To suggest topics or sites for Web Watch, please visit http://www.physicstoday.org/suggestwebwatch.html. Compiled and edited by Charles Day

In 1902, an archaeologist noticed that a rocklike block recovered from a wrecked Roman ship had a cog attached to it. By the 1950s, the block had been dated to 80 BC and cleaned enough to reveal the outlines of a sophisticated mechanism of clocklike gears. Its purpose was the calculation of planetary orbits. Research on the remarkable find continues to this day and is summarized and illustrated on the website of the Antikythera Mechanism Research Project.

Curved metallic reflectors and natural sunlight are the ingredients for what artist Janet Saad-Cook calls her Sun Drawings. Photographs and descriptions of the intricate, rainbow-hued illuminations can be found on her website.

Offers an extensive and richly illustrated tour of black hole physics. Astronomer Roeland van der Marel created the award-winning site.

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