Ever wonder what it would be like to ride the doomsday asteroid as it screamed in from outer space and put a quick end to civilization as we know it?
But thanks to NASA and a gazillion of your tax dollars, you can do just that. And it's pretty cool. It's called "Great Zooms From Space," and it comes to you courtesy of the folks at Goddard Space Flight Center in Greenbelt.
FOR THE RECORD - A caption with a photograph published on Page 3F of the Today section yesterday should have identified the site in the aerial shot as the White House. Instead, the text implied that it was Hollywood, Calif.
The Sun regrets the errors.
Using 30 years of photo imagery - most from NASA's Terra and Landsat satellites - and the commercial Ikonos satellite, all stitched together by some very powerful computers, NASA has assembled a collection of virtual thrill rides and made them available on the Web at www.gsfc.nasa.gov/gsfc/earth/imaging/landsat.htm. It was a sort of Earth Day gift from NASA to the people who pay the bills.
Pick your Ground Zero city.
The Washington "zoom" begins several thousand miles in space. The full Earth hangs below, a satisfying green and brown, capped by a lot of snow and ice in Alaska and Canada.
As the zoom begins, the Earth draws closer and fills the screen. We quickly realize we are headed for the East Coast, moving way faster than any conceivable spacecraft. It all looks green and lush, and miraculously cloud-free, thanks to a seamless mosaic of images taken on clear days.
The Middle Atlantic Coast rushes up, then the Chesapeake region and the Potomac River. Soon we can see the gray scars of roads, buildings and pavement - like a spring frost on the lawn.
And now the urban patterns begin to look familiar. There's the Mall, lined with museum buildings, the White House. ... Suddenly, we screech to a stop perhaps 2,000 feet above the Capitol dome. It's a peaceful Sunday morning, judging from the shadow angles and the empty Capitol parking lot. And the planet is saved.
The Atlanta Zoom is much the same, except that it comes to a stop above the state Capitol building, where we hover like the mother ship from the movie "Independence Day." The Los Angeles zoom shrieks down over Southern California and stops above a famous Hollywood landmark.
The plunge into San Francisco stops at Fisherman's Wharf.
The science imagery experts at Goddard are working on a similar "great zoom" for Baltimore.
Wherever you go, pack a sandwich. Downloads may be prohibitively slow on old computers and dial-up Web connections.
But if it's working for you, spend some time and poke around this site. There are satellite images and photo animations that show dramatic and scary urban growth over the past decade in Las Vegas and Shenzhen, China.
Scientists seeking to understand how the planet is changing - and how we are changing it - study these visible-light images, and others gathered at invisible wavelengths, for what they can teach us about the health of crops and vegetation, trends in surface temperature and carbon content in the foliage.
Watch the Aral Sea in Kazakhstan, and Lake Chad, in Africa, dry up as it has over the past 25 years. Or swoop in over Mozambique in a dual-screen flyover showing how a lush farming valley was transformed by flooding last year into a vast lake.
You can see the green forest return to heal the volcanic scars on the flanks of Mount St. Helens or witness the expansion of human settlements and agriculture across the forests of Bolivia and Brazil, like mold growing on bread.
One can only imagine what the view will be like in another 30 years. Hold onto your seats.