Science & Technology
Magnetic fields emanating from stars and planets can usually be attributed to convection currents forcing molten metal to shift about in so called "dynamo action", which converts mechanical energy into magnetic energy. In small stars like our Sun, the magnetic field can become so intense in regions on the surface that it traps heat, causing dark sunspots to form. But physicists believe that most larger stars do not have convection currents stretching to their surface and therefore would have a zero - or at least small - magnetic field. This should mean they are devoid of surface structure.
Recently, however, observations of irregular surface distributions of heavy elements on large blue "B-type" stars have swept aside this assumption. In particular, alpha Andromedae, which is 97 light-years from Earth, has a predicted magnetic field less than 10 Gauss, yet appears to have spots of mercury all over its surface.
The fossil, discovered in the Atapuerca Sierra in the northern province of Burgos, is a human tooth. Jose Maria Bermudez de Castro, co-director of research at the Atapuerca site, was quoted as saying the tooth could be as old as 1.2 million years.
The fossil, which gives a new perspective to human history, was found in the entry to Sima del Elefante, a pleistocene deposit that was the last to be systematically excavated in Atapuerca.
Earth contains a heavy version of silicon that is absent from Mars.
The finding, detailed in today's issue of the journal Nature, suggests Earth's core formed under very different conditions from those on Mars. It also supports the idea that the moon formed from material torn from early Earth by a collision with a planet-sized rock.
The initiative at the £300 million hospital at Larbert, Stirlingshire, is intended to allow hospital porters to spend more time dealing with patients.
By adding Tasers to robots it already makes for the military, iRobot Corp. says it hopes to give soldiers and law enforcement a defensive, non-lethal tool.
But some observers fear such developments could ultimately lead to robots capable of deciding on their own when to shoot and kill.
Comment: But questions of moral agency do arise.
What is the difference between a robot and a psychopath taking life or death decisions over others if they are both equally heartless?
It is not known how large the storm might grow, but already it is thousands of miles across. If it balloons, as dust storms have done in the past, it could hamper operations of NASA's Mars rovers Spirit and Opportunity.
Comment: Bad weather on Earth, bad weather on Mars. Coincidence?
Jupiter's turbulent clouds are always changing as they encounter atmospheric disturbances while sweeping around the planet at hundreds of miles per hour. But these Hubble images reveal a rapid transformation in the shape and color of Jupiter's clouds near the equator, marking an entire face of the globe.
|
| ©AP Photo/Amr Nabil |
| The mummy of Pharaoh Queen Hatshepsut is displayed at the Egyptian museum in Cairo, Egypt |
CAIRO, Egypt - A tooth found in a relic box led archaeologists to identify a long-overlooked mummy as that of Egypt's most powerful female pharoah _ possibly the most significant find since King Tutankhamun's tomb was uncovered in 1922, experts said Wednesday.







Comment: Unless, of course, we live in a Matrix.