Tag: asteroids

Thirty ton meteorite excavated in Argentina

9:10 am

In what is one of the largest asteroid chunks ever found on Earth, an excavation team from a local astronomy club this week excavated a thirty ton iron-nickel meteorite from the ground.

Dubbed Gancedo after a nearby town, it isn’t a record-holder, but it sure is big. What I found interesting from the article, however, is this:

Gancedo’s fall to Earth occurred between 4,000 and 6,000 years ago. Locals knew of the fall for centuries, even making iron tools from meteorites found in the strewnfield. In the 16th century, the Spanish became interested in stories of a piece of iron that fell from the sky, and in 1774 don Bartolomé Francsico de Maguna led an expedition that came across a mass of iron, referred to as Mesón de Fierro (“Table of Iron” in Spanish). Another 1,400-pound fragment from Campo del Cielo named Otumpa now resides at the British Museum in London. With more than 100 tons of meteorite recovered, Campo del Cielo is the top producer in terms of pure meteorite mass worldwide.

The Campo del Cielo strewnfield extends over an ellipse 3 km wide by 19 km long over an area northwest of Buenos Aires, and meteorites found here have a polycrystalline coarse octahedrite composition characteristic of iron-nickel meteorites. They are also unusually pure even among iron-nickel meteorites, consisting of 93% iron. Most of the remaining 7% is nickel, and less than 1% are trace elements.

The evidence here is that a very dense asteroid, weighing a minimum of 100 tons but probably several times that, smashed into the Earth about five thousand years ago. Yet, all life on Earth was not wiped out, as is repeatedly suggested might happen whenever a similarly sized asteroid zips close past the Earth. In fact, there is no evidence this impact had any significant global environmental effects.

Remember this the next time another asteroid of similar size zips past the Earth and the media doom-sayers begin to sing their siren song again.

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

11:39 am

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.

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Dawn moves to higher orbit around Ceres

9:41 am

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.

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New and very distance outer solar system objects beyond Neptune

10:11 am

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.

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Costs rise on Obama’s asteroid mission

9:05 am

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.

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Ceres lacks large craters

10:59 am

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.

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More bright spots on Ceres

10:17 am

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.

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

3:48 pm

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.

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Rosetta’s finale set for September 30

8:41 am

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?

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Dawn data suggests recent hydrothermal activity on Ceres

11:38 am

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.

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Moon discovered orbiting Kuiper Belt Object Makemake

6:57 pm

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.

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Ceres’s brightest spot

2:30 pm

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.

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Newly discovered asteroid quasi-moon of Earth

11:41 pm

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.

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Planetary Resources has raised $21 million

10:44 am

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.

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Luxembourg signs deal with asteroid mining company

10:32 am

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.

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Hubble discovers moon circling Kuiper belt object

10:10 am

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.

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The asteroid didn’t do it all

12:34 am

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.

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Update on Dawn at Ceres

10:07 am

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.

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