The Oort Cloud Might be More Active Than We Thought

The paths of hyperbolic-orbit comets. Credit: NAOJ

Every now and then a comet or asteroid comes to our solar system from interstellar space. We have observed two interstellar objects in recent years, Oumuamua in 2017, and Borisov in 2019. One would assume then that in the past at least some interstellar objects have struck Earth. But we’ve never found an interstellar meteorite. A new study argues that this is because the Oort cloud is much more active than we thought.

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The Geminids Will be Peaking on December 14th. They’re Usually the Most Active Meteor Shower Every Year

Meteor showers are a great way to share a love of astronomy with those who might not be as familiar with it. Almost everyone loves watching streaks of light flash across the sky, but usually, it’s so intermittent that it can be frustrating to watch. That’s not the case for the next few weeks, though, as the annual Geminid meteor shower is underway until December 24th.

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Supercomputer Simulates What Happens When Meteors Strike the Atmosphere

In space, it’s almost always raining dust. Most of that dust is so small a microscope would have a hard time seeing it.  Created by asteroid impacts, millions of these fine dust particles collide with Earth’s upper atmosphere every second.  When they hit that atmosphere, they start a complex dance of plasmas and energy that can be difficult to see and understand.

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3,600 Years ago, a 50-Meter-Wide Meteor Exploded in the Sky and Destroyed a City Near the Dead Sea

This is an artist’s depiction of a 10-kilometer (6-mile) diameter asteroid striking the Earth. New evidence in Australia suggests an asteroid 2 to 3 times larger than this struck Earth early in its life. Credit: Don Davis/Southwest Research Institute.
This is an artist’s depiction of a 10-kilometer (6-mile) diameter asteroid striking the Earth. New evidence in Australia suggests an asteroid 2 to 3 times larger than this struck Earth early in its life. Credit: Don Davis/Southwest Research Institute.

An archeological dig has uncovered evidence of a massive cosmic airburst event approximately 3,600 years ago that destroyed an entire city near the Dead Sea in the Middle East. The event was larger than the famous Tunguska airburst event in Russia in 1908, with a blast 1,000 times more powerful than the Hiroshima atomic bomb. The event flattened the thriving city of Tall el-Hammam, located in what is now Jordan.

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The Tears of the Hero: Get Ready for the 2021 Perseid Meteors

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A sure-fire summer shower, the Perseid meteors are set to put on a spectacular show this year.

It’s one of my fondest astronomical observing memories of childhood. Growing up in Northern Maine, it was a family tradition to set the lawn chairs out on warm mid-August nights, and watch with my mom and brother as the Perseid meteors slid silently through the inky black sky.

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Video Shows a Meteoroid Skipping off Earth’s Atmosphere

Here’s something we don’t see very often: an Earth-grazing meteoroid.

On September 22, 2020, a small space rock skipped through Earth’s atmosphere and bounced back into space. The meteoroid was spotted by the by a camera from the Global Meteor Network, seen in the skies above Northern Germany and the Netherlands. It came in as low as 91 km (56 miles) in altitude – far below any orbiting satellites – before it skipping back into space.

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Completely Harmless Asteroid Almost Certainly Won’t Hit Earth Just Before the US Election

A long-trailed, earthgrazing Eta Aquarid meteor I saw on May 6, 2013. Credit: Bob King

In a year of devastating wildfires, destructive derechos, early and active hurricanes, widespread social unrest, contentious politics and more — all amid an unprecedented global pandemic — it might seem fitting that ‘asteroid impact’ would be added to the 2020 bingo card.

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There Could be Meteors Traveling at a Fraction of the Speed of Light When They Hit the Atmosphere

Multi-photo composite showing Perseid meteors shooting from their radiant point in the constellation Perseus. Earth crosses the orbit of comet 109P/Swift-Tuttle every year in mid-August. Debris left behind by the comet burns up as meteors when it strikes our upper atmosphere at 130,000 mph. Credit: NASA

It’s no secret that planet Earth is occasionally greeted by rocks from space that either explode in our atmosphere or impact on the surface. In addition, our planet regularly experiences meteor showers whenever its orbit causes it to pass through clouds of debris in the Solar System. However, it has also been determined that Earth is regularly bombarded by objects that are small enough to go unnoticed – about 1 mm or so in size.

According to a new study by Harvard astronomers Amir Siraj and Prof. Abraham Loeb, it is possible that Earth’s atmosphere is bombarded by larger meteors – 1 mm to 10 cm (0.04 to 4 inches) – that are extremely fast. These meteors, they argue, could be the result of nearby supernovae that cause particles to be accelerated to sub-relativistic or even relativistic speeds – several thousand times the speed of sound to a fraction of the speed of light.

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Bright Fireball Explodes Over Ontario, Meteorite Fragments Might Have Reached the Ground

. Credit: NASA’s All Sky Fireball Network

On Wednesday, July 24th, the people of the Great Lakes region were treated to a spectacular sight when a meteor streaked across the sky. The resulting fireball was observed by many onlookers, as well as the University of Western Ontario’s All-Sky Camera Network. This array runs across southern Ontario and Quebec and is maintained in collaboration with NASA’s Meteoroid Environment Office (MEO) at the Marshall Space Flight Center.

What is especially exciting about this event is the possibility that fragments of this meteorite fell to Earth and could be retrieved. This was the conclusion reached by Steven Ehlert at the MEO after he analyzed the video of the meteorite erupting like a fireball in the night sky. Examination of these fragments could tell astronomers a great deal about the formation and evolution of the Solar System.

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