Taxonomy term

meteorite

Meteorite impacts may have kick-started ancient subduction

Earth in the Hadean Eon, between 4.56 billion and 4 billion years ago, was much too hot to support active plate tectonics as we know it today, where cold, established plates slowly march around Earth. Yet some evidence, including from tiny zircon crystals dating to the Hadean, has suggested that a form of plate tectonics was active by about 4.1 billion years ago — about a billion years before many researchers think modern plate tectonics started. The mechanisms that could have initiated and sustained early tectonics are unclear, but according to a new study, constant bombardment of early Earth by meteorites could have triggered temporary bursts of early tectonism.

22 Feb 2018

Minerals deformed by meteorites reveal age of impact

Researchers have discovered a new way to determine when a meteorite hit Earth, a technique that could not only help scientists date ancient meteorite strikes but also determine when planetary crusts first formed.

03 Oct 2017

Why meteors snap, crackle and pop

Keen-eared observers sometimes report hearing popping, whistling or buzzing at the same time they see meteors pass far overhead, a perplexing phenomenon called the electrophonic effect. What causes the effect — or if it’s even real — has been discussed for centuries; famed astronomer Edmond Halley is said to have dismissed it as a figment of people’s imaginations. In a new study in Geophysical Research Letters, researchers suggest that not only is it real, but that it is caused by radio waves induced by meteors and converted to sound waves near Earth’s surface.

17 Aug 2017

Platinum may point to impact theory for Younger Dryas

Some large meteorite strikes leave obvious craters on Earth’s surface, while others that hit water or ice or explode in the air may only leave subtle markers in the soil, such as exotic minerals or elevated levels of rare elements like platinum or iridium. In a new study, researchers report spikes of platinum in sediments at archaeological sites across North America, offering new evidence, they suggest, of a major meteorite strike about 12,800 years ago, just before the onset of a global cold period known as the Younger Dryas. The lack of a telltale crater dating to this time, however, has left scientists debating for years whether an impact actually occurred and what, if any, role it had in setting off the cold snap and affecting some of Earth’s human and animal populations.

21 Jun 2017

Meteorites did not spark Ordovician biodiversification

During the Ordovician Period, roughly 470 million years ago, an asteroid the size of a small moon collided with another rocky object in the belt between Mars and Jupiter, shattering the asteroid into billions of pieces. Fragments from the epic collision still occasionally fall to Earth today, making up a large share of the meteorites recovered. But in the immediate wake of the Ordovician event, many pieces rained down on the planet, settling on the surface and in layers of rock forming at the time. In a new study, researchers studying some of these meteorite-rich layers have refined the timescale for the collision. The results bring into question a proposed link between the meteorite bombardment and an evolutionary uptick known as the Great Ordovician Biodiversification Event (GOBE).

23 May 2017

Mystery impact may have kicked off dramatic warming event

About 56 million years ago, the planet warmed rapidly in a mysterious event known as the Paleocene-Eocene Thermal Maximum (PETM). Researchers recently discovered evidence in the rock record from around the same time that points to an extraterrestrial impactor striking Earth, but whether the two events are related is yet to be determined.

06 Feb 2017

New type of meteorite found in Sweden

Meteorites offer a glimpse into the workings and origins of our solar system. Now, a meteorite found in a Swedish quarry, reported in a new study in Nature Communications, is opening a whole new window: The find has been classified as a new type of meteorite, never before seen on Earth.

18 Oct 2016

Iron meteorites likely hidden below Antarctic ice

Despite the fact that meteorites fall relatively evenly across the surface of the planet, most meteorites retrieved by humans have come from Antarctica. This is because meteorites are easily buried and preserved in Antarctic ice; over time, the ice melts and exposes the dark-colored fallen rocks for relatively easy recovery on the continent’s white surface. But iron-rich meteorites, common among specimens found in other parts of the planet, are unusually rare in Antarctica. Researchers may now have figured out why.

14 Jul 2016

Meteorites might have created Earth’s earliest continents

Massive meteorite impacts on Earth are destructive events, gouging enormous craters in the crust and raining debris over the planet’s surface. But such huge impacts may have also created some of its earliest continental kernels, called cratons, during Archean times.
 
08 Jan 2016

Red Planet Roundup: November 2015

With two rovers patrolling the surface of Mars, five spacecraft orbiting above it, and scientists here on Earth studying the Red Planet from afar, new findings are announced often. Here are a few of the latest updates.
 
14 Nov 2015

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