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Space

Last Updated: Monday July 20 2009 13:18 GMT

Where does space begin?

Earth from space

There is no clear boundary because the atmosphere gradually thins the higher you go.

The lowest artificial satellites can orbit at about 160km (100 miles) above the Earth.

Here are how high a few things fly from Earth.

  • Space shuttle - 300km (185 miles)
  • International Space Station 350km (220 miles)
  • Passenger aircraft - 9km (6 miles)