A Bit More Detail

• Bad Astronomer Phil Plait notes new evidence that the Pathfinder probe landed, on Mars, on the shores of an ancient sea.


• The Crux reports on tholins, the organic chemicals that are possible predecessors to life, now found in abundance throughout the outer Solar System.


• D-Brief reports on the hard work that has demonstrated some meteorites which recently fell in Turkey trace their origins to Vesta.


• Colby King at the Everyday Sociology Blog explores sociologist Eric Klinenberg's concept of social infrastructure, the public spaces we use.


• Far Outliers reports on a Honolulu bus announcement in Yapese, a Micronesian language spoken by immigrants in Hawai'i.


• JSTOR Daily considers the import of the autobiography of Catherine the Great.


• Language Hat reports, with skepticism, on the idea of "f" and "v" as sounds being products of the post-Neolithic technological revolution.


• Marginal Revolution's Tyler Cowen is critical of the idea of limiting the number of children one has in a time of climate change.


• Jim Belshaw at Personal Reflections reflects on death, close at hand and in New Zealand.


• Strange Company reports on the mysterious disappearance, somewhere in Anatolia, of American cyclist Frank Lenz in 1892, and its wider consequences.


• Starts With A Bang's Ethan Siegel identifies five types of cosmic events capable of triggering mass extinctions on Earth.


• Towleroad reports on the frustration of many J.K. Rowling fans with the author's continuing identification of queer histories for characters that are never made explicit in books or movies.


• Window on Eurasia has a skeptical report about a Russian government plan to recruit Russophones in neighbouring countries as immigrants.


• Arnold Zwicky explores themes of shipwrecks and of being shipwrecked.

• Neanderthals, like contemporary humans, had the sort of prolonged childhoods which lend themselves to intelligence. National Geographic reports.


• The cool chill water of oceans is starting to be used to cool data centres. VICE reports.


• Brazil is set to embark on a substantial process to restore Amazonian rainforest. VICE reports.


• The Dawn probe found evidence of subsurface ice on rocky asteroid-belt protoplanet Vesta. Universe Today reports.

• blogTO notes a house on downtown Toronto's Jersey Avenue, a near-laneway, that is on the market at nearly eight hundred thousand dollars.


• Centauri Dreams warns that with the passage of Dawn and New Horizons and Cassini, an era of unmanned space exploration will come to an end.


• Crooked Timber's Belle Waring considers Western/Asian cultural differences on gender.


• The Dragon's Gaze links to one paper seeking to detect exoplanet rotation rates and other data via eclipses, and links to another noting the discovery of N2H in a ring around TW Hydrae.


• The Dragon's Tales reports on the results of a genetic analysis of the dwarf mammoths of Wrangel Island.


• A Fistful of Euros looks at how the Second World War started Ireland's break from the Sterling zone.


• The Frailest Thing considers the good of tech criticism.


• Joe. My. God. celebrates a decade of same-sex marriage in Spain.


• Language Hat looks at how promoters of a literature or a work can get things they champion translate.


• The Planetary Society Blog has two posts celebrating its role in the New Horizons probe.


• Towleroad notes that YouTube star Shane Dawson has just come out as bisexual.


• Window on Eurasia looks at an incipient Cossack separatism.

• blogTO shares a list of the five most cliched music video locations in Toronto.


• The Dragon's Tales notes that Germany has abandoned its support for upgrading the Ariane 5, instead opting for a new Ariane 6.


• Eastern Approaches notes the surprise election of Transylvanian Saxon Klaus Iohannis as president of Romania.


• The Everyday Sociology Blog looks at the sociology of aging.


• Geocurrents' Martin Lewis compares the diverging political patterns of northern California and Minnesota.


• Joe. My. God. links to the new Giorgio Moroder single and notes the AHF's anti-PReP ad.


• Language Hat notes that the Mayan glyphs on the walls of Chipotle restaurants actually mean something.


• Lawyers, Guns and Money mocks Nicolas Sarkozy's opposition to same-sex marriage.


• The Map Room's Jonathan Crowe shares geological maps of Vesta, produced by the Dawn probe.


• pollotenchegg lists the ten largest Ukrainian cities of the long 19th century.


• Window on Eurasia notes the firebombing of some Crimean Tatar mosques.

• James Bow writes about his recent life changes.


• The Dragon's Gaze links to a paper examining what the distribution of the Neptunian Trojans means about the movements of that ice dwarf.


• Languages of the World's Asya Perelstvaig summarizes, in two parts, a mid-19th century study of the Crimean Tatars.


• Lawyers, Guns and Money does not like the politicization of the California judiciary.


• Marginal Revolution looks at a study into street harassment in Mexico City.


• The Planetary Society Blog features a post by Marc Rayman looking at some of the propulsion-related problems of the Dawn probe.


• Torontoist's Historicist feature looks at the Toronto towers of Estonian-Canadian architect Uno Prii.


• Towleroad looks at the life of a pair of gay cowboys in Australia.


• Window on Eurasia notes the growing Chinese presence in Central Asia, looks at the decline of rural Russia, and notes Ukrainian alienation from Russia.

• Anders Sandberg notes how the book and film 2001 are touchstones still for what we might fear of our future.


• Centauri Dreams touched on quite a few issues while I was offline, noting a proposed solar-sail probe to Halley's Comet, notes the positive implications of geysers and liquid water for life on Enceladus, notes the exceptional distance of exoplanet Kepler-421b from its star and precisely measures the size and orbit of Kepler-93b and looks at the dryness of hot Jupiters and studies the misaligned gas discs of the stars of binary HK Tauri, and looks at ways to keep Earth-like planets orbiting red dwarfs habitable for hundreds of billions of years.
  
• The Dragon's Gaze notes that Gliese 1214b is an evaporating hot Neptune, looks at the search for rogue exoplanets in the Pleiades, mourns the non-existence of Gliese 581g and Gliese 481d, points to evidence that X-ray source IGR J17361-4441 was blocked partially and briefly by an exoplanet, looks at the search of exoplanets around nearbuy red dwarf stars, links to a reexamination of some Kepler exoplanet candidates and their stars by the Hubble space telescope, and notes that most worlds more than 1.6 times the radius of Earth are likely to be Neptunes.


• At The Dragon's Tales, the planet-reshaping impacts of the Late Heavy Bombardment on the early Earth are noted, as are forces acting on solar sails, as is a proposal to use the Voyager 1 spacecraft's movements and signals to look for distant planets, as is a paper suggesting that Titan's inner sea is as salty as the Earth's.


• The Planetary Society Blog notes (1, 2, 3) the Rosetta spacecraft's rendezvous with its target comet, notes a conference examining the habitability of Mars, looks at an odd mountain on Vesta, and links to an inventive revisiting of Venera images of the Venus surface.


• Progressive Download's John Farrell celebrates the ESA's Georges Lemaître ATV, named after a Belgian cosmologist of note.

Starting in early February 2015, Dawn will suspend thrusting occasionally to point its camera at Ceres. The first time will be on Feb. 2, when they are 260,000 miles (420,000 kilometers) apart. To the camera's eye, designed principally for mapping from a close orbit and not for long-range observations, Ceres will appear quite small, only about 24 pixels across. But these pictures of a fuzzy little patch will be invaluable for our celestial navigators. Such "optical navigation" images will show the location of Ceres with respect to background stars, thereby helping to pin down where it and the approaching robot are relative to each other. This provides a powerful enhancement to the navigation, which generally relies on radio signals exchanged between Dawn and Earth. Each of the 10 times Dawn observes Ceres during the approach phase will help navigators refine the probe's course, so they can update the ion thrust profile to pilot the ship smoothly to its intended orbit.

Whenever the spacecraft stops to acquire images with the camera, it also will train the visible and infrared mapping spectrometer on Ceres. These early measurements will be helpful for finalizing the instrument parameters to be used for the extensive observations at closer range in subsequent mission phases.

[. . .]

When Dawn next peers at Ceres, nine days after the first time, it will be around 180,000 miles (290,000 kilometers) away, and the pictures will be marginally better than the sharpest views ever captured by the Hubble Space Telescope. By the third optical navigation session, on Feb. 21, Ceres will show noticeably more detail.

At the end of February, Dawn will take images and spectra throughout a complete Ceres rotation of just over nine hours, or one Cerean day. During that period, while about 100,000 miles (160,000 kilometers) distant, Dawn's position will not change significantly, so it will be almost as if the spacecraft hovers in place as the dwarf planet pirouettes beneath its watchful eye. Dawn will see most of the surface with a resolution twice as good as what has been achieved with Hubble. (At that point in the curving approach trajectory, the probe will be south of Ceres's equator, so it will not be able to see the high northern latitudes.) This first "rotation characterization," or RC1, not only provides the first (near-complete) look at the surface, but it may also suggest to insightful readers what will occur during the RC3 orbit phase.

There will be six more imaging sessions before the end of the approach phase, with Ceres growing larger in the camera's view each time. When the second complete rotation characterization, RC2, is conducted on March 16, the resolution will be four times better than Hubble's pictures. The last photos, to be collected on March 24, will reveal features seven times smaller than could be discerned with the powerful space observatory.

[N]ext week’s departure for the Dawn spacecraft from Vesta will be monumental. Dawn is on track to become the first probe to orbit and study two distant solar system destinations. The spacecraft is scheduled to leave the giant asteroid Vesta on Sept. 4 PDT (Sept. 5 EDT) to start its two-and-a-half-year journey to the dwarf planet Ceres.

“Thrust is engaged, and we are now climbing away from Vesta atop a blue-green pillar of xenon ions,” said Marc Rayman, Dawn’s chief engineer and mission director. “We are feeling somewhat wistful about concluding a fantastically productive and exciting exploration of Vesta, but now have our sights set on dwarf planet Ceres.

In the video above, the Dawn team looks back at the highlights of the year-plus stay in orbit around Vesta. Dawn’s orbit provided close-up views of Vesta, revealing unprecedented detail about the giant asteroid. The mission revealed that Vesta completely melted in the past, forming a layered body with an iron core. The spacecraft also revealed the scarring from titanic collisions Vesta suffered in its southern hemisphere, surviving not one but two colossal impacts in the last two billion years. Without Dawn, scientists would not have known about the dramatic troughs sculpted around Vesta, which are ripples from the two south polar impacts.

“We went to Vesta to fill in the blanks of our knowledge about the early history of our solar system,” said Christopher Russell, Dawn’s principal investigator, based at the University of California Los Angeles (UCLA). “Dawn has filled in those pages, and more, revealing to us how special Vesta is as a survivor from the earliest days of the solar system. We can now say with certainty that Vesta resembles a small planet more closely than a typical asteroid.”

Vesta has been viewed as a massive asteroid, but after studying the surface in detail, scientists are describing it as "transitional".

The Dawn spacecraft has been orbiting Vesta - one of the Solar System's most primitive objects - since July 2011.

They have documented many unexpected features on its battered surface.

Mission scientists presented their latest results at the Lunar and Planetary Science Conference (LPSC) in The Woodlands, Texas.

Dawn's principal investigator, Christopher T Russell, told the meeting that the science team found it hard not to refer to the object as a planet.

He said the rounded asteroid showed evidence of geological processes that characterise rocky worlds like Earth and the Moon.

Vesta is the second most massive of the asteroids, measuring some 530km (330mi) in diameter. It is dominated by a huge crater called Rheasilvia and bears many other scars left by the hammering it has received at the hands of other asteroid belt denizens.

One important transitional feature of Vesta can be found in its topography, or elevation. Vertical elevation on the Moon or Mars might reach tens of kilometres, but these objects are also very large.

"This means the topography is about 1% of the radius," Dr Ralf Jaumann, from the German Aerospace Center (DLR), told BBC News, "If you go to Vesta, it is 15%, and if you go to the largest outer asteroid - Lutetia - it is 40%."

In short, this mathematical relationship between topography and radius (half an object's diameter), puts Vesta in an intermediate position between small asteroids and rocky planets.

Another aspect concerns the way its surface has been modified, or "processed", by the many collisions. This is evident in dark material that can be seen in images of its terrain.

The dark material seems to be related to impacts and their aftermath. Scientists think carbon-rich asteroids could have hit Vesta at speeds low enough to produce some of the smaller deposits without blasting away the surface.

Higher-speed asteroids could also have collided with Vesta's surface and melted the volcanic basaltic crust, darkening existing surface material.

Scientists are confident there has been volcanism on the asteroid during its history. This is because there are hundreds of pieces of Vesta sitting in museums around the world.

They form a particular class of meteorite called the HEDs; more of these objects have fallen to Earth than all the meteorites from the Moon and Mars put together. Studies of HED meteorites have revealed telling chemical signatures of volcanic activity.

Dave Williams, from Arizona State University, told BBC News: "We know [from the HED meteorites] there were lava flows at some point in history, so I expected there to be at least a few lava flows, maybe a few channels, shields or cones. Looking at all the images in places that have been illuminated thus far, we don't see any evidence of that.

"That's because of all the impact processing over Solar System history. It has destroyed all the evidence."

Vesta is most commonly called an asteroid because it lies in the orbiting rubble patch known as the main asteroid belt between Mars and Jupiter. But the vast majority of objects in the main belt are lightweights, 100-kilometers-wide (about 60-miles wide) or smaller, compared with Vesta, which is about 530 kilometers (330 miles) across on average. In fact, numerous bits of Vesta ejected by collisions with other objects have been identified in the main belt.

"I don't think Vesta should be called an asteroid," said Tom McCord, a Dawn co-investigator based at the Bear Fight Institute, Winthrop, Wash. "Not only is Vesta so much larger, but it's an evolved object, unlike most things we call asteroids."

The layered structure of Vesta (core, mantle and crust) is the key trait that makes Vesta more like planets such as Earth, Venus and Mars than the other asteroids, McCord said. Like the planets, Vesta had sufficient radioactive material inside when it coalesced, releasing heat that melted rock and enabled lighter layers to float to the outside. Scientists call this process differentiation.

McCord and colleagues were the first to discover that Vesta was likely differentiated when special detectors on their telescopes in 1972 picked up the signature of basalt. That meant that the body had to have melted at one time.

Officially, Vesta is a "minor planet" -- a body that orbits the sun but is not a proper planet or comet. But there are more than 540,000 minor planets in our solar system, so the label doesn't give Vesta much distinction. Dwarf planets – which include Dawn's second destination, Ceres -- are another category, but Vesta doesn't qualify as one of those. For one thing, Vesta isn't quite large enough.

Dawn scientists prefer to think of Vesta as a protoplanet because it is a dense, layered body that orbits the sun and began in the same fashion as Mercury, Venus, Earth and Mars, but somehow never fully developed. In the swinging early history of the solar system, objects became planets by merging with other Vesta-sized objects. But Vesta never found a partner during the big dance, and the critical time passed. It may have had to do with the nearby presence of Jupiter, the neighborhood's gravitational superpower, disturbing the orbits of objects and hogging the dance partners.