Mysterious fireballs streaked across the sky and crash-landed in Chile last week, setting both the ground and curiosity ablaze. What they were and where they came from is still a mystery, as a first analysis has just ruled out the obvious favorite: meteorites.

On September 25, witnesses reported seeing blazing fireballs light up the sky over Chiloé Island, in the archipelago off southern Chile. Not long after, small bush fires were reported in seven locations across the island, which were quickly put out by volunteers.

The obvious explanation, as astrophysicist and Chilean of the Year, Jose Maza told national broadcaster TVN, was a meteorite or space debris. Residents noted the fireball was moving extremely quickly, burning a bright red, which suggested a meteor, but space junk is just as common, with around 200-400 known objects falling each year.

However, officials from the National Service of Geology and Mining have since analyzed the charred sites strewn across the town of Dalcahue and found no evidence of a meteorite.

“[G]eologists went to the site examining the area of the supposed impact. They worked on seven points corresponding to burnt thickets, where they found no remains, vestiges, or evidence of a meteorite falling,” the report stated.

The geologists told TVN that they have collected soil samples for a more thorough analysis, and will release their conclusions in a few weeks.

So, technically what we have here right now is an unidentified flying object. Yep, a UFO.

Since it’s highly unlikely to be aliens, and a meteorite seems to have been ruled out, the most likely scenario is some kind of space junk falling to Earth. Largely we are unaware of the majority of space junk as it usually burns up in the atmosphere, falls in the ocean (which covers 70 percent of the planet), or lands somewhere remote and unpopulated.

It’s very rare for space junk to actually hit the ground near people, and no one has ever been killed or seriously injured by falling debris. The only known occurrences of people being hit by space debris are five Japanese sailors on a ship that was hit by falling pieces of a Russian spacecraft in 1969, and a curious event in 1997 where a woman in the US got lightly brushed by material that turned out to be from a Delta 2 rocket booster.

The most famous space debris events, of course, involve the space stations Mir and Skylab. America's first space station, Skylab, had a memorable return to Earth in 1979 when part of it crash-landed in Western Australia, who fined the US for littering. Mir, Russia's space station, fell to Earth in 2001. The largest object to ever reenter Earth's atmosphere, it fortunately landed in the Pacific Ocean, but not before we caught some spectacular scenes of it blazing across the sky.