The Oort Cloud Could Have More Rock Than Previously Believed

This artist's concept puts Solar System distances in perspective. The scale bar is in astronomical units, with each set distance beyond 1 AU representing 10 times the previous distance (logarithmic scale.) The image shows Voyager 2's location in 2018. (It also shows where the star Ross 248 will be in 40,000 years, when it will briefly be the closest star to the Sun.) Image Credit: NASA/JPL-Caltech

The Oort Cloud is a collection of icy objects in the furthest reaches of the Solar System. It contains the most distant objects in the Solar System, and instead of orbiting on a plane like the planets or forming a ring like the Kuiper Belt, it’s a vast spherical cloud centred on the Sun. It’s where comets originate, and beyond it is interstellar space.

At least that’s what scientists think; nobody’s ever seen it.

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InSight Heard Four Meteoroids Crash Into Mars

These craters were formed by a Sept. 5, 2021, meteoroid impact on Mars, the first to be detected by NASA’s InSight. Taken by NASA’s Mars Reconnaissance Orbiter, this enhanced-color image highlights the dust and soil disturbed by the impact in blue in order to make details more visible to the human eye. Credits: NASA/JPL-Caltech/University of Arizona.

For the first time, a spacecraft has detected acoustic and seismic waves from impacts on Mars. NASA’s InSight lander made the detections from four meteoroids that crashed on Mars in 2020 and 2021. Ever since the mission landed on the Red Planet in 2018, scientists have been hoping to be able to detect impacts with InSight’s seismometer, which was mainly designed to sense Marsquakes. But these impacts are the first the lander has detected.

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Space Force is Releasing Decades of Tracking Data on a Thousand Bright Meteor Fireballs

Bright Fireball Credit: Adrian West

When a meteoroid enters the Earth’s atmosphere at a very high speed it heats up. This heating up produces a streak of light and is termed a meteor. When a meteor is bright enough, about the brightness of Venus or brighter, it becomes a fireball. Sometimes these fireballs explode in the atmosphere, becoming bolides. These bolides are bright enough to be seen even during the day.

Studying bolides as they pass through the atmosphere can help model larger asteroids, something of interest to the Planetary Defense Coordination Office (PDCO) which is run by NASA. These asteroids can be deadly if they are large enough, and learning how to predict their behavior is essential to protecting our planet from a devastating impact with long-term implications for the survival of many species on Earth.

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A Tiny Asteroid was Discovered Mere Hours Before it Crashed Into the Earth

2022 EB5 captured by Paolo Bacci and Martina Maestripieri from at 21h 10min UT, which is 12 minutes before it entered the atmosphere, while it was only 12 300 km form Earth and its apparent speed close to 65?/sec. Credit: P. Bacci, M. Maestripieri

Last week, a small asteroid was detected just two hours before it impacted Earth’s atmosphere. Luckily, it was only about 3 meters (10 feet) wide, and the space rock, now known as 2022 EB5 likely burned up in Earth’s atmosphere near Iceland at 21:22 UTC on March 11.

While it is wonderful that astronomers can detect asteroids of that size heading towards our planet — as well as determine the asteroid’s trajectory and precisely predicted its impact location — the last-minute nature of the discovery definitely causes a pause. What if it had been bigger?

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It’s Been Constantly Raining Meteors on Mars for 600 Million Years. Earth too.

An impact crater on Mars. Image Credit: NASA

New research shows that Mars has faced a constant rain of meteors during the last 600 million years. This finding contradicts previous research showing that the impact rate has varied, with prominent activity spikes. Why would anyone care how often meteors rained down on Mars, a planet that’s been dead for billions of years?

Because whatever Mars was subjected to, Earth was also likely subjected to.

Who wouldn’t want to know our planet’s history?

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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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Researchers Have Taught a Drone to Recognize and Hunt Down Meteorites Autonomously

Almahata Sitta 15. The black fragment of Almahata Sitta meteorite number 15 shows up black against the lighter coloured rocks of the Nubian desert in Northern Sudan. Image credit: Peter Jenniskens (SETI Institute/NASA Ames)

Planetary scientists estimate that each year, about 500 meteorites survive the fiery trip through Earth’s atmosphere and fall to our planet’s surface. Most are quite small, and less than 2% of them are ever recovered. While the majority of rocks from space may not be recoverable due to ending up in oceans or remote, inaccessible areas, other meteorite falls are just not witnessed or known about.

But new technology has upped the number known falls in recent years. Doppler radar has detected meteorite falls, as well as all-sky camera networks specifically on the lookout for meteors. Additionally, increased use of dashcams and security cameras have allowed for more serendipitous sightings and data on fireballs and potential meteorite falls.

A team of researchers is now taking advantage of additional technology advances by testing out drones and machine learning for automated searches for small meteorites.  The drones are programmed to fly a grid search pattern in a projected ‘strewn field’ for a recent meteorite fall, taking systematic pictures of the ground over a large survey area. Artificial intelligence is then used to search through the pictures to identify potential meteorites.  

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100-meter Asteroid Created a Strange Impact Event in Antarctica 430,000 Years Ago

Mocked up illustration of touchdown impact on Antarctica. Credit: Mark A. Garlick.

The effects of ancient asteroid impacts on Earth are still evident from the variety of impact craters across our planet. And from the Chelyabinsk event back in 2013, where an asteroid exploded in the air above a Russian town, we know how devastating an “airburst” event can be.

Now, researchers in Antarctica have discovered evidence of a strange intermediate-type event – a combination of an impact and an airburst. The event was so devastating, its effects are still apparent even though it took place 430,000 years ago.

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MESSENGER Saw a Meteoroid Strike Mercury

Artist’s illustration depicting how MESSENGER observed the first meteoroid impact on another planet’s surface. Particles (neutral atoms) ejected by the meteoroid skyrocketed over 3,000 miles above Mercury’s surface, outside the bow shock of Mercury’s magnetosphere. There, photons of light turned the neutral particles into charged particles (ions), which one of MESSENGER’s instruments could detect. Credit: modified from Jacek Zmarz

Telescopes have captured meteoroids hitting the Moon and several spacecraft imaged Comet Shoemaker–Levy 9 smacking into Jupiter in 1994. But impacts as they happen on another rocky world have never been observed.

However, the MESSENGER (MErcury Surface, Space ENvironment, GEochemistry and Ranging) mission may have seen an impact take place back in 2013. In looking at archival data from the mission, scientists found evidence of a meteoroid impact on Mercury.  While this data isn’t a ‘no-doubt’ photo of the event, it does tell scientists more about impacts and how they affect Mercury’s wispy-thin atmosphere.

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