Tag: asteroids

Fractured surface in Occator Crater on Ceres

10:03 am

fractures in Occator Crater

Cool image time! Dawn, now in its final very close orbit above the surface of Ceres, has released some new images. The image on the right, cropped to post here, was taken from a distance of only 22 miles, and shows a fracture network and some very pronounced cliffs on the wall of Occator Crater. The sunlight is coming from the right. You can also see a bright spot on an east-facing slope with what looks like an apron of lighter avalanche material below it. The flat smooth surface of the floor of this same canyon is likely because it is filled with dust, which has ponded there.

These fractures suggest that the wall of the crater is undergoing a slow motion avalanche, with sections separating off and slowly sagging into the crater below, creating the fractures.

Leave a comment

Ryugu from 25 miles

8:56 am

Ryugu from 25 miles

The Hayabusa-2 science team has released its first image of Ryugu, posted to the right, from a distance of only 25 miles. From the project manager:

The shape of Ryugu is now revealed. From a distance, Ryugu initially appeared round, then gradually turned into a square before becoming a beautiful shape similar to fluorite [known as the ‘firefly stone’ in Japanese]. Now, craters are visible, rocks are visible and the geographical features are seen to vary from place to place. This form of Ryugu is scientifically surprising and also poses a few engineering challenges.

First of all, the rotation axis of the asteroid is perpendicular to the orbit. This fact increases the degrees of freedom for landing and the rover decent operations. On the other hand, there is a peak in the vicinity of the equator and a number of large craters, which makes the selection of the landing points both interesting and difficult. Globally, the asteroid also has a shape like fluorite (or maybe an abacus bead?). This means we expect the direction of the gravitational force on the wide areas of the asteroid surface to not point directly down. We therefore need a detailed investigation of these properties to formulate our future operation plans.

They are going to have to spend some time in orbit to figure out not only where to land, but how to do it. More information on the mission can be found here.

Leave a comment

Ryugu seen from 150-200 miles

8:41 am

Ryugu from 150 milesl

Cool image time! Hayabusa-2’s approach to asteroid Ryugu continues. The image to the right, cropped to post here, shows one of four images taken by the spacecraft on June 17 and June 18. In this image the distance is about 150 miles. As noted in the Hayabusa-2 press release,

The shape of the asteroid looks like a spinning top (called a “Coma” in Japanese), with the equatorial part wider than the poles. This form is seen in many small asteroids that are rotating at high speed. Observed by radar from the ground, asteroid Bennu (the destination of the US mission, OSIRIS-REx), asteroid Didymous (the target of the US DART project), and asteroid 2008 EV5 that is approaching the Earth, all have a similar shape.

On the surface of asteroid Ryugu, you can see a number of crater-like round recessed landforms. In the first image, one large example can be seen with a diameter exceeding 200m. This moves to the left and darkens as the asteroid rotates and the lower part becomes cast in shadows.

The bulge at the equator forms a ridge around the asteroid like a mountain range. Outside this, the surface topology appears very ridge-shaped and rock-like bulges are also seen. These details should become clearer as the resolution increases in the future.

Based on the visible landforms, they presently estimate Ryugu’s rotation period to be about 7.5 hours.

One comment

Questions raised about NEOWISE asteroid data analysis

10:05 am

A computer entrepreneur has raised questions about the data analysis used by the scientists in charge of NASA’s NEOWISE space telescope (formerly called the Wide-field Infrared Space Telescope, or WISE).

Myhrvold, a former chief technologist for Microsoft, founded the patent-buying firm Intellectual Ventures in Bellevue, Washington, in 2000; on the side, he pursues interests ranging from modernist cuisine to palaeontology. A few years ago, he began exploring ways to detect dangerous space rocks. He soon argued3 that the Large Synoptic Survey Telescope, a ground-based telescope being built in Chile, would have the capacity to find nearly all the same asteroids as NASA’s proposed successor to NEOWISE, called NEOCam.

That turned his attention to how asteroids could be studied in space, and to the NEOWISE data. “I thought, this will be great, maybe we’ll be able to find some new and interesting things in here,” he says. But Myhrvold soon became frustrated with the quality and analysis of the data. He posted a critical preprint on arXiv in May 2016, and the peer-review game was on.

His first peer-reviewed critique was published in Icarus in March4. In it, he explored the mathematics of how asteroids radiate heat, and said that the NEOWISE team should have accounted for such effects more thoroughly in its work.

The latest paper1 holds the bulk of the NEOWISE critique. Among other things, Myhrvold argues that the NEOWISE team applied many different modelling techniques to many different combinations of data to achieve its final results. He also criticizes the choice to include previously published data on the diameter of certain asteroids in the data set, rather than using NEOWISE measurements — which, though less precise, are at least consistent with the rest of the database. Such choices undermine the statistical rigour of the database, he says.

Alan Harris, a planetary scientist with the consulting firm MoreData! in La Cañada Flintridge, California, was one of the paper’s reviewers. “In my opinion, it has important things to say,” he says. “It is my hope that the scientific community will read the paper and pay attention to the analysis Myhrvold has presented, as he has raised a number of significant issues.”

The disagreement involves the NEOWISE team’s estimate of asteroid sizes, based on the infrared data. Myhrvoid questions their estimates.

More details about the clashes between Myhrvoid and the NEOWISE science team over the past two years can be found here. The NASA scientists do not come off well. They appear to be very defensive, acting to stonewall any review of their work. Repeatedly they attempted to defy Myhrvoid’s FOIA requests (only made when they refused to release their raw data), including redacting significant information for no justifiable reason.

I have really only one question: Does the behavior of these NASA planetary scientists sound familiar? To me it does, and what it reminds me of speaks very badly for the science being done in the NEOWISE mission at NASA.

7 comments

Landslides on Ceres

9:31 am

Landslides on rim of Occator Crater

Cool image time! With Dawn completing its descent into its final low orbit only about 30 miles above the surface of Ceres, it is beginning to take some very spectacular images. Above is a cropped section from a full image taken on June 9th of the rim of Occator Crater from an altitude of 27 miles. It shows evidence of landslides on the crater’s rim, as well as at least two bright patches. If you click on it you can see the entire picture.

Crater on Ceres

Nor is this the only cool image released As Dawn descended to its new orbit, it took one very cool oblique image of the planet’s horizon. On the right I have cropped a small section out of one such image, taken on May 30th from an altitude of 280 miles. If you click on it you can see the full image, showing numerous other small craters all around it, to the horizon.

Note the bright streaks on the crater walls, suggestive of more landslides as well as seepage of the thought-to-exist brine from below the surface.

For the next year or so, as Dawn winds down its mission, expect a lot more very intriguing pictures of Ceres. I am especially eager to see close-ups of the bright spots at the center of Occator Crater.

Leave a comment

New analysis suggests Ceres has more organic molecules than previously estimated

12:11 pm

The uncertainty of science: A new analysis of data from Dawn now suggests that the surface of Ceres has a greater percentage of organic molecules than previously estimated.

To get an initial idea of how abundant those compounds might be, the original research team compared the VIR data from Ceres with laboratory reflectance spectra of organic material formed on Earth. Based on that standard, the researchers concluded that between six and 10 percent of the spectral signature they detected on Ceres could be explained by organic matter.

But for this new research, Kaplan and her colleagues wanted to re-examine those data using a different standard. Instead of relying on Earth rocks to interpret the data, the team turned to an extraterrestrial source: meteorites. Some meteorites — chunks of carbonaceous chondrite that have fallen to Earth after being ejected from primitive asteroids — have been shown to contain organic material that’s slightly different from what’s commonly found on our own planet. And Kaplan’s work shows that the spectral reflectance of the extraterrestrial organics is distinct from that of terrestrial counterparts.

“What we find is that if we model the Ceres data using extraterrestrial organics, which may be a more appropriate analog than those found on Earth, then we need a lot more organic matter on Ceres to explain the strength of the spectral absorption that we see there,” Kaplan said. “We estimate that as much as 40 to 50 percent of the spectral signal we see on Ceres is explained by organics. That’s a huge difference compared to the six to 10 percent previously reported based on terrestrial organic compounds.”

Please note: Both estimates depend on assumptions that could easily be wrong. Ceres might have less organics, or more, than either estimate. Or somewhere in the middle. These estimates are merely educated guesses.

And remember, organic molecules does not mean life. It only means the molecules use carbon as a component.

Leave a comment

Hayabusa-2 takes first photos of target asteroid Ryugu

8:34 am

On June 10 Hayabusa-2 took its first photos of Ryugu, the asteroid it will reach later this month.

The Sunday photos were taken when Hayabusa2 was about 930 miles (1,500 kilometers) from Ryugu. Last week, JAXA released a few ONC-T images taken on June 6, when the probe was 1,615 miles (2,600 km) from the space rock.

Hayabusa2, which launched in December 2014, is scheduled to arrive at Ryugu on or around June 27. At that time, the probe will begin orbiting the asteroid at an altitude of about 12 miles (20 km), JAXA officials have said.

Hayabusa2 will then start prepping for a series of complex, up-close studies of the space rock. If all goes according to plan, over the ensuing 12 months, the spacecraft will deploy three rovers and a lander on Ryugu’s surface, gouge out a small crater using an explosives-bearing impactor, and collect samples from the newly created crater.

The spacecraft will depart Ryugu in November or December 2019, and its collected samples will come back to Earth in a special return capsule in late 2020.

The image suggests that the asteroid is “not significantly elongated.”

Leave a comment

No giant planet needed in Kuiper Belt to shape orbits of outer known planets

9:27 am

Using computer models astronomers have found that the tiny objects in the Kuiper Belt could be sufficient, instead of one giant undiscovered planet, to provide the gravity necessary to explain the orbits of the solar system’s outer planets.

They call theorized giant planet “Planet Nine,” which seems silly since Pluto really still fills that role. Nonetheless, this work also might explain the process that flung some surprisingly large objects so far out into the Kuiper Belt.

They ran supercomputer simulations of how bodies might interact in the outer Solar System far beyond Pluto, in the icy region known as the Kuiper belt. They found that a flock of Moon-sized worlds could do many of the same things as Planet Nine.

Over millions of years, the collective gravity of these smaller worlds would nudge the orbits of distant objects. The worlds would jostle one another like bumper cars and, occasionally, cause an object to move into a very distant orbit. Their simulations suggest that more-massive objects would be flung into the most distant orbits — as some observations have suggested.

We must also remind ourselves that this conclusion is based on a computer model, and is filled with uncertainty. We also do not yet have a full census of objects in the Kuiper Belt, which means this model required many assumptions.

Leave a comment

Boulder-sized asteroid discovered just before it hit Earth

8:59 am

The Catalina Sky Survey, designed to find asteroid with the potential of hitting the Earth, discovered a boulder-sized such asteroid this past weekend just hours before it burned up in the atmosphere.

Although there was not enough tracking data to make precise predictions ahead of time, a swath of possible locations was calculated stretching from Southern Africa, across the Indian Ocean, and onto New Guinea. Reports of a bright fireball above Botswana, Africa, early Saturday evening match up with the predicted trajectory for the asteroid. The asteroid entered Earth’s atmosphere at the high speed of 10 miles per second (38,000 mph, or 17 kilometers per second) at about 16:44 UTC (9:44 a.m. PDT, 12:44 p.m. EDT,6:44 p.m. local Botswana time) and disintegrated several miles above the surface, creating a bright fireball that lit up the evening sky. The event was witnessed by a number of observers and was caught on webcam video.

When it was first detected, the asteroid was nearly as far away as the Moon’s orbit, although that was not initially known. The asteroid appeared as a streak in the series of time-exposure images taken by the Catalina telescope . As is the case for all asteroid-hunting projects, the data were quickly sent to the Minor Planet Center in Cambridge, Massachusetts, which calculated a preliminary trajectory indicating the possibility of an Earth impact. The data were in turn sent to the Center for Near-Earth Object Studies (CNEOS) at NASA’s Jet Propulsion Laboratory in Pasadena, California, where the automated Scout system also found a high probability that the asteroid was on an impact trajectory. Automated alerts were sent out to the community of asteroid observers to obtain further observations, and to the Planetary Defense Coordination Office at NASA Headquarters in Washington. However, since the asteroid was determined to be so small and therefore harmless, no further impact alerts were issued by NASA.

The video at the link makes it appear that the asteroid has hit the ground, but that is not what happened.

Leave a comment

The surface properties of 122 asteroids revealed

1:12 pm

Using archive data produced by the Wide-field Infrared Explorer telescope (WISE, renamed NEOWISE) astronomers have been able to estimate the surface properties of 122 small asteroids located in the asteroid belt.

“Using archived data from the NEOWISE mission and our previously derived shape models, we were able to create highly detailed thermophysical models of 122 main belt asteroids,” said Hanuš, lead author of the paper. “We now have a better idea of the properties of the surface regolith and show that small asteroids, as well as fast rotating asteroids, have little, if any, dust covering their surfaces.” (Regolith is the term for the broken rocks and dust on the surface.)

It could be difficult for fast-rotating asteroids to retain very fine regolith grains because their low gravity and high spin rates tend to fling small particles off their surfaces and into space. Also, it could be that fast-rotating asteroids do not experience large temperature changes because the sun’s rays are more rapidly distributed across their surfaces. That would reduce or prevent the thermal cracking of an asteroid’s surface material that could cause the generation of fine grains of regolith. [emphasis mine]

If this conclusion holds, it means that mining these asteroids might be much easier. Dust can be a big problem, as it can clog up equipment and interfere with operations. It also acts to hide the underlying material, making it harder to find the good stuff.

Leave a comment

Pluto formed from a billion comets?

9:09 am

Scientists have come up with a new theory for the origin of Pluto, based on data from New Horizons and Rosetta, that suggests the planets formed from the accretion of a billion comets or Kuiper Belt objects.

“We’ve developed what we call ‘the giant comet’ cosmochemical model of Pluto formation,” said Dr. Christopher Glein of SwRI’s Space Science and Engineering Division. The research is described in a paper published online today in Icarus. At the heart of the research is the nitrogen-rich ice in Sputnik Planitia, a large glacier that forms the left lobe of the bright Tombaugh Regio feature on Pluto’s surface. “We found an intriguing consistency between the estimated amount of nitrogen inside the glacier and the amount that would be expected if Pluto was formed by the agglomeration of roughly a billion comets or other Kuiper Belt objects similar in chemical composition to 67P, the comet explored by Rosetta.”

This is only a hypothesis, but it is intriguing. It suggests that Pluto’s make-up came only from the outer parts of the solar system, thus constraining how much mixing between the solar system’s inner and outer regions occurred. For scientists trying to understand the formation of the entire solar system, this lack of mixing would be significant. It means that the gas giants, while migrating inward, never migrated outward.

5 comments

Why jets formed on Comet 67P/C-G

9:02 am

Scientists analyzing the data produced by Rosetta while it was flying in formation with Comet 67P/C-G have determined that the comet’s complex topology acted almost like nozzles to encourage evaporating material to form jets.

The new study shows for the first time that mainly the unusual shape and jagged topography of the comet are responsible for this phenomenon. The researchers analyzed images at different observation geometries of the Hapi region located on the “neck” of the comet, the narrow part connecting its two lobes. In computer simulations, they were able to reproduce these images thus gaining a better understanding of the driving processes.

In particular, two effects proved to be decisive. Some regions on the surface are located at lower altitudes or in the shade. The first rays of sunlight reach them later. In contrast, the frost evaporates particularly efficiently from the early and strongly illuminated regions. In addition, pits and other concave structures virtually concentrate gas and dust emissions – much like an optical lens.

This means that predicting the evaporation patterns on other comets will require first obtaining a detailed map of the surface, showing both its topography and make-up. This also means that any future explorers will first have to send a robot scouting mission so that they can plan a safe arrival during active periods.

One comment

Asteroid that formed in the inner solar system discovered in Kuiper Belt

9:24 am

Astronomers have discovered a carbonaceous asteroid in the distant Kuiper Belt beyond Pluto, even though it likely formed in the inner solar system.

The asteroid’s existence serves to confirm models of the solar system’s formation that say that the orbits of gas giants migrate inward and outward during the formation process, and as they do so they can fling material out of the inner solar system. This asteroid is the first evidence of this process.

At the same time, the data here is quite slim. They have only found one such asteroid. It could be that it was flung into the Kuiper Belt by other processes. If the formation model is correct, many more such Kuiper Belt asteroids will be eventually be found.

Leave a comment

Diamonds from space!

9:46 am

Researchers have discovered nano-sized diamonds inside a recovered meteorite that suggest a formation process deep within a planet at least the size of Mercury.

The researchers used transmission electron microscopes to determine their composition and morphology, and found that the diamonds contained inclusions (impurities) made of chromite, phosphate and iron-nickel sulfides.

These inclusions are common in diamonds formed underground here on Earth, but this marks the first time they’ve been found in alien rocks. That’s interesting enough on its own, but it has much bigger implications – the team calculated that these diamonds could only have formed under pressure of more than 20 gigapascals. That means they must have been born inside a planet at least as big as Mercury, and possibly up to the size of Mars.

But there’s still more to the story. The fact these diamonds made it to Earth implies that their home planet, whatever it may have been, is no longer with us, since it would take quite a cataclysm to wrench them out of their birthplace deep underground and fling them into space. Instead, the team believes the diamonds came from a planetary embryo.

Not so fast. Though the researchers themselves, in the released paper, assume that the diamonds could only have formed from inside a now destroyed large planet, this leaves out the possibility that the diamonds formed inside one of the existing terrestrial planets, were moved upward toward the surface by later geological process (as happens to diamonds are here on Earth), and then were thrown from the planet by a later nearby impact. This scenario is just as likely.

Nonetheless, this discovery is fascinating. More than anything, it illustrates the inconceivable amount of time that has passed in creating our solar system. Any of these scenarios requires time, time in quantities that no human can really understand or conceptualize.

2 comments

Star’s close approach 70,000 years ago pinned to cometary orbits

10:03 am

Astronomers now think they have pinned the orbits of about 340 comets to another star’s close approach to our solar system 70,000 years ago.

About 70,000 years ago, when the human species was already on Earth, a small reddish star approached our solar system and gravitationally disturbed comets and asteroids. Astronomers from the Complutense University of Madrid and the University of Cambridge have verified that the movement of some of these objects is still marked by that stellar encounter. At a time when modern humans were beginning to leave Africa and the Neanderthals were living on our planet, Scholz’s star – named after the German astronomer who discovered it – approached less than a light-year from the Sun. Nowadays it is almost 20 light-years away, but 70,000 years ago it entered the Oort cloud, a reservoir of trans-Neptunian objects located at the confines of the solar system.

This discovery was made public in 2015 by a team of astronomers led by Professor Eric Mamajek of the University of Rochester (USA). The details of that stellar flyby, the closest documented so far, were presented in The Astrophysical Journal Letters.

Now two astronomers from the Complutense University of Madrid, the brothers Carlos and Raúl de la Fuente Marcos, together with the researcher Sverre J. Aarseth of the University of Cambridge (United Kingdom), have analyzed for the first time the nearly 340 objects of the solar system with hyperbolic orbits (very open V-shaped, not the typical elliptical), and in doing so they have detected that the trajectory of some of them is influenced by the passage of Scholz´s star.

It is likely that the close approach influenced a lot more objects, many of which might not have yet arrived in the inner solar system. Moreover, their computer models suggest that the star might have come closer to the Sun than 0.6 light years.

8 comments

Scientists theorize that Oumuamua came from a binary star system

8:17 am

Based on statistics and computer modeling, some scientists believe that the interstellar object Oumuamau likely came from stellar binary system.

For the new study, published in the journal Monthly Notices of the Royal Astronomical Society, Jackson and his co-authors set about testing how efficient binary star systems are at ejecting objects. They also looked at how common these star systems are in the Galaxy. They found that rocky objects like ‘Oumuamua are far more likely to come from binary than single star systems. They were also able to determine that rocky objects are ejected from binary systems in comparable numbers to icy objects.

Their conclusion does make sense, though any good scientist would retain a gigantic sense of skepticism. While it is statistically reasonable to conclude that a majority of interstellar objects should come from binary systems, there is no guarantee that Oumuamua in particular did so. Even if the odds were one in a million, there is always that one, and the universe often seems prone to fooling us.

One comment

Dawn finds recent changes on Ceres

4:28 pm

New data from Dawn has found at least one spot on Ceres where recent changes appear to have occurred on the surface.

Observations obtained by the visible and infrared mapping spectrometer (VIR) on the Dawn spacecraft previously found water ice in a dozen sites on Ceres. The new study revealed the abundance of ice on the northern wall of Juling Crater, a crater 12 miles (20 kilometers) in diameter. The new observations, conducted from April through October 2016, show an increase in the amount of ice on the crater wall. “This is the first direct detection of change on the surface of Ceres,” said Andrea Raponi of the Institute of Astrophysics and Planetary Science in Rome.

Raponi led the new study, which found changes in the amount of ice exposed on the dwarf planet. “The combination of Ceres moving closer to the sun in its orbit, along with seasonal change, triggers the release of water vapor from the subsurface, which then condenses on the cold crater wall. This causes an increase in the amount of exposed ice. The warming might also cause landslides on the crater walls that expose fresh ice patches.”

There is a certain irony here. For eons, the only alien body that humans were able to get a good look at, the Moon, was also an object where almost nothing changed. Even today, after humans have visited its surface and numerous orbiting spacecraft have photographed its surface in numbing detail, the Moon has generally been found to be stable and unchanging. Though impacts do occur, and the surface does evolve over time, the Moon is probably one of the most static bodies in the solar system.

The irony is that this lunar stability gave us an incorrect impression of the rest of the solar system. Based on the Moon, it was assumed that airless or almost airless bodies like Mercury, Mars, Pluto, the large moons of Jupiter and Saturn, and asteroids like Ceres would also be stable and unchanging. What we have instead found is that the Moon is the exception that proves the rule. Most of these other worlds are unlike the Moon. They show a lot of surface evolution, over relatively short time scales. They change.

Leave a comment

Funding shortfall causes Planetary Resources to cut back

8:32 am

Because of their failure to close a round of investment fund-raising, Planetary Resources has been forced to cut back, including some layoffs and delaying several proposed later missions.

The delayed investment, though, forced Planetary Resources to lay off some of its employees. Lewicki declined to say how many were let go from a peak of 70 employees prior to the layoffs.

That setback also affects the schedule for future asteroid prospecting missions. In his conference talk, Lewicki showed a video of a planned mission where several small spacecraft, launched as secondary payloads, fly to near Earth asteroids to measure their water content. In past presentations featuring that video, company officials said the mission was scheduled for launch in 2020.

However, Lewicki didn’t state in this talk when that mission would launch, and acknowledged later the funding problems would delay it until some time after 2020. “The 2020 date was assuming we would get all the necessary financing on schedule last year,” he said.

To me, this article illustrates why Planetary Resources failed to obtain its investment funds. They pitch themselves as an asteroid mining company, but very little of what they are doing has anything to do with actual mining, or obtaining profits from that mining. At the moment, they remain an Earth observation company with capabilities not as good as a host of other similar companies expressly dedicated to this task.

I say this not because I am against asteroid mining, or think it cannot make a profit. I just think Planetary Resources has oversold itself, which can be deadly in the harsh competitive market.

2 comments

Interstellar object Oumuamua tumbling chaotically

8:46 am

A new analysis of the data obtained when the interstellar object Oumuamua flew through the solar system in October 2016 suggests that it is tumbling in a chaotic manner, and that the surface is spotty.

Straight away, they discovered that ‘Oumuamua wasn’t spinning periodically like most of the small asteroids and bodies that we see in our solar system. Instead, it is tumbling, or spinning chaotically, and could have been for many billions of years.

While it is difficult to pinpoint the exact reason for this, it is thought that `Oumuamua impacted with another asteroid before it was fiercely thrown out of its system and into interstellar space. Dr Fraser explains: “Our modelling of this body suggests the tumbling will last for many billions of years to hundreds of billions of years before internal stresses cause it to rotate normally again.

To me, this data settles the question about whether Oumuamua is not an artificial structure. It is not. If it were, an impact that would have caused this kind of tumbling would have almost certainly destroyed it. Instead, it likely broke the original bolide up, producing many fragments, including Oumuamua and its elongated shape.

As for the object’s spottiness:

Dr Fraser explains: “Most of the surface reflects neutrally but one of its long faces has a large red region. This argues for broad compositional variations, which is unusual for such a small body.”

It is really a shame we couldn’t get a closer look before it sped away.

Leave a comment

New Horizons takes the most distant pictures from Earth ever taken

8:43 am

Kuiper Belt Object 2012 HE85

The New Horizons science team has released three images taken by the spacecraft from almost 3.8 billion miles from Earth, the most distant images ever taken.

The routine calibration frame of the “Wishing Well” galactic open star cluster, made by the Long Range Reconnaissance Imager (LORRI) on Dec. 5, was taken when New Horizons was 3.79 billion miles (6.12 billion kilometers, or 40.9 astronomical units) from Earth – making it, for a time, the farthest image ever made from Earth.

…LORRI broke its own record just two hours later with images of Kuiper Belt objects 2012 HZ84 and 2012 HE85 – further demonstrating how nothing stands still when you’re covering more than 700,000 miles (1.1 million kilometers) of space each day.

The images themselves are not spectacular to look at, though the two images of two different Kuiper Belt objects are the best ever taken of such objects, and certainly contain data that scientists will be able to use. The image on the right is one of these objects, 2012 HE85. For example, note how it does not appear to be round.

This exercise is in preparation for the January 1, 2019 fly-by of 2014 MU69, where the images will be sharp and detailed, and provide us a good look at such a distant object.

3 comments

Fractures in the floor of Occator Crater

9:42 am

Fractures in floor of Occator Crater

Cool image time! The Dawn science team has released an image of Ceres, cropped to post here in the right, that shows a spiderweb of fractures radiating out from a single point in the floor of Occator Crater.

These fractures have been interpreted as evidence that material came up from below and formed a dome shape, as if a piston was pushing Occator’s floor from beneath the surface. This may be due to the upwelling of material coming from Ceres’ deep interior. An alternative hypothesis is that the deformation is due to volume changes inside a reservoir of icy magma in the shallow subsurface that is in the process of freezing, similar to the change in volume that a bottle of water experiences when put in a freezer.

In the image sunlight is coming from the right. This fractured area can be seen in this earlier simulated oblique image of Occator Crater, in the southwest corner of the crater floor, well away from the crater’s more well known bright areas.

One comment

Arecibo returns to operation with images of asteroid Phaethon

10:02 am

The Arecibo Observatory in Puerto Rico has resumed science observations after recovering from Hurricane Maria with new radio images of the asteroid Phaethon.

After several months of downtime after Hurricane Maria blew through, the Arecibo Observatory Planetary Radar has returned to normal operation, providing the highest-resolution images to date of near-Earth asteroid 3200 Phaethon during its Dec. 16 flyby of Earth. The radar images, which are subtle at the available resolution, reveal the asteroid is spheroidal in shape and has a large concavity at least several hundred meters in extent near the leading edge, and a conspicuous dark, circular feature near one of the poles. Arecibo’s radar images of Phaethon have resolutions as fine as about 250 feet (75 meters) per pixel.

The images also revealed that Phaethon, which is considered a potentially hazardous near Earth asteroid, is about 3.6 miles across and is about a half mile larger than previously believed.

Leave a comment

Oumuamua has a thick carbon crust built up by its interstellar travel

8:59 am

New results of observations of the interstellar object Oumuamua suggest that it has a thick crust of organic carbon soot that was slowly built up during the millions of years it traveled between the stars.

New observations of the cigar-shaped body found evidence for a deep surface layer that formed when organic ices – such as frozen carbon dioxide, methane and methanol – that make up the object were battered by the intense radiation that exists between the stars.

…The deep outer crust may have formed on the body over millions or even billions of years and gives ‘Oumuamua a dark red colour, according to researchers who investigated the object with the William Herschel Telescope on La Palma in the Canary Islands and the European Southern observatory in Chile’s Atacama desert.

There have been a slew of news stories today about these results, all focusing not on the crust of the object, which tells us nothing really about its interior, but on one quote by one scientist from the press release, who theorized — based on zero data — that the interior of the object could be icy. From this quote I have seen at least a half dozen stories exclaiming that Oumuamua thus could be like a comet, based on no information at all.

All we have learned is that traveling for a long time in interstellar space causes a build up of carbon-rich materials on the surface of an object. What might be hidden under that crust remains entirely unknown. It could be icy, but we don’t know that.

5 comments

A variety of geological activity caused bright areas on Ceres

10:33 am

Occator Crater

Based on the data obtained of Ceres from Dawn scientists have concluded that a variety of geological activities caused the bright areas on the planet, and that some of those activities could still be happening today.

Since Dawn arrived in orbit at Ceres in March 2015, scientists have located more than 300 bright areas on Ceres. A new study in the journal Icarus, led by Nathan Stein, a doctoral researcher at Caltech in Pasadena, California, divides Ceres’ features into four categories.

The first group of bright spots contains the most reflective material on Ceres, which is found on crater floors. The most iconic examples are in Occator Crater [shown in the image above, reduced and cropped to post here], which hosts two prominent bright areas. Cerealia Facula, in the center of the crater, consists of bright material covering a 6-mile-wide (10-kilometer-wide) pit, within which sits a small dome. East of the center is a collection of slightly less reflective and more diffuse features called Vinalia Faculae. All the bright material in Occator Crater is made of salt-rich material, which was likely once mixed in water. Although Cerealia Facula is the brightest area on all of Ceres, it would resemble dirty snow to the human eye.

More commonly, in the second category, bright material is found on the rims of craters, streaking down toward the floors. Impacting bodies likely exposed bright material that was already in the subsurface or had formed in a previous impact event.

Separately, in the third category, bright material can be found in the material ejected when craters were formed.

The mountain Ahuna Mons gets its own fourth category — the one instance on Ceres where bright material is unaffiliated with any impact crater. This likely cryovolcano, a volcano formed bythe gradual accumulation of thick, slowly flowing icy materials, has prominent bright streaks on its flanks.

The report is somewhat vague about why they think that there might be some geological activity even today.

The image above, released as part of this press release, gives us a simulated oblique look at Occator Crater and its bright areas. It is definitely worth it to look at the full resolution image.

3 comments

The organic dust of Comet 67P/C-G

11:36 am

A study of the dust released by Comet 67P/C-G and captured by Rosetta shows that carbon molecules appear to comprise the comet’s largest component, and that this material is found in the form of very large macromolecules.

As the study shows, organic molecules are among those ingredients at the top of the list. These account for about 45 percent of the weight of the solid cometary material. “Rosetta’s comet thus belongs to the most carbon-rich bodies we know in the solar system,” says MPS scientist and COSIMA team member Dr. Oliver Stenzel. The other part of the total weight, about 55 percent, is provided by mineral substances, mainly silicates. It is striking that they are almost exclusively non-hydrated minerals i.e. missing water compounds. “Of course, Rosetta’s comet contains water like any other comet, too,” says Hilchenbach. “But because comets have spent most of their time at the icy rim of the solar system, it has almost always been frozen and could not react with the minerals.” The researchers therefore regard the lack of hydrated minerals in the comet’s dust as an indication that 67P contains very pristine material.

…The current findings also touch on our ideas of how life on Earth came about. In a previous publication, the COSIMA team was able to show that the carbon found in Rosetta’s comet is mainly in the form of large, organic macromolecules. Together with the current study, it becomes clear that these compounds make up a large part of the cometary material. Thus, if comets indeed supplied the early Earth with organic matter, as many researchers assume, it would probably have been mainly in the form of such macromolecules.

Organic here does not mean life, but is instead used as chemists use it, to mean the molecule includes the element carbon. The results do suggest however that the early solar system had a lot of carbon available, and that much of it was in a relatively pure form available to interact with other elements.

3 comments

Interstellar object resembles asteroid

6:43 pm

Astronomers who have been observing the interstellar object that zipped past the Sun last month have concluded that it mostly resembles asteroids seen in our own solar system.

From its changing brightness, the team inferred that U1 is highly elongated with rough dimensions 30m x 30m x 180m. About twice the height of the Statue of Liberty, the 6:1 aspect ratio of U1 is “similar to the proportions of a fire extinguisher — although U1 is not as red as that,” says David Jewitt (UCLA), the first author of the study.

“With such an elongated shape, U1 probably needs a little cohesive strength to hold it together. But that’s not really unusual,” remarked study coauthor Jayadev Rajagopal (National Optical Astronomy Observatory). Commenting on its size, rotation, and color, Rajagopal mused that, “the most remarkable thing about U1 is that, except for its shape, how familiar and physically unremarkable it is.”

I wonder if they are still tracking it.

4 comments
1 … 13 14 15 16 17 … 30