Thursday, December 12, 2013
Wednesday, December 11, 2013
Monday, December 9, 2013
Sunday, December 8, 2013
Saturday, December 7, 2013
Thursday, December 5, 2013
Saturn's hexagon is a persisting hexagonal cloud pattern around the north pole of Saturn, located at about 78°N. The sides of the hexagon are about 13,800 km (8,600 mi) long, which is longer than the Earth's diameter. It rotates with a period of 10h 39m 24s, the same period as Saturn's radio emissions from its interior. However, the hexagon does not shift in longitude like other clouds in the visible atmosphere.
Saturn's south pole does not have a hexagon, according to Hubble observations. But it does have a vortex, and there is also a vortex inside the northern hexagon.
Saturn's polar hexagon discovery was made by the Voyager mission in 1981--82, and it was revisited since 2006 by the Cassini mission. Cassini was only able to take thermal infrared images of the hexagon, until it started to become visible by light in January 2009. Cassini also recently was able to take a video of the hexagonal weather pattern, while traveling at the same speed as the planet, therefore recording only the movement of the hexagon.
Hexagon on Saturn
Wednesday, December 4, 2013
Monday, December 2, 2013
Sunday, December 1, 2013
Saturday, November 30, 2013
Friday, November 29, 2013
The SNCASO SO.9000 Trident was a mixed power French prototype interceptor aircraft of the 1950s. Capable of supersonic flight the project was cancelled in July 1957 after only 12 examples had been built.
The French Air Staff tasked SNCASO to develop a point defence interceptor, studies began in October 1948. The aircraft that emerged was a shoulder wing monoplane, to be primarily powered by a SEPR rocket engine and augmented with wing-tip mounted turbojets. First flown on 2 March 1953 by test pilot Jacques Guignard the aircraft used the entire length of the runway to get airborne powered only by its turbojets. From March 1955 the Trident I flew with new turbojets, the more powerful Dassault-built MD 30 Viper ASV.5, which produced 7.34 kN (1,654 lbf) thrust each. With these engines it soon exceeded Mach 1 in a shallow dive without rocket power.
Test flights of the SO.9000 were described by the author Bill Gunston as 'hairy' until the rocket motor was added in September 1954. During the 18-month test programme the aircraft completed over 100 flights, eventually reaching a speed of Mach 1.8 and an altitude of 20,000 metres (65,000 ft).
A Trident II was lost due to an accident on 21 May 1957 The project was cancelled in July 1957.