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"http://yt.cl.nr/iQOHRKKNNLQ" In this segment I ask why astronauts in the space station are weightless. The most common answer is because there is no gravity in space. But of course there is gravity in space, especially where the space station is located (only about 400km from Earth's surface). So astronauts still experience a gravitational pull - it's just that they and the space station are in free fall so they are accelerating together towards the Earth. The space station doesn't crash into the Earth because of its orbital velocity - it's going 28,000 km/h so as it falls, the Earth curves away from it.

"http://yt.cl.nr/_mCC-68LyZM" If you drop a heavy object and a light object simultaneously, which one will reach the ground first? A lot of people will say the heavy object, but what about those who know both will land at the same time? What do they think? Some believe both objects have the same gravitational pull on them and/or both fall to the ground with the same constant speed. Neither of these things is true, however. The force is greater on the heavy object and both objects accelerate at the same rate as they approach the earth, i.e. they both speed up but at the same rate.

"http://yt.cl.nr/OZY8279b7BU" At 15,000 metres Prof Brian Cox experiences what a world without gravity would be like.

"http://yt.cl.nr/8V2ncwumv9o" Col. Joseph Kittinger -1960 - set world records for highest parachuting jump (102,800 ft. or 20 miles, 31km), highest balloon jump and fastest speed (close to speed of sound) by a person through the atmosphere.