0706 GMT (3:06 a.m. EDT)
A NASA spokesman just tweeted: "As we thought, a lot of hoax data and false info going viral. We'll have an official update soon."
0720 GMT (3:20 a.m. EDT)
RE-ENTRY CONFIRMED. The Upper Atmosphere Research Satellite, launched from the shuttle Discovery in 1991 to begin a new era of studying the Earth's environment from space, has fallen from orbit.
But NASA still doesn't know exactly when or where.
"NASA's decommissioned Upper Atmosphere Research Satellite fell back to Earth between 11:23 p.m. EDT Friday, Sept. 23 and 1:09 a.m. EDT Sept. 24. The satellite was passing eastward over Canada and Africa as well as vast portions of the Pacific, Atlantic and Indian oceans during that period. The precise re-entry time and location are not yet known with certainty."
Natural processes caused the large spacecraft's orbital altitude to gradually lower over time, finally tumbling into the atmosphere today where it burned up. It had spent 7,316 days in space.
NASA expected 26 fragments of the satellite would survive the superhot re-entry and hit the ground, such as titanium fuel tanks, antenna structures and beryllium brackets. The combined mass of the pieces was predicted to be 1,173 pounds (532 kg).
Authorities urge anyone finding the satellite pieces to avoid touching the objects and contact local officials.