Modeled human skull from the New Hebrides is on display at the Museum of Anthropology.

One of the great drawbacks of placing a precious object, such as the Hope Diamond, in a museum is that it is then only visible to the tiny portion of the public that happens to live nearby--or that happens to have the time and money to go there. At least, that used to be a necessary drawback, before the rise of the Internet.

As museums grow more computer-savvy and take advantage of increasing bandwidth, many of them are starting to offer virtual tours of their collections, often including images available only in cyberspace. At the same time, some government institutions, university laboratories and even enterprising individuals are placing their own high-quality images online. Armchair travelers now find they have numerous choices when they want to visit to a well-curated science museum or exhibit on the Web.

Our tour might as well begin in someplace remote--why not take advantage of those international phone lines? Singapore's National Heritage Board maintains a fast, graphically meticulous site (what else?) that contains a nice selection of images of Asian culture, art, artifacts and modern lifestyles. The Tandanya National Aboriginal Cultural Institute documents works by the aboriginal peoples of Australia. Even at the University of Michigan's Museum of Anthropology there is a taste of the exotic: currently on display are paintings from New Guinea and Tankas (painted cloths) from Tibet.

Web museums let you travel through time as well as through space. The History of Science Museum in Florence houses an intriguing collection of artifacts connected with Galileo Galilei--including, astoundingly enough, the preserved middle finger of the great scientist's right hand. For those who cannot get enough Galileo memorabilia, more can be found on the web site of the Telescopio Nazionale GALILEO, also in Italy; continuing the gruesome theme, Telescopio Nazionale offers a look at Galileo's fifth lumbar vertebra. (Intrigued by anatomy? Visit the Visible Human Project, which has released to the public some mind-bending images of sectional slices of a human cadaver.)

For a journey much farther into the past, drop by one of the two excellent dinosaur museums on the Internet: the University of California Museum of Paleontology and the Royal Tyrrell Museum's dinosaur hall. (In fact, the entire Royal Tyrrell Museum, located in Drumheller, Alberta, is well worth a look.) A more commercial view of dinosaurs is available at the Dinosaur Art and Modeling site.

Other relics from the depths of geologic history can be found in the charmingly no-frills Gem and Gemology Image Gallery, located at the University of Wisconsin. The Smithsonian Gem and Mineral Collection contains a truly staggering collection of images, including the renowned Hope Diamond.

The main Smithsonian Institution site serves as a general starting point for visiting the Institution's many museums. Do not overlook the rich database maintained by Smithsonian Photographic Services. Not all of the Smithsonian museums offer extensive online images, although the National Air and Space Museum has done a nice job in placing its controversial Enola Gay exhibit on the Web.

Continuing upward from the Air and Space Museum, try out the sobering Earth Viewer (a bit slow but worth the wait), which generates interactive views of the earth as seen from a wide variety of perspectives--if you ever wanted to watch a sunset from the Hubble Space Telescope, this is your chance.

Astronomy Picture of the Day provides a regular astronomy fix and includes a substantial image archive. Our tour ends at the National Space Science Data Center, which has collected what might be considered the mother of all exhibits: highlights of just about every kind of astronomical object, presented in a tidy and entirely manageable format. It is the kind of museum that truly would be a nuisance to visit without the aid of the Internet.