Tuesday 20 September 2011

GRACE


The Gravity Recovery And Climate Experiment (GRACE), a joint mission of NASA and the German Space Agency, has been making detailed measurements of Earth's gravity field since its launch in March 2002.
Gravity is determined by mass. By measuring gravity, GRACE shows how mass is distributed around the planet and how it varies over time. 
GRACE is a collaborative endeavor involving the Center for Space Research at the University of Texas, Austin; NASA's Jet Propulsion Laboratory, Pasadena, Calif.; the German Space Agency and Germany's National Research Center for Geosciences, Potsdam. The Jet Propulsion Laboratory is responsible for the overall mission management under the NASA ESSP program.


Thursday 15 September 2011

Tuning neurons

"Have you ever wondered why certain sets of musical notes sound perfectly melodious while others make you want to cover your ears? Now, physicists in Europe have developed a model that suggests that certain notes sound harmonious because of the consistent rhythmic firing of neurons in the auditory system."
Physicists in tune with neurons - physicsworld.com

Wednesday 7 September 2011

Magnetic scan without magnet

Magnetic scans with a tiny magnet, by Michael Schirber, a discussion of the paper entitled Near-Zero-Field Nuclear Magnetic Resonance by M. P. Ledbetter, T. Theis, J. W. Blanchard, H. Ring, P. Ganssle, S. Appelt, B. Blümich, A. Pines, and D. BudkerPhys. Rev. Lett. 107, 107601 (Published September 1, 2011)
"Nuclear magnetic resonance is a powerful technique for analyzing molecular structure in biology, medicine, and materials science. Conventionally, it calls for huge magnets to align nuclear spins and to detect them with high sensitivity, but recent work has demonstrated that similar analysis can be done without a magnetic field. The problem with this zero-field technique is that it can’t unambiguously identify molecules. Now, in a paper in Physical Review Letters, Micah Ledbetter of the University of California, Berkeley, and his collaborators address this limitation, showing that a very small magnetic field can provide extra signatures for chemical discrimination."
http://physics.aps.org/synopsis-for/10.1103/PhysRevLett.107.107601

Friday 5 August 2011

Collision may have shaped the Moon

"Differences between the near and far sides of the Moon could be the result of a collision between the Moon and a "Trojan" companion that occurred billions of years ago. That is the conclusion of geophysicists in the US and Switzerland who have done computer simulations on how the Moon would be affected by such a massive impact."
Trojan collision may have shaped the Moon - physicsworld.com

Flowing water may exist on Mars

"Liquid water might exist on Mars today, according to a group of scientists in the US. Images from NASA's Mars Reconnaissance Orbiter (MRO) reveal that dark, narrow, finger-like structures follow slopes in certain regions of the southern hemisphere of the planet during its summer months."
Flowing water may exist on Mars - physicsworld.com

Thursday 28 July 2011

Spinons

"An international group of researchers has measured, for the first time, the phenomenon of spin–charge separation in bulk in a solid. They also found that the material violates the empirical Wiedemann–Franz law that has held true for more than 150 years."
Spinons take the heat - physicsworld.com
In fact, it is well kwown that the Wiedermann-Franz law is an approximation.

Thursday 21 July 2011

Artificial leaves make fuel


"Two teams of researchers in the US have taken important steps towards the creation of commercially viable "artificial leaf" – a hypothetical device that can turn sunlight into electrical energy or fuel by mimicking some aspects of photosynthesis.
Earlier this year, the chemist Daniel Nocera at the Massachusetts Institute of Technology (MIT) announced artificial-leaf prototypes at the annual meeting of the American Chemical Society in California. Now, working with two different teams of researchers, he has published two papers on different devices that represent progress towards effective and commercially viable versions of the artificial leaf."
Artificial leaves make fuel from sunlight - physicsworld.com

Shoemaker (formerly Teague) Impact Structure

"The Shoemaker (formerly Teague) Impact Structure—located in Western Australia in a drainage basin south of the Waldburg Range—presents an other-worldly appearance in this astronaut photograph. The Shoemaker impact site is approximately 30 kilometers (19 miles) in diameter and clearly defined by concentric ring structures formed in sedimentary rocks (brown to dark brown, image center). The rocks were deformed by the impact event approximately 1.63 billion years ago (as reported by the Earth Impact Database). Other age-dating analyses of granitic rocks at the core of the structure call this age into question (Pirajno et al. 2003)."
http://eol.jsc.nasa.gov/EarthObservatory/Shoemaker_Impact_Structure.htm
"Beginning with the Mercury missions in the early 1960s, astronauts have taken photographs of the Earth. Our database tracks the locations, supporting data, and digital images for these photographs. We process images coming down from the International Space Station on a daily basis and add them to the 1,101,059 views of the Earth already made accessible on our website."

Monday 18 July 2011

Biofuel for flights

"Lufthansa, Europe's second-largest airline, became the first carrier in the world to offer regular scheduled flights running on biofuel, with four daily round trips between Hamburg and Frankfurt.
The airline will use a biofuel blend using 50 per cent so- called hydrotreated renewable jet fuel, Lufthansa said. The fuel is made from feedstocks including inedible plants and wood chips. Lufthansa will fly an Airbus A321 on the services." Read more
http://www.smh.com.au/travel/travel-news/lufthansa-begins-worlds-first-regular-biofuel-flights-20110718-1hks1.html

La portata

Testo e immagini adattate da 
Halliday Resnick Walker
Fondamenti di Fisica