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duminică, 28 octombrie 2012

Descoperire: un nou tip de raze cosmice

Folosind satelitul european cu raze-x XMM-Newton, cercetătorii de la CNRS şi CEA au descoperit o nouă sursă de raze cosmice. Aceste raze cosmice produc o emisie caracteristică de raze-x prin interacţiunea cu atomii din gazul înconjurător.

În vecinătatea clusterului Arches, lângă centrul Căii Lactee, aceste particule sunt accelerate în unda de şoc generată de zeci de mii de stele tinere care se mişcă cu viteze de aproximativ 700.000 km/h. Aceste raze cosmice produc o emisie caracteristică de raze X prin interacţiunea cu atomii din gazul înconjurător. Originea lor diferă de cea a razelor cosmice descoperite cu exact o sută de ani în urmă de Victor Hess, origine ce provine din explozia supernovelor. Aceste descoperiri sunt publicate în revista Astronomy & Astrophysics.

'White Widow' Scenario for Birth of Type Ia Supernovae

J. Craig Wheeler has studied the exploding stars called supernovae for more than four decades. Now he has a new idea on the identity of the "parents" of one of the most important types of supernovae -- the Type Ia, those used as "standard candles" in cosmology studies that led to the discovery of dark energy, the mysterious force causing the universe's expansion to speed up.

Wheeler lays out his case for supernova parentage in the current issue of The Astrophysical Journal. He explains why he thinks the parents of Type Ia could be a binary star made up of white dwarf star (the burnt-out remnant of a Sun-like star) and a particular type of small star called an "M dwarf."

Monster Galaxy May Have Been Stirred Up By Black-hole Mischief

Astronomers using NASA's Hubble Space Telescope have obtained a remarkable new view of a whopper of an elliptical galaxy that may have been puffed up by the actions of one or more black holes in its core.

Spanning a little more than one million light-years, the galaxy is about 10 times the diameter of our Milky Way galaxy. The bloated galaxy is a member of an unusual class of galaxies with a diffuse core filled with a fog of starlight where there would normally be a concentrated peak of light around a central black hole. Viewing the core is like seeing a city with no downtown, just houses sprinkled across a vast landscape.

Big Bang and religion mixed in Cern debate

Some of Europe's most prominent scientists have opened a debate with philosophers and theologians over the origins of everything.

The event, in Geneva, Switzerland, is described as a search for "common ground" between religion and science over how the Universe began.

It will focus on the Big Bang theory.

Hyperfast Stars Point to Black Hole Slingshot

The black hole at the center of our Milky Way galaxy is by far the nearest such supermassive gravitational monster to our sun, yet observing this space-time maelstrom is a challenge because it is 27,000 light-years away and obscured in visible light by intervening star clouds and dust lanes in the galactic plane.

The region of space profoundly warped by the black hole is a little more than a light-year across.

Egypt’s ‘collapsing’ pyramids

My first introduction to working in Egypt was a project in Cairo’s historic old quarter, following the 1992 earthquake that caused widespread and devastating damage. Cintec International won the contract to repair and reinforce a number of badly affected structures, with work commencing in 1998.

The project consisted of some 15 notable mosques and maqaads, successfully strengthened using Cintec’s patented anchoring systems. Most of the essential work was completed by early 2005, with ongoing localised repairs still being undertaken as and when required.

Archaeologists find burnt stucco floor related to astronomical event 1,350 years ago

TECOZAUTLA, MEXICO.- During the excavations in Pañhu, an archaeological zone which will soon open its doors to the public in the municipality of Tecozautla, Hidalgo, archaeologists registered a burn stucco floor, evidence that its main pyramid was desacralized approximately 1,350 years ago. This coincides with an astronomical event which was thought, by its inhabitants, to be a cataclysm. 

Archaeologist Fernando Lopez Aguilar, director of the site’s investigation project promoted by the National Institute of Anthropology and History (INAH – Conaculta), informed that there was a solar eclipse at sunrise the 3rd of August in the year 650 AD. 

History of Hattuşa’s excavation on display

Yapı Kredi Culture Center displays a photography documenting a century of archaeological excavations in the Hattuşa, situated in the northern province of Çorum. The exhibition features photographs drawn from German Archaeological Institute

Istanbul’s Yapı Kredi Cultural Center has opened a new exhibition on Hattuşa, inviting viewers to dig through the history of the past 100 years of archaeological excavations at the ancient Hittite capital in northern Turkey.