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Post Info TOPIC: Micrometeorites


L

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RE: Micrometeorites
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Have you ever heard of micro meteorites? I've heard of them because my friend James H. Lever, along with Susan Taylor, his scientist wife, told me all about them.
Jim Lever is homegrown talent. He grew up in Niagara Falls and went to A.N. Myer Secondary School, where he excelled as a student. He continued to excel at McMaster University and at the University of Toronto ending up with a PhD.
Since then, he's done a ton of work and research in the cold regions of the north and south of our planet.

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L

Posts: 131433
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Micro-meteorites
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Magnetic particle

This particle (x100 magnification) was obtained by collecting run off water from a roof. Magnetic particles were then extracted so see if any could be classified as micro meteorites. Not sure if this is one or not as most references suggest spheres.

The particle is moving in the video because a strong magnet is being moved nearby.



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L

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Sugar grain sized meteorites rocked the climates of early Earth and Mars

Bombardments of micro-meteorites on Earth and Mars four billion years ago may have caused the planets climates to cool dramatically, hampering their ability to support life, according to research by Imperial scientists published on 1 April in the journal Geochimica et Cosmochimica Acta.
Micro-meteorites, the size of sugar grains, come from the rocky asteroid belt between Mars and Jupiter, and are dragged by gravity towards Earth and Mars. As they enter the planets upper atmospheres, they heat up to temperatures of approximately 1,000 degrees Celsius and release gases, including sulphur dioxide. This sulphur dioxide forms aerosols consisting of solid and liquid particles, which deflect sunlight away from the surface, making the planets cooler.

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L

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Oldest Fossilised Space Dust
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Tiny Iron Spheres Are Oldest Fossilised Space Dust

Japanese researchers have discovered the first micrometeorites known to land on Earth. No larger than droplets of fog, the spherical, iron-rich particles arrived 240 million years ago, 50 million years before the previous record-holding space dust.

"These are the oldest fossil micrometeorites I've ever heard of, and the preservation is fantastic. They look exactly like their modern equivalents. If we can figure out where these things came from, they can help inform us about the history of the solar system" - geologist Susan Taylor of the U.S. Army Corps of engineers, who wasn't involved in the work, published in Geology May 4.

Geologist Tetsuji Onoue of Kagoshima University discovered the new specimens in ancient shale and chert rock from Ajiro Island, at the southern tip of Japan.

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L

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Micrometeorites
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Title: Composition and accretion rate of fossil micrometeorites recovered in Middle Triassic deep-sea deposits
Authors: Tetsuji Onoue, Tomoki Nakamura, Takeshi Haranosono and Chika Yasuda

Micrometeorites, which are submillimetre-sized extraterrestrial particles that survive atmospheric entry, originate from dust-producing objects such as comets and asteroids. Although ancient micrometeorites found in sedimentary rocks are of key interest as a historical record of meteoroid populations in the solar system, they are rare and prone to severe chemical weathering. Here we report the recovery of well-preserved micrometeorites, older than 240 Ma, in radiolarian chert from Japan. The collection of micrometeorites comprised 258 cosmic spherules, which are particles that totally melted during atmospheric entry, and 2 coarse-grained unmelted micrometeorites. These micrometeorites are much older than any previous micrometeorite collection in the sedimentary record. Using this collection, we calculated the accretion rate of iron-type cosmic spherules to the Earth during the Anisian Stage of the Middle Triassic. The estimated accretion rate for Anisian iron-type spherules smaller than 125 m is 25 8 t yr^-1. Analysis of the accretion rate for cosmic spherules also reveals high accretion rates of small spherules (~8-36 m) for a 0.74 m.y. period in the late Anisian. However, the possible link between an enhancement in the accretion rate of small cosmic spherules in the late Anisian and variations in the flux of extraterrestrial matter to the Earth requires further scrutiny.

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