Explore the cosmos - without leaving your computer

With all of NASA's successes and failures in space and here on the home planet, and even amid debates about the agency's mission and how its money would best be spent, perhaps the most consistently positive reactions to its work come from the photographs. They are worth a thousand words, as the saying goes, and yet likely to leave the viewer speechless. The images in NASA's vast collections tend to appeal on a basic, almost instinctive level - with judgment limited to aesthetic appeal or visual impact rather than risk/benefit analysis or budgetary considerations. There are probably thousands of routes into the NASA photo libraries, and a simple Google or Yahoo search will reveal most of them, but a few specific examples have been generating some buzz on the web of late. This week we'll look at a handful of sites dedicated to the kinds of pictures you just can't take at home.

We start with a small but timely collection at the Jet Propulsion Laboratory's online 'annual report' for 2005. The Year In Pictures is an auto-launching Flash slide show, sampling 12 months of milestones and discoveries related to such subjects as Saturn, Mars, and the Deep Impact mission to comet Tempel 1. After running the slide show (which includes an animated view of Deep Impact approaching its 'final destination'), Year In Pictures automatically moves to a static gallery of the featured images, which link to news releases and options to download low-, mid-, or high resolution (up to 10 megabytes) copies of the photographs. Finally, a Links page takes surfers to the individual home pages of each of the projects featured on the site.

A more interactive NASA production is the Planet Selector featured on the agency's Solar System Exploration home page. As the name implies, the SSE site sticks relatively close to home, and the Planet Selector introduces us to the neighbors with a nicely designed interface, reminiscent of what one expects to see in your better science fiction movies. (Sadly, it doesn't float holographically in front of the monitor - at least, not in front of my monitor.)

Each planet is accompanied by brief 'biographies,' and particulars about a NASA mission related to that specific world - with the introductory information linking to full treatments including updates, detailed information, and more images than you could ever want to download. For a more concise sampling of pertinent facts, a hemispheric grid hovering above each planet offers such options as "Vital Statistics," some rather surprising details (Earth is hit by up to 22 millions pounds of meteors each day), thumbnail slide shows, and basic but helpful visualization aids. ("If the Earth was the size of a nickel, our Sun would be as tall as a typical front door.")

Beside and below the Planet Selector, SSE menus offer links to such categories as News, Multimedia, and History - all worthy of exploration (and not surprisingly, the options behind Multimedia could be a review in and of itself). But be warned that all these links will dump the Planet Selector interface in order to load the more conventional NASA pages. If you plan to come back, and want to avoid opening the Selector on every return, be sure to use your right-click option of opening the new links into their own windows or tabs.

Taking advantage of the purely dramatic possibilities of NASA's imagery (and the fact that the agency doesn't usually copyright its photographs), the globally dispersed Frontier Multimedia has created a pair of self-running presentations as free samples of commercial products. Deep Space takes a couple of dozen images gathered from NASA's vaults and turns them into a dynamic collection of zooming, panning, and dissolving nebulae, star clusters, and similarly photogenic phenomena (including an extraordinary shot of Saturn's rings). Along the bottom of the screen, captions identify the subjects along with their frequently staggering distances from the home planet, while a choral music track adds a touch of reverence to the presentation. Below the screen, player controls allow visitors to set playback volume, pause and resume at will, or simply use a scroll button to move through the exhibition manually.

As a follow-up to Deep Space, the Frontier team turned the virtual cameras around and produced The Good Earth - using photographs gathered by satellites, the space shuttle, and the International Space Station. Here, the images not only reveal the photogenic (such as Australia's Lake Disappointment) or the astonishing (a sandstorm moving across the Qatar desert), but evidence of human impact as well (a river estuary clogged with silt as a result of logging). As with Deep Space, there is a choral track to provide an audio element to the experience, but Good Earth also adds the Christmas Eve broadcast from Apollo 8 - an excerpt from Genesis as read by the first humans to see the Earth rising above the horizon of another world. The Good Earth closes with an animation of night falling over the entire planet, which, while not scientifically accurate, was sufficiently popular that the folks at Frontier turned it into a screensaver. You can find the animated nightfall on their home page.

And speaking of animations, if you prefer a bit of movement in your images, the European Space Agency's Hubble site has a massive collection of videos available for online viewing or download. The ESA video collection offers almost 350 selections, such as short animations of the telescope itself, zooming portraits of supernova remnants and 3-D 'rotations' of the Eagle Nebula, and a full-length DVD production (broken into download-digestible segments). And in the interests of accessibility, all the videos are available in formats that range from thumbnail-sized QuickTime and MPEG files to television broadcast quality.

But the videos only constitute one section of the ESA's Hubble site, and those so inclined can also move on to the more than 2000 still images (available in multiple sizes and formats), check status reports as the telescope moves toward the end of its life, or download free postcards, wallpapers, desk calendars, and full-sized posters. And in answer to the space-age age-old question of just how real the colors actually are in those especially spectacular images, Hubble's North American home page explains the entire process in Behind The Pictures.

Others? Well, there's the Astronomy Picture of the Day, the Image eXchange and the Earth Observatory, not to mention GRIN (Great Images in NASA). And there's always the collections available at the NASA Image of the Day Gallery. Suffice it to say that if you're drawn to images taken of - or from - space, you'll be able to find images as big or as small, in presentations as basic or as complex, as you like.

Pace yourself.