Vietnamese officials were left scratching their heads after three mysterious metal balls crash landed in a residential area in the country's north on Saturday.
Local residents described hearing "what sounded like thunder, despite no signs of rain," according to English language Vietnamese news outlet VietnamNet Bridge. When they went outside, they found three strange metal spheres that appeared to have fallen from the sky.
The origin of the "space balls," as they were dubbed by BBC News, has not yet been determined.
None of the objects were deemed to be explosives, and defense ministry officials have described them as likely space debris.
Vietnam probes mysterious "space balls" https://t.co/wuJx5gZWmj #NewsFromElsewhere pic.twitter.com/rB6F92ZFDh— BBC Monitoring (@BBCMonitoring) January 6, 2016
One had landed in the garden of a house while another actually hit a home, though no one was injured. A third sphere landed in a vacant field. Each object was between 15 and 40 inches across and weighed up to about 80 pounds; their surfaces were scorched, according to Vietnamese news outlets.
Those same sources have speculated that the spheres were manufactured in Russia because of the Russian writing on the sides of the balls.
Vietnamese officials believe that the balls are space junk, but because they are largely intact, they may have come from lower in the atmosphere.
"This may be the result of a failed launch of satellite," professor Nguyen Khoa Son of Vietnam's State Space Science and Technology Program told VietnamNet Bridge.
All three balls were seized by Vietnam's Air Defence Army and are being investigated.
Initially, some speculated that the metals spheres came from the Vietnamese Army, but officials quickly dismissed that theory.
This isn't the first time that mysterious metal spheres have plummeted to earth and caused confusion. In November 2015, Spanish officials reported that similar spheres plunged into a field in southern Spain.
At the time, they also speculated that the orbs may have come from a satellite or another piece of space material.