Tag: asteroids

Hubble image shows several dozen boulders flung from Dimorphos

9:40 am

Boulders drifting from Dimorphos
Click for original image.

Using the Hubble Space Telescope, astronomers have photographed several dozen boulders that were flung off of the asteroid Dimorphos following the impact by the space probe DART. The picture to the right, reduced and brightened to more clearly show those boulders, was taken on December 19, 2022, four months after DART’s impact.

These are among the faintest objects Hubble has ever photographed inside the Solar System. The ejected boulders range in size from 1 meter to 6.7 meters across, based on Hubble photometry. They are drifting away from the asteroid at around a kilometre per hour.

The blue streak is the dust tail that has streamed off of Dimorphos since the impact, pushed away from the sun by the solar wind.

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The possibility of more than one exoplanet sharing the same orbit

9:27 am

PDS 70, as seen by ALMA
The Trojan debris clouds around PDS 70, as seen by ALMA

The uncertainty of science: Astronomers have detected evidence that suggests the possibility of more than one exoplanet sharing the same orbit around PDS 70, a star 400 light years away.

This young star is known to host two giant, Jupiter-like planets, PDS 70b and PDS 70c. By analysing archival ALMA observations of this system, the team spotted a cloud of debris at the location in PDS 70b’s orbit where Trojans are expected to exist.

Trojans occupy the so-called Lagrangian zones, two extended regions in a planet’s orbit where the combined gravitational pull of the star and the planet can trap material. Studying these two regions of PDS 70b’s orbit, astronomers detected a faint signal from one of them, indicating that a cloud of debris with a mass up to roughly two times that of our Moon might reside there.

The press release — as well as most news reports — touts the possibility that they have found a second planet in this orbit. They have not, and are likely not going to. As noted above, the data indicates the presence of “a cloud of debris”, which is most likely a clustering of Trojan asteroids, just as the more than 12,000 asteroids we see in the two Trojan points in Jupiter’s orbit.

Nonetheless, this is the first detection of what appears to be a Trojan clustering in the accretion disk of a young star.

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NASA gives up on finding a new asteroid target for Janus

10:02 am

Without funding for its own launch vehicle, and unable to find a new asteroid target that can be reached by any future planned NASA launch, NASA has decided to shelf the Janus asteroid mission, putting the spacecraft into storage.

Designed to send twin small satellite spacecraft to study two separate binary asteroid systems, Janus was originally a ride-along on the Psyche mission’s scheduled 2022 launch. Psyche’s new October 2023 launch period, however, cannot deliver the two spacecraft to the mission’s original targets, and Janus was subsequently removed from the manifest.

The spacecraft will remain in storage, and might be revived at some point in the future, should another mission’s launch allow it to reach some other asteroid.

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More evidence found suggesting supernovae occurred near the solar system during its formation

9:22 am

Scientists have now detected more evidence that suggests a supernovae occurred very close to our solar system during its early period of formation.

Astronomers have for decades found such evidence inside meteorites. Small spherical inclusions called chondrules are thought by some to have formed when the heat of a nearby supernova caused melting. The new study finds more evidence in isotopes also found in primitive meteorites dubbed short-lived radionuclides (SLRs).

While SLRs probably existed in the part of the filament where the Sun and Solar System formed, the meteorite samples contained too much of a particular aluminum isotope for the interstellar medium to have been the Solar System’s only SLR source. Cosmic rays, which can convert stable isotopes to radioactive ones, had a better chance of explaining the number of isotopes found in the meteorites. However, it would have taken too long for this process to produce the levels of SLRs found in the early Solar System.

It is most likely that such high SLR levels could have come from either very intense stellar winds, which would have occurred during massive star formation, or from what was left after one of the massive stars went supernova.

You can read the published paper here.

If true, this data adds weight to the possibility that our solar system is somewhat unique, which in turn suggests finding just another like it — with life — might be difficult.

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China conducts parachute tests for returning asteroid sample to Earth

9:53 am

China has successfully conducted tests of the parachute design that will be used by the sample return capsule of its Tianwen-2 mission to grab samples from the near Earth asteroid dubbed 469219 Kamoʻoalewa.

The mission will launch on a Long March 3B rocket in 2025, and rendezvous with the asteroid in 2025. After getting its samples and releasing the sample return capsule, the plan is to then send Tianwen-2 to Comet 311P/PANSTARRS, arriving in the 2030s.

The probe uses fanlike solar panels, apparently copied from those used by NASA’s Lucy asteroid probe. China also has copied the touch-and-go sample grab methods used by OSIRIS-REx and Hayabusa-2, but it will also try its own original idea, to anchor to the asteroid and use drills in the probe’s landing legs.

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NASA: Psyche asteroid mission now targeting October ’23 launch

9:51 am

A report [pdf] from NASA on the steps taken by JPL to get the Psyche asteroid mission back on track after it failed to meet its launch date last fall says those steps are working, and the spacecraft should now succeed in meeting its new October ’23 launch date.

Both the report and today’s press release are filled with vague PR blather interspersed with complementing JPL for addressing the issues, including hiring about a dozen more people to get the main software issue that had prevented last year’s launch solved. I noticed one point however that was not mentioned clearly in the press release nor had been made clear in the earlier investigation report that today’s newly released report labels as “COVID-19 Related” issues.

The return to majority in-person work has made a tremendous difference in restoring visibility and informal communications across the project. Drop-in meetings, social coffee hours, off-site intensives, and individuals “walking the floor” have improved team interaction, problem-solving, efficiency, and trust. The team is also making judicious use of remote and hybrid access options as appropriate to ensure flexibility while not compromising their collaboration.

In other words, the panic over Wuhan had so restricted in-person contact at JPL that it had hampered the project’s development. Based on the vague language used to describe almost everything else mentioned in this new report, it appears that this issue more than anything else contributed the launch delay. Not surprisingly, no one at NASA, JPL, Caltech, or in the government wishes to make this admission bluntly. It would illustrate once again the foolishness of the lockdown policies imposed during the panic by the government and academia.

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Astronomers think they have completed the census of Near Earth asteroids

10:14 am

Astronomers in a new paper [pdf] have concluded that the census of Near Earth asteroids is largely now complete, and have begun focusing their effort on narrowing down the list of potentially dangerous asteroids in that census. From the press release:

Researchers from CU Boulder and NASA have completed a census of hundreds of large asteroids orbiting near Earth—gauging which ones could come precariously close to our planet over the next thousand years. The researchers identified at least 20 asteroids that scientists may want to study more to make certain they pose no threat to life on Earth in the next millennium.

To be clear, the researchers say the odds of any of these rocky bodies striking the planet are extremely low, and are next to zero for the coming century. But because the fallout from such an impact would be catastrophic, it’s important to be sure, said Oscar Fuentes-Muñoz, lead author of the study. “We don’t want to alarm people, because the results are not alarming,” said Fuentes-Muñoz, a doctoral student in the Ann and H.J. Smead Department of Aerospace Engineering Sciences. “But there are a lot of uncertainties in predicting so far into the future.”

To sum up, none of those 20 asteroids has any chance of hitting the Earth in the next few hundred years. Beyond that the uncertainties make it difficult to predict. Reducing those uncertainities is now the focus of their work.

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Lucy makes course correction in preparation for 1st asteroid fly-by

9:36 am

Lucy's route through the solar system
Lucy’s route through the solar system

The asteroid probe Lucy on May 9, 2023 fired its engines to successfully make a minor course correction in preparation for a fly by of the asteroid Dinkinesh, located in the main asteroid belt between Mars and Jupiter.

Even though the spacecraft is currently travelling at approximately 43,000 mph (19.4 km/s), this small nudge is enough to move the spacecraft nearly 40,000 miles (65,000 km) closer to the asteroid during the planned encounter on Nov. 1, 2023. The spacecraft will fly a mere 265 miles (425 km) from the small, half-mile- (sub-km)-sized asteroid, while travelling at a relative speed of 10,000 mph (4.5 km/s).

Dinkinesh, the white dot inside the main asteroid belt in the lower left of the map to the right, is the first of eight asteroids Lucy will fly past.

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UAE asteroid mission will rendezvous with seven asteroids and will include lander

10:08 am

Though the mission was first announced in 2021, the UAE only recently revealed at a science conference the mission’s specific targets and plan.

From the conference poster [pdf]:

The mission will launch in 2028 and visit 7 main belt asteroids, including 6 high-speed flyby encounters en route to a rendezvous with the asteroid 269 Justitia. The mission is enabled by solar electric propulsion and gravity assist flybys of Venus, Earth, and Mars, bringing the total number of mission encounters to 10. The trajectory design presented will include the overall timeline of the mission, launch targets, launch period, overall duration of the encounters, design of the encounters, and trajectory modeling. Mission design analyses include designing the Deep space maneuvers (DSMs) prior to the rendezvous with Justitia and design Justitia’s orbits and maneuvers to accomplish the lander deployment.

As with the UAE’s Al-Amal Mars Orbiter, the country is relying on an American university, the University of Colorado, as well as the commercial company, Advanced Space, to design, build, and operate the spacecraft. In this sense the UAE is paying these American entities to fly the mission while requiring them to train its own engineers and scientists.

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Meteorite crashes through roof of NJ home

9:53 am

On May 8, 2023 a family in New Jersey returned home to discover a 4×6 inch meteorite on the floor of one bedroom, having crashed through the roof of their home.

Suzy Kop, a resident of the home, told CBS Philadelphia that meteorite landed in her father’s bedroom, but no one was home. “I thank God that my father was not here, no one was here, we weren’t hurt or anything,” Kop told the station.

She found the object, she said, amid debris in the room after it came through the ceiling. At first, she said she believed it had been thrown. “I did touch the thing, because I thought it was a random rock, I don’t know, and it was warm,” she told CBS Philadelphia.

Though not unprecedented, there are only a few recorded examples of meteorites landing in populated areas like this.

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The inexplicable tail of the asteroid Phaethon is from sodium, not dust

9:39 am

For years astronomers have puzzled over the strange behavior of the asteroid Phaethon, which though rocky would still produce a tail like a comet whenever its orbit took it close to the Sun.

New research by astronomers using several space telescopes designed to study the Sun has determined that this tail is made of sodium, not dust as previously believed, which also suggests that many of the other “comets” these solar telescopes have detected close to the Sun might instead be asteroids like Phaeton.

Hoping to find out what the tail is really made of, Zhang looked for it again during Phaethon’s latest perihelion in 2022. He used the Solar and Heliospheric Observatory (SOHO) spacecraft — a joint mission between NASA and the European Space Agency (ESA) – which has color filters that can detect sodium and dust. Zhang’s team also searched archival images from STEREO and SOHO, finding the tail during 18 of Phaethon’s close solar approaches between 1997 and 2022.

In SOHO’s observations, the asteroid’s tail appeared bright in the filter that detects sodium, but it did not appear in the filter that detects dust. In addition, the shape of the tail and the way it brightened as Phaethon passed the Sun matched exactly what scientists would expect if it were made of sodium, but not if it were made of dust.

Knowing these new facts, it might make it possible to map the asteroids that orbit very close to the Sun but are hard to detect optically using standard telescopes because of the Sun’s brightness. Instead, astronomers might be able to map them using these solar telescopes.

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Lucy snaps its first pictures of four of the Trojan asteroids it will visit

10:05 am

Lucy's first look at four Trojan asteroid targets
Click for original movie.

Lucy's route through the solar system
Lucy’s route through the solar system

Though still many millions of miles away and really nothing more than tiny dots moving across the field of stars, the science team for the asteroid probe Lucy have used the probe to take its first pictures of four of the eight Trojan asteroids it will visit during its travels through the solar system, as shown on the map to the right. The dots along its path show where Lucy will fly past asteroids, some of which are binaries.

The image at the top is a screen capture from a very short movie created from all of the images Lucy took of each asteroid. If you click on the picture you will see that movie. As I say, at this distance, more than 330 million miles away, the asteroids are nothing more than dots. The short films of each were obtained by pictures taken over periods from two to 10 hours long, depending on the asteroid.

These asteriods are all in the L4 Trojans, the first that Lucy will visit from ’27 to ’28.

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