Tag Archives: asteroids

Ahuna Mons, Ceres’s biggest mountain, is an ice volcano

Ahuna Mons

Using data from Dawn scientists have concluded that Ceres’s biggest mountain, Ahuna Mons (shown on the right), was created by water volcanism.

“Ahuna is the one true ‘mountain’ on Ceres,” said David A. Williams, associate research professor in Arizona State University’s School of Earth and Space Exploration. “After studying it closely, we interpret it as a dome raised by cryovolcanism.” This is a form of low-temperature volcanic activity, where molten ice — water, usually mixed with salts or ammonia — replaces the molten silicate rock erupted by terrestrial volcanoes. Giant mountain Ahuna is a volcanic dome built from repeated eruptions of freezing salty water.

The implications of this fact are important, as it suggests that Ceres’s interior was warm enough for long periods, enough to melt ice. Where that heat came from however is a mystery, considering the dwarf planet’s small size.

Dawn moves to higher orbit around Ceres

In order to save fuel as well as obtain a different view of Ceres, engineers are moving Dawn to a higher orbit.

On Sept. 2, Dawn will begin spiraling upward to about 910 miles (1,460 kilometers) from Ceres. The altitude will be close to where Dawn was a year ago, but the orientation of the spacecraft’s orbit — specifically, the angle between the orbit plane and the sun — will be different this time, so the spacecraft will have a different view of the surface.

New and very distance outer solar system objects beyond Neptune

Astronomers have discovered several new objects orbiting the Sun at extremely great distances beyond the orbit of Neptune.

The most interesting new discovery is 2014 FE72:

Another discovery, 2014 FE72, is the first distant Oort Cloud object found with an orbit entirely beyond Neptune. It has an orbit that takes the object so far away from the Sun (some 3000 times farther than Earth) that it is likely being influenced by forces of gravity from beyond our Solar System such as other stars and the galactic tide. It is the first object observed at such a large distance.

This research is being done as part of an effort to discover a very large planet, possibly as much as 15 times the mass of Earth, that the scientists have proposed that exists out there.

Costs rise on Obama’s asteroid mission

The year delay in Obama’s as yet unfunded unmanned asteroid mission, a preliminary to a proposed manned asteroid mission, has caused its budget to grow from $1.25 billion to $1.4 billion.

More significantly,

NASA’s cost estimate for [the unmanned] ARRM excludes launch and operations. In a March 2016 report, the Government Accountability Office (GAO) review of NASA’s major programs showed a cost of $1.72 billion. Gates explained that the $1.72 billion includes the launch vehicle cost, set at approximately $500 million as a placeholder since NASA has not determined which of three launch vehicles will be used (Delta IV Heavy, Falcon Heavy, or the Space Launch System).

…The next administration will have to decide if the costs are worth the benefits. Although NASA has decided they are, the House Appropriations Committee disagrees. It denied funding for the program in its report on the FY2017 Commerce-Justice-Science (CJS) appropriations bill, which funds NASA. The bill has not passed the House yet, however, and there is no similar language in the Senate version, so NASA is not currently prohibited from spending money on the project.

So far, NASA has been funding this Obama project by stealing money from other projects in NASA, since Congress has consistently refused to appropriate extra money for it. This approach has worked up until now, as they are only funding initial design work. Where they think they will get the money for a full mission however remains a complete mystery to me.

Ceres lacks large craters

The uncertainty of science: Using data from Dawn, scientists have found that the solar system’s largest asteroid, Ceres (also called a dwarf planet by confused scientists), has a mysterious lack of large craters.

Marchi and colleagues modeled collisions of other bodies with Ceres since the dwarf planet formed, and predicted the number of large craters that should have been present on its surface. These models predicted Ceres should have up to 10 to 15 craters larger than 250 miles (400 kilometers) in diameter, and at least 40 craters larger than 60 miles (100 kilometers) wide. However, Dawn has shown that Ceres has only 16 craters larger than 60 miles, and none larger than 175 miles (280 kilometers) across.

They postulate two theories to explain the lack. First, Ceres might have formed far out beyond Neptune, though this theory is not favored because some models still say that even here Ceres should have large craters. Second,

One reason for the lack of large craters could be related the interior structure of Ceres. There is evidence from Dawn that the upper layers of Ceres contain ice. Because ice is less dense than rock, the topography could “relax,” or smooth out, more quickly if ice or another lower-density material, such as salt, dominates the subsurface composition. Recent analysis of the center of Ceres’ Occator Crater suggests that the salts found there could be remnants of a frozen ocean under the surface, and that liquid water could have been present in Ceres’ interior.

Past hydrothermal activity, which may have influenced the salts rising to the surface at Occator, could also have something to do with the erasure of craters. If Ceres had widespread cryovolcanic activity in the past — the eruption of volatiles such as water — these cryogenic materials also could have flowed across the surface, possibly burying pre-existing large craters. Smaller impacts would have then created new craters on the resurfaced area.

This theory doesn’t really work that well either, because it fails to explain why only the big craters got erased.

More bright spots on Ceres

More bright spots on Ceres

Cool image time! The most recently released Dawn image of Ceres, cropped on the right, included these bright streaks running down the side of an unnamed crater. They are especially intriguing because they so much resemble the seepage lines scientists have found on slopes on Mars. On Mars the lines appear to come and go on a seasonal basis, while on Ceres they appear to have been caused by a one-time event, after which not much has changed. In both cases, however, they appear to be caused by some liquid seepage that came from below the surface.

NASA okays New Horizons mission extension, rejects Dawn asteroid fly-by

NASA has approved an extension of the New Horizons mission to fly past Kuiper Belt object 2014 MU69 on January 1, 2019.

In the same press release the agency announced that they have decided that they will get more worthwhile science by keeping Dawn in orbit around Ceres for the reminder of its life, rather then sending it on a proposed fly by of another asteroid.

Rosetta’s finale set for September 30

The Rosetta science team has set September 30th as the date when they will complete the spacecraft’s mission with a controlled descent onto Comet 67P/C-G’s surface.

Unlike in 2011, when Rosetta was put into a 31-month hibernation for the most distant part of its journey, this time it is riding alongside the comet. Comet 67P/Churyumov-Gerasimenko’s maximum distance from the Sun (over 850 million km) is more than Rosetta has ever journeyed before. The result is that there is not enough power at its most distant point to guarantee that Rosetta’s heaters would be able to keep it warm enough to survive.

Instead of risking a much longer hibernation that is unlikely to be survivable, and after consultation with Rosetta’s science team in 2014, it was decided that Rosetta would follow its lander Philae down onto the comet. The final hours of descent will enable Rosetta to make many once-in-a-lifetime measurements, including very-high-resolution imaging, boosting Rosetta’s science return with precious close-up data achievable only through such a unique conclusion. Communications will cease, however, once the orbiter reaches the surface, and its operations will then end.

The decision to end the mission this way makes great sense. I only question their decision to purposely end all communications upon impact. Though it is likely that communications will be lost anyway, wouldn’t it be better to try to get data back, like the scientists did with the American NEAR spacecraft when it touched down on the asteroid Eros at the end of its mission?

Dawn data suggests recent hydrothermal activity on Ceres

New data from Dawn now suggests that the bright spot in Occator Crater on Ceres contains the highest concentration of carbonate materials found so far outside of Earth, and was caused by recent hydrothermal activity.

De Sanctis’ study finds that the dominant mineral of this bright area is sodium carbonate, a kind of salt found on Earth in hydrothermal environments. This material appears to have come from inside Ceres, because an impacting asteroid could not have delivered it. The upwelling of this material suggests that temperatures inside Ceres are warmer than previously believed. Impact of an asteroid on Ceres may have helped bring this material up from below, but researchers think an internal process played a role as well.

More intriguingly, the results suggest that liquid water may have existed beneath the surface of Ceres in recent geological time. The salts could be remnants of an ocean, or localized bodies of water, that reached the surface and then froze millions of years ago.

Moon discovered orbiting Kuiper Belt Object Makemake

Worlds without end: Astronomers have discovered a moon orbiting Makemake, the fouth largest object in the Kuiper Belt.

A nearly edge-on orbital configuration helped it evade detection, placing it deep within the glare of the icy dwarf during a substantial fraction of its orbit. Makemake is one of the largest and brightest known Kuiper Belt Objects (KBOs), second only to Pluto. The moon is likely less than 100 miles wide while its parent dwarf planet is about 870 miles across. Discovered in 2005, Makemake is shaped like football and sheathed in frozen methane.

Tracking this moon’s orbit will help astronomers get a better understanding of Makemake itself, whose oblong shape has baffled them since its discovery.

Ceres’s brightest spot

Brightest Spot in Occator Crater on Ceres

Cool image time: While I was in Washington the Dawn science team released a very nice close-up image of the bright spots inside Occator Crater on Ceres. On the right is a cropped version which focuses solely on the central brightest spot. The spot appears to overlie a central dome with a depression in the middle. Other data says the spot is the low area in the crater, and the linear cracks that radiate away as well as in concentric rings around the spot suggest that this central area has subsided, causing those cracks.

Make sure you look at the full image, as it includes the other smaller spots that are also inside Occator.

Newly discovered asteroid quasi-moon of Earth

A newly discovered asteroid has a solar orbit that makes it Earth’s constant companion.

As it orbits the sun, this new asteroid, designated 2016 HO3, appears to circle around Earth as well. It is too distant to be considered a true satellite of our planet, but it is the best and most stable example to date of a near-Earth companion, or “quasi-satellite.”

“Since 2016 HO3 loops around our planet, but never ventures very far away as we both go around the sun, we refer to it as a quasi-satellite of Earth,” said Paul Chodas, manager of NASA’s Center for Near-Earth Object (NEO) Studies at the Jet Propulsion Laboratory in Pasadena, California. “One other asteroid — 2003 YN107 — followed a similar orbital pattern for a while over 10 years ago, but it has since departed our vicinity. This new asteroid is much more locked onto us. Our calculations indicate 2016 HO3 has been a stable quasi-satellite of Earth for almost a century, and it will continue to follow this pattern as Earth’s companion for centuries to come.”

The asteroid is thought to be between 120 to 300 feet across.

Planetary Resources has raised $21 million

The competition heats up: Planetary Resources, the company that claims its goal is to mine asteroids, has raised $21 million to build and launch an Earth resources satellite.

They plan to create a 10-satellite constellation to provide this data commercially.

While everything this company is doing will eventually make asteroid mining easier and more effective, nothing they are doing now has anything to do with mining asteroids. Their first project was to build a prototype orbiting telescope to look for asteroids. This second project will sell data about the Earth.

Luxembourg signs deal with asteroid mining company

The competition heats up: As part of its outer space development program, the government of Luxembourg has signed a deal with asteroid mining company Deep Space, Inc. to build an orbital demonstration test satellite.

The inaugural project of this exciting new partnership is Prospector-X™, an experimental, low Earth orbit technology demonstration mission, designed to test the company’s innovative deep space technology. These key enabling technologies will be instrumental to the success of the company’s first deep space resource exploration missions in the near future. The Prospector-X spacecraft will be built at Deep Space Industries’ new European headquarters, in Luxembourg, in conjunction with the company’s international and American partners, including the Interdisciplinary Centre for Security, Reliability, and Trust (SnT) at the University of Luxembourg.

It essentially appears that Luxembourg is creating its own space program, focused entirely on profit by acting as the venture capitalist for private commercial companies. Most interesting.

Hubble discovers moon circling Kuiper belt object

Worlds without end: Hubble has spotted a small moon orbiting the distant Kuiper Belt object Makemake.

The moon — provisionally designated S/2015 (136472) 1 and nicknamed MK 2 — is more than 1,300 times fainter than Makemake. MK 2 was seen approximately 13,000 miles from the dwarf planet, and its diameter is estimated to be 100 miles across. Makemake is 870 miles wide. The dwarf planet, discovered in 2005, is named for a creation deity of the Rapa Nui people of Easter Island.

The asteroid didn’t do it all

The uncertainty of science: A new study adds weight to the theory that the dinosaurs were already in decline when the asteroid hit 65 million years ago.

While some have argued that dinosaurs began petering out some 5 million or 10 million years before their final doom, the new paper suggests it started happening much earlier, maybe 50 million years before the asteroid catastrophe. In terms of species, “they were going extinct faster than they could replace themselves,” said paleontologist Manabu Sakamoto of the University of Reading in England. He led a team of British scientists who analyzed three large dinosaur family trees, looking for evidence of when extinctions began to outnumber the appearances of new species.

They found that starting to happen about 50 million years before the asteroid for most groups of dinosaurs. Two other groups showed increases rather than declines; if their results are included, the overall time for the start of dinosaur decline shrinks to 24 million years before the final demise.

I wrote a science article on this subject back in 1999, and even then the science was far from settled, with most paleontologists strongly arguing that the asteroid was only the final blow and that many other factors, including the big volcano eruption in India about that time, also contributed to the dinosaur’s extinction. That journalists and the planetary science community have pushed the asteroid as the sole factor in that extinction has been a disservice to science. The science has never been that certain.

Update on Dawn at Ceres

Link here. Though the story initially focuses on the possibility that the mission might be extended a few extra months until the spacecraft’s fuel runs out, it also gives a good summary of what has been learned so far about the dwarf planet, including the theory that Ceres was once an “ocean world.”

[Carol Raymond, Dawn’s deputy principal investigator,] said Ceres appears to be a former ocean world and could have once been similar to Europa or Enceladus, the icy moons of Jupiter and Saturn. “One of the things that we anticipated about Ceres before getting there is that it’s a former ocean world,” Raymond said. “We’re so interested in going to Europa and Enceladus, and these other interesting objects in the outer solar system because we think they harbor subsurface oceans at present, and possible habitable environments, and possibly even locations where there’s extant life.

“Ceres appears to have been one of those objects in the past, when it was younger and hotter,” Raymond said. “What we’re looking at now is, we believe, the remnant of a frozen ocean. The salt is left over from the brines that were concentrated as the ocean froze out, so it’s all a fairly consistent story that Ceres is a former ocean (world) where the ocean froze, and now we’re interrogating the chemistry, essentially, of that ocean-rock interface through the subsurface layers that we’re detecting on Ceres.”

The data has found the high latitudes to have lots of hydrogen, suggesting water-ice on or near the surface. The bright salt patches also suggest frozen water below the surface that left behind the salt when it reached the surface and evaporated away.

WISE completes another year of asteroid hunting

After being mothballed in space and then reactivated, NASA’s WISE infrared telescope (renamed NEOWISE for no good reason) has now completed its second year of observations, looking for near-Earth objects (NEOs).

NASA’s Near-Earth Object Wide-field Survey Explorer (NEOWISE) mission has released its second year of survey data. The spacecraft has now characterized a total of 439 NEOs since the mission was re-started in December 2013. Of these, 72 were new discoveries. Near-Earth Objects (NEOs) are comets and asteroids that have been nudged by the gravitational attraction of the giant planets in our solar system into orbits that allow them to enter Earth’s neighborhood. Eight of the objects discovered in the past year have been classified as potentially hazardous asteroids (PHAs), based on their size and how closely their orbits approach Earth. [emphasis mine]

Unfortunately, the press release does not provide any details about those eight potentially hazardous asteroids.

A possible impact on Jupiter?

On March 17 two different amateur astronomers have taken videos of a bright flash on Jupiter which suggests something had crashed into the gas giant.

March 17th’s impact, if the evidence for it holds up, becomes the fourth such event in the past decade. The largest of these occurred July 19, 2009, and it left a distinctly dark “powder burn” in Jupiter’s upper atmosphere first spotted by Australian astro-imager Anthony Wesley. That was followed by three lesser strikes on June 3, 2010 (recorded independently by Wesley and Christopher Go); on August 10, 2010 (independently seen by Masayuki Tachikawa and Kazuo Aoki); and on September 10, 2012 (seen visually by Dan Petersen and independently recorded by George Hall).

Counting the historic multiple-hit crash of Comet Shoemaker-Levy 9 in July 1994, that’s a grand total of six impacts on Jupiter in the past 22 years.

New Horizons’ future research goals

On Monday at a planetary science conference Alan Stern, the project scientist for New Horizons, outlined the science goals in studying the Kuiper Belt should the spacecraft’s mission be extened through 2021.

The main goal will be the January 1, 2019 fly-by of Kuiper Belt object 2014 MU69, estimated to be between 12 to 24 miles across. However, the proposal also includes the following:

“In addition to making a close flyby of MU69, we’re also going to be close enough in range to study quite a number of other small KBOs, and some large ones that are on the Pluto scale,” Stern said. New Horizons will be able to study them in ways that could never be accomplished from Earth. The closeness of the spacecraft will enable high resolution observations, and the ability to look for satellites that cannot be seen from Earth observatories or with the Hubble Telescope.

“Because we are looking back on the rest of the solar system, at the Kuiper Belt and the Centaur Population,” Stern said, “we’re going to be able to study another 18 or 20 small bodies to determine whether or not the recently discovered rings around the centaur Chariklo are a common occurrence, or something anomalous. And I don’t know of any other way over the next several years, except through New Horizons, that we can develop a data set like that.”

What I find amazing is that it appears from Stern’s remarks that NASA has not yet approved this proposal. Before the team discovered 2014 MU69, I would have been more skeptical about extending the mission, but since they will be able to do a close fly-by of a type of object never before seen, and considering the time and cost it takes to get to the Kuiper Belt, it seems foolish now to not approve this mission extension.

New close-up of Occator Crater’s spots

Occator Crater central spot

The Dawn science team have released new images taken from the spacecraft’s low orbit observations, including a close-up of the central white spot at Occator Crater, the brightest spot on Ceres.

The image on the right is a cropped though full resolution version of the full image. I have reduced it only slightly. As they note,

Occator Crater, measuring 57 miles (92 kilometers) across and 2.5 miles (4 kilometers) deep, contains the brightest area on Ceres, the dwarf planet that Dawn has explored since early 2015. The latest images, taken from 240 miles (385 kilometers) above the surface of Ceres, reveal a dome in a smooth-walled pit in the bright center of the crater. Numerous linear features and fractures crisscross the top and flanks of this dome. Prominent fractures also surround the dome and run through smaller, bright regions found within the crater.

Changes in Ceres’s white spots

The uncertainty of science: Ground-based observations of Ceres now suggest that the white spots imaged by Dawn undergo subtle unexpected variations

As Ceres rotates every 9 hours, HARPS is so sensitive that it can detect the very slight Doppler shift in spectrum frequency as the bright spots rotate toward and away Earth, but during observations for 2 nights in July and August 2015, more changes not related to Ceres’ spin were detected. “The result was a surprise,” said co-author Antonino Lanza, also from the INAF–Catania Astrophysical Observatory. “We did find the expected changes to the spectrum from the rotation of Ceres, but with considerable other variations from night to night.”

And it appears that these changes are consistent with some kind of volatile (ice) being exposed to sunlight and venting vapor into space, causing an increase in reflectivity. It seems that when Occator experiences solar heating, plumes are produced and then evaporate, creating a complex spectroscopic signal that evolves during that hemisphere’s daytime. This finding appears to be consistent with earlier observations made by Dawn showing a mysterious haze over Occator.

The problem with this theory is that it assumes the white spots are comprised of water ice. However, data from Dawn has instead suggested that the white spots are not water but salt deposits.

It could be that the white spots are salt left behind when water vented from inside Ceres evaporates away, but so far the data from Dawn has not found any evidence of water at the spots. If it was venting there, Dawn should have seen it.

Ceres’s big mountain

Ahuna Mons on Ceres

The Dawn science team has released an oblique angle image of Ceres’s big mountain, Ahuna Mons. I have cropped and reduced it above to show it here.

Despite looking almost toylike in this image, the mountain is quite monstrous, especially considering Ceres’s relatively small size.

This mountain is about 3 miles (5 kilometers) high on its steepest side. Its average overall height is 2.5 miles (4 kilometers). These figures are slightly lower than what scientists estimated from Dawn’s higher orbits because researchers now have a better sense of Ceres’ topography.

Consider: Mount Everest is not quite six miles high, on a planet with a diameter about 7926 miles across. Ceres however is only about 600 miles across at its widest, which means a 3 mile high mountain is 0.5% of Ceres’s entire width! Such a thing could only occur on such a small body, whose gravity is not quite great enough to force things into a completely spherical shape. It is for this reason it could be argued that Ceres doesn’t qualify as a dwarf planet, but would be better labeled a giant asteroid.

Dawn’s chief engineer reviews the mission

In a long and very detailed post, the chief engineer and mission director of Dawn gives us a very detailed update on the successful state of the spacecraft’s mission.

Not only does he describe what has been gathered at Ceres since the spacecraft arrived a year ago, he gives us this crucial information about the state of this paradigm-shattering ion engine spacecraft, the first to travel to two different objects in the solar system:

Dawn has faced many challenges in its unique voyage in the forbidding depths of space, but it has surmounted all of them. It has even overcome the dire threat posed by the loss of two reaction wheels (the second failure occurring in orbit around Vesta 3.5 years and 1.3 billion miles, or 2.0 billion kilometers, ago). With only two operable reaction wheels (and those no longer trustworthy), the ship’s remaining lifetime is very limited.

A year ago, the team couldn’t count on Dawn even having enough hydrazine to last beyond next month. But the creative methods of conserving that precious resource have proved to be quite efficacious, and the reliable explorer still has enough hydrazine to continue to return bonus data for a while longer. Now it seems highly likely that the spacecraft will keep functioning through the scheduled end of its primary mission on June 30, 2016.

NASA may choose to continue the mission even after that. Such decisions are difficult, as there is literally an entire universe full of interesting subjects to study, but resources are more limited. In any case, even if NASA extended the mission, and even if the two wheels operated without faltering, and even if the intensive campaign of investigating Ceres executed flawlessly, losing not an ounce (or even a gram) of hydrazine to the kinds of glitches that can occur in such a complex undertaking, the hydrazine would be exhausted early in 2017. Clearly an earlier termination remains quite possible.

Dawn has proven the value of ion engines. I would expect to see them used many more times in the future, especially missions heading to low gravity environments.

The cratered surface of Ceres

Craters on Ceres

Cool image time! As Dawn continues its survey of Ceres the science team is beginning to release images looking sideways at the planet, rather than straight down, in order to get a better understanding of the topography. The image to the right is an example. It shows the area around 37-mile-wide Fluusa Crater. I have cropped it to emphasize the most rugged areas, especially the jagged cliff meandering away towards the horizon.

This image provides a hint at the differences between Ceres and the Moon. Up until now Dawn images have given the impression that Ceres is very much like the heavily cratered lunar surface. The terrain in this image however suggests to me that Ceres’ surface crust is much less dense because of the low gravity, and thus has a light puffy feel to it. The Moon’s surface is rarely this uneven, as its higher gravity has pounded things down, smoothing them out somewhat.

Tests confirm meteorite at India impact site

The uncertainty of science: Even as NASA officials poo-poo the suspected meteorite impact in India that killed a bus driver, India scientists have done a chemical analysis of one of the rocks found near the site and found it to be a meteorite fragment.

According to a preliminary report by National College Instrumentation Facility (NCIF) in Trichy, a Scanning Electron Microscope (SEM) study on samples retrieved from the campus in Vellore where the blast occurred shows the “presence of carbonaceous chondrites”.

“Carbonaceous denotes objects containing carbon or its compounds and chondrites refer to non-metallic meteorite parts containing mineral granules,” K Anbarasu, a geologist who is also principal of the Trichy-based National College, told The Indian Express.

There remains uncertainty because the fragments tested did not actually come from the impact crater itself.

Anbarasu said the preliminary SEM study was conducted on “small pieces of black material” found near the blast site. “The crater formed at the spot had been already disturbed by other investigators. So we inspected the entire campus as any meteor incident would scatter several objects across the area before landing. Finally, we spotted several small pieces of this black material, one the size of a paperweight, on the terrace of a building nearby,” Anbarasu said.

Nonetheless, I think it unprofessional and inappropriate for a NASA official to comment on this event half a globe away. There is no way that they can really determine anything from the available photos taken of the impact site, and thus they should shut up.

The first recorded human death from a meteorite?

Officials in India are reporting what could be the first recorded death of a human by meteorite impact.

According to local reports, a bus driver was killed on Saturday when a meteorite landed in the area where he was walking, damaging the window panes of nearby buses and buildings. Three other people were injured.

The story is not yet confirmed, and could easily be proven wrong.

Flying over Ceres

The Dawn science team has released a new animation using the images taken by the spacecraft. The colors have been enhanced to emphasize the geological differences on the surface. I have embedded it below the fold.

The movie was produced by members of Dawn’s framing camera team at the German Aerospace Center, DLR, using images from Dawn’s high-altitude mapping orbit. During that phase of the mission, which lasted from August to October 2015, the spacecraft circled Ceres at an altitude of about 900 miles (1,450 kilometers).

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