A Sonic Boom

Is this what a sonic boom looks like? When an airplane travels at a speed faster than sound, density waves of sound emitted by the plane cannot precede the plane, and so accumulate in a cone behind the plane. When this shock wave passes, a listener hears all at once the sound emitted over a longer period: a sonic boom. As a plane accelerates to just break the sound barrier, however, an unusual cloud might form. The origin of this cloud is still debated. A leading theory is that a drop in air pressure at the plane described by the Prandtl-Glauert Singularity occurs so that moist air condenses there to form water droplets. This, an F/A-18 Hornet was photographed just as it broke the sound barrier. Large meteors and the space shuttle frequently produce audible sonic booms before they are slowed below sound speed by the Earth’s atmosphere.

Poorest President in the World Donates 90% of Salary to Charity

Usually presidents are not associated with poverty. Some, like Venezuelan President Hugo Chavez, are even linked to big spending and generous welfare programs.But the President of Uruguay, José Mujica, has earned the nickname of the “poorest,” or the “most generous,” president in the world — depending on how you see things— afterrevealing that he donates 90 percent of his earnings, to charitable causes.

In a recent interview, Mujica told Spain’s El Mundo that he earns a salary of $12,500 a month, but only keeps $1,250 for himself, donating the rest to charity.

The president said that the only big item he owns is his VW car, valued at $1,945 dollars. The farmhouse in which he lives in Montevideo is under his wife’s name, Lucía Topolansky, a Senator, who also donates part of her salary.

Felix Baumgartner’s supersonic freefall from 128k’

After flying to an altitude of 39,045 meters (128,100 feet) in a helium-filled balloon, Felix Baumgartner completed a record breaking jump for the ages from the edge of space, exactly 65 years after Chuck Yeager first broke the sound barrier flying in an experimental rocket-powered airplane. Felix reached a maximum of speed of 1,342.8 km/h (833mph) through the near vacuum of the stratosphere before being slowed by the atmosphere later during his 4:20 minute long freefall. The 43-year-old Austrian skydiving expert also broke two other world records (highest freefall, highest manned balloon flight), leaving the one for the longest freefall to project mentor Col. Joe Kittinger.

Lightning tears the sky apart above the glow of the Chilean volcano


Flames reach up to the heavens as lightning flashes criss-cross the sky.
These extraordinary images show the full force of Mother Nature as a Chilean volcano erupts for the first time in 50 years.
Ash has been thrown six miles up into the sky and the South American government has ordered the evacuation of thousands of residents.
Winds fanned the ash toward neighbouring Argentina, darkening the sky in the ski resort city of San Carlos de Bariloche, in the centre of the country, and its airport has also been closed.

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