Mysterious metal sphere washes up on Japanese beach, baffles authorities

A 4.9-foot metal sphere washed up on Enshuhama beach in Hamamatsu City, 150 miles southwest of Tokyo, and authorities don't know what it is or where it came from.

The sphere was first spotted by a passerby who reported it to the authorities. Upon arriving at the scene, police quickly cordoned off the area and called in the bomb squad to investigate. The ball was X-rayed and found to be hollow. The beach remains closed.

So what exactly is this mysterious metal ball? Could it be a buoy or some other type of marine equipment? An experimental device? A piece of space debris?

Could it be a remnant of the tsunami that struck Japan in 2011? The tsunami caused widespread destruction and swept a huge amount of debris out to sea. It's possible that this ball was part of that debris and has been floating around in the ocean ever since.