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Asteroids & The Asteroid Belt

ramonmercado said:
Asteroid in unusual orbit.
For the first time, an asteroid has been found orbiting closer to the sun than Venus — a neighborhood where asteroids are thought to be rare and tricky to find. ...
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Update ...

Further study has determined more about this first discovered Vatira asteroid. Its estimated size is larger than prior models and analyses had predicted, so this discovery is motivating review of prior work on the subject. The research publication resulting from the discovery and additional analysis has been submitted, but it is still in the preprint stage.

Astronomers Have Discovered a 2-km Asteroid Orbiting Closer to the Sun than Venus

Astronomers have painstakingly built models of the asteroid population, and those models predict that there will be ~1 km sized asteroids that orbit closer to the Sun than Venus does. The problem is, nobody’s been able to find one. Until now.

Astronomers working with the Zwicky Transient Facility say they’ve finally found one. But this one’s bigger, at about 2 km. If its existence can be confirmed, then asteroid population models may have to be updated.

A new paper presenting this result is up on arxiv.org, a pre-press publication site. It’s titled “A kilometer-scale asteroid inside Venus’s orbit.” The lead author is Dr. Wing-Huen Ip, a Professor of Astronomy at the Institute of Astronomy, National Central University, Taiwan.

The newly-discovered asteroid is named 2020 AV2. 2020 AV2 has an aphelion distance of only 0.65 astronomical units, and is about 2 km in diameter. Its discovery is surprising since models predict no asteroids this large inside Venus’ orbit. It could be evidence of a new population of asteroids, or it could just be the largest of its population. ...
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FULL STORY: https://www.universetoday.com/14776...teroid-orbiting-closer-to-the-sun-than-venus/
 
Here are the bibliographic details and draft abstract from the preprint version of the research paper. The full pre-publication article can be downloaded at the link below.

A kilometer-scale asteroid inside Venus's orbit
W.-H. Ip, et al. ...
Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2009.04125 [astro-ph.EP]

Near-Earth asteroid population models predict the existence of asteroids located inside the orbit of Venus. However, despite searches up to the end of 2019, none have been found. Here we report the discovery by the Zwicky Transient Facility of the first known asteroid located inside of Venus' orbit, 2020 AV2, possessing an aphelion distance of 0.65 au and ∼2 km in size. While it is possible that 2020 AV2 is the largest of its kind, we find that its discovery is surprising in the context of population models where the expected count is close to zero. If this discovery is not a statistical fluke, then 2020 AV2 may come from a yet undiscovered source population of asteroids interior to Venus, and currently favored asteroid population models may need to be adjusted.

SOURCE: https://arxiv.org/abs/2009.04125
 
ramonmercado said:
Bennu is literally exploding with news.

For the last year, NASA’s OSIRIS-REx spacecraft has been circling a large asteroid named Bennu that regularly passes uncomfortably
close to Earth. The spacecraft has been painstakingly mapping the asteroid’s rocky surface using a suite of cameras and other instruments that will help it determine where to land next year. Once NASA selects a final landing site, OSIRIS-REx will kiss Bennu just long enough to scoop up a sample to bring back to Earth in 2023.

Many scientists expect the Bennu sample to revolutionize our understanding of asteroids, especially those that are near Earth and pose the greatest threat to life as we know it. But as detailed in a paper published today in Science, NASA has already started making surprising discoveries around this alien world. Earlier this year, the OSIRIS-REx team witnessed particles exploding from the asteroid’s surface—and it’s not sure why.

“No one has ever seen an active asteroid up close like this,” says Carl Hergenrother, an astronomer at the University of Arizona and the scientist who proposed Bennu as the target for OSIRIS-REx. “It wasn’t that long ago that the conventional wisdom was that asteroids are these dead bodies that didn’t change very much.”

In January, the navigation cameras on OSIRIS-REx captured three ejection events that each spewed about 100 centimeter-sized asteroid particles into space. The spacecraft also detected a significant number of particles already orbiting Bennu like a cloud of gnats. Their diverse orbits suggest that particle ejections are a common event on the asteroid and occur all across its surface, rather than in a few select spots. Indeed, in the year since the three ejection events that are reported today in Science, Hergenrother says OSIRIS-REx has detected several other smaller ejections. ...

https://www.wired.com/story/no-one-knows-why-rocks-are-exploding-from-asteroid-bennu/
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Update.

After almost two years circling an ancient asteroid hundreds of millions of miles away, a NASA spacecraft this week will attempt to descend to the treacherous, boulder-packed surface and snatch a handful of rubble.

The drama unfolds Tuesday as the U.S. takes its first crack at collecting asteroid samples for return to Earth, a feat accomplished so far only by Japan.

Brimming with names inspired by Egyptian mythology, the Osiris-Rex mission is looking to bring back at least 2 ounces (60 grams) worth of asteroid Bennu, the biggest otherworldly haul from beyond the moon.

The van-sized spacecraft is aiming for the relatively flat middle of a tennis court-sized crater named Nightingale—a spot comparable to a few parking places here on Earth. Boulders as big as buildings loom over the targeted touchdown zone. ...

https://phys.org/news/2020-10-touch-and-go-spacecraft-sampling-asteroid.html
 
kamalktk said:
Success! Yay science!

They don't know just how much of the asteroid they've collected yet, but if they didn't get enough they have plans to do the maneuver again at another site.

OSIRIS-REx Spacecraft Successfully Touches Asteroid

https://www.nasa.gov/press-release/nasa-s-osiris-rex-spacecraft-successfully-touches-asteroid
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I watched it live, very impressive. Also like the way they are going to check the actually have a sample - stick the arm out and spin around and compare readings with the last time (pre sample) they did the same manoeuvre!
 
The Bennu collection mission was so successful they can't close the door on the collector.

https://www.cnn.com/2020/10/23/world/asteroid-bennu-sample-update-scn-trnd/index.html

"The mission team analyzed images Thursday taken of the collector head of the spacecraft that showed that a substantial sample was collected -- but there is so much material in the head that the flap designed to keep the sample inside is jammed.
...
The mission was required to collect at least 2 ounces, or 60 grams, of the asteroid's surface material. Based on the images they analyzed, the researchers are confident that the collector head on the end of the spacecraft's robotic arm actually captured 400 grams of material. And that's only what's visible to them through the perspective of the camera. "
 
Does anybody here have knowledge or access to historical data, models or just raw information about meteor/comet/asteroid activity in 1946?
 
Ringo said:
Does anybody here have knowledge or access to historical data, models or just raw information about meteor/comet/asteroid activity in 1946?
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Can you be more specific about what you're seeking?

Comets would be easy to research for past years.

As of 1946 far fewer asteroids were known (compared to now), and the only data I believe you'd find would be their paths among the stars. If you're specifically interested in possible impactors (of earth) I doubt anyone has any compiled data on calculated paths and positions from 1946.

Basic schedules for the major meteor showers would be pretty much the same as today. Specific fireballs, etc., are unlikely to be documented in a single place. The International Meteor Organization wasn't founded until 1988, and their publicly accessible data only dates back as far as 1972.
 
I'll PM you if that's OK.
 
Hayabusa2 mission will land the first subsurface asteroid samples on Earth


https://www.cnn.com/2020/12/05/world/hayabusa2-asteroid-sample-earth-return-scn-trnd/index.html

Watch the livestream of the capsule's fiery return to Earth through the JAXA YouTube channel. The mission is also sharing updates through its Twitter account, Hayabusa2@JAXA.

Although this event is occurring between 3:30 and 4:30 a.m. Australian time on Sunday, it will occur between 11:30 a.m. and 12:30 p.m. ET Saturday. The capsule is expected to land on Earth about 15 minutes after it enters Earth's atmosphere.

A fireball will streak across the early morning sky of the Australian outback during reentry.
 
kamalktk said:
Hayabusa2 mission will land the first subsurface asteroid samples on Earth


https://www.cnn.com/2020/12/05/world/hayabusa2-asteroid-sample-earth-return-scn-trnd/index.html

Watch the livestream of the capsule's fiery return to Earth through the JAXA YouTube channel. The mission is also sharing updates through its Twitter account, Hayabusa2@JAXA.

Although this event is occurring between 3:30 and 4:30 a.m. Australian time on Sunday, it will occur between 11:30 a.m. and 12:30 p.m. ET Saturday. The capsule is expected to land on Earth about 15 minutes after it enters Earth's atmosphere.

A fireball will streak across the early morning sky of the Australian outback during reentry.
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This being 2020 it'll turn out that the samples contain tiny tentacled lifeforms which thrive on Earth, will expand to monster size and start eating us.
 
Welcome home, little soldier.


Asteroid space capsule completes 5 billion kilometre mission, touching down in a blaze of light in outback South Australia
Posted 1hhour ago, updated 24mminutes ago
Key points:
  • Early on Sunday, the capsule turned into a fireball 120 kilometres above earth
  • It landed near Woomera, with authorities locating it after an aerial search
  • Scientists hope the collected samples explain how the Earth was made habitable
https://www.abc.net.au/news/2020-12...-mission-capsule-lands-in-outback-sa/12949898
 
ramonmercado said:
This being 2020 it'll turn out that the samples contain tiny tentacled lifeforms which thrive on Earth, will expand to monster size and start eating us.
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Let's hope so. As long as they leave everything else alone, maybe eat the wasps too.
 
rynner2 said:
Astronomers classify asteroids according to their orbit types ...
(Apohele asteroids, or alternatively Interior-Earth Objects (IEOs) or Atira asteroids, are a subclass of Aten asteroids. They have not only their perihelion within Earth's orbit, but also their aphelion; that is, their entire orbit is within Earth's (which has a perihelion of 0.983 AU).) ...
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A recently identified Atira asteroid orbits the sun faster than any other sizable known object except Mercury.
Newly Discovered Space Rock Loops The Sun Quicker Than Any Known Asteroid

A newly discovered asteroid has the second-shortest orbit that we know in the entire Solar System, pipped only by Mercury.

It's named 2021 PH27, and it takes just 113 days to complete a circuit around the Sun, on an unstable elliptical orbit that crosses the orbital paths of both Venus and Mercury.

This means that it comes extremely close to the Sun at its closest approach, or perihelion, skimming close enough to reach scorching temperatures up to 480 degrees Celsius (900 Fahrenheit).

It also means that the asteroid's time is limited: within a million years, it will either be flung off its current trajectory, or it will be annihilated in a collision with one of the two planets or the Sun. ...

"Most likely 2021 PH27 was dislodged from the Main Asteroid Belt between Jupiter and Mars and the gravity of the inner planets shaped its orbit into its current configuration," said astronomer Scott Sheppard of the Carnegie Institution for Science.

"Although, based on its large angle of inclination of 32 degrees, it is possible that 2021 PH27 is an extinct comet from the outer Solar System that ventured too close to one of the planets as the path of its voyage brought it into proximity with the inner Solar System."

Spotting asteroids inside Earth's orbit – known as Atira asteroids when their orbits are entirely contained within Earth's – are usually very hard to see, since they tend to be very close to the Sun in the sky. ...
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FULL STORY: https://www.sciencealert.com/newly-...he-shortest-asteroid-year-in-the-solar-system
 
That wonderful person Anton Petrov explores the idea of Sodom's destruction by a giant meteor explosion:

 
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Christianity Today points out that this interpretation is highly controversial. It requires that Sodom be relocated in both time and space.
https://www.christianitytoday.com/n...ical-archaeology-tall-el-hammam-airburst.html
However, amid the wave of headlines, the unofficial peer reviews on social media from a number of archaeologists with varying degrees of familiarity with the Tall el-Hammam excavation were highly skeptical. As Christianity Today reported seven years ago, few archaeologists outside of those working on the excavation team believe that Tall el-Hammam is Sodom.
“In my opinion, this is an example of evidence being marshaled to support the identification of the site as Sodom, as opposed to letting the site speak for itself and then—if the evidence supports it—put forth a proposal of it as Sodom," archaeologist Robert Mullins told CT. Chair of the Department of Biblical Studies at Azusa Pacific University, he currently codirects the excavation at Abel Beth Maacah, a site in northern Israel. He is also listed on the Tall el-Hammam excavation website as a ceramic consultant.
Mullins, along with other evangelical archaeologists and Bible scholars, cite chronology as a major issue with the Sodom identification. The Bible’s internal chronology places Abraham and the events in his life, including the destruction of Sodom and Gomorrah, three to four centuries earlier. At 1650 BC, the Israelites were in Egypt, with the Exodus still 200 years in the future.
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Destructive events caused by warfare which had similar results were quite commonplace in this period, and do not require meteors as an explanation.
Archaeologists Steve Ortiz, director of Lipscomb University’s Lanier Center of Archaeology, agreed that while Tall el-Hammam is an important site, its destruction date is too late to fit the Sodom scenario. He dismissed the fireball hoopla to CT. “[Their] destruction does not look any different than any other destruction,” he said. “We have Assyrian and Egyptian destructions at Gezer that looks just as dramatic.”
Israeli archaeologist Aren Maeir of Bar Ilan University noted a lack of citations to other studies of the archaeology of destruction and thought the destruction the report described was not that unusual. “I see some things that remind me of phenomena that we have in the Iron Age IIA (1000–925 BC) destruction at Tell es-Safi/Gath (e.g. vitrified or “melted” bricks, ultra-high temperatures, and other things)—a destruction that is most likely caused by the conquest and destruction of the site by Hazael of Aram,” he said. Hazael’s attack on Gath is reported in 2 Kings 12:17.
The archaeological disagreement over Sodom centers not only on the chronology but also on the location. Sodom is conventionally located more to the south end of the Dead Sea.
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This was not an asteroid, if it occurred at all; there was no crater, so it was an airburst. I'm skeptical because these airburst events are remarkably rare; we only know of one (Tunguska), and it seems unlikely that a rare event of this kind would have happened near a location where it could be recorded as a historical event, at a time when such records were practically non-existent. But it is not impossible.
 
The asteroid Ryugu has multiple odd features. Researchers have come up with an explanation for these oddities - Ryugu is the remnant of a dead comet.
We may finally know why spinning-top asteroid Ryugu has such a weird shape

Scientists may have finally solved the mysterious origins of the diamond-shaped asteroid Ryugu: It may be the remnants of a long-dead comet.

The new origin theory, taken from findings from Japan's Hayabusa2 mission, suggests that the 0.5-mile-wide (0.8 kilometer) asteroid is actually the rocky remains of a dead comet that, after losing its ice, was smooshed together by its own gravity.

The new suggestion could explain a set of unusual observations from Hayabusa2. The spacecraft, which launched in 2014 and rendezvoused with Ryugu in 2018, spent a year surveying the asteroid's rocky surface before returning to Earth in 2020. That data, when combined with remote observations, yielded a few findings: Ryugu is made up of many small rocks rather than being one large boulder, it was deformed into the shape of a spinning top from rapid rotation and it is made of an unusually large amount of organic matter, or matter rich in carbon. ...
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FULL STORY: https://www.livescience.com/ryugu-could-be-extinct-comet
 
EnolaGaia said:
The asteroid Ryugu has multiple odd features. Researchers have come up with an explanation for these oddities - Ryugu is the remnant of a dead comet.

FULL STORY: https://www.livescience.com/ryugu-could-be-extinct-comet
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Interesting finds.

Ongoing efforts to deconstruct the chemistry of the most pristine asteroid sample ever to grace a laboratory has now revealed a trove of organic molecules, lending evidence to theories that suggest biology has its roots ultimately in space.

It's been more than two years since material from the surface of the asteroid Ryugu was transported to Earth in an air-tight capsule. Since then, researchers from around the world have worked together to study its composition in order to better understand how it fits in with the evolution of our Solar System.

These latest results confirm links between the carbon-based compounds found on stony 'chondrite' meteorites that have crashed to Earth's surface, and the chemistry of the asteroids they came from.

By looking at the similarities and differences between the Ryugu samples and carbonaceous chondrite meteorites on Earth, scientists can take a fresh look at meteorites in our collections. In other words, actual asteroid samples are useful in confirming hypotheses made from the bits of them arrive on our planet's surface after a brief baking through the atmosphere.

https://www.sciencealert.com/astero...h-life-building-molecules-latest-tests-reveal
 
Massive asteroid to pass by Earth on weekend
https://www.bbc.co.uk/news/science-environment-65061818
An asteroid large enough to destroy a city will pass between the orbits of the Earth and the Moon this weekend - luckily for us, missing both.
The object, named 2023 DZ2, was discovered a month ago.
On Saturday, it will pass within 515,000km of the moon, before flying by Earth hours later.
It is rare for such a huge asteroid - estimated to be between 40 and 90 metres in diameter - to come so close to the planet.
According to NASA, it's an important opportunity for astronomers to increase their knowledge of asteroids, in the event that a dangerous object were discovered with the potential to hit Earth.
"There is no chance of this 'city killer' striking Earth, but its close approach offers a great opportunity for observations," said the European Space Agency's planetary defence chief, Richard Moissl.
As it is passing just 68,000km away, the asteroid will be visible through binoculars and small telescopes across the globe.
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Closest approach at 19.52 UTC 25/3/2023.
 
Our quasi moon. Bit like a quasi wabbit.

Scientists recently discovered an asteroid that tags along with Earth during its yearly journey around the sun.

Dubbed 2023 FW13, the space rock is considered a "quasi-moon" or "quasi-satellite," meaning it orbits the sun in a similar time frame as Earth does, but is only slightly influenced by our planet’s gravitational pull. It is estimated to be 50 feet (15 meters) in diameter — roughly equivalent to three large SUVs parked bumper to bumper. During its orbit of the sun, 2023 FW13 also circles Earth, coming within 9 million miles (14 million kilometers) of our planet. For comparison, the moon has a diameter of 2,159 miles (3,474 km) and comes within 226,000 miles (364,000 km) of Earth at the closest point of its orbit, according to NASA.

2023 FW13 was first observed in March by the Pan-STARRS observatory, which is located atop the volcanic mountain Haleakalā in Hawaii. The asteroid's existence was then confirmed by the Canada-France-Hawaii Telescope in Hawaii and two observatories in Arizona before being officially listed on April 1 by the Minor Planet Center at the International Astronomical Union, a network of scientists responsible for designating new planets, moons and other objects in the solar system.

https://www.livescience.com/space/t...-travelling-alongside-our-planet-since-100-bc
 
EnolaGaia said:
A recently identified Atira asteroid orbits the sun faster than any other sizable known object except Mercury.

FULL STORY: https://www.sciencealert.com/newly-...he-shortest-asteroid-year-in-the-solar-system
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Atita as a potential candidate to be turned into a space habitat.

How to change an asteroid into a space habitat, in just 12 years​

The basic idea of turning an asteroid into a rotating space habitat has existed for a while. Despite that, it's always seemed relatively far off regarding technologies, so the concept hasn't received much attention over the years. But, if you're retired and have an underlying interest in researching space habitats, developing a detailed plan for turning an asteroid into one seems like a great use of time.

And that is precisely what David W. Jensen, a retired Technical Fellow at Rockwell Collins, recently did. He released a 65-page paper on the arXiv preprint server that details an easy-to-understand, relatively inexpensive, and feasible plan to turn an asteroid into a space habitat.
Fully diving into the report's details would be far beyond the scope of this article, but we can hit the highlights. Dr. Jensen breaks the discussion into three main categories—asteroid selection, habitat style selection, and mission strategy to get there (i.e., what robots to use). Let's tackle each of them in turn.

Asteroid selection focused on which asteroid would make the best candidate to be transformed into a rotating space habitat. Considerations for this part include what the asteroid is made of, its proximity to Earth (and "delta-V," i.e., how much energy it takes to reach), and its overall size.

After a relatively in-depth selection process, Dr. Jensen decided on one in particular as a good candidate—Atira. This S-type asteroid has an entire class of asteroids named after it. Atira comes in at about a 4.8 km diameter and even has its own moon—a 1-km-diameter asteroid that orbits it closely. It wasn't the closest potential asteroid, with its closest approach at about 80 times the distance to the moon. Still, its orbit is stable in the "Goldilocks zone" of our solar system, which would help stabilize the internal temperature of the habitat it would eventually be turned into.

So what type of habitat should it be turned into? Dr. Jensen looked at four common types—the "dumbbell," sphere, cylinder, and torus. One of the most critical considerations is gravity—or "artificial gravity"—caused by centripetal force. Dr. Jensen mentions the detrimental effects of living in low-gravity situations for long periods, which necessitates using some artificial replacement for it.

But to get centripetal force, the station has to rotate. Atira already has a slight rotation, but part of creating a space habitat would include spinning the asteroid itself up to a reasonable rotational speed that could accurately mimic the gravity a person would feel on Earth. ...

https://phys.org/news/2023-08-asteroid-space-habitat-years.html
 
Rotating an asteroid to create gravity is an old idea, but it does have some problems. If the asteroid rotates fast enough to create gravity, it will cause stress inside the rock, possibly causing it to fall apart. Additionally any dust, boulders and fragments that are loose anywhere on the surface of the object would fall off into space, causing a potential hazard to spacecraft visiting the habitat. Finally the asteroid is likely to be irregular in shape, so the rotation could be unstable - if you build rivers and ponds inside the torus, they could slosh and flood every time the asteroid shifted its axis slightly.

To make a comfortable, stable habitat I'd completely reconfigure the mass distribution of the asteroid to ensure stable rotation- but that could take longer than just a few years.
 
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Here's a design for a habitat made from an asteroid which has been completely disassembled to make a stable rotating structure covered in solar panels.
rubble-pile-asteroids-2.jpg

From here
https://phys.org/news/2022-12-rubble-pile-asteroids-space-habitats.html
 
Mythopoeika said:
Ringworld?
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Similar but much smaller so I'd guess easier to build because the strain on the material would be less. I'd guess that you'd need some sort of mirror arrangement at the end to reflect sunlight into the habitat area which would be more economic than artificial lighting (?) Also arrivals and departures would probably be easier there.
I'd also guess there'd also be a need to screen the solar panels against damage or periodically clean micrometeorite dust off them. But @eburacum will know more about it and the engineering challenges.
 
Most dust would be flung off by the rotation. But any impact damage would need to be replaced; not an easy task on a rotating habitat.
 

Largest known asteroid impact structure on Earth is buried in southeast Australia​


The Deniliquin structure could be up to 520 kilometers wide.

The Australian continent and its predecessor continent, Gondwana, have been the target of numerous asteroid impacts. These have resulted in at least 38 confirmed and 43 potential impact structures, ranging from relatively small craters to large and completely buried structures.

7QeeSzdckteKPByFnMusUA-970-80.jpg


This map shows the distribution of circular structures of uncertain, possible or probable impact origin on the Australian continent and offshore. Green dots represent confirmed impact craters. Red dots represent confirmed impact structures that are more than 100 km wide, whereas red dots inside white circles are more than 50 km wide. Yellow dots represent likely impact structures. (Image credit: Andrew Glikson and Franco Pirajno)

The Deniliquin structure has all the features that would be expected from a large-scale impact structure. For instance, magnetic readings of the area reveal a symmetrical rippling pattern in the crust around the structure's core. This was likely produced during the impact as extremely high temperatures created intense magnetic forces.

rt4mHGAkiYHEvS9yHFp5pH-970-80.jpg


This ‘total magnetic intensity’ image of the Deniliquin impact structure portrays its 520km-diameter multi-ring pattern, the central core, radial faults and the location of shallow drill holes. (Image credit: Geoscience Australia, Glikson and Yeates, 2022)

A central low magnetic zone corresponds to 30-km-deep deformation above a seismically defined mantle dome. The top of this dome is about 10km shallower than the top of the regional mantle.

Magnetic measurements also show evidence of "radial faults": fractures that radiate from the center of a large impact structure. This is further accompanied by small magnetic anomalies which may represent igneous "dikes," which are sheets of magma injected into fractures in a pre-existing body of rock.

The impact that caused it may have occurred during what’s known as the Late Ordovician mass extinction event. Specifically, I think it may have triggered what’s called the Hirnantian glaciation stage, which lasted between 445.2 and 443.8 million years ago, and is also defined as the Ordovician-Silurian extinction event.

This huge glaciation and mass extinction event eliminated about 85% of the planet’s species. It was more than double the scale of the Chicxulub impact that killed off the dinosaurs.

https://www.space.com/worlds-largest-asteroid-impact-structure-in-australia

maximus otter
 
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