Japan Reactors, Seen From SpaceA plume of white steam billows from ruined reactor 3 (the second structure from the left) at Japan's Fukushima Daiichi nuclear power plant, as seen in a Wednesday satellite image—two days after an explosion blew the roof off the unit's secondary containment building.Varying levels of damage are visible in the all four reactor units at left, while the two tall white rectangular structures at right, reactor buildings 5 and 6, remain intact.Authorities on site are resorting to ever more desperate measures to quell the worst nuclear crisis in 25 years, which began after Japan’s recent earthquake and tsunami resulted in loss of power to the generating station's crucial cooling systems.To avert a catastrophic meltdown, authorities have tried dropping water from helicopters and shooting it from military trucks' water cannons. But radiation levels are creating peril for workers, and residents within a 12-mile (20-kilometer) radius have been evacuated. U.S. officials have urged a wider evacuation area and warn that it could take weeks to get the crisis under control.More Tsunami News, Pictures, Video, and Facts