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

Millikan's experiment

Testo e immagine adattati da
Halliday - Resnick - Crane
Fisica II

Dipolo

Un dipolo elettrico è un sistema composto da due cariche elettriche uguali e opposte di segno. È uno dei più semplici sistemi di cariche che si possano studiare e rappresenta inoltre l'approssimazione basilare del campo generato da un insieme di cariche globalmente neutro tramite lo sviluppo in multipoli di quest'ultimo.



Immagini adattate dal libro
Halliday, Resnick, Krane, Fisica 2







n.14 - Esercizio - elettrostatica