Question

2. It is an open secret that two Hubble Telescopes were made at the same time, and that the US Airforce secretly launched the second one into space. While the first telescope is used to show us the parts of the universe that are as far from Earth as it is possible to be, it is widely believed that the second one is used to spy on people on Earth. This is almost certainly true, but some of the “urban myths" about how much information can be gained from the telescope are not. For example, some people believe that messages on the screen of a cell-phone could be read by the telescope. Estimate the maximum distance at which the Hubble telescope could resolve the printing on this page. Compare this to the minimum altitude of a satelite orbiting Earth, 160 km. Could Hubble conceivably read a cell-phone? (The Hubble Telescope has a circular aperture of diameter 2.4 m.)

Answer 1

Remember that: 1.222 sino D Here: d sino tan L Then: d 1.222 L D The distance is: dD L 1.222 A distance between letter: d = 2 mm D = 2.4 m а 600 nm Then: 2 x 10-3 X 2.4 L 6557.3 m = 6.56 km 1.22 x 600 x 10-9