Interesting Science

Two small, semiaquatic mammals can use their sense of smell even when underwater, according to a new study.

The finding stems from high-speed video that shows a star-nosed mole* rapidly blowing out bubbles of air and sucking them back in while foraging underwater.

The bizarre-looking rodent is already known as the world's fastest mammalian forager.

The mole has now displayed equal prowess as a lightning-fast underwater sniffer, blowing and inhaling air bubbles at a rate of five to ten times a second.

The bubbles make contact with a target, such as morsel of earthworm or fish, and apparently pick up the target's scent before being sucked back up the nose.

When you watch the video, "you're essentially seeing [the moles] sniffing underwater," said Kenneth Catania (lab), a biologist at Vanderbilt University in Nashville, Tennessee.

Continued at "Moles, Shrews Can Smell Prey While Underwater, Study Suggests"

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Based on the journal Nature paper:

"Olfaction: Underwater 'sniffing' by semi-aquatic mammals"

by Kenneth C. Catania

Abstract

Terrestrial species that forage underwater face challenges because their body parts and senses are adapted for land - for example, it is widely held that mammals cannot use olfaction underwater because it is impossible for them to inspire air (sniff) to convey odorants to the olfactory epithelium. Here I describe a mechanism for underwater sniffing used by the semi-aquatic star-nosed mole (Condylura cristata) and water shrew (Sorex palustris). While underwater, both species exhale air bubbles onto objects or scent trails and then re-inspire the bubbles to carry the smell back through the nose. This newly described behaviour provides a mechanism for mammalian olfaction underwater.

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*Current Info on star-nosed moles:

...Like many other moles, C. cristata is fossorial, digging a network of tunnels through moist soil. The tunnels are 3.3 to 7.6 cm wide, typically wider than tall, and can extend as much as 270 m along the edge of a suitably wet habitat. The mole digs shallow surface tunnels for foraging but, unlike the eastern mole, it does not dig deeper burrows for protection in the winter. The surface tunnels vary in depth from 3 to 60 cm, only occasionally coming close enough to the surface to cause a raised ridge. The loose soil dug from the tunnels is pushed out onto the surface, forming 'molehills' that can be 60 cm wide and 15 cm high. A spherical nest about 13 cm in diameter is constructed in the tunnel system above the water line, often under a log or similar protective object, and lined with dry leaves or grass. Unlike other North American moles, C. cristata is semiaquatic, so many of its tunnels open under the surface of a stream or lake. Its fossorial forelimbs also make good paddles and it swims underwater with alternate strokes of both front and hind feet, resulting in a characteristic zigzag motion. Condylura cristata is also more active on the surface than other moles, using runways (often made by other small mammals) through meadow or marsh vegetation. Condylura cristata is active throughout the winter, burrowing through snow and even swimming under the ice of frozen ponds. (Baker, 1983; Fisher, 1885; Hamilton, 1931; Hickman, 1983; Kurta, 1995; Lyon, 1936; Merriam, 1884; Rust, 1966; Tenny, 1871; Wiegert, 1961) supersensitive organs, identification of prey can be made in under half a second. [More]

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**Current info on the water shrew:

Water shrews are solitary creatures, active throughout the day and night. Their activity patterns are characterized by two periods; one between sunset and 2300 h, the second occurs one hour prior to sunrise (Sorenson, 1962). For every 30 minutes of activity, the shrew spends the next hour resting (van Zyll de Jong, 1983).

When active, water shrews dive and swim in water to forage for food. Water shrews can control their own metabolic demands so that they can dive year-round, even in winter-cold bodies of water (Boernke, 1977). Each dive can last from 31.1 to 47.7 seconds (Beneski and Stinson, 1987). In water, the fur is lined with a layer of air that reduces their heat loss by 50% (Calder, 1969) as well as make them buoyant. Therefore, when water shrews swim or dive, they must paddle vigorously to keep from floating to the surface. The hind feet, and the stiff hairs on them, propel them through the water. Immediately after swimming, water shrews dry off their fur using the hind feet. Besides swimming, some water shrews have been seen walking on the surface of water (Jackson, 1928). It has been suggested that water shrews can walk on water because they can trap air bubbles in the stiff hairs of their feet (Jackson, 1928).[More]

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Also reported in this week's Washington Post's Science Notebook

Technorati: moles, shrews, smell, underwater, research

Permanent Link posted by John Latter @ 6:34 PM 0 comments

Scientists at Manchester University (UK) have discovered that a dinosaur traditionally regarded as one of the most violent actually used its giant razor-sharp claw to climb trees.

The velociraptor* was immortalised in Steven Speilberg's 1993 film Jurassic Park, where it was depicted as a vicious hunter that slashed open its prey's intestine with its sickle-shaped claw.

But palaeontologist Dr Phillip Manning from Manchester University and scientists from the National History Museum in London have discovered this fearsome-looking appendage was of little use for this purpose.

The researchers found a replica claw attached to the end of a robotic arm was better at hooking on to flesh than slashing it during a simulated attack.

They also replicated the dinosaur's hind leg motion and this led to the discovery it was better suited to climbing.

Full article at "Dinosaur claws used for climbing - research"
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A related Natural History Museum report from 2005:

Disarming dangerous dinosaurs

Scientists at the University of Manchester and the Natural History Museum have been studying the large foot claw found on small meat-eating dinosaurs such as Velociraptor and Deinonychus . These dinosaurs both belong to a group called dromaeosaurs.

The study has found that instead of slicing through flesh and disembowelling prey, as previously thought, the dinosaur primarily used its foot claw as a tool to hold on to and perhaps clamber over its victims.

The dromaeosaur's sharp serrated teeth would then tear into the flesh of its prey whilst clinging tightly to its victim. This is similar to the hunting techniques of modern day big cats, which use their protracted claws to cling onto their prey as their powerful jaws deliver the killer blow. (Continued)
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*Info on Velociraptors:

Velociraptor (meaning "swift thief") is a genus of dromaeosaurid theropod dinosaur that existed approximately 83 to 70 million years ago during the later part of the Cretaceous Period. There is only one universally recognized species, V. mongoliensis, although others have been attributed in the past. Fossils of this species have been found in central Asia, from both Inner and Outer Mongolia.

Smaller than other dromaeosaurids like Deinonychus and Achillobator, the turkey-sized Velociraptor nevertheless shared many of the same anatomical features. It was a bipedal carnivore with a long, stiffened tail and had an enlarged, sickle-shaped claw on each hindfoot, which is thought to have been used to kill its prey. Velociraptor can be distinguished from other dromaeosaurids by its long and low skull, with an upturned snout.

Due in large part to its prominent role in Michael Crichton's novel Jurassic Park and the subsequent motion picture series, Velociraptor (commonly shortened to 'raptor') is one of the dinosaur genera most familiar to the general public. It is also well-known to paleontologists, with over a dozen recovered fossil skeletons - the most of any dromaeosaurid. One particularly famous specimen shows a Velociraptor locked in combat with a Protoceratops.
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3-D Animations of a Velociraptor and Protoceratops engaging in combat from the American Museum of Natural History.

Technorati: paleontology, dinosaurs, velociraptor

Permanent Link posted by John Latter @ 12:08 AM 0 comments

A fast, efficient image enhancement technique developed at the National Institute of Standards and Technology (NIST) and originally applied to improving monochrome microscope images has proved itself equally effective at the other end of the scale - sharpening details on color images of distant galaxies produced by the Hubble Space Telescope**. That the technique's practical value would span from inner space to outer space was a welcome surprise to NIST mathematician Alfred Carasso*.

Removing blur is a problem common to almost all imaging, from home snapshots to scientific instrumentation. Mathematically, blurring can be thought of as a set of mathematical operations that are applied to every point in an image and that result in that point being spread out and diffused. In principle, if you know the blurring function, the exact set of operations, you can remove the blur by delicate numerical analysis, being careful not to amplify noise.

Continued at "Hubble: NIST Math Technique Opens Clearer Window on Universe" [Astronomy]

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Based on the journal Optical Engineering paper:

"APEX blind deconvolution of color Hubble space telescope imagery and other astronomical data"

by Alfred S. Carasso

Abstract

The APEX method is a noniterative direct blind deconvolution technique that can sharpen certain kinds of high-resolution images in quasi real time. The method is predicated on a restricted class of blurs, in the form of 2-D radially symmetric, bell-shaped, heavy-tailed, probability density functions. Not all images can be usefully enhanced with the APEX method. However, the method is found effective on a broad class of galaxy images, including Hubble space telescope advanced camera for surveys (ACS) color imagery. APEX-detected optical transfer functions that successfully sharpen these images are very far from Gaussian, and of a type seldom found in the imaging literature. Several examples are given where significantly sharper and visually striking reconstructions are obtained, with sharpening confirmed by the tripling or quadrupling of image gradient norms.

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*Dr. Alfred S. Carasso's (homepage) research interests:

Leading authority on 'deconvolution' and other ill-posed problems of applied mathematics. Invented 'slowly divergent' computational schemes for inverse heat conduction calculations in gun barrels, rocket nozzles, and nuclear reactors. Developed 'pulse probing and continuous deconvolution' technique for dynamic characterization of structural networks, ultrasonic testing in NDE, and system identification in electronic black-boxes. Invented 'slow evolution' constraint for stabilizing digital image deblurring computations in presence of noise, with applications in biomedical imaging, (X-rays, CT, PET, SPECT, MRI), acoustic imaging, undersea imaging, imaging through atmospheric turbulence, and night vision systems. Patents pending on new procedure for image restoration.

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*Info on the Hubble Space Telescope:

Launched in April of 1990 and poised for many more years of trailblazing science ranging from our own solar system to the edge of the observable universe, NASA's Hubble Space Telescope is fulfilling the hopes astronomers have long held for a large, optically superb telescope orbiting above the Earth’s distorting atmosphere and providing uniquely clear and deep views of the cosmos.

The only one of NASA's four "Great Observatories" (Hubble, Compton Gamma-Ray Observatory, Chandra X-Ray Observatory, and Spitzer Space Telescope) that is serviceable by Space Shuttle astronauts, Hubble has seen its capabilities grow immensely in its sixteen historic years of operation. This has been the direct result of the installation of new, cutting-edge scientific instruments and more powerful engineering components. Replacement of aging or failed parts has been an important part of servicing and has been responsible for the telescope's longevity.

All of the Great Observatories have a particular range of light, or "electromagnetic radiation," to which they are designed and are sensitive. Hubble’s domain extends from the ultraviolet, through the visible (to which our eyes are sensitive), and to the near-infrared. In terms of the wavelength of light, Hubble’s coverage ranges from 1,200 Angstroms in the ultraviolet (1 Angstrom = 1 hundred-millionth of a centimeter) to 2.4 microns (24,000 Angstroms) in the near-infrared. Hubble’s UV-to-near-IR spectral range is a key piece of "astronomical real estate" - a dominant range of wavelengths emitted by stars and galaxies - and Hubble takes advantage of this access with both imaging and spectroscopy.

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Image Citations:

A (Left): Galaxy UGC 10214 ("Tadpole"), imaged in 2002 by the Advanced Camera for Surveys (ACS) aboard NASA's Hubble Space Telescope, shows what NASA called a "Whitman's Sampler of galaxies" from the universe's 13-billion-year evolution.

B (Right): Applying the APEX method to the Tadpole galaxy image brings both "foreground" objects and background galaxies into significantly sharper focus.

Technorati: astronomy, hubble, telescope

Permanent Link posted by John Latter @ 9:22 AM 0 comments

UK: A Hull York Medical School (HYMS) researcher has played a key role in a study which has cast important new light on Neanderthals.

Dr Markus Bastir was part of an Anglo-Spanish team which studied 43,000-year-old Neanderthal remains at El Sidron in Spain, revealing significant physical differences between those from northern and southern Europe.

Dr Bastir, who was based in the functional morphology and evolution research unit* (fme) of HYMS for the last two years, analysed the mandibles of Neanderthals discovered at El Sidron. The analysis revealed north-south variations, with southern European Neanderthals showing broader faces with increased lower facial heights. The research findings are published in the Proceedings of the National Academy of Sciences (PNAS).

It comes as the University of Hull's Centre for Medical Engineering and Technology (CMET), in which the fme is a partner, carried out detailed imaging of part of the upper jaw of what could be Britain's most substantial Neanderthal fossil discovered at Kent's Cavern in Torbay in 1926. The imaging using CMET's micro Computerised Tomography facilities was carried out on behalf of the Natural History Museum's Ancient Human Occupation of Britain project supported by the Leverhulme Trust.

Dr Bastir first studied the facial evolution of Neanderthals while at the Museo Nacional de Ciencias Naturales in Madrid. Later in the fme at HYMS, he analysed the mandibles of the El Sidron remains, under the supervision of Professor Paul O'Higgins, using 3D geometric morphometric software and imaging facilities.

"This revealed an astonishing North-South morphological gradient and gives us an idea of typically Southern-European Neanderthal facial shape," Dr Bastir said.

Professor O'Higgins said the two studies helped to demonstrate the growing importance of the HYMS functional morphology and evolution Unit, which has been established with more than £3million funding support from the Leverhulme Trust, the European Union, the Australian Research Council, the Natural Environment Research Council (NERC), Biotechnology and Biosciences Research Council (BBSRC) and the Arts and Humanities Research Council (AHRC).

"At York we have developed an exciting collaboration with colleagues from the Department of Archaeology to form PALAEO - the Centre for Human Palaeoecology and Evolutionary Origins, while at Hull we have formed a partnership with colleagues in Engineering and Computer Science in establishing the Centre for Medical Engineering and Technology," he added.

"Through the grant support we have raised we have been able to pick the best students and post doctoral fellows from Europe and more widely bringing them to Hull and York to work on leading edge issues in our field."

Source: University of York (UK) press release 21st December, 2006 [Anthropology]

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Related PNAS paper:

Paleobiology and comparative morphology of a late Neandertal sample from El Sidron, Asturias, Spain

Antonio Rosas, Cayetana Martinez-Maza, Markus Bastir et al.

Published online before print December 12, 2006, 10.1073/pnas.0609662104
PNAS | December 19, 2006 | vol. 103 | no. 51 | 19266-19271

Abstract

Fossil evidence from the Iberian Peninsula is essential for understanding Neandertal evolution and history. Since 2000, a new sample approx 43,000 years old has been systematically recovered at the El Sidron cave site (Asturias, Spain). Human remains almost exclusively compose the bone assemblage. All of the skeletal parts are preserved, and there is a moderate occurrence of Middle Paleolithic stone tools. A minimum number of eight individuals are represented, and ancient mtDNA has been extracted from dental and osteological remains. Paleobiology of the El Sidron archaic humans fits the pattern found in other Neandertal samples: a high incidence of dental hypoplasia and interproximal grooves, yet no traumatic lesions are present. Moreover, unambiguous evidence of human-induced modifications has been found on the human remains. Morphologically, the El Sidron humans show a large number of Neandertal lineage-derived features even though certain traits place the sample at the limits of Neandertal variation. Integrating the El Sidron human mandibles into the larger Neandertal sample reveals a north-south geographic patterning, with southern Neandertals showing broader faces with increased lower facial heights. The large El Sidron sample therefore augments the European evolutionary lineage fossil record and supports ecogeographical variability across Neandertal populations.

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*The Functional Morphology and Evolution Research Unit at HYMS:

Research in the unit focuses on the functional, evolutionary and developmental bases of morphological variation in humans, primates and other mammals.

One major research strand in the unit aims to explain how skeletal and dental morphologies arise during evolution in terms of developmental processes and functional adaptations. The key underpinning technologies are geometric morphometrics, CT imaging, Finite Element Analysis, polarising and scanning electron microscopy. The advances in morphometrics that have arisen during this work are also being applied in functional studies and imaging.

Another focus of research in the unit is on biogeographic and temporal variation in modern and fossil primates, relating morphological variation and functional morphology to environmental change. In addition, the unit is currently developing research projects in collaboration with biomechanicists to study the effects of different locomotor repertoires on morphology and energy efficiency.

The work of the Functional Morphology and Evolution unit is directly applicable to the study of human evolution and the understanding of modern human biological variation. In addition, the unit's work has important medical applications through the use of morphometrics in CT, MR and other diagnostic imaging modalities and also in kinematic analyses of facial and body motion.

Permanent Link posted by John Latter @ 8:49 PM 0 comments

Most planets have a magnetic field, like Earth, but with different strength or structure. It shields the planet from the energetic particles of the solar wind. The origin of the magnetic field is explained by a dynamo process, driven by the convective flow of an electrically conducting fluid in the planet's core. Computer models based on the dynamo theory reproduce the properties of Earth's magnetic field well, but the weakness of Mercury's field is a puzzle. Theory predicts that it should have 30% of Earth's strength, but only 1% has been observed.

Ulrich Christensen (info) of the Max-Planck-Institute for Solar System Research, Katlenburg-Lindau, Germany, presents a new model, in which the outer part of Mercury's iron core does not convect and a dynamo operates only in its deep part. Computer simulations show that here a strong but fluctuating magnetic field is generated. Similar to the skin effect in high frequency technology, where rapidly varying currents and magnetic fields hardly penetrate to the centre of a wire, only a small fraction of the dynamo-generated field can escape through the stagnant part of the iron core.

NASA's MESSENGER spacecraft*, being on its way to Mercury, and the ESA mission BepiColombo**, planned for the next decade, will test the model predictions for Mercury's field. If they are confirmed, remaining doubts about the general validity of the dynamo theory for the generation of planetary magnetic fields will be removed.

Press Release via "Mercury's Magnetic Field Explained?" [Astronomy]

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Based on the journal Nature paper:

"A deep dynamo generating Mercury's magnetic field"

by Ulrich R. Christensen

Abstract

Mercury has a global magnetic field of internal origin and it is thought that a dynamo operating in the fluid part of Mercury's large iron core is the most probable cause. However, the low intensity of Mercury's magnetic field - about 1% the strength of the Earth's field - cannot be reconciled with an Earth-like dynamo. With the common assumption that Coriolis and Lorentz forces balance in planetary dynamos1, a field thirty times stronger is expected. Here I present a numerical model of a dynamo driven by thermo-compositional convection associated with inner core solidification. The thermal gradient at the core-mantle boundary is subadiabatic and hence the outer region of the liquid core is stably stratified with the dynamo operating only at depth, where a strong field is generated. Because of the planet's slow rotation the resulting magnetic field is dominated by small-scale components that fluctuate rapidly with time. The dynamo field diffuses through the stable conducting region, where rapidly varying parts are strongly attenuated by the skin effect, while the slowly varying dipole and quadrupole components pass to some degree. The model explains the observed structure and strength of Mercury's surface magnetic field and makes predictions that are testable with space missions both presently flying and planned.

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*Info on Nasa's MESSENGER can be found at the mission website:

The MESSENGER core team consists of individuals from across all aspects of the mission, managing how each of the sub teams work together, influence each other, and affect the mission as a whole.

The Science Team is composed of scientists from different institutions and with different areas of expertise to form a comprehensive, diverse team that is well qualified to address the scientific objectives of the mission.

Each of the MESSENGER instruments has a team devoted to its development, calibrations, and operations during the mission, working to ensure that the returned scientific data will provide unprecedented insights into Mercury.

Each subsystem of the spacecraft has a team of highly qualified engineers involved in the design, testing, and operations of the mission, committed to seeing MESSENGER become the first spacecraft to orbit Mercury.

MESSENGER participation can be found all across the country, with some international contributions too. An interactive map shows the many involvements that all come together to create the mission. (abridged)

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**About the BepiColombo mission:

BepiColombo, an ESA mission in cooperation with Japan, will explore Mercury, the planet closest to the Sun. Europe's space scientists have identified the mission as one of the most challenging long-term planetary projects, largely because Mercury's orbit so close to the Sun makes the planet difficult for a spacecraft to reach and difficult to observe from a distance. Scientists want to study Mercury because of the valuable clues it will provide in understanding how planets form.

Only one probe has visited Mercury so far, NASA's Mariner 10 which flew past three times in 1974-5 and returned the only close-up images of the planet so far. The information gleaned when BepiColombo arrives will throw light not only on the composition and history of Mercury, but also on the history and formation of the inner planets in general, including the Earth.

The mission will consist of two separate spacecraft that will orbit the planet. ESA is building one of the main spacecraft, the Mercury Planetary Orbiter (MPO), and the Japanese space agency ISAS/JAXA will contribute the other, the Mercury Magnetospheric Orbiter (MMO).

The MPO will study the surface and internal composition of the planet, and the MMO will study Mercury's magnetosphere, that is the region of space around the planet that is dominated by its magnetic field.

Technorati: astronomy, mercury

Permanent Link posted by John Latter @ 7:58 PM 0 comments

In partially solving a mystery that has baffled archeologists for centuries, a Drexel University professor has determined that the Great Pyramids of Giza were constructed* with a combination of not only carved stones but the first blocks of limestone-based concrete cast by any civilization.

Michel Barsoum, professor of materials engineering, shows in a peer-reviewed paper to be published December 1 (2006) in the Journal of the American Ceramic Society how the Egyptian builders of the nearly 5,000-year-old pyramids were exceptional civil and architectural engineers as well as superb chemists and material scientists. His conclusions could lead to a seismic shift in the kind of concrete used in construction and provide developing nations a way to build structures utilizing inexpensive and easily accessible materials.

Barsoum will present his findings at a news conference November 30 at 5:30 p.m. (Central Europe standard time) at Le Palais de la decouverte, Avenue Franklin D. Roosevelt, in Paris, France.

The longstanding belief is that the pyramids were constructed with limestone blocks that were cut to shape in nearby quarries using copper tools, transported to the pyramid sites, hauled up ramps and hoisted in place with the help of wedges and levers. Barsoum argues that although indeed the majority of the stones were carved and hoisted into place, crucial parts were not. The ancient builders cast the blocks of the outer and inner casings and, most likely, the upper parts of the pyramids using a limestone concrete, called a geopolymer.

To arrive at his findings, Barsoum, an Egypt native, and co-workers analyzed more than 1,000 micrographs, chemical analyses and other materials over three years. Barsoum, whose interest in the pyramids and geopolymers was piqued five years ago when he heard theories about the construction of the pyramids, says that to construct them with only cast stone builders would have needed an unattainable amount of wood and fuel to heat lime to 900 degrees Celsius.

Barsoum's findings provide long-sought answers to some of the questions about how the pyramids were constructed and with such precision. It puts to rest the question of how steep ramps could have extended to the summit of the pyramids; builders could cast blocks on site, without having to transport stones great distances. By using cast blocks, builders were able to level the pyramids' bases to within an inch. Finally, builders were able to maintain precisely the angles of the pyramids so that the four planes of each arrived at a peak.

Although these findings answer some of the questions about the pyramids, Barsoum says the mystery of how they were built is far from solved. For example, he has been unable to determine how granite beams - spanning kings' chambers and weighing as much as 70 tons each - were cut with nothing harder than copper and hauled in place.

The type of concrete pyramid builders used could reduce pollution and outlast Portland cement, the most common type of modern cement. Portland cement injects a large amount of the world's carbon dioxide into the atmosphere and has a lifespan of about 150 years. If widely used, a geopolymer such as the one used in the construction of the pyramids can reduce that amount of pollution by 90 percent and last much longer. The raw materials used to produce the concrete used in the pyramids - lime, limestone and diatomaceous earth - can be found worldwide and is affordable enough to be an important construction material for developing countries, Barsoum said.

Source: Drexel University - Dateline Drexel (Keyword: Giza - November 30, 2007)

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Based on the paper:

M. W. Barsoum, A. Ganguly, G. Hug (2006)
Microstructural Evidence of Reconstituted Limestone Blocks in the Great Pyramids of Egypt
Journal of the American Ceramic Society 89 (12), 3788–3796.
doi:10.1111/j.1551-2916.2006.01308.x

Abstract

How the Great Pyramids of Giza were built has remained an enduring mystery. In the mid-1980s, Davidovits proposed that the pyramids were cast in situ using granular limestone aggregate and an alkali alumino-silicate-based binder. Hard evidence for this idea, however, remained elusive. Using primarily scanning and transmission electron microscopy, we compared a number of pyramid limestone samples with six different limestone samples from their vicinity. The pyramid samples contained microconstituents (micro-c's) with appreciable amounts of Si in combination with elements, such as Ca and Mg, in ratios that do not exist in any of the potential limestone sources. The intimate proximity of the µc's suggests that at some time these elements had been together in a solution. Furthermore, between the natural limestone aggregates, the µc's with chemistries reminiscent of calcite and dolomite - not known to hydrate in nature - were hydrated. The ubiquity of Si and the presence of submicron silica-based spheres in some of the micrographs strongly suggest that the solution was basic. Transmission electron microscope confirmed that some of these Si-containing micro-c's were either amorphous or nanocrystalline, which is consistent with a relatively rapid precipitation reaction. The sophistication and endurance of this ancient concrete technology is simply astounding.

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*Info on current construction theories:

Many varied estimates have been made regarding the workforce needed to construct the Great Pyramid. Herodotus, the Greek historian in the 5th century BCE, estimated that construction may have required 20,000 workers for 20 years. Recent evidence has been found that suggests the workforce was in fact paid [citation needed], which would require accounting and bureaucratic skills of a high order. Polish architect Wieslaw Kozinski believed that it took as many as 25 men to transport a 1.5-ton stone block. Based on this, he estimated the workforce to be 300,000 men on the construction site, with an enormous additional 60,000 off-site. [More]

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[Archaelogy; alt Archeology] Egyptology info: Egyptology.com and KMT - "A Modern Journal of Ancient Egypt"]

Technorati: archaeology, egyptology

Permanent Link posted by John Latter @ 2:46 PM 1 comments

A 2,100-year-old clockwork machine whose remains were retrieved from a shipwreck more than a century ago has turned out to be the celestial super-computer of the ancient world.

Using 21st-century technology to peer beneath the surface of the encrusted gearwheels, stunned scientists say the so-called Antikythera Mechanism* could predict the ballet of the Sun and Moon over decades and calculate a lunar anomaly that would bedevil Isaac Newton himself.

Built in Greece around 150-100 BC and possibly linked to the astronomer and mathematician Hipparchos, its complexity was probably unrivalled for at least a thousand years, they say.

'It's beautifully designed. Your jaw drops when you work out what they did and what they put into this,' said astronomer Mike Edmunds of Cardiff University, Wales, in an interview with AFP.

'It implies the Greeks had great technical sophistication.'

The Antikythera Mechanism is named after its place of discovery, where Greek divers, exploring a Roman shipwreck at a depth of 42 metres (136 feet) in 1901, came across 82 curious bronze fragments.

At first, these pieces, thickly encrusted and jammed together after lying more two millennia on the sea floor, lay forgotten. But a closer look showed them to be exquisitely made, hand-cut, toothed gearwheels.

It was clear that, within this find, 29 gearwheels fitted together, possibly making some sort of astronomical calendar. But of what, exactly?

Source/continuation: originally at "Enigma of ancient world's computer is cracked at last"

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Based on the journal Nature paper:

Freeth, T.; Bitsakis, Y., Moussas, X., Seiradakis, J. H., Tselikas, A., Mankou, E., Zafeiropulou, M., Hadland, R., Bate, D., Ramsey, A., Allen, M., Crawley, A., Hockley, P., Malzbender, T., Gelb, D., Ambrisco, W., and Edmunds, M. G. (2006).
Decoding the ancient Greek astronomical calculator known as the Antikythera Mechanism.
Nature 444: 587-591. DOI:10.1038/nature05357

Abstract

The Antikythera Mechanism is a unique Greek geared device, constructed around the end of the second century bc. It is known that it calculated and displayed celestial information, particularly cycles such as the phases of the moon and a luni-solar calendar. Calendars were important to ancient societies10 for timing agricultural activity and fixing religious festivals. Eclipses and planetary motions were often interpreted as omens, while the calm regularity of the astronomical cycles must have been philosophically attractive in an uncertain and violent world. Named after its place of discovery in 1901 in a Roman shipwreck, the Antikythera Mechanism is technically more complex than any known device for at least a millennium afterwards. Its specific functions have remained controversial because its gears and the inscriptions upon its faces are only fragmentary. Here we report surface imaging and high-resolution X-ray tomography of the surviving fragments, enabling us to reconstruct the gear function and double the number of deciphered inscriptions. The mechanism predicted lunar and solar eclipses on the basis of Babylonian arithmetic-progression cycles. The inscriptions support suggestions of mechanical display of planetary positions, now lost. In the second century bc, Hipparchos developed a theory to explain the irregularities of the Moon's motion across the sky caused by its elliptic orbit. We find a mechanical realization of this theory in the gearing of the mechanism, revealing an unexpected degree of technical sophistication for the period.

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Also see the June 1959 Scientific American paper "An Ancient Greek Computer" (p.60-7) by Derek J. de Solla Price:

Among the treasures of the Greek National Archaeological Museum in Athens are the remains of the most complex scientific object that has been preserved from antiquity. Corroded and crumbling from 2,000 years under the sea, its dials, gear wheels and inscribed plates present the historian with a tantalizing problem. Because of them we may have to revise many of our estimates of Greek science. By studying them we may find vital clues to the true origins of that high scientific technology which hitherto has seemed peculiar to our modern civilization, setting it apart from all cultures of the past.

From the evidence of the fragments one can get a good idea of the appearance of the original object [see illustration on page 62]. Consisting of a box with dials on the outside and a very complex assembly of gear wheels mounted within, it must have resembled a well- made 18ih-century clock. Doors hinged to the box served to protect the dials, and on all available surfaces of box, doors and dials there were long Greek inscriptions describing the operation and construction of the instrument. At least 20 gear wheels of the mechanism have been preserved, including a very sophisticated assembly of gears that were mounted eccentrically on a turntable and probably functioned as a sort of epicyclic or differential, gear-system.

Nothing like this instrument is preserved elsewhere. Nothing comparable to it is known. from any ancient scientific text or literary allusion. On the contrary, from all that we know of science and technology in the Hellenistic Age we should have felt that such a device could not exist. Some historians have suggested that the Greeks were not interested in experiment because of a contempt-perhaps induced by the existence of the institution of slavery-for manual labor. On the other hand it has long been recognized that in abstract mathematics and in mathematical astronomy they were no beginners but rather "fellows of another college" who reached great heights of sophistication. Many of the Greek scientific devices known to us from written descriptions show much mathematical ingenuity, but in all cases the purely mechanical part of the design seems relatively crude. Gearing was clearly known to the Greeks, but it was used only in relatively simple applications. They employed pairs of gears to change angular speed or mechanical ad- vantage, or to apply power through a right angle, as in the water-driven mill.

Even the most complex mechanical devices described by the ancient writers Hero of Alexandria and Vitruvius contained only simple gearing. For example, the taximeter used by the Greeks to measure the distance travelled by the wheels of a carriage employed only pairs of gears (or gears and worms) to achieve the necessary ratio of movement. It could be argued that if the Greeks knew the principle of gearing, they should have had no difficulty in constructing mechanisms as complex as epicyclic gears. We now know from the fragments in the National Museum that the Greeks did make such mechanisms, but the knowledge is so unexpected that some scholars at first thought that the fragments must belong to some more modern device.

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A related news release from Hewlett-Packard:

HP Helps Unlock Mysteries of World's Oldest "Computer"
PALO ALTO, California, Nov. 30, 2006

HP researchers are literally shining a light on what may be the world's oldest computer.

The Antikythera Mechanism is an ancient astronomical device built by the Greeks around 80 B.C. and found on a shipwreck off the Greek island of Antikythera by sponge divers in 1901. It is believed to have been created to track lunar and solar cycles for agricultural and religious purposes, but its precise function - and how it works - has eluded scholars for more than a century.

In September 2005, members of the Antikythera Research Project invited HP Labs research scientists Tom Malzbender and Dan Gelb to Athens to apply their patented reflectance imaging techniques to the front and rear surfaces of the more than 70 fragments that comprise the mechanism, including metal plates and gears, some of which are inscribed with faded Greek characters.

The technique involves taking photos of an artifact from a fixed point and 50 different light sources arrayed in a hemisphere over the object. The HP researchers' computer program then ties the images together, enabling an archaeologist to change the angle of light or texture of the surface of the object to make faint markings appear more vivid.

"One of the advantages of reflectance imaging is that you can change the quality of the surface of an object, by, for example, making dull surfaces shiny, like obsidian," said Gelb, senior research scientist, HP Labs. "That way, the faint markings on these ancient artifacts become more visible and that helps scholars determine their meaning."

By capturing the images digitally, the technique also enables scholars around the world to study the rare, delicate objects without having to travel to where they're stored or to handle them.

Some of the reflectance images, technically described as polynomial texture maps, are available at Interactive Relighting of the Antikythera Mechanism.

The results of Malzbender and Gelb's work, in collaboration with researchers from the U.K. and Greece, appear today in the British science journal, Nature ("Decoding the ancient Greek astronomical calculator known as the Antikythera Mechanism"). The other researchers used an X-ray technique, called computer tomography, to probe the depths of the device.

The new research explains how the gears work and identifies twice as many markings on the device as previously detected.

"The Antikythera Mechanism is the only technological device from the ancient world and the oldest computer or calculator known to man," said Malzbender, distinguished technologist, HP Labs. "Nothing like it appears until the Renaissance, when clocks first appeared."

This isn't the first time that the HP Labs researchers' work has been used for archaeological purposes. In 2000, Malzbender volunteered the resources of the technology to capture faded Sumerian tablets for researchers at Yale and the University of Southern California. It was this work that caught the attention of the Antikythera project.

The technology was originally developed not for archaeology, but as a method for improving photorealism and rendering efficiency in 3D graphics. It also could be used in criminal forensics, detecting distinctive characteristics in footprints or tire marks, for example. The technology also still has potential commercial uses for HP, but many of the techniques have been made available to the scientific world for academic purposes.

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Visit the The Antikythera Mechanism Research Project for more information

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*Similar devices in ancient literature

Cicero mentions two separate machines similar to the Antikythera mechanism.

The first was built by Archimedes and brought to Rome by the Roman general Marcus Claudius Marcellus after Archimedes' death at the siege of Syracuse in 212 BC. Marcellus had a high respect for Archimedes and this was the only item he kept from the siege. The device was kept as a family heirloom, and Cicero was shown it by Gallus about 150 years later. The motions of the sun, moon and five planets were shown by the device. Gallus gave a 'learned explanation' of it and demonstrated it for Cicero.

...Cicero also says that another such device was built 'recently' by his friend Posidonius, "... each one of the revolutions of which brings about the same movement in the sun and moon and five wandering stars [planets] as is brought about each day and night in the heavens..." Cicero, De Natura Deorum II.88 (or 33-34)

Technorati: antikythera, archaeology

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A team of scientists found a new class of organics in comet dust captured from comet Wild 2 in 2004 by NASA's Stardust spacecraft.

The discovery is described in a technical paper, 'Organics Captured from Comet Wild 2 by the Stardust Spacecraft,'* in the December 15 issue of Science Express, the online edition of the journal Science.

In January 2004, the Stardust spacecraft flew through comet dust and captured specks of it in a very light, low-density substance called aerogel. Stardust's return capsule parachuted to the Utah Test and Training Range on Jan. 15, 2006, after a seven-year mission. The science canister containing the comet particles and interstellar dust particles arrived at Johnson Space Center on Jan. 17. From there, the cometary samples have been processed and distributed to about 150 scientists worldwide who are using a variety of techniques to determine the properties of the cometary grains.

'A portion of the organic material in the samples is unlike anything seen before in extraterrestrial materials,' said Scott Sandford, the study's lead author and a scientist from NASA's Ames Research Center in California's Silicon Valley. 'Capturing the particles in aerogel was a little bit like collecting BBs by shooting them into Styrofoam.'

The comet organics collected by the Stardust spacecraft are more 'primitive' than those seen in meteorites and may have formed by processes in nebulae, either in space clouds between the stars, or in the disk-shaped cloud of gas and dust from which our solar system formed, the study's authors found. [Astrobiology]

Continued at "NASA Study Finds New Kind of Organics in Stardust Mission"

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*A Science Special Online Collection: Stardust includes:

1) Organics Captured from Comet 81P/Wild 2 by the Stardust Spacecraft

Abstract

Organics found in comet 81P/Wild 2 samples show a heterogeneous and unequilibrated distribution in abundance and composition. Some organics are similar, but not identical, to those in interplanetary dust particles and carbonaceous meteorites. A class of aromatic-poor organic material is also present. The organics are rich in oxygen and nitrogen compared with meteoritic organics. Aromatic compounds are present, but the samples tend to be relatively poorer in aromatics than are meteorites and interplanetary dust particles. The presence of deuterium and nitrogen-15 excesses suggest that some organics have an interstellar/protostellar heritage. Although the variable extent of modification of these materials by impact capture is not yet fully constrained, a diverse suite of organic compounds is present and identifiable within the returned samples.

2) Isotopic Compositions of Cometary Matter Returned by Stardust

Abstract

Hydrogen, carbon, nitrogen, and oxygen isotopic compositions are heterogeneous among comet 81P/Wild 2 particle fragments; however, extreme isotopic anomalies are rare, indicating that the comet is not a pristine aggregate of presolar materials. Nonterrestrial nitrogen and neon isotope ratios suggest that indigenous organic matter and highly volatile materials were successfully collected. Except for a single 17O-enriched circumstellar stardust grain, silicate and oxide minerals have oxygen isotopic compositions consistent with solar system origin. One refractory grain is 16O-enriched, like refractory inclusions in meteorites, suggesting that Wild 2 contains material formed at high temperature in the inner solar system and transported to the Kuiper belt before comet accretion.

3) There is a video (or rather, 5 videos) presentation here

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Also see "Astrobiology and Stardust"

Carl Sagan once said "We are all star stuff." But how? What does that really mean? One of the fundamental questions of astrobiology, how does life originate and evolve?, provides a structure in which to examine the relationship between life and the cosmos. Everywhere life has been found on Earth, which is essentially every place in which it has been sought, life's intimate connection with water has also been found. Within the framework of contemplating life's cosmic origins, one must also ask about the history of water on Earth. NASA's Stardust mission has provided the opportunity for astrobiologists to gain deeper insight into this history.

Many scientists from the NASA Astrobiology Institute** (NAI) have been involved in the Stardust mission, spearheaded by none other than Stardust PI Don Brownlee at the University of Washington. The list also includes Scott Sanford of the NAI NASA Ames Team, lead author of one of the papers in this week's Science, and George Cody of the NAI Carnegie Institution of Washington Team.

"Comets are important to the understanding of the origin of life," said Brownlee, "we have always considered Stardust an astrobiology mission." Results from analysis of the Stardust samples have brought new insight to bear on the relationship between the inner and outer solar system. "The samples we've obtained from Stardust have helped us understand both the origin of water and other volatiles, as well as their delivery mechanisms to the early Earth," said Brownlee.

-------**From "About the NAI":

"Astrobiology is devoted to the scientific study of life in the universe - its origin, evolution, distribution, and future. This multidisciplinary field brings together the physical and biological sciences to address some of the most fundamental questions of the natural world: How do living systems emerge? How do habitable worlds form and how do they evolve? Does life exist on worlds other than Earth? How could terrestrial life potentially survive and adapt beyond our home planet?

Scientists now realize that the origin and evolution of life itself cannot be fully understood unless viewed from a larger perspective than just our own Earth. Biologists are working with astronomers to describe the formation of life's chemical precursors, to discover new planets, and to determine their habitability; with chemists to understand the transition from molecular interaction to life itself; with geologists to search for evidence of water and key minerals on other planets; with paleontologists and evolutionary molecular biologists to look for and comprehend the earliest forms of life, as well as with climatologists, planetary scientists, and researchers from nearly every field of science.

In 1998 NASA established the NASA Astrobiology Institute (NAI) as one element of its research program in astrobiology. The NAI is currently composed of 12 Lead Teams, which together represent over 700 investigators across the United States, and it has international partnerships with astrobiology research organizations around the world.

The major research themes of astrobiology are described in detail in the NASA Astrobiology Roadmap."

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Technorati: nasa, astrobiology, research

Permanent Link posted by John Latter @ 11:35 AM 0 comments

An open access/free PLoS Biology article by the science writer Tabitha M. Powledge**.

Citation: Powledge TM (2006) What Is the Hobbit? PLoS Biol 4(12): e440 DOI: 10.1371/journal.pbio.0040440

Who - or what - is Homo floresiensis? The tiny hominid bones, which a joint Australian-Indonesian team unearthed in 2003 on the Indonesian island of Flores, have quickly become as celebrated (and derided) as any find in the tempestuous history of human paleontology. The mystery that shrouds these ancient skeletons, nicknamed hobbits after the diminutive characters in J. R. R. Tolkien's novels, seems to deepen with every study published. Two main camps have emerged, each certain they can settle the question. But many other paleoanthropologists confess they still have no idea.

H. floresiensis Discovered

The discovery team declared their find a new human species, H. floresiensis, based primarily on a single near-complete skeleton of one very small individual with a very small brain, known as LB1. Compared to H. sapiens, LB1, whose age was estimated from tooth wear at about 30 years, was only one meter tall - about the size of a 4-year-old H. sapiens child - with a brain the size of a newborn's. Although there are also fragments of eight other small individuals, they provide no information about brain size, nor is much skeleton preserved. Nonetheless, they possess a combination of features never before seen in human fossils, which makes it credible that a previously unknown population of people smaller than today's pygmies lived on Flores between 90,000 and 12,000 years ago.

Stone tools found at the site raise the possibility that hobbits had culture, even though LB1's brain size would make a chimpanzee sneer. H. floresiensis, the discovery team claimed, could be the first human example of island dwarfing. This phenomenon, thought to be evolution's response to limited resources, is known for other mammals, including dwarf elephants from Flores itself. But this is not the only possible conclusion. A long-awaited paper [1], which appeared online in Proceedings of the National Academy of Sciences of the United States of America (PNAS) on August 23, 2006, offers a radically different interpretation of these skeletal remains.

H. floriensis Disputed

The lead author of the PNAS paper is Teuku Jacob, the "Grand Old Man" of Indonesian paleoanthropology. Jacob was not a member of the discovery team, but his lab at Gadjah Mada University in Yogyakarta on Java is home to many hominid fossils discovered in the region. For reasons still unclear, soon after the journal Nature published the discovery papers in October 2004, the hobbit bones were conveyed to Jacob's lab from the Center for Archaeology in Jakarta, about 450 kilometers away.

The result was an international uproar played out in the media. Australian members of the discovery team were irate because their finds were moved without their permission and were no longer available for study. Other paleontologists expressed alarm at what seemed like one group of scientists making off with finds of another. Jacob said he had been invited to take them.

Moreover, Jacob pronounced that the bones did not belong to a new hominid species, but were those of H. sapiens after all. How to account, then, for the diminutive size of LB1? Jacob concluded that LB1 suffered from microcephaly, a disorder resulting in abnormal development of the brain and, often, body. His diagnosis was backed by Indonesian colleagues and also a few Australian and American researchers whom he permitted to study the bones.

After complex negotiations, most of the bones were returned to Jakarta in February 2005. But the uproar revived when discovery team member Michael Morwood of the University of New England (Armidale, Australia) protested that LB1's pelvis was smashed and another hobbit's jaw was broken and repaired clumsily. Jacob responded that the bones were fine when they left his lab.

When the criticisms of Jacob and his collaborators were finally published in August 2006, they reiterated previous claims that the LB1 skull was unnaturally asymmetrical, showing signs of deformity. The paper also reported that many LB1 traits resemble those of Austromelanesians, and some are similar to Rampasasa pygmies living near the dig site at Liang Bua cave. Hobbits are probably related to them, the authors said, and therefore not a new species. Moreover, LB1 was microcephalic. The authors proffered specific anatomic details to establish their case. However, even when researchers agree on details of hobbit anatomy, it seems they can't agree on their meaning.

Chinless Wonders

Take the chin. Chins mark a skeleton as sapiens; no other hominids have them. Everyone agrees that the two hobbit mandibles lack chins. But the PNAS paper asserts that appearing chinless does not necessarily mean that the hobbits were not H. sapiens. The paper included a photo of a live Rampasasa pygmy with what the authors termed a negative chin.

But paleoanthropologist Jeffrey Schwartz from the University of Pittsburgh (Pittsburgh, Pennsylvania, United States) points out that although having a chin signifies our own species, there are individual exceptions, so chinlessness doesn't say much. "Having a chin provides information. Not having a chin doesn't."

If chinlessness can't illuminate the discussion, what about teeth? Hobbit teeth are a strong reason to think they may not be a new species. Everyone agrees that compared with other hominids, which have big teeth, hobbit teeth are small, like sapiens teeth. Not only are they small, according to paleoanthropologist John Hawks of the University of Wisconsin (Madison, Wisconsin, United States), hobbit teeth are small in the sapiens pattern: first molars are biggest and third molars smallest. H. erectus and Australopiths have different patterns.

Robert Eckhardt of Pennsylvania State University (State College, Pennsylvania, United States), an author of the PNAS paper, argues that chance convergence of traits in different hominid lineages is unlikely to explain these similarities. Coauthor Etty Indriati, colleague of Jacob's at Gadjah Mada, notes that hobbit teeth also share features with Rampasasa pygmy teeth, such as rotation of the premolar, that imply genes in common.

Ralph Holloway, paleoanthropologist at Columbia University (New York, New York, United States), who shares the critics' belief that LB1's brain was pathological, nevertheless was dissatisfied with the PNAS paper. "It's the kind of paper that should be published, but they could have done a better job on it." Hobbits, he says, should have been compared to several populations. Indriati responds that it is sounder scientifically to compare LB1 with Flores pygmies, its closest neighbors in both space and time.

The Meaning of Asymmetry

Holloway agrees that LB1's cranium is asymmetrical. But he and others also agree with University of New England co-discoverer Peter Brown that asymmetry could result from being under several meters of deposits for several thousand years, plus the difficulties of recovering and reconstructing bones described originally as like wet blotting paper. Hobbit bones were never fossilized. "To use that asymmetry to make a case for pathology, you know, I don't think that's a very strong argument," Holloway says.

The PNAS authors reinforced the case for asymmetry with striking composite photographs of LB1's face (see the Figure). They divided right and left sides at the midline and mirrored each side to yield two photos displaying obvious differences in right and left side facial architecture. A "heuristic device to emphasize the left-right differences," according to Eckhardt. However, says paleoanthropological craniofacial specialist Todd Rae of Durham University in the United Kingdom, "You can know if it's markedly asymmetrical only by comparing it statistically to other specimens that have also undergone the process of burial and recovery - i.e., other fossils."

The Hobbit's Brain

A March 2005 paper in the journal Science, whose authors include a subset of the discovery team, reported that a virtual endocast of LB1's cranium, which has brain features imprinted on it, suggested that hobbits were not simply miniature versions of sapiens or erectus, but still may have had human-like thinking abilities because the prefrontal cortex and temporal lobes seemed expanded. The region, known as Brodmann area 10, is thought to be the seat of higher cognitive processes like memory, communication, and planning.

By contrast, Holloway, who has also studied an LB1 endocast, says the brain's small size and some other features hint at pathology. Parts of area 10 called the gyri recti seem too thin, he reports, and he has never seen a human endocast so flattened out before, which also suggests abnormality. Like several other researchers, Holloway has tried (and failed) to find direct correspondences between LB1's cranium and those of people with microcephaly. Microcephaly, meaning simply small head, is an umbrella term for a miscellany of conditions with scores of different genetic and environmental causes and myriad manifestations. The most recent study, published online in Anatomical Record on October 9, 2006, concludes that "it is not possible to match any of these syndromes exactly with the LB1 fossil," although the authors argue that some microcephalic syndromes share features with LB1, including stature, head size, and anomalies of jaw and teeth. As all the studies point out, nothing so far unearthed in the clinical literature or the fossil record matches LB1's peculiar head. Those negatives, of course, don't rule out deformity, especially deformity unique to the hobbits; isolated populations routinely develop distinctive abnormalities.

Debbie Argue of Australian National University (Canberra, Australia) and co-authors of an October 2006 paper in the Journal of Human Evolution say LB1 is probably not microcephalic, and they endorse the designation of a new species. They also say the hobbits are not pygmy-like. They suggest instead (as have others) that, whereas LB1's cranium is not like anything else in the hominid fossil record, some other hobbit bones resemble much older early human (but non-Homo) fossils known only from Africa - the Australopithcines.

A Very Ancient Mariner?

The original Nature paper had speculated that hobbits might have been a dwarfed descendant of H. erectus. H. erectus was near our size, huge compared with tiny LB1, and members of the discovery team have backed away from that notion. Argue and colleagues concur that H. erectus is an unlikely ancestor because of differences in cranial shape and limb proportions. William Jungers and Susan Larson of the State University at Stony Brook (New York, United States) have analyzed hobbit postcranial material at recent paleoanthropology meetings. They have found limb proportion convergences with Lucy, the most famous member of Australopithecus afarensis. Still, they say, shoulder characteristics more closely match early H. erectus.

At least a genetic link to H. erectus is not geographically outrageous. H. erectus had been in the region for nearly 2 million years; in fact, the type specimen was found more than a century ago on the Indonesian island of Java.What is a hobbit?

But, unlike big-brained erectus, whose brain was 75% of the size of ours, there is no evidence whatever that small-brained Australopiths (35% the size of ours) ever ventured out of Africa - let alone invented boats and sailed off to Indonesia more than 3 million years ago. The Argue et al. paper speculates on ways very early hominids might have migrated to the region. Something like this astounding seagoing scenario - a really, really ancient mariner - seems to be required if H. floresiensis had Australopith ancestry.

Hawks speculates that this quandary might go away if we knew more about the environmental and developmental factors that determine human body size. "We have no idea what explains body size, and the hypotheses about this are not compelling."

Maybe LB1's pelvis looks Australopithecine, Hawks suggests, not because the hobbits descend from a seafaring Lucy, but because that's what the pelvis of a very small human biped looks like. "It has the virtue of not depending on external events to explain it," Hawks says. "It's just a consequence of being small. You still have to explain why they're small." If we knew why growing big or small was advantageous, we might learn whether island dwarfing applies to people as well as elephants.

Richard Potts of the Smithsonian Institution (Washington, DC, United States) suggests something similar. What would happen, he wonders, if an early, smaller-brained erectus was subjected to island dwarfing? Would ancestral Australopithecine features emerge, perhaps as a result of changes in fetal development? "We'd like to know that, but you know, we just don't."

Were Hobbits Toolmakers?

The debate over the hobbit brain has been fueled by stone tools found at the site. A commentary accompanying the original two papers suggested that some were like tools associated elsewhere with modern humans. This suggested to others that hobbits had a complex culture.

Stone tool experts, however, say the tools are not particularly sophisticated. They are simple, made using techniques that hominids have used for millions of years and humans are still using today.

A team led by Adam Brumm of Australian National University has tried to show that hobbits were part of a line of Flores tool makers who had been chipping sharp flakes from stone for upwards of 700,000 years. The researchers based their analysis on more than 500 stone artifacts excavated at another Flores site 50 kilometers from Liang Bua and dated between 800,000 and 740,000 years ago. No erectus remains have been found on Flores so far, but paleoanthropologists assume they made and used the tools. The paper compared the very old tools with those found at Liang Bua and noted specific similarities.

The Flores tools are unique but also simple, according to Potts. "The tools we see on Flores, the older as well as the younger, cannot be exactly matched with anything that's known anywhere else" he says, "but the overall strategy of the technology and the overall size of the materials is consistent with what we find in mainland China."

Harold Dibble of the University of Pennsylvania Museum agrees. They would fit perfectly at a million-year-old site, he says, but also are a type made by native Australians today. "These are simple tools," says Dibble, "Could they have been made by a small brain? Sure."

The Politics of Hobbitry

H. floresiensis debates have been marked by a degree of acrimony that may seem excessive and even a bit scandalous to outsiders. But a number of paleoanthropologists opine that it's pretty much the usual fossil furor - even though it's been punctuated by public name-calling, a high level of rancor, and exceptionally gaudy episodes like the hobbit bones' unanticipated travels.

"I don't think there's anything special about this dispute except that it's taking place in a particular cultural context of Indonesian politics, which science gets drawn into, just as it does in every other country, at least certain fields of science," says Potts. "There are aspects of etiquette and the way of treating other people that may represent a bit of a clash between the Australian principal investigators and the Indonesian science community, which tends to be a little bit less, well, freelance about such things. I think that there may be a bit of a culture clash there."

There are also other theories about LB1 and compatriots. Holloway, for example, says he hasn't given up on his notion that hobbits may have been taken care of and kept as pets by other Flores H. sapiens, "sent out to fetch the wood or the occasional dead rat, bring it back, whatever!"

The most extreme proposition comes from Schwartz: "It's an interesting assemblage of bits and pieces that probably represent different kinds of hominids and maybe even some non-hominids," he argues. "It's more interesting to me that there might be these different morphologies represented, and the implications of that, than to do a Rube Goldberg hominid and say, ‘Look how weird this is.’"

"To be very blunt, this is just stupid," says co-discoverer Peter Brown. For example, he explains, LB1's arm articulates with the skeleton, meaning they are from the same individual and not different taxa. But Brown thinks LB1's skeletal proportions and brain size are unlikely to be due to dwarfing of H. erectus. Instead, the most likely ancestor of H. floresiensis was small-bodied and small-brained. "This is not the same as saying the ancestor was an Australopithecine."

DNA analysis might help, but prospects are gloomy. The site is hot and wet, perfect for destroying genetic material. There's been at least one effort to find DNA in hobbit bone, carried out in the lab of ancient DNA specialist Svante Paabo of the Max Planck Institute (Leipzig, Germany). It failed.

So on present evidence, the debate about whether hobbits were a different kind of human or simply deformed can't be settled. It is even possible that both sides are partly right. Hobbits are so different from anything else in the hominid record that calling them a new human species is by no means crazy. But even some scientists who buy the new species argument think there may have been something wrong with LB1 and that the much-disputed brain is indeed abnormal.

What is the hobbit? "I don't know," Holloway admits, and he has plenty of company. But, he observes, the puzzling hobbits don't change the major outlines of human evolution. "I think it's sort of a side issue."

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[1] "Pygmoid Australomelanesian Homo sapiens skeletal remains from Liang Bua, Flores: Population affinities and pathological abnormalities"

T. Jacob et al.

Published online before print August 23, 2006, 10.1073/pnas.0605563103
PNAS | September 5, 2006 | vol. 103 | no. 36 | 13421-13426

Abstract

Liang Bua 1 (LB1) exhibits marked craniofacial and postcranial asymmetries and other indicators of abnormal growth and development. Anomalies aside, 140 cranial features place LB1 within modern human ranges of variation, resembling Australomelanesian populations. Mandibular and dental features of LB1 and LB6/1 either show no substantial deviation from modern Homo sapiens or share features (receding chins and rotated premolars) with Rampasasa pygmies now living near Liang Bua Cave. We propose that LB1 is drawn from an earlier pygmy H. sapiens population but individually shows signs of a developmental abnormality, including microcephaly. Additional mandibular and postcranial remains from the site share small body size but not microcephaly.

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**Tabitha Powledge is also author of the European Molecular Biology Organization (EMBO) paper Skullduggery:

The discovery of an unusual human skeleton has broad implications

When a team of Indonesian and Australian palaeontologists discovered a nearly complete but very strange 18,000-year-old human skeleton in an Indonesian cave in 2003, the find provoked questions about modern human origins. Do these ancient bones belong to a new human species? Are they, as many have claimed, the most important find in hominid palaeontology for decades? Or is this creature - indelibly christened 'the Hobbit' because it is so tiny - simply one of an isolated people who suffered from a deforming malady? The huge stakes in this competitive, caustic debate can be summed up succinctly: money and fame. But Hobbit investigations may eventually have less impact on the study of human evolution than they do on the standing of palaeoanthropology, and on the continuing crusade against the Darwinian account of how life on Earth evolved.

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