Seriously, Ceres and Comets Look Surprising
Here are surprises found at asteroid Ceres and Comet 67P by spacecraft arriving there this year.
The DAWN spacecraft is continuing its science orbits around asteroid Ceres (also classified as a dwarf planet). Here are some of the recent headlines:
Dwarf planet Ceres offers big surprises for scientists (PhysOrg):
The closer we get to Ceres, the more perplexing the dwarf planet grows. NASA’s Dawn spacecraft has found several more bright spots as well as a pyramid-like peak jutting out of the frigid world’s surface.
The discovery is painting an increasingly complex portrait of one of the biggest “fossils” from the early solar system.
“I expected to be surprised because we knew so little about Ceres,” Christopher Russell, Dawn’s principal investigator and a planetary scientist at the University of California, Los Angeles, said in an email. “I never expected bright spots and a pyramid to be the surprises.”
Mystery haze appears above Ceres’s bright spots (Nature News). “Discovery bolsters idea that intriguing marks are made of ice, not salt.” Relation to Pluto? “Ceres’s striking 5-kilometre-high mountain, informally dubbed the pyramid, may be like the mountains seen last week on Pluto by the New Horizons spacecraft, Russell adds.”
Strange Bright Spots on Ceres Create Mini-Atmosphere on Dwarf Planet (Space.com): The spots appear to have a haze layer above them, indicating possible sublimation. “This is our major mystery,” Russell said. “Overall, Dawn’s observations are showing Ceres to be a relatively active world rather than an inert chunk of rock and ice,” the article states.
Dawn has also spotted numerous long, linear features whose cause is unknown, as well as one big mountain that mission team members have dubbed “The Pyramid.” This massif, which is about 3 miles (5 km) tall and 19 miles (30 km) wide, features a flat top and strangely streaked flanks, Russell said.
New names and insights at Ceres (PhysOrg): some of the features have been named. The crater with the bright spots has been named Occator by the IAU. Other features are named after other pagan gods. Article includes map and rotating globe of Ceres in false color.
Update 8/10/15: Crater counts come up short, creating a “mystery” of the “missing craters.” Ceres has only 10% the number of craters scientists predicted from its assumed age. “There is a story there — what it is, exactly, needs to be seen,” a member of the DAWN science team remarked on Space.com. Ceres never seems to have been volcanically or tectonically active. The only possibility scientists are toying with is moving ice. Crater count results are preliminary, but “I don’t think we will find a factor of 10 more craters,” they said.
Rosetta’s Philae Lander was featured in a special edition of Science Magazine. Here are the primary findings reported there and on other sites:
CHO-bearing organic compounds at the surface of 67P/Churyumov-Gerasimenko revealed by Ptolemy (Science Mag): “an apparent absence of aromatic compounds such as benzene, a lack of sulfur-bearing species, and very low concentrations of nitrogenous material.”
Organic compounds on comet 67P/Churyumov-Gerasimenko revealed by COSAC mass spectrometry (Science Mag): “The absence of large quantities of NH3, HCHO, and CO2 in our best fit may seem surprising because they were expected to be present as components of cometary ice.” It’s a stretch to call cyanide (HCN) a “prebiotic” material, but they say, “The complexity of cometary nucleus chemistry and the importance of N-containing organics imply that early solar system chemistry fosters the formation of prebiotic material in noticeable concentrations.”
The landing(s) of Philae and inferences about comet surface mechanical properties (Science Mag): “the cometary matter near the surface may be processed and thus not representative of the pristine state after formation.”
Philae’s comet discoveries create series of conundrums (Nature): “One puzzle is that the surface of comet 67P/Churyumov–Gerasimenko is much harder than scientists had expected,” Elizabeth Gibney writes. But that’s not compatible with another finding: “The data also show the comet to be very porous — between 75% and 85% empty space.”
Some scientists say the findings suggest that the comet is not an unaltered time capsule from the dawn of the Solar System, as researchers had presumed.
“It seems like the more we know, the less we know,” says Geraint Morgan, a co-investigator on the lander’s Ptolemy instrument and a physical chemist at the Open University in Milton Keynes, UK. “The comet is more complicated than we might have imagined.” ….
That the comet could have changed since its formation has implications for the wider mission, which had assumed that such bodies had existed largely unaltered since the start of the Solar System, says Seiferlin. But both the hard crust and a large variety of surface materials and structures found on the comet could be the result of recent modifications, he says.
Surprising Comet Discoveries by Rosetta’s Philae Lander Unveiled (Space.com)
“Before the landing of Philae, we believed cometary surfaces might be very soft (loose regolith under low gravity). Some colleagues even feared the lander may sink deeply into the surface at touchdown,” Philae project manager Stephan Ulamec, of the German Aerospace Center (DLR), told Space.com via email. “Although we were aware of our limited knowledge, the fact that some of the material is so hard, and that the surface is so heterogen[eous], was indeed a bit surprising.“
Spacecraft Sees What a Comet Is Made Of (National Geographic): the comet “has a surface that varies from hard as asphalt to soft as a sandy beach. Its interior isn’t like a rocky snowball, as scientists thought it might be, but rather a smooth mixture of dust and ice. And it’s home to organic compounds that not only have never been seen on a comet before, but also support the idea comets brought the building blocks of life to Earth billions of years ago.”
Comets: Soft Shell, Hard Core? (Science Daily): “the near surface material might have changed since its formation. Up to now, many researchers had assumed that it has remained in virtually the same state since its formation about 4.5 billion years ago.”
Science on the Surface of a Comet (Astrobiology Magazine): “Taken together, these first pioneering measurements performed on the surface of a comet are profoundly changing our view of these worlds and continuing to shape our impression of the history of the Solar System.”
Comet yields ‘rich array’ of organics (BBC News): article quotes Ian Wright who bows before the holy OOL (origin of life):
“I see this cometary material that we’re analysing as frozen primordial soup. It’s the kind of stuff that if you had it, and warmed it up somehow, and put it in the right environment, with the right conditions, you may eventually get life forming out of it.
“What we may be looking at here is our abiological ancestral material – this is stuff that went into the mix to produce life.
“In many ways it’s quite a humbling thing to be working on, because this is life before life happened.“
Inside Imhotep [Crater] (PhysOrg): “A few bright patches are seen on exposed walls. They appear bluer than the average colour of the comet in colour-composite images and suggest the presence of ice. If they are confirmed as water-ice, these could be some of the youngest areas on the comet.”
Need we point out that secular astronomers were wrong again? Just about every body in the solar system has turned out to be much different than predicted by slow-and-gradual, bottom-up models (see a partial list in the 6/05/03 commentary). We have been told for decades that comets are dirty snowballs, fluffy objects unchanged for billions of years. Wrong. DAWN scientists are surprised at Ceres, like they were surprised at Vesta last year. No one is saying that the observations match what they predicted from accretion models. We expect more surprises for the secular crowd as data continue to come down.
The origin-of-life stuff is just silly. Ian Wright deserves three SEQOTW awards. He bows down before chemicals like cyanide and soot, humbled in the presence of great possibilities. So let him test it scientifically. Warm it up, put it in the right environment, in the right conditions, and see if life forms. It will be a long wait (see online book).