An obsolete, out-of-control Chinese space station is expected to come crashing back to Earth in a fiery ball of debris next year, sparking concerns that some pieces might survive re-entry and strike the planet's surface, perhaps in one of Canada's southern-most cities.

China's state-run Xinhua News Agency says the Tiangong 1 space station's orbit has been decaying by approximately 100 metres each day, with experts predicting it will "burn up in Earth's atmosphere in the latter half of 2017." China has lost contact with the space station and it's unknown where it will crash.

Science reporter Ivan Semeniuk of the Globe and Mail says the Tiangong 1 is an unusually large piece of space debris, and poses a greater risk of striking the Earth than the old satellites that typically burn up in the atmosphere when they fall. He adds that China has lost control of the space station, so it will be a "gamble" to see where it comes down.

"We can safely rule out parts of the world that are above latitude 43 north – which is most of Canada – and 43 south," Semeniuk told CTV's Your Morning on Wednesday. The 43rd parallel passes south of most of Canada, although it does cut through the Ontario cities of Sarnia and London.

Semeniuk added that, although the space station debris will likely miss Canada, "most of the populated world" is still in its range.

The cylindrical space station measures 10.4 metres long by 3.35 metres wide.

The last piece of space debris near this size was Russia's MIR space station, which came down in a controlled descent in 2003. That vehicle was significantly larger than the Tiangong 1, at 19 metres long, 31 metres wide and 27.5 metres tall.

NASA's Skylab went through a more nail-biting descent back in 1979, when its out-of-control demise became a worldwide phenomenon. People held Skylab crash parties, and the San Francisco Examiner offered $10,000 to the first person who could retrieve a piece of the wreckage. A 17-year-old from Australia ended up collecting the bounty.

Semeniuk says space debris is a "growing threat" to our planet, as more and more satellites build up in low Earth orbit. "It's a global problem that affects everybody and is going to require countries to work together," he said.

Small objects like satellites typically burn up as they fall to Earth, due to the friction created as they pass through the planet's atmosphere.

China launched its Tiangong 2 space station earlier this month, to replace the Tiangong 1.