Asteroids, Comets, and Meteors

[wjfox]

There’s a tiny chance the asteroid headed for Earth could hit the moon

10 February 2025

Asteroid 2024 YR4 is on a potential crash course with Earth, but there’s a very slight chance the moon could take the hit.

Based on current observations, there is a 2.1 per cent chance that the asteroid – about as long as the Leaning Tower of Pisa is tall – will crash into our planet on 22 December 2032. Although it is very likely to miss, a direct strike on a populated area would be catastrophic. But if it is in fact heading directly our way, new calculations show that there is a very small chance – about 0.3 per cent – that this stony missile will impact the moon instead.

That the moon could feasibly take the hit for all 8 billion of us would be quite the cosmic plot twist. But it’s within the realm of possibility, according to orbital calculations by David Rankin at the University of Arizona, a member of the asteroid-hunting Catalina Sky Survey.

A lunar impact would be preferable to an Earth impact. The moon might be left with a fresh crater anywhere from about 500 to 2000 metres across, but humanity would be unharmed. “There is the possibility this would eject some material back out that could hit the Earth, but I highly doubt it would cause any major threat,” says Rankin.

Gareth Collins at Imperial College London agrees. “We would be quite safe on Earth,” he says. “Some small ejecta fragments might reach Earth, but [would be] totally harmless” and would burn up in the atmosphere.

https://www.newscientist.com/article/24 ... -the-moon/



Credit: NASA/JPL-Caltech

[wjfox]

Odds of asteroid 2024 YR4 hitting Earth in 2032 have reached new high

18 February 2025

NASA has upgraded the risk of asteroid 2024 YR4 hitting Earth in 2032 to 2.6 per cent, or about a 1-in-38 chance, the highest odds yet of collision.

Astronomers discovered that the asteroid was barrelling towards Earth in December and it has been a focus of the world’s telescopes and space agencies ever since. As they gather more data on the asteroid’s precise orbit, astronomers have been able to calculate the likelihood of it hitting Earth with greater precision. The asteroid is thought to be between 40 and 90 metres wide and has the potential to release energy equivalent to 7.7 megatonnes of TNT should it hit Earth – enough to destroy a city.

According to NASA, the odds of collision in 2032 have been edging up from a 1-in-83 chance since it was first spotted. It has since moved to 1-in-67, to 1-in-53, to 1-in-43 and now to 1-in-38.

https://www.newscientist.com/article/24 ... -new-high/



Credit: NASA

[wjfox]

[firestar464]

It's safe now. Anyway, back to our usually scheduled programming...

https://cneos.jpl.nasa.gov/sentry/detai ... 2024%20YR4

[caltrek]

UPDATE on the Potentially Earth-Impacting Asteroid 2024 YR4
by Philip Plait
February 24, 2025

Introduction:

(Bad Astronomy) The asteroid 2024 YR4 is still in the news, but this time the news is better: the chance of an impact (as I write this) is now less than 1%. It’ll very likely drop even more when JWST observations are made in March.

Not to say I told you so, but I told you this would happen. It usually does.

In earlier articles I’ve written that due to uncertainty in the exact motion of the asteroid now, its possible location in the future is inside a cone with the vertex at the asteroid and spreading out ahead of it. If the Earth is inside the cone then there’s a chance of impact, though usually a small one (the Earth occupies a very small fraction of that cone).

That’s true in a general sense, but in some cases we can do better. We can nail down some aspects of the orbit (say, its tilt relative to Earth’s) while other aspects are less well known. That can flatten the cone, for example.

As the orbit is better quantified, the possibility of impact can actually go up, because the Earth may still be occupying some “probability space” for the asteroid’s location at a future date. If that space shrinks but the Earth is still inside it, the impact chance goes up. But at some point that space may shrink so much that Earth is outside it, and the chance goes down.

Read more here: https://badastronomy.beehiiv.com/p/the ... way-down

Here is an earlier article on that same topic: https://badastronomy.beehiiv.com/p/wil ... bably-not

[firestar464]

Now that it's so unlikely now, would use of JWST to observe it still be a good use of of the telescope?

[weatheriscool]

[caltrek]

Gemini South Observes Shape and Origin of Near-Earth Asteroid 2024 YR4
April 8, 2025

Introduction:

(NOIR Lab) Using observations from the Gemini South telescope in Chile, one half of the International Gemini Observatory, partly funded by the U.S. National Science Foundation and operated by NSF NOIRLab, astronomers have constructed a 3D representation of the newly discovered near-Earth asteroid 2024 YR4. The team determined that the unusually-shaped rock is one of the largest objects in recent history that could impact the Moon, and that it likely originated from the main asteroid belt.

2024 YR4 was first detected on 27 December 2024 by the Asteroid Terrestrial-impact Last Alert System (ATLAS). At the time, the asteroid made a close approach to Earth, passing at a distance of just 0.017 astronomical units (approximately 2.5 million kilometers, or 1.5 million miles). Initial uncertainty regarding its trajectory warranted further investigation, leading astronomers to secure critical special Director's Discretionary Time on Gemini South for follow-up observations using the Gemini Multi-Object Spectrograph (GMOS) on 7 February 2025.

In late January 2025, one month after its discovery, 2024 YR4 rose above the International Asteroid Warning Network (IAWN) notification threshold of 1% probability of a future impact with Earth, projected for 22 December 2032. This potential threat gained international attention among the public and the media. With further analysis, the Earth impact probability then dropped below 1% in late February. While the asteroid will miss Earth during this encounter, there remains a few percent chance it could hit the Moon instead.

Interested in characterizing the now famous asteroid, the team of astronomers, led by Bryce Bolin of Eureka Scientific, used the Gemini South telescope in Chile, one half of the International Gemini Observatory, partly funded by the U.S. National Science Foundation and operated by NSF NOIRLab, to capture images of it in multiple different wavelengths. Detailed analysis of the asteroid's lightcurve (pattern of light output in time) allowed the team to determine its composition, orbital characteristics and 3D shape.

Read more here: https://noirlab.edu/public/news/noirlab2514/?lang

[weatheriscool]

NASA's Lucy spacecraft is speeding toward another close encounter with an asteroid
https://phys.org/news/2025-04-nasa-lucy ... eroid.html
by Marcia

NASA's Lucy spacecraft will swoop past a small asteroid this weekend as it makes its way to an even bigger prize: the unexplored swarms of asteroids out near Jupiter.

It will be the second asteroid encounter for Lucy, launched in 2021 on a quest that will take it to 11 space rocks. The close approaches should help scientists better understand our early solar system when planets were forming; asteroids are the ancient leftovers.

The upcoming flyby is a dress rehearsal for 2027 when Lucy reaches its first so-called Trojan asteroid near Jupiter.

[wjfox]

[caltrek]

Space Junk Falling to Earth Needs to be Tracked. Meteoroid Sounds Can Help
May 2, 2025

Introduction:

(Eurekalert) Every year, Earth gets a bit bigger. Thousands of metric tons of space dust fall from the sky, while about 50 tons per year of meteorites crash land somewhere on the surface. Since the 1960s, space junk has also occasionally returned to Earth, falling from a hazy sphere of trash encircling the planet. Remnants of rockets, tools lost by space-walking astronauts, defunct satellites, and more fly through lower Earth orbit, reaching speeds of 18,000 miles per hour. When any item—whether space rock or space junk—enters the atmosphere, scientists try to track its path to estimate where it will land. Will the item in question plunk straight down, or will it fly along at an angle before skittering to a halt? In a new study to be presented at the General Assembly of the European Geosciences Union next week, Elizabeth Silber, a scientist at Sandia National Laboratories, will consider how infrasound sensors—instruments that detect sounds at lower frequencies than humans can hear—listen for bolides. Bolides are the bright flashes and booms from large meteoroids breaking apart high in the sky. These events release huge amounts of energy, creating shock waves that travel as infrasound signals across thousands of kilometers. But here’s the challenge: bolides aren’t like explosions that happen in one place. They are moving, generating sound along their path as they travel through the sky. This movement matters, especially for meteoroids and space debris that enter shallow angles. In those cases, different infrasound stations might pick up signals coming from different directions, making it harder to pinpoint the source.

Motivated by this problem, Silber used a network of infrasound sensors around the world maintained by the Comprehensive Test Ban Treaty Organization (CTBTO), an organization tasked with listening for illicit explosions. These instruments also record anything else that claps or booms, from thunder to supersonic aircraft. Using signals specifically from bolides, Silber isolated the purely geometric component for her analysis. She found that if a bolide enters Earth’s atmosphere at a relatively steep angle— greater than 60°—analysis of the infrasound signal gets the trajectory right. But when it comes more horizontally, the uncertainty increases.

Read more here: https://www.eurekalert.org/news-releases/1082351


This photograph taken by an International Space Station astronaut shows a bright meteor from the Perseid meteor shower in Earth’s atmosphere. The brightest meteors are known as fireballs, or bolides
Credit: NASA

[caltrek]

The title of this thread should have included planetoids (or dwarf planets) IMHO.

Newest Member of the Solar System Just Announced – And It’s in an Extreme Orbit
by Dr. Alfredo Carpineti
May 23, 2025

Introduction:

(IFL Science) The Solar System has just gotten a new official member. Currently, with the name of 2017 OF201, this is a trans-Neptunian object (TNO). This means that it orbits the Sun further away than Neptune. Actually, its orbit is so big that it takes about 25,000 years to complete.

The discovery of the object was officially announced on May 21, 2025, by the International Astronomical Union’s Minor Planet Center. It is estimated to have a diameter of about 700 kilometers (435 miles), big enough for this to be a dwarf planet.

“2017 OF201 spends only 1 percent of its orbital time close enough to us to be detectable. The presence of this single object suggests that there could be another hundred or so other objects with similar orbit and size; they are just too far away to be detectable now,” discovery team leader Sihao Cheng from the Institute for Advanced Study said in a statement.

“Even though advances in telescopes have enabled us to explore distant parts of the universe, there is still a great deal to discover about our own Solar System.”

One percent is a small number, and it indicates just how big this TNO’s orbit is. With a diameter a third of Pluto's, it is incredible that it has been spotted.

Read more here: https://www.iflscience.com/newest-memb ... it-79322

[caltrek]

Politecnico di Milano Returns to Deep Space - 2028 Mission to Earth-grazing Asteroid Apophis
May 27, 2025

Introduction:

(Eurekalert) After Rosetta, DART and Hera, Politecnico di Milano is preparing for a return to deep space. In 2028, the university will take part in the European Space Agency’s RAMSES mission to study Apophis which is a 350-metre-wide asteroid that will pass remarkably close to Earth, just 31,000 km away, on 13 April 2029.

The DART (Deep-space Astrodynamics Research and Technology) Laboratory, part of the Department of Aerospace Science and Technology, has been selected by ESA to contribute to the RCS-1 CubeSat, which is being developed by Tyvak International. This miniature satellite will travel aboard the RAMSES probe. Led by Professors Francesco Topputo and Fabio Ferrari, the Politecnico team will be responsible for mission design, development of autonomous guidance systems, and acquisition of close-up images of the asteroid’s surface.

CubeSats are compact, low-cost satellites that deliver significant scientific and technological value. In the RAMSES mission, they will operate autonomously in the vicinity of Apophis which is a fast-moving body travelling within geostationary orbit.

Scientifically, RCS-1 will provide key insights into Apophis's physical and dynamic properties through imagery and data gathered during the flyby. CubeSat RCS-1 will serve as a test platform for new autonomous navigation algorithms developed by the Politecnico team.

RAMSES, an ESA-proposed mission, aims to rendezvous with Apophis ahead of its 2029 flyby. The probe is scheduled to arrive by February 2029 to observe the asteroid and monitor any changes caused by Earth’s gravitational pull during its close approach.

Read more here: https://www.eurekalert.org/news-releases/1085298

[wjfox]

China launches the Tianwen-2 asteroid sample return mission

written by Justin Davenport
May 28, 2025

The Chinese space program is preparing to join the Japan Aerospace Exploration Agency (JAXA) and NASA in returning samples from an asteroid to Earth. The Tianwen-2 probe and its Chang Zheng 3B/E (CZ-3B/E) rocket launched successfully from Launch Complex 2 (LC-2) at the Xichang Satellite Launch Center in southwest China on Wednesday, May 28, at 17:31 UTC.

The CZ-3B/E Y110 flew on an eastbound path and launched Tianwen-2 on an Earth escape trajectory. Tianwen-2 will orbit asteroid 469219 Kamo’oalewa, also known as 2016 HO3, before flying past Earth en route to Comet 311P/PANSTARRS. The mission’s launch site, Xichang, in Sichuan province, reached operational status in 1984 and has been used for other Chinese launches beyond Earth, such as the Chang’e 1 lunar orbiter.

[...]

The spacecraft, built by CAST, incorporates eight science instruments as well as a return capsule to bring over 100 g of asteroid samples back to Earth. Tianwen-2, formerly known as ZhengHe after the Chinese Ming Dynasty explorer, masses around 2,000 kg and is designed for a 10-year mission duration. The mission will be run by CNSA from its facilities and will make use of Chinese deep space network facilities.

The spacecraft’s eight science instruments include a visible infrared imaging spectrometer, a thermal radiation spectrometer, a multispectral camera, a medium field color camera, a detection radar, a magnetometer, charged and neutral particle analyzers, and an ejecta analyzer. A pair of navigational instruments is also on board Tianwen-2: a narrow field of view navigation sensor as well as a laser integrated navigation sensor

Tianwen-2 will take one year to reach Kamo’oalewa after its launch, reaching the object in 2026, and will orbit the asteroid before attempting to retrieve a sample. The spacecraft is equipped with a “touch-and-go” device similar to ones on NASA’s OSIRIS-REx and JAXA’s Hayabusa2, but is also outfitted with an “anchor and attach” method, which has not been used on an asteroid before. For the latter approach, Tianwen-2 features four robotic arms, each with a drill.

https://www.nasaspaceflight.com/2025/05 ... -2-launch/



Credit: CNSA

[weatheriscool]

See the First Image From China's Tianwen-2 Asteroid Mission
This is the first real photo of Tianwen-2 released to the public.
By Adrianna Nine June 10, 2025

From Tianwen-2's beginnings at the Chinese Academy of Sciences in 2018 to its successful launch last month, the China National Space Administration (CNSA) kept the spacecraft's appearance tightly under wraps. Only computer illustrations of Tianwen-2 were shared publicly during those seven years, and CNSA elected not to live stream the first leg of its journey, despite launch streams having become an industry norm.

This weekend, though, we finally got a glimpse of what China's asteroid-hunting spacecraft looks like. A brief mission update reporting on Tianwen-2's health included an in-space photo of the spacecraft—the first such image, but hopefully not the last.

The image depicts one of Tianwen-2's two round solar panels, which deployed in space to aid the spacecraft's chemical propellants in steering it around the cosmos. The main body's flank is visible at the left. The photo was likely snapped by Tianwen-2's medium-field color camera, which will capture contextual images of Kamo'oalewa when it reaches the asteroid next year.

https://www.extremetech.com/science/see ... id-mission

[wjfox]

[weatheriscool]

[weatheriscool]

[firestar464]

More on that by FOX 5 Atlanta:

https://www.fox5atlanta.com/news/meteor ... ite-debris

[caltrek]

Please Welcome Our THIRD Interstellar Alien Visitor!
By Philip Plait
July 3, 2025

Introduction:

(Bad Astronomy Newsletter) On July 1, 2025, astronomers with ATLAS, the Asteroid Terrestrial-impact Last Alert System, were alerted that a new object was detected moving across the sky. This was no ordinary space rock though: its trajectory and velocity indicated it was not from our solar system. In other words, it’s coming from another star, across the gulf of interstellar space!

The object was given a provisional designation of A11pl3Z when it was first discovered, but was given the official name 3I/ATLAS once it was confirmed. It’s likely several kilometers across, which is determined by its brightness and distance.

At first the orbital calculation (the determination of its path calculated by how it’s moving across the sky over time) was a bit shaky, which is typical; the longer you observe an object the better the prediction gets. But astronomers have a cool trick they can use: once a rough orbit is determined, they can check older images to see if the object was in them but missed. And sure enough, 3I/ATLAS was seen in ATLAS observations from June 25-28 (and by the Zwicky Transient Facility back to June 14) extending the baseline and allowing for better calculations.

Read more here: https://badastronomy.beehiiv.com/p/ano ... em-e720