Eleven point two kilometers per second, at which satellites can be freed from the gravitation of the earth, is called "escape speed".

卫星以11.2千米每秒的速度前进可以脱离地球引力，这被称为“逃逸速度”。

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This spinning motion, at speeds of hundreds of kilometers per second, may cause matter in the disk to take on a spiral shape.

这种以每秒数百公里的速度旋转的运动，可能会使圆盘上的物质呈现出螺旋形状。

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The velocity of the Earth in orbit is about 30 kilometers per second.

地球在轨道里的速度，约为30千米每秒。

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At the time of Endeavour's launch, NASA says the International Space Station was traveling at a speed of about eight kilometers-per-second, above western Romania.

VOA: standard.2010.02.08

Traveling through the sky at a few kilometers per second, friction with the air can cause the meteor to break up into several pieces.

CNN: Meteor shows why it is crucial to keep an eye on the sky

The latest estimate is that the Chelyabinsk meteor was about 56 feet (17 meters) across, weighed more than 7, 000 tons and was moving about 18 kilometers per second (40, 000 mph) when it blew apart, she said.

CNN: Planet of sound: Meteor blast resonated around Earth

The latest estimate is that the Chelyabinsk meteor was about 56 feet (17 meters) across, weighed more than 700, 000 tons and was moving about 18 kilometers per second (40, 000 mph) when it blew apart, she said.

CNN: Planet of sound: Meteor blast resonated around Earth