JWST Finds the Smallest Asteroids Ever Seen in the Main Belt

An artist’s illustration of NASA’s James Webb Space Telescope revealing, in the infrared, a population of small main-belt asteroids. Image Credits: Ella Maru and Julien de Wit

The JWST was never intended to find asteroids. It was built to probe some of our deepest, most demanding questions about the cosmos: how the first stars formed, how galaxies have evolved, how planets like ours take shape, and even how life originated. However, it’s first and foremost a powerful infrared telescope and its unrivalled infrared prowess is helping it contribute to another important goal: defending Earth from dangerous asteroids.

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Yes, the Odds of an Asteroid Striking Earth Have Doubled. No, You Don’t Need to Worry

The estimated trajectory of 2024 YR4. Credit: ESA/Planetary Defence Office

At the end of 2024, astronomers detected an asteroid in the night sky. It was given the designation Y, since it was discovered in the last half of December, and R4 since it was the 117th rock to be found in the last couple of weeks of December, and since it was discovered in 2024, it was assigned the name 2024 YR4. Naturally, once a rock is found, astronomers start keeping track of it, measuring its position to get a handle on its orbit. In this case, the estimated orbit put it at a 1% chance of striking Earth. As more measurements were taken, those odds have more than doubled. As of this writing, it now has a 2.3% chance of striking Earth on December 22, 2032. While you might think this resembles the plot of Don’t Look Up, none of this is too unusual.

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Hybrid Gas/Drill Asteroid Sampler Could Improve Collection Amounts

Asteroid sampling missions are getting increasingly complex. Recent announcements about the existence of amino acids in the sample OSIRIS-REx returned from Bennu in 2023 will likely result in more interest in studying the small bodies strewn throughout our solar system. Engineering challenges abound when doing so, though, including one of the most important – how to collect a sample from the asteroid. A new paper from researchers at the China Academy of Space Technology looks at a gas-drive sample system they believe could hold the key to China’s future asteroid sample return mission.

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An Asteroid Has a 1% Chance of Impacting Earth in 2032

Artist's impression of asteroid 2024 YR4. Credit: ESA

The odds of a sizable asteroid striking Earth are small, but they’re never zero. Large asteroids have struck Earth in the past, causing regional devastation. A really large asteroid strike likely contributed to the extinction of the dinosaurs. So we shouldn’t be too surprised that astronomers have discovered an asteroid with a better than 1% chance of striking our world. Those odds are large enough we should keep an eye on them, but not large enough that we should start packing bags and fleeing to the hills.

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NASA Scientists Discover “Dark Comets” Come in Two Populations.

An artist's concept of a dark comet floating in space. Courtesy Nicole Smith.
An artist's concept of a dark comet floating in space. Courtesy Nicole Smith.

On October 19th, 2017, the Panoramic Survey Telescope and Rapid Response System-1 (Pan-STARRS-1) in Hawaii announced the first-ever detection of an interstellar object, named 1I/2017 U1 ‘Oumuamua (the Hawaiin word for “scout”). This object created no shortage of confusion since it appeared as an asteroid but behaved like a comet (based on the way it accelerated out of the Solar System). Since then, scientists have noticed a lot of other objects that behave the same way, known as “dark comets.”

These objects are defined as “small bodies with no detected coma that have significant nongravitational accelerations explainable by outgassing of volatiles,” much like ‘Oumuamua. In a recent NASA-supported study, a team of researchers identified seven more of these objects in the Solar System, doubling the number of known dark comets. Even more important, the researchers were able to discern two distinct populations. They consist of larger objects that reside in the outer Solar System and smaller ones in the inner Solar System.

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Could We Use An Asteroid to Shield Astronauts On Their Way to Mars?

Illustration of the asteroid Bennu. Credit: NASA Jet Propulsion Laboratory

Radiation is a primary concern for long-duration human spaceflight, such as the planned trips to Mars, which are the stated goal of organizations such as NASA and SpaceX. Shielding is the standard way to protect astronauts from radiation during those flights. However, shielding is heavy and, therefore, expensive when it is launched off the Earth. What if, instead, astronauts could hitch a ride on a giant mass of shielding already in space that will take them directly to their destination? That is the basic thought behind a paper from Victor Reshetnyk and his student at Taras Shevchenko National University in Kyiv. 

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How Much Are Asteroids Really Worth?

Asteroid mining concept. Credit: NASA/Denise Watt
Asteroid mining concept. Credit: NASA/Denise Watt

Popular media love talking about asteroid mining using big numbers. Many articles talk about a mission to Psyche, the largest metallic asteroid in the asteroid belt, as visiting a body worth $10000000000000000000, assumedly because their authors like hitting the “0” key on their keyboards a lot. But how realistic is that valuation? And what does it actually mean? A paper funded by Astroforge, an asteroid mining start-up based in Huntington Beach, and written by a professor at the Colorado School of Mine’s Space Resources Program takes a good hard look at what metals are available on asteroids and whether they’d genuinely be worth as much as the simple calculations say that would be.

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Scientists Reveal a New Way to Study Near-Earth Asteroids

A timelapse image of the fireball event from start to finish. Credit: Western Meteor Group

On November 18th, 2022, shortly before midnight, the Catalina Sky Survey (CSS) in Arizona and other observatories worldwide detected a small object (now designated 2022 WJ1) heading toward Earth. For the next three hours, the CSS and the Southern Ontario Meteor Network (SOMN) at the University of Western Ontario monitored the object before it entered Earth’s atmosphere above Southern Ontario. At 03:26 a.m. EST (12:26 a.m. PST) on November 19th, the object appeared as a bright fireball that scattered meteorite fragments across the Niagara region.

This event triggered an international collaboration to hunt down the fragments for analysis, but none have been found yet. In a recent study led by Western University and Lowell Observatory, an international team of scientists described a new approach for studying near-Earth asteroids (NEA) based largely on 2022 WJ1. The study is significant in that the team determined the NEA’s composition—the smallest asteroid characterized to date—and established a new and integrated methodology for studying other NEAs that may impact Earth someday.

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Here’s What We Know About Earth’s Temporary Mini-Moon

2024-PT5

For a little over a month now, the Earth has been joined by a new ‘mini-moon.’ The object is an asteroid that has been temporarily accompanying Earth on its journey around the Sun. By 25th November it will have departed but before then, astronomers across the world have been turning their telescopes to study it. A new paper of 2024 PT5 reveals its basaltic nature – similar to volcanic rocks on Earth – with a composition that makes it similar to lunar material. There have been many close encounters to Earth allowing many of its secrets to be unveiled.

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Tiny Fragments of a 4-Billion Year Old Asteroid Reveal Its History

Asteroid Ryugu contains organic molecules called polycyclic aromatic hydrocarbons, thought to be chemical building blocks for life. Courtesy ISAS/JAXA
Asteroid Ryugu as seen by Japan's Hayabusa 2 spacecraft, which returned a sample of the ancient asteroid to Earth in 2020. Image Courtesy ISAS/JAXA

In June 2018, Japan’s Hayabusa 2 mission reached asteroid 162173 Ryugu. It studied the asteroid for about 15 months, deploying small rovers and a lander, before gathering a sample and returning it to Earth in December 2020.

The Ryugu sample contains some of the Solar System’s most ancient, primitive, and unaltered material, opening a window into its earliest days about 4.6 billion years ago.

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