphic demonstrations by the Experimental Cosmology Group, led by UC Santa Barbara physicist Philip Lubin and Gary B. Hughes, a researcher and professor at California Polytechnic State University-San Luis Obispo.

In order to simulate the laser's deflection capabilities, researchers used basalt, which is composed of materials similar to those of an asteroid. The team directed a laser at the basalt until it began to turn from a mineral to a gas. As the "asteroid" lost mass, it became a propellant.

"What happens is a process called sublimation or vaporization, which turns a solid or liquid into a gas," said Travis Brashears, a student at the University of California-Berkeley involved in the research. "That gas causes a plume cloud — mass ejection — which generates an opposite and equal reaction or thrust — and that's what we measure."


Magnets were used to spin the basalt, simulating a rotating asteroid. The laser system was also used to slow the rotation of the target.

Comment: This technology is likely being developed for reasons other than space exploration and mining asteroids.


Fireball 2

Did a bright fireball crash to earth close to Ashbourne in the UK?

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Did a bright meteor crash to earth close to Ashbourne last night? STOCK PHOTO
The News Telegraph has been contacted by reader Michelle Brooks to find out if anyone else saw a possible meteorite crash to earth last night.

Michelle said she saw a bright, fast moving fireball streak across the night skies close to Waterhouses.

She said: "It happened about 11.20pm.

"My front room window faces directly North and I guess the position was NNE .

"t was low and the 'ball' disappeared behind a rooftop the tail disappeared very quickly as normal.

"From my perspective I'd say it was football sized not a tiny pin prick we usually see.

"It was also very low indeed, not far from horizon when it disappeared from my view behind a rooftop in the distance."