A refrigerator-sized tank of toxic ammonia, tossed from the international space station last year, is expected to hit earth tomorrow afternoon or evening. The 1,400-pound object was deliberately jettisoned — by hand — from the ISS's robot arm in July 2007. Since the time of re-entry is uncertain, so is the location. "NASA expects up to 15 pieces of the tank to survive the searing hot temperatures of re-entry, ranging in size from about 1.4 ounces (40 grams) to nearly 40 pounds (17.5 kilograms). ... [T]he largest pieces could slam into the Earth's surface at about 100 mph (161 kph). ...'If anybody found a piece of anything on the ground Monday morning, I would hope they wouldn't get too close to it,' [a NASA spokesman] said."