Hubble's ocean of glass

摘要

The Hubble Space Telescope has for the past 25 years powered NASA's dream of putting people into space. Launched on 24 April 1990, it was designed to be looked after by flesh -and-blood astronauts, and repairs and maintenance have run up a bill that would have paid for several new telescopes. But what would have been the point of that? Hubble has been the training ground fora generation of spacefarers. Servicing it has taught NASA everything it knows about building and maintaining the International Space Station. It is also a very fine instrument indeed. Its work is celebrated in Taschen's new book Expanding Universe, which intersperses pictures taken by Hubble, like the one of the variable star Monocerotis below, with images of Hubble's planning and construction. This includes the photo of the 2.4-metre primary mirror shown on the left, which is so smooth that if you were to scale it up to the size of the Atlantic Ocean, its waves would be less than 10 centimetres high.