Normally my digital peregrinations take me to destinations like Facebook, YouTube and BOINGBOING.net. But lately I've been spending time in the Crab Nebula, Cassiopeia A and the Sombrero Galaxy. These addictive celestial visits come courtesy of two remarkable interactive astronomy programs from a pair of companies that would love to vaporize each other—Google and Microsoft. When superpower countries like the United States and the former Soviet Union contemplated moving their conflicts to outer space, there was justifiable fear and dread. But a similar escalation by software superpowers may turn out to be a boon for all.

Last summer Google integrated an astronomy component into its Google Earth program, and last month made the program accessible straight from the Web. Later this spring Microsoft will release its own attempt to boldly go where no man has gone before, a Windows-only program called WorldWide Telescope.

Both efforts offer a means to embark on celestial explorations that skillfully integrate astounding images from telescopes that capture galaxies, star systems and even evidence of black holes from thousands of light-years away, including three of the most celebrated satellite-based probes: Hubble, the Chandra X-ray and the Spitzer Infrared (no hooker jokes, please). Both efforts offer users a chance to navigate their way through the ether. Both include an incredible amount of information (Google Sky has 200 million viewable galaxies; WorldWide Telescope will launch with 1.2 million galaxies but soon add 2 billion more). Both allow amateur stargazers to enhance the programs with their own observations. And both have astronomers raving about how these will not only popularize the field but also help scientists do their work.

You would expect that when two bitter competitors go head-to-head on similar products, the sniping would approximate a Hillary-Barack level of acrimony. But though my questions to each company were painstakingly crafted to elicit snotty remarks about the other's program, neither Google nor Microsoft rose to the bait. (Maybe this is in part because neither company has plans to monetize its space program—for now at least, these are loss leaders for mind-share and good will.) Each refers to the other's product with respect, and the two companies say they hope and expect that though the programs currently encode celestial data a bit differently, eventually Sky and Telescope will be interoperable. "If there's one thing that's universal, it's sky and space," says Google Sky's product manager, Lior Ron.

Yet despite the fact that both draw on the same publicly available images, there are differences, reflecting each company's unique DNA. Google Sky began as one of those "20 percent" projects, where an engineer gets to spend a fifth of his time on anything he chooses. It was launched as a part of Google Earth, which features terrestrial satellite imagery; conceptually Google Sky is what happens when you turn the orbiting cameras in the opposite direction. Users can add layers of new content onto Google Sky, much as they can with Google Earth.

WorldWide Telescope, on the other hand, grows out of Microsoft's high-end research division, where some world-class wizards, notably computer scientist Jim Gray, have been lending their talents to the scientific community to help organize satellite imagery for years. (WorldWide Telescope is dedicated to Gray, who went missing on his sailboat last year.) Since the lead developer, Curtis Wong, has an impressive background in creating multimedia experiences (he was responsible for some early groundbreaking CD-ROM documentaries), the WWT has a powerful and intuitive interface (so attractive that astronomers are hoping to use an upcoming pro version for serious scientific work). One of its key features is the ability to create elaborate guided tours of specific slices of the skies. Like podcasts, the multimedia tours will be available to WWT users. "Stories draw people into the sky, and we allow people to share their own stories about the sky," says Wong. Some of the early tours are by professional astronomers, like Alyssa Goodman's primer on space dust. Wong himself has created a Cassiopeia fly-by with a soundtrack by guitarist Robert Fripp. Another tour has been created by a precocious 6-year-old.