The Arecibo Radio Telescope

Those who see the Arecibo radio telescope for the first time are astounded by the enormous size of the reflecting surface The huge spherical reflector is 1,000 feet in diameter and 167 feet deep, and covers an area of about twenty acres. The dish surface is made of almost forty thousand perforated aluminum panels, each measuring 3 feet by 6 feet, supported by a network of steel cables strung across the underlying dish to position them. Suspended 450 feet above the reflector is a...

The Search for a New Home

Lately, many people have begun wrestling with the question of whether humans should begin a search for a new home far from the earth's polluted environment. Alan Dressler is one of several astronomers who have discussed such a search, and the following statement can be found on the Web site Origins (www.origins.jpl.nasa.gov) It will require ambitious telescopes to detail the conditions of such a world with evidence for seas and continents, and seasonal variations. We cannot yet know whether the...

Galileos First Ideas About Telescopes

Galileo is correctly credited with the first use of the telescope for viewing objects in the heavens, but letters between him and friends suggest that he first had other, more pragmatic applications for the telescope. He believed that he could make money selling his telescopes to wealthy Italian princes so that they could use them for military purposes. In Zdenek Kopal's book Telescopes in Space, the author provides two such letters, the first dating from 1609 and the second from 1610. One...