Planets heated by dark matter

Audacious notion of the week: planets heated by dark matter - March 30, 2011
"It’s dark outside, permanently. The sun twinkles in the distance barely bigger than other stars. But the ground is warm, and oceans are teaming with life. That’s the scenario envisioned by Dan Hooper and Jason Steffen of Fermi National Laboratory in Batavia Illinois, who released a preprint yesterday about the possibility of dark matter heating planets that are otherwise too far from their host stars to be habitable."

More Nature.com

According to Dan Hooper and Jason Steffen, they " have calculated the capture rate of dark matter particles in Earth-like and super-Earth planets, and determined the resulting surface temperature of those planets that would result from dark matter annihilations. While planets in the local region of our galaxy receive only a negligible quantity of energy from dark matter annihilations," the authors" find that planets in dwarf spheroidal galaxies and in the innermost volume of the Milky Way could plausibly accumulate and annihilate enough dark matter to heat their surfaces to temperatures capable of sustaining liquid water, even in the absence of energy from starlight or other standard sources. Although" they "expect ecologically relevant quantities of energy to be released through dark matter annihilations only within the interiors of planets that reside in very special environments (such as near the Galactic Center, or near the center of a dwarf spheroidal galaxy), and only in the case of dark matter models which feature large elastic scattering cross sections with nuclei (near the current upper limits)," the authors "expect that within such models planets will exist which derive enough heat from dark matter to almost indefi nitely sustain surface temperatures suffi cient to yield liquid water. Even in the absence of starlight, such planets could plausibly contain life. And, given their extremely long lifetimes, such planets may prove to be the ultimate bastion of life in our universe."

The candy floss of rocks

"The earliest rocks in the solar system, from which the terrestrial planets were born, were more like candy floss than hard rock, according to a new analysis carried out by a team including researchers in the UK and Australia. This is the first geological evidence to support the idea that the first solid material in the solar system was extremely porous before it was subsequently compacted into larger bodies, which become the planets we know today."

Earth grew from 'candy floss' rocks - physicsworld.com

Injectable polymer implants stimulate rebuilding of bones

"The need for artificial joint replacements in people with osteoarthritis could soon be bypassed with injectable polymer implants that stimulate rebuilding of bone structures.
The research is being headed by Bristol University’s team of stem cell and tissue engineering experts in collaboration with researchers from Qatar and Canada. Speaking to The Engineer, lead investigator Dr Wael Kafienah of Bristol explained the rationale behind the project."
Injectable polymer implants stimulate rebuilding of bones | News | The Engineer

Folding furrows

Folds on the surface of soft materials are shown to be a consequence of a nonlinear instability.

"Even as we probe physics on ever-smaller scales, materials that can be held and manipulated with our hands often still resist our understanding. Elastic materials, in particular, still confound because of the nonlinear relationship between strain and the displacement of the material needed to maintain the rotational invariance of the elastic energy. The effects of these nonlinearities are often more pronounced at free surfaces, where strain can be alleviated by a large rotation of the surface. When a slab of an elastic material such as rubber is compressed, it develops a sulcus—a sharp furrow in its surface that plunges into the material. First reported for photographic gelatin films over one hundred years ago, they are not just a laboratory curiosity. Sulci create large strains that can lead to material failure. They are also a common motif in the morphogenesis of many organs, most famously in the characteristic folds on the surface of the human brain or, say, the arm of an infant ..."
Physics - Folding furrows, Physics 4, 19 (2011), DOI: 10.1103/Physics.4.19, Folding furrows, Christian D. Santangelo, a viewpoint on: Unfolding the Sulcus, by Evan Hohlfeld and L. Mahadevan, Phys. Rev. Lett. 106, 105702 (2011) – Published March 07, 2011, Download PDF

U.S. Geological Survey

The United States Geological Survey (USGS) is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology, geography, geology, and hydrology. The USGS is a fact-finding research organization with no regulatory responsibility. http://www.usgs.gov/
http://www.usgs.gov/natural_hazards/
http://earthquake.usgs.gov/
http://volcanoes.usgs.gov/

SuperMoon, ovvero la SuperLuna

"The moon will be at its closest to earth since 1993 on March 19th next.
The “Lunar Perigee”, or ‘SuperMoon’ as some astrologers refer to it as, is the opposite of the “Lunar Apogee”, when the Moon is furthest from Earth. Generally, the Moon looks about 12-14% larger at its perigee compared to its apogee. Full moon (19 March) will occur during Lunar Perigee meaning it will look much larger than normal especially when it rises on the eastern horizon at sunset, or given the right atmospheric conditions."

http://www.irishweatheronline.com/news/supermoon-lunar-perigee-on-march-19.html

"La "superluna” el 19 de marzo alimenta especulaciones. El anuncio de una “superluna” para el 19 de marzo comienza a levantar una serie de especulaciones sobre los efectos apocalípticos que ésta tendrá sobre la Tierra. Para este 19 de marzo nuestro satélite alcanzará su distancia más cercana a la Tierra en 19 años, acercándose a 356,578 kilómetros.."

http://connuestroperu.com/index.php?option=com_content&task=view&id=15875&Itemid=56

The Sixth Extinction (ActionBioscience)

The Sixth Extinction, by Niles Eldredge
"There is little doubt left in the minds of professional biologists that Earth is currently faced with a mounting loss of species that threatens to rival the five great mass extinctions of the geological past. As long ago as 1993, Harvard biologist E.O. Wilson estimated that Earth is currently losing something on the order of 30,000 species per year — which breaks down to the even more daunting statistic of some three species per hour. Some biologists have begun to feel that this biodiversity crisis — this “Sixth Extinction” — is even more severe, and more imminent, than Wilson had supposed."

The Sixth Extinction (ActionBioscience)

Life from Space: An Emerging Paradigm

Life from Space: An Emerging Paradigm (ActionBioscience)
"This article summarizes Evolution of Life: A Cosmic Perspective, an original paper by Chandra Wickramasinghe and Sir Fred Hoyle posted on this site (click on above title to read their paper). There, readers will also find a link to the commentary by the peer reviewer of that paper, which provides counterpoint views to the authors’ controversial ideas. The hypothesis, called cosmic ancestry/panspermia, posited by the authors is not widely accepted by the mainstream scientific community. It is published on this site in consideration of the authors’ distinguished contributions to science to date and to provide an opportunity for both scientists and the public to evaluate ideas presented in their paper."
More http://www.actionbioscience.org/newfrontiers/wickramasinghe.html

Life from space

"Richard Hoover, an astrobiologist at the US space agency's Marshall space flight centre in Alabama, said filaments and other structures in rare meteorites appear to be microscopic fossils of extraterrestrial beings that resemble algae known as cyanobacteria. Some of the features look similar to a giant bacterium called Titanospirillum velox, which has been collected from the Ebro delta waterway in Spain, according to a report on the findings.... Hoover, an expert on life in extreme environments, has reported similar structures in meteorites several times before. So far, none has been confirmed as the ancient remains of alien life.
But writing in the Journal of Cosmology, Hoover claims that the lack of nitrogen in the samples, which is essential for life on Earth, indicates they are the remains of extraterrestrial life forms that grew on the parent bodies of the meteorites when liquid water was present, long before the meteorites entered the Earth's atmosphere."

More http://www.guardian.co.uk/science/2011/mar/06/nasa-scientist-evidence-extraterrestrial-life

Image processing?

"An interdisciplinary group of researchers is calling for the help of other scientists to help them to understand how some of the key features of human vision have evolved. The team, led by Gasper Tkačik, a physicist at the University of Pennsylvania, has compiled a database of roughly 5000 images of the Okavango Delta region in Botswana. This tropical savannah habitat is believed to be similar to the conditions that existed in Africa around 20–30 million years ago, at the time of the origins of Old World monkeys, when the basic adaptations in our visual system are thought to have evolved."
Snapping the birthplace of the human eye - physicsworld.com
by James Dacey Snapping the birthplace of the human eye - physicsworld.com

American mastodon

Mastodons  were large tusked mammal species of the extinct genus Mammut which inhabited Asia, Africa, Europe, North America and Central America from the Oligocene through Pleistocene, 33.9 mya to 11,000 years ago. The American mastodon is the most recent and best known species of the group.
The American mastodon, Mammut americanum,  lived from about 3.7 million years ago until about 10,000 BC. It was the last surviving member of the mastodon family. It is known from fossils found ranging from present-day Alaska and New England in the north, to Florida, southern California, and as far south as Honduras and El Salvador.
http://en.wikipedia.org/wiki/Mastodon

http://www.sdnhm.org/exhibits/mystery/fg_mastodon.html
http://en.wikipedia.org/wiki/American_mastodon
http://www.bbc.co.uk/nature/life/American_mastodon

North Atlantic strait at its warmest for 2000 years

"A stretch of water east of Greenland, considered to be the Arctic's main source of heat from the North Atlantic, is warmer now than it has been in at least 2000 years. That is the claim of researchers in Europe and the US who suggest further warming will amplify the effects of climate change in the Arctic region."
North Atlantic strait at its warmest for 2000 years - physicsworld.com

A star and six planets

"A newfound planetary system has six worlds, five of which rank among the smallest known, and the list of unconfirmed candidates has swelled to four figures.

Thirty million kilometers away, trailing the pale blue dot that is Earth as it orbits the sun, is a spacecraft designed to find some of the countless other pale blue dots that may speckle the galaxy. NASA launched this spacecraft, known as Kepler, in 2009 to take a census of Earth-like planets in the hopes of figuring out how common—or how rare—are the conditions under which life has thrived here."

more Scientific American

Una stella e sei pianeti

"Una stella molto simile al Sole ed intorno a lei 6 pianeti che ruotano, un vero e proprio Sistema solare. Ma non è certo il nostro, dato che sta a 2.000 anni luce dalla Terra, una distanza enorme su scala umana, ma molto piccola i termini astronomici. La stella si chiama Kepler 11 e la scoperta del sistema di sei pianeti, tutti piccoli e alcuni con caratteristiche di tipo terrestre, è riportata nella rivista Nature del 3 febbraio."

More http://www.ilsole24ore.com/art/tecnologie/2011-02-02/scoperto-piccolo-sistema-solare-205724.shtml?uuid=AaVAfG5C

"Eye" of Sahara

During a survey by means of Google Maps of the desert near the Nile, I have seen this structure, which seems an eye on the sand.

It is small when compared to the huge Richat structure in Mauritania.

Richat Structure

The Richat Structure is a huge circular feature in the Sahara desert of Mauritania near Ouadane. It has attracted attention since the earliest space missions because it forms an eye. The structure has a diameter of approx 50 kilometres. It was initially supposed a meteorite impact structure.

Image obtained by Google Maps

Archimedes's steam cannon

A steam cannon is a cannon where projectiles are launched by steam. The first steam cannon was designed by Archimedes during the Siege of Syracuse. Leonardo da Vinci was also known to have designed one. The device is metal tube, which would be placed in a furnace: one end of the tube is closed and the other loaded with a projectile. Once the tube reached a high enough temperature, a small amount of water in injected in behind the projectile. Leonardo da Vinci guessed that the water would rapidly expand into vapour, blasting the projectile out the front of the barrel.
See how the  ArchiMITes cannon is working: http://web.mit.edu/2.009/www//experiments/steamCannon/ArchimedesSteamCannon.html

Gulf Stream edging northwards along Canadian coast

The Gulf Stream off eastern Canada appears to have advanced northward of its historical position in recent decades, possibly in response to anthropogenic climate change. That is according to researchers in North America and Switzerland who say that the changes could have some profound implications for marine life off the coast of Canada.

Gulf Stream edging northwards along Canadian coast - physicsworld.com

Molecular motors

"Inside cells there are proteins that convert chemical energy into useful work. For example, kinesins and dyneins haul cargo around the cell. Myosin molecules can bind to actin filaments and exert forces, which is how our muscles work. Other molecules rotate, such as the protein that creates the molecules that are the prime fuel of our cells. The general method by which these molecular motors operate is through a Brownian ratchet mechanism. However, whereas the classic Brownian ratchet does not actually work, molecular motors harness molecular binding energies to satisfy the second law of thermodynamics. Typically, binding of an ion or molecule (such as ATP) to the motor leads to a conformational change in the protein. This conformational change can act like a power-stroke in the motor. Hydrolysis of ATP or release of the bound ion then returns the motor to its original state, thereby completing a cycle (or, in the case of rotational motors, a binding and release event typically only produces a substep of a complete rotation)." from  Does cell biology need physicists?, by
Charles W. Wolgemuth, http://physics.aps.org/articles/v4/4

"The busy life in living cells involves a great deal of transport activities and mechanical tasks, which are undertaken by motor proteins* —molecular machines that convert chemical energy into mechanical work. In recent years, these remarkable machines have inspired artificial devices that deliver mechanical work  or propel themselves in a viscous environment. We do not yet understand the mechanism behind the complex mechanochemical coupling in motor proteins. Standard rules used in macroscale engineering do not work at the nanoscale. New strategies are needed for the development of artificial nanoscale machines." http://physics.aps.org/articles/v3/108

*Motor proteins are a class of molecular motors that are able to move along the surface of a suitable substrate. They are powered by the hydrolysis of ATP and convert chemical energy into mechanical work. more http://en.wikipedia.org/wiki/Motor_protein

Coronary stent

Most balloon angioplasty procedures include the insertion of tiny cylindrical wire mesh structures, called cardiovascular stents*, into the artery to prevent the elastic recoil that follows arterial dilatation. The scaffolding characteristics of the stent provide strength to the artery wall. However, vascular injury during stent deployment and/or recognition of the stent as a foreign material triggers neointimal hyperplasia, causing re-closure of the artery. A recent advancement to counteract restenosis is to employ drug-eluting stents to locally deliver immunosuppressant andantiproliferative drugs.  Furthermore,  auxetic (negative Poisson's ratio) stent structures were proposed that exhibits high circumferential strength in its expanded configuration and low flexural rigidity in its crimped configuration. 

*A stent is an artificial tubular structure inserted into a natural passage/conduit to prevent, or counteract, a localized flow constriction. The term may also refer to a tube used to temporarily hold such a natural conduit open to allow access for surgery.
See also http://en.wikipedia.org/wiki/Coronary_stent

Note the structure of the two stents. Stretching the tube corresponds in increasing the diameter. This image has been obtained after elaboration of the original one: Zwei Stents von schräg vorne mit Zentimetermaß. Ort der Aufnahme: Baden-Baden, Deutschland, Frank C. Müller.