Tag: asteroids

Interstellar meteor impacted Earth in 2014

10:28 am

According to classified military data just released, it appears that an asteroid from interstellar space impacted the Earth in 2014, with some of its pieces possibly hitting the ocean in the south Pacific.

The meteor ignited in a fireball in the skies near Papua New Guinea, the memo states, and scientists believe it possibly sprinkled interstellar debris into the South Pacific Ocean. The confirmation backs up the breakthrough discovery of the first interstellar meteor—and, retroactively, the first known interstellar object of any kind to reach our solar system—which was initially flagged by a pair of Harvard University researchers in a study posted on the preprint server arXiv in 2019.

Amir Siraj, a student pursuing astrophysics at Harvard who led the research, said the study has been awaiting peer review and publication for years, but has been hamstrung by the odd circumstances that arose from the sheer novelty of the find and roadblocks put up by the involvement of information classified by the U.S. government.

The speed and angle in which the object hit the atmosphere are why the scientists believe it comes from outside the solar system.

Siraj is actually hoping to mount a mission to recover parts of this asteroid, something that is extremely unlikely. First, the meteor itself was small, so it likely all burned up in re-entry. Second, even if pieces survived, finding them on the bottom of the Pacific is likely impossible.

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Astronomers confirm asteroid discovered in 2020 is an Earth Trojan

9:57 am

Astronomers have now confirmed that an asteroid discovered in 2020, dubbed 2020 XL5, is an orbit that makes it the second Earth Trojan asteroid discovered, orbiting the Sun in the same orbit as the Earth but 60 degrees ahead of us.

In December 2020, 2020 XL5 was spotted by astronomers with the Pan-STARRS 1 survey telescope in Hawaii and added to the International Astronomical Union’s Minor Planet Center database. Amateur astronomer Tony Dunn went on to calculate the object’s trajectory using NASA’s publicly-available JPL-Horizon’s software and found that it orbits L4, the fourth Earth-sun Lagrange point, a gravitationally balanced region around our planet and star. 2010 TK7, the first-confirmed Earth Trojan asteroid, is also at L4.

The confirmation that it is definitely a Trojan was then made using both new observations as well as a review of archival images, allowing the astronomers to not only refine the asteroid’s orbit, but determine that it is a C-type asteroid, dark with lots of carbon. The data also suggests that in about 4,000 years, 2020 XL5 will drift from its Trojan point.

There are certainly more such asteroids, but detecting them is difficult from Earth because they can only be seen in twilight.

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Lucy update: cause of solar array issue identified

8:49 am

Lucy solar panel graphic

According to the principal scientist for the Lucy asteroid mission, engineers think they have identified what caused one of Lucy’s two fanlike solar arrays to fail to deploy completely.

The +Y array, rather than unfurling a full 360 degrees, instead went 347 degrees. In that configuration, the spacecraft is still generating more than 90% of its expected power. “Power is not an issue for the spacecraft, nor will it be through the entire mission if we have to fly it like it is.”

The arrays unfurl when a motor pulls on a lanyard, swinging one end of the array around and into place. Levison said that the most likely reason the array did not latch is that, for some reason, there was a loss of tension in the lanyard during deployment. That caused it to fall off a spool and wrap around the motor shaft. About 75 centimeters of lanyard remains to be pulled in.

It appears they in April will turn on the array’s motor to try to pull the lanyard in that last little bit. If that doesn’t work, they will then simply leave things as they are, as it appears the array is open enough to give them sufficient power for their mission.

There are risks to that course, however. Because the array is not latched open, it could begin to close, and thus result in less power to the spacecraft. Furthermore, its unlatched state appears to make some planned engine burns too risky.

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Lucy update: Engineers testing solar panel fix on ground

3:44 pm

Engineers for the asteroid probe Lucy have begun doing ground tests on a duplicate solar array motor on Earth to see if their plan will work to get the partly deployed solar panel in space opened and latched.

If all goes right, they are aiming for an April attempt at deploying the panel.

In the meantime, the spacecraft continues its coast outwards, presently being about 30 million miles from Earth. Even though one solar array is not fully open, it appears the spacecraft is getting “ample power” for its present operations. It is unclear if this power — with one solar panel not fully opened — will be sufficient once the spacecraft reaches the region of Jupiter’s Trojan asteroids, much farther from Earth.

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A tumbling 1,100-foot-wide asteroid

10:04 am

Nereus tumbling on December 10th close approach
Click for full image.

Using the Goldstone radio antenna in California, scientists have been able to take some of the highest resolution radar images of the 1,100-foot-wide asteroid Nereus during its close approach to Earth on December 10, 2021.

The montage to the right, cropped to post here, shows twelve images from the 39-image sequence, which can also be viewed as an animation here.

During the asteroid’s close approach, an image resolution of about 12.3 feet (3.75 meters) per pixel was possible, revealing surface features such as potential boulders and craters, plus ridges and other topography. Asteroid Nereus’ previous approach in 2002 was near enough to Earth to reveal the asteroid’s size and overall shape, but too distant to show surface features. The new observations will also help scientists better understand the asteroid’s shape and rotation while providing them new data to further refine its orbital path around the Sun.

The asteroid will not make a similar close-approach again until 2060.

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NASA issues vague update on Lucy’s solar panel deployment issue.

9:29 am

Lucy solar panel graphic

NASA today released a very vague update describing the work of the Lucy engineering team in trying to work out a fix to the incomplete deployment of one of Lucy’s solar panels.

A project team completed an assessment Dec. 1 of the ongoing solar array issue, which did not appear to fully deploy as planned after launch in late October. Initial ground tests determined additional motor operations are required to increase the probability of the latching Lucy’s array in place as intended, and the team has recommended additional testing.

Spacecraft operations included discharging and charging the battery while pointed at Earth, moving the spacecraft to point to the Sun, operating the solar array motor with the launch day parameters, moving back to pointing at Earth, and then another battery discharge and recharge. The solar arrays charge the batteries, then the batteries are deliberately discharged, and the solar array circuits are used to recharge the batteries; performing these charging and discharging processes gives the team more information about the solar array circuits.

The team gathered information on two of the 10 gores – the individual solar array panel segments that make up the full array — that previously had no data. NASA now has data on all 10 gores confirming they are open, producing power as expected, and not stuck together. [emphasis mine]

Apparently they have been doing a variety of testing of the array to assess its precise condition. The highlighted words are the most important, as this data suggests that all ten fan sections, as shown in the graphic above, are partly open, and that an attempt to fully deploy the solar panel should work.

The Lucy team has apparently decided to approach this work very slowly and cautiously, that they have time to do so as Lucy continues its slow journey to Jupiter’s Trojan asteroids.

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NASA upgrades software for monitoring potentially dangerous asteroids

9:59 am

NASA has installed a major upgrade to the software it uses for monitoring, tracking, and predicting the future orbits of potentially dangerous asteroids.

Sentry [the original software used for the past 20 years] was very effective at calculating orbital paths based on how an asteroid is affected by the gravitational pull of the Sun and planets, but there were a few factors that it couldn’t account for. In the long run, these uncertainties can snowball into many possible orbits that may or may not impact Earth.

The Yarkovsky effect, for instance, is where the Sun unevenly heats the surface of an asteroid as it spins, creating thermal forces between the “day” and “night” sides of the rock that can produce thrust. Other times, asteroids that swing past Earth very closely could be nudged into different orbits by the planet’s gravity, changing the paths of their eventual return.

The first Sentry system couldn’t incorporate either of these two factors, meaning that for special case asteroids like Bennu or Apophis, astronomers would have to manually analyze their orbits, which is a complex and time-consuming process.

But Sentry-II is designed to account for things like these. This latest version uses a different algorithm that models thousands of random points within the uncertainty space of an asteroid’s orbit, then figures out which ones have a chance of striking Earth in future. This, the team says, could help find scenarios that have very low probability of impact.

What this upgrade means is that as new asteroids are discovered the software will be able to very quickly calculate with better accuracy any potential impacts in the coming centuries. The results won’t be perfect, but less manual work will be necessary, meaning fewer dangerous asteroids will fall through the cracks.

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SpaceX successfully launches NASA asteroid mission

8:58 am

Last night SpaceX’s Falcon 9 rocket successfully launched NASA’s DART asteroid mission.

The first stage landed successfully, completing its third flight. This was SpaceX’s 26th launch in 2021, setting a new record for the company and in fact for any private company ever.

DART’s mission is to test one method for changing an asteroid’s orbit.

After launch tonight, DART will take aim on an asteroid called Dimorphos. The spacecraft will strike Dimorphos at nearly 15,000 mph (about 6.6 kilometers per second).

The primary science goal of the mission is to measure how the high-speed collision next September, which will destroy the DART spacecraft, disrupts the orbit of Dimorphos around nearby Didymos. The data could help plan a future mission to deflect an asteroid on a course to hit Earth.

Dimorphos and its larger companion Didymos pose no near-term threat to Earth, but the asteroids will be close enough to our planet next year for astronomers to observe DART’s impact using ground-based telescopes. The asteroids orbit the sun in an elongated path that occasionally bring them into Earth’s neighborhood. That makes them potentially hazardous asteroids, although scientists say there is no near-term threat from the pair.

No space mission has ever explored Didymos and Dimorphos, but scientists who have observed them through telescopes say the asteroids are about a half-mile (780 meters) and 525 feet (160 meters) in diameter, respectively.

An Italian cubesat is also on board, and will separate from DART about ten days before impact so that it can observe the impact with two camera.

The leaders in 2021 launch race:

43 China
26 SpaceX
18 Russia
5 Europe (Arianespace)

China now leads the U.S. 43 to 41 in the national rankings. For the U.S. SpaceX’s launch last night topped the U.S. total from last year, which was this country’s highest launch total since the 1960s.

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Lucy update: Instruments all working, no action yet on solar array

9:22 am

According to an update from the Lucy science team today, they have completed the checkout of the asteroid probe’s instruments, and found them all operating properly. However, no action has yet been taken to try to correct the partially deployed solar panel.

The team has used an engineering model of the solar array motor and lanyard to replicate what was observed during the initial solar array deployment. The test data and findings suggest the lanyard may not have wound on the spool as intended. Testing continues to determine what caused this outcome, and a range of scenarios are possible. The team isn’t planning to attempt to move or further characterize the current state of the solar array deployment before Wednesday, Dec. 1, at the earliest.

It appears the spacecraft is still on its planned course.

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Scientists: Asteroid in an orbit entwined with the Earth might be Moon rock

11:45 am

Data obtained by scientists using ground-based telescopes now suggests that the small asteroid Kamo`oalewa, which has an orbit that makes it a quasi-Moon of the Earth, might have originally come from the Moon.

From their paper’s abstract:

We find that (469219) Kamoʻoalewa rotates with a period of 28.3 (+1.8/−1.3) minutes and displays a reddened reflectance spectrum from 0.4–2.2 microns. This spectrum is indicative of a silicate-based composition, but with reddening beyond what is typically seen amongst asteroids in the inner solar system. We compare the spectrum to those of several material analogs and conclude that the best match is with lunar-like silicates. This interpretation implies extensive space weathering and raises the prospect that Kamo’oalewa could comprise lunar material.

Kam’oalewa — which is only about 150 feet across — is one of five such quasi-Earth-moons. All orbit the Sun in orbits that are similar to the Earth’s and are such that the asteroids periodically loop around our planet each year.

This data will be useful to the Chinese, who are planning a mission to Kamo-oalewa in ’24 to grab samples.

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Lucy’s solar panel problem could be due to strap

9:20 am

According to the engineering team for the Lucy asteroid mission, they now think the incomplete deployment of one of the probe’s solar panels was caused by a strap.

The joint Anomaly Response Team has been studying the array using an engineering model. Initial tests indicate that the lanyard that pulls out the solar array may not have completed the process successfully; however, it is still uncertain what caused this condition. The team is conducting more tests to determine if this is indeed the case, and what the root cause might be.

An attempt to characterize the array deployment by attempting to move it would occur no earlier than Nov. 16.

Meanwhile, they have been turning on Lucy’s instruments one by one, with everything functioning as planned, except for that one solar panel. The panel however is a serious concern, as the spacecraft is heading out to the orbit of Jupiter, where it will need every inch of solar panel surface area to get enough power to operate. At the moment it appears the panel is deployed somewhere between 75% to 95%.

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Update on Lucy: panels generating more than 90% of expected power

9:38 pm

According the Lucy science team, the spacecraft’s solar panels are generating more than 90% of the expected power at this stage of the mission, despite the fact that one panel did not deploy completely and has not latched in final position.

“We’re very happy to report that we are getting most of the power we expected at this point in the mission,” said Joan Salute, associate director for flight programs at NASA’s planetary science division. “It’s not 100%, but it is fairly close. So that is great news.’

In an interview with Spaceflight Now, Salute said the power output from the solar arrays appears to be “most likely above 90%” of the expected level of 18,000 watts. “We don’t know if it’s a latch problem, or that it is only partially deployed,” Salute said.

If correct, there is an excellent chance the mission will not be seriously hindered, even if they cannot get the panel fully deployed or latched. At the same time, there are worries about firing Lucy’s main engine for major course corrections with the panel unlatched. The first major course correction is scheduled for mid-November.

The engineers are presently reviewing their data. One option might be to order the spacecraft to re-attempt a full deployment, in the hope that the process will complete during that second attempt.

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Early solar system had gap separating its inner and outer regions

9:29 am

New research looking at the make-up of asteroids now suggests that the early solar system had a gap that separated the formation of planets between its inner and outer regions.

Earlier data had suggested that asteroids come in two fundamentally different groups. This new research, looking the magnetic field strength of these two groups, has confirmed this distinction, and provided additional information about the formation process of each.

Surprisingly, they found that their field strength was stronger than that of the closer-in noncarbonaceous meteorites they previously measured. As young planetary systems are taking shape, scientists expect that the strength of the magnetic field should decay with distance from the sun.

In contrast, Borlina and his colleagues found the far-out chondrules had a stronger magnetic field, of about 100 microteslas, compared to a field of 50 microteslas in the closer chondrules. For reference, the Earth’s magnetic field today is around 50 microteslas.

A planetary system’s magnetic field is a measure of its accretion rate, or the amount of gas and dust it can draw into its center over time. Based on the carbonaceous chondrules’ magnetic field, the solar system’s outer region must have been accreting much more mass than the inner region.

In other words, the accretion of planets in the outer region was faster and producing larger objects, while the inner region was slower and producing smaller objects. The data also suggests that gap existed about 4.5 billion years ago, at about the location of the asteroid belt. All in all, this scenario matches the solar system we see today.

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A Lucy solar panel on Lucy fails to latch properly after deployment

8:40 am

Partly deployed panel

Engineers at Lockheed Martin (the prime contractor) and Northrop Grumann (which built the panels) are now troubleshooting an issue with one of the solar panels on the asteroid probe Lucy, which failed to latch properly after deployment.

The NASA graphic to the right illustrates this issue, though the graphic might not accurately portray the exact circumstance at Lucy. To get more solar power, Lucy’s panels are larger, and thus were designed to unfurl like a fan rather than the more commonly used accordion design. One panel has not completed that unfurling.

NASA’s announcement tries to minimize the issue but this quote from the link makes it clear that this could be a very big problem.

It’s not yet clear whether the array in question is, in fact, fully deployed but not latched in place or whether it did not reach full deployment and is not generating the same amount of power as its counterpart. It’s also not yet clear whether Lucy can safely fire its maneuvering thrusters with an unlatched array.

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ULA’a Atlas-5 successfully launches the Lucy asteroid probe

6:08 pm

ULA’a Atlas-5 rocket early this morning successfully launched the Lucy asteroid probe on a 12 year mission to study eight Trojan asteroids over a period from 2025 to 2031. One tidbit about the mission is especially creative:

Scientists named the Lucy mission after the fossilized remains of a human ancestor, called Lucy by the scientists who discovered her in Ethiopia in 1974.

The leaders in the 2021 launch race:

36 China
23 SpaceX
17 Russia
4 Northrop Grumman
4 ULA

The U.S. and China are once again tied in the national rankings, at 36 each.

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New Horizons discovers two binary asteroids in Kuiper Belt

10:32 am

Overview map
Click for full map.

As New Horizons traveled from Pluto to the asteroid Arrokoth in 2018, scientists used it to take images of the relatively nearby asteroids that it was passing, and found that two of those asteroids appeared elongated.

[T]he team fit the shapes with a two-body model: two asteroids in a tight orbit. Even though the individual rocks weren’t resolved, the modeling showed that two bodies were better able to explain the elongation, as well as the brightness seen. The model for 2011 JY31 had two 50-km-wide objects nearly 200 km apart, while for 2014 OS393, the model had slightly smaller bodies (30 km across) that orbited each other 150 km apart.

The map, cropped and further annotated by me, shows New Horizons’ path during this time period, with the two binary asteroids indicated in blue.

This data, combined with the double lobe shape of Arrokoth (formerly named Ultima Thule), strongly suggests that it was not unusual for these primitives asteroids in the early solar system to coalesce from comparably sized partners.

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UAE to launch probe to asteroid belt

9:01 am

The new colonial movement: The United Arab Emirates (UAE) today announced that it is planning an unmanned probe to visit a number of asteroids in the asteroid belt.

The project targets a 2028 launch with a landing in 2033, a five-year journey in which the spacecraft will travel some 3.6 billion kilometers (2.2 billion miles). The spacecraft would need to slingshot first around Venus and then the Earth to gather enough speed to reach an asteroid some 560 million kilometers (350 million miles) away.

It appears they have not yet chosen their targets in the belt.

The big question will be how much of this project will be built in the UAE, and how much they will have to farm out to others. For their Al-Amal Mars orbiter, the satellite was mostly built by U.S. universities, as they trained UAE engineers, who now run the mission entire.

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Two nearby asteroids found with more precious metals than Earth’s entire global supply

10:04 am

The precious metals on asteroid 1986 DA, compared to the world's reserves

Capitalism in space: Astronomers have now identified two metal-rich asteroids in orbit near the Earth, with one having a precious metal content that likely exceeds the Earth’s entire reserves.

From the paper’s conclusion:

We estimated that the amounts of Fe, Ni, Co, and the PGM present in 1986 DA could exceed the reserves worldwide. Moreover, if 1986 DA is mined and the metals marketed over 50 yr, the annual value of precious metals for this object would be ∼$233 billion.

The graphic to the right, figure 13 from the paper, illustrates the amount of precious metals available in asteroid 1986 DA, compared to the world’s entire reserves (FE=iron, Ni=nickel, Co=cobalt, Cu=copper, PGM=platinum group metals, Au=gold). From this single metal asteroid a mining operation could literally double the metal that had been previously mined on Earth.

In estimating the value of these metals, the paper tries to account for the certain drop in price caused by the flooding of so much material into the market. It is a guess however. What is clear is that this asteroid could easily serve as a supply house not for Earth but for all future colonies in space. While expensive for Earth use, for colonies already in space the material would be relatively easy to reach and mine. The colonies will already have the transportation infrastructure, since they couldn’t exist without rockets and interplanetary spacecraft. And mining and processing this asteroid material will be far easier and cheaper than trying to find it on Mars and then process it.

Asteroid 1986 DA is estimated to be about 1.7 miles across, based on radar data obtained during a close Earth fly-by in 2019. The second asteroid, 2016 ED85, appears to have a similar content from spectroscopy, but no radar data has as yet been obtained of it, so much less is known.

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Biden signs budget continuing resolution, preventing shutdown

9:00 am

At the very last second Congress and President Biden passed and signed another budget continuing resolution that will keep the federal government operating till December and thus preventing another shutdown.

From NASA’s narrow perspective, the action means that the asteroid mission Lucy will likely launch in October as planned. From the perspective of the nation, this last second action merely illustrates the overall failure of the federal government and the elected officials who have been tasked to run it. They are all incompetent, and wouldn’t last five seconds in a real job outside the government.

That the voters keep re-electing them also speaks poorly of America today. We all should be ashamed.

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Orbit of biggest comet ever detected refined

10:59 am

Astronomers have now been able to better refine the orbit and size of Comet Bernardinelli-Bernstein, comet with the largest nucleus ever detected.

A new analysis, led by Bernardinelli and Bernstein themselves, found that the comet nucleus is around 150 km wide, based on its brightness. If so, that makes it the largest comet ever discovered, by quite a margin. Most are only a few kilometers to several dozen kilometers wide, while some particularly big ones, like Hale-Bopp, may be up to 80 km (50 miles) wide. The previous record-holder, Sarabat’s Comet of 1729, has been estimated at about 100 km wide.

The team was also able to calculate the orbit of Comet BB in more detail. This object is on an incredibly long round trip into and out of the solar system – at its most distant point, some 1.5 million years ago, it was about 40,400 AU away. Last time it swung through our neighborhood was about 3.5 million years ago, when it came within 18 AU of the Sun.

But its current inward journey will be its closest so far. Astronomers have already calculated that in 2031, Comet BB will peak at 10.9 AU, almost reaching the orbit of Saturn.

It is presently unclear how bright the comet will be when it reachest its closest point. It will be much farther from the Sun than most bright comets, but its large size may change what is normally expected.

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Government shutdown threatens Lucy asteroid mission

9:00 am

Government marches on! The possibility that the federal government could shut down because of the inability of Congress and the Biden administration to pass a funding bill or raise the debt limit now threatens the launch of the Lucy mission to the asteroid belt.

If no budget agreement is reached the government will shut down on October 1st. If the debt limit isn’t raised that shutdown could follow soon thereafter, even if a budget is passed.

The launch window for the mission is from October 16 to November 7, 2021. If the spacecraft does not launch in that window the science team says it will likely require a major rethinking of the entire project, as it will be difficult to find another opportunity to visit the same set of asteroids.

Right now the chances of a shutdown are very high, as the Democrats are pushing big spending bills without any negotiations with the Republicans. In answer, the Republican caucus has said that none of its members will support raising the debt limit. Without the latter any passed spending bill will soon be moot, as the debt limit will soon be reached, blocking further government spending.

Though I personally would be very saddened if Lucy was prevented from launching, that loss would be well compensated for by having the federal government out of business. The evil and corruption promoted by it far outweighs the good work done by several minor space missions.

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China’s Chang’e-5 orbiter returning to lunar space

9:25 am

The new colonial movement: In a somewhat bold move, Chinese engineers appear to now be shifting the Chang’e-5 orbiter so that it will be able to return to lunar space to fly past the Moon.

The orbiter, one of four distinct Chang’e-5 mission spacecraft, delivered a return module containing 1.731 kilograms of lunar samples to Earth Dec. 16 before firing its engines to deep space for an extended mission.

The Chang’e-5 orbiter later successfully entered an intended orbit around Sun-Earth Lagrange point 1, roughly 1.5 million kilometers, in March. There it carried out tests related to orbit control and observations of the Earth and Sun.

New data from satellite trackers now suggests Chang’e-5 has left its orbit around Sun-Earth L1 and is destined for a lunar flyby early September 9 Eastern time.

This data comes not from China but from amateur astronomers who specialize in tracking satellites.

The fly-by could provide the spacecraft the velocity it needs to reach near Earth asteroid Kamo’oalewa, which China has said it is targeting for a 2024 sample return mission. Such a reconnaissance will help them design the sample return mission.

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First hi-res radio wavelength images of metal asteroid Psyche

9:46 am

Psyche in thermal

Using the ALMA telescope in Chile astronomers have obtained the highest resolution radio images of the surface of the metal-rich asteroid Psyche yet obtained. The image to the right is from their just published paper. From the article:

These new images reveal that some regions of the asteroid have surface temperatures different from the average, indicating that Psyche’s composition is not uniform. The researchers also found that Psyche has a relatively high thermal inertia compared to other asteroids, yet it radiates approximately 60% less heat than would be expected for an object with such a high inertia. The researchers hypothesize that this is because the asteroid’s surface is at least 30% metal. However, the light reflecting off Psyche’s surface is unpolarized, which would not be the case for an object with a smooth or solid metallic surface. They therefore hypothesize that metallic grains are spread throughout its surface material, causing the light to scatter.

Though Psyche is large, 178 by 144 by 101 miles, it is not spherical like Ceres, the largest asteroid in the asteroid belt at 580 miles diameter. Thus, somewhere from the size of Psyche to the size of Ceres we move from an irregular asteroid body to a spherical planetary body, as it appears most planetary scientists define planets.

The probe Psyche is scheduled to launch in August ’22 to arrive at Psyche in ’26.

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Asteroid discovered with shortest orbit yet

8:55 am

Astroid's orbit
Click for full image.

Astronomers have discovered an asteroid that circles the Sun with the shortest orbit yet found, flying mostly inside the orbit of Mercury.

The illustration to the right shows the asteroids orbit, which is also tilted 32 degrees from the plane of the solar system.

The orbit of the approximately 1-kilometer-diameter asteroid takes it as close as 20 million kilometers (12 million miles or 0.13 au), from the Sun every 113 days. Asteroid 2021 PH27, revealed in images acquired during twilight, also has the smallest mean distance (semi-major axis) of any known asteroid in our Solar System — only Mercury has a shorter period and smaller semi-major axis. The asteroid is so close to the Sun’s massive gravitational field, it experiences the largest general relativistic effects of any known Solar System object.

Relatively few asteroids have been found with orbits shorter than Earth’s, because to find them astronomers have to turn their telescopes sunward, where viewing is limited to the early evening or early morning. Few space-based telescopes in all wavelengths also don’t look this way much, because of the risk of damage from the intense sunlight.

It is thus unknown exactly how many asteroids exist with similar orbits. There may be many, with many having short eccentric orbits, similar to comets, that extend out to Earth’s orbit and thus pose a risk. Or there may be few, since such orbits so close to the Sun are likely to cause the asteroid’s break-up and destruction over time.

Knowing how many of course is important, in order to obtain a full census of those asteroids in the solar system that might hit the Earth. To get it will likely require placing a probe designed to look for them.

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China to fly asteroid sample mission in ’24

9:19 am

The new colonial movement: Chinese scientists have revealed that China is now building an asteroid sample mission to launch in ’24 and grab samples in ’25 from the near Earth asteroid dubbed Kamoʻoalewa.

According to a correspondence in Nature Astronomy, there are two typical approaches to sampling asteroids like Kamoʻoalewa, namely anchor-and-attach and touch-and-go.

The former requires delicate and dangerous interactions with the planetary body but allows more controllable sampling and more chances for surface analysis. The latter, used by Hayabusa 2 and OSIRIS-Rex, is a quick interaction facilitated by advanced navigation, guidance and control and fine control of thrusters.

China’s mission will use both architectures in order to “guarantee that at least one works.” The paper states that there is “still no successful precedent for the anchor-and-attach architecture,” meaning a possible deep space first. A 2019 presentation reveals that China’s spacecraft will attempt to land on the asteroid using four robotic arms, with a drill on the end of each for anchoring.

The attempt to do both these approaches is audacious, especially because the evidence from both OSIRIS-REx and Hayabusa-2 is that it will be difficult to safely land and hold onto a rubble pile asteroid. The material is too loosely held together.

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OSIRIS-REx scientists refine Bennu’s future Earth impact possibilities

1:28 pm

Using the orbital and gravity data compiled during OSIRIS-REx’s visit to the asteroid Bennu, scientists have refined its future orbits as well as the most likely moments it might impact the Earth.

In 2135, asteroid Bennu will make a close approach with Earth. Although the near-Earth object will not pose a danger to our planet at that time, scientists must understand Bennu’s exact trajectory during that encounter in order to predict how Earth’s gravity will alter the asteroid’s path around the Sun – and affect the hazard of Earth impact.

Using NASA’s Deep Space Network and state-of-the-art computer models, scientists were able to significantly shrink uncertainties in Bennu’s orbit, determining its total impact probability through the year 2300 is about 1 in 1,750 (or 0.057%). The researchers were also able to identify Sept. 24, 2182, as the most significant single date in terms of a potential impact, with an impact probability of 1 in 2,700 (or about 0.037%).

Although the chances of it hitting Earth are very low, Bennu remains one of the two most hazardous known asteroids in our solar system, along with another asteroid called 1950 DA.

This paper’s conclusions are confirming what had been found earlier in the mission, while OSIRIS-REx was still flying in formation with the asteroid. Nonetheless, it is essential to refine these numbers as precisely as possible, so this confirmation is excellent news.

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Comet spewed out an unusual amount of alcohol during solar flyby

1:04 pm

A review of the data gathered when Comet 46P/Wirtanen made its close fly-by of the Sun in 2018 has found that the comet released an unusual amount of alcohol during that flyby.

The data also showed that the temperature of the comet’s coma did not cool as much as expected at larger distances from the comet.

“46P/Wirtanen has one of the highest alcohol-to-aldehyde ratios measured in any comet to date,” said Neil Dello Russo, a cometary scientist at Johns Hopkins University Applied Physics Laboratory and co-author of the study. “This tells us information about how carbon, oxygen, and hydrogen molecules were distributed in the early solar system where Wirtanen formed.”

Keck Observatory data also revealed a strange characteristic. Normally, as comets orbit closer to the Sun, the frozen particles in their nucleus heat up, then boil off, or sublimate, going directly from solid ice to gas, skipping the liquid phase. This process, called outgassing, is what produces the coma – a giant cloak of gas and dust glowing around the comet’s nucleus. As the comet gets even closer to the Sun, solar radiation pushes some of the coma away from the comet, creating the tails.

With comet 46P/Wirtanen however, the team made a strange discovery: Another process beyond solar radiation is mysteriously heating up the comet.

“Interestingly, we found that the temperature measured for water gas in the coma did not decrease significantly with distance from the nucleus, which implies a heating mechanism,” said co-author Erika Gibb, professor and chair of the Department of Physics and Astronomy at University of Missouri–St. Louis.

They have theories about why they got these results, such as a chemical reaction with sunlight or the presence of large ice chunks breaking off the comet that reflect light and increase the ambient temperature of the coma. Nothing is confirmed however.

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Astronomers discover “comet” bigger than the largest comets approaching inner solar system

9:25 am

Astronomers have discovered an object 80 to 100 miles in diameter, larger than the largest comets, approaching the inner solar system and coming from the theorized Oort Cloud of material thought to exist between a tenth and a third of a light year from the Sun.

The object is probably rich in ice like a comet and is currently around three billion kilometres from the Sun. It will reach its closest point, known as perihelion, in 2031. At that time, it will be positioned below the plane of the solar system, near the orbit of Saturn.

Part of the interest in C/2014 UN271 is that it may be something of a transition object. Astronomers believe that many of the long period comets, that occasionally appear with bright tails, actually come from the Oort Cloud. Stars wandering near the Sun can nudge these objects from their positions and over millennia they work their way inwards, with the gravity of the giant planets tweaking their paths on each visit until they reside where we see them today.

“The fact that [C/2014 UN271] has a perihelion so far away from the Sun might be telling us that it’s done this a couple of times but is still in that process of eventually becoming some of those long period comets we know and love,” explains Meg Schwamb a Kuiper Belt and Oort Cloud expert at Queen’s University Belfast.

Initially astronomers thought because of its size that it was not a comet, but new observations have detected the first signs of a coma, suggesting that it will provide us a very interesting and extended show when it reaches its closest point in 2031. Because that perihelion is around the orbit of Saturn, the object will not be traveling very fast, so its passage through the inner solar system will take several years. Its size also suggests it will have a lot of material that can sublimate off to produce a tail.

The object was discovered by two astronomers, Gary Bernstein and Pedro Bernardinelli. If it turns out to be a comet it will then be named Comet Bernardinelli-Bernstein, or Comet B-B for short.

UPDATE: It is official. The object is now officially a comet, and named Comet Bernardinelli-Bernstein.

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Japanese scientists complete inventory of Ryugu asteroid samples

9:00 am

In a press conference yesterday the Japanese space agency JAXA announced that scientists have completed their inventory of the samples brought back from the asteroid Ryugu by the Hayabusa-2 spacecraft, and are now ready to begin distributing those samples to scientists around the world for more detailed research.

JAXA has cataloged the soil samples brought back by Hayabusa 2 last December, by size, color and shape. From now, 269 researchers from 14 countries, including Japan and the United States, will conduct an in-depth analysis of the soil’s structures and components over the course of about a year.

As expected, the inventory found the samples had a large amount of hydrogen, oxygen, and carbon atoms. Even before Hayabusa-2’s arrival, Ryugu had been catalogued as a “hydrated” asteroid, which means it was thought to contain a lot of hydrogen and oxygen, the basic elements of water. The inventory has now confirmed this.

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Ryugu’s most primitive boulders

1:18 pm

In a just published paper scientists reveal how they think they have identified the oldest rocks on the rubble pile asteroid Ryugu, and found them to be distributed across the entire face of the asteroid.

These boulders are light enough that they would float on water.

Ryugu is thought to have initially formed as a fluffy planetesimal that coalesced from accumulated dust in the early Solar System, and subsequently underwent processes such as thermal evolution and compression. This parent body was then later destroyed in a collision and fragments of this reaccumulated into the asteroid. However, planetesimals have never been seen, so whether they really existed or what they may have looked like is one of the biggest challenges in understanding the planet formation process. The boulders discovered in this research are thought to be a material that most strongly retains the appearance of the fluffy planetesimals that triggered the birth of the planets in the Solar System.

Additionally, the data from all the scientific instruments onboard Hayabusa2 that were used to examine the surface of Ryugu revealed that fragments of material similar to those of the ultra-high porosity boulders are globally distributed over the asteroid surface, and may have been collected in the sample taken by Hayabusa2. If highly primitive material with the ultra-high porosity discovered here is also found in the collected samples, it will both clarify the formation and evolutional history of Ryugu’s parent body, and also provide evidence of planetesimal formation in the early stage of the Solar System formation process.

There is no word yet from the scientists studying the Hayabusa-2 samples on what they have found. This paper gives them an idea of what could be the most important type of rock to look for.

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