Handbook of Space Astronomy and Astrophysics

... Some weeks later the Einsteins were taken to the Mt. Wilson Observatory in California. Mrs. Einstein was particularly impressed by the giant telescope. 'What on Earth do they use it for?, she asked. Her host explained that one of its chief purposes was to find out the shape of the Universe. "Oh", said Mrs. Einstein, "my husband does that on the back of an envelope. - Bennett Cerf in "Try and Stop Me