Jonathan McDowell, a Harvard astrophysicist, told The Guardian that the announcement suggested China lost control of the station. This means it would be impossible to predict where the debris will land.
"You really can't steer these things," he added. "Even a couple of days before it re-enters we probably won't know better than six or seven hours, plus or minus, when it's going to come down. Not knowing when it's going to come down translates as not knowing where its going to come down."
McDowell said most of the space station would melt as it passed back into the atmosphere, saying that "there will be lumps of about 100kg or so, still enough to give you a nasty wallop if it hit you."
China will launch its next space lab, the Tiangong-2, on Thursday, Wu said.
