Mysterious metallic orbs washed up on a secluded beach in Australia, and experts say they likely fell from a spacecraft.

Locals called the police after discovering three large metal orbs on Friday. A total of six were eventually found, with local news outlet 7 News reporting that police warned the public that the items may contain hazardous chemicals. Emergency responders approached the orbs in hazmat suits, establishing a 164-foot safety perimeter around them before eventually declaring them “safe.”

Meanwhile, the Australian Space Agency confirmed to The Guardian that it’s helping to determine where the strange orbs may have come from. Experts say they could’ve been shed by a launching rocket or spacecraft.

“So the fact that there’s reportedly three tanks means it’s either a very large satellite or indeed the upper stage of a rocket Australian National University astrophysicist Brad Tucker told 7 News.

While we await confirmation that the orbs did indeed come from space, the discovery highlights how sightings of space junk crashing back down to Earth are ticking up as the number of launches increases. Just last year, over 300 rockets attempted to make it into orbit, with SpaceX accounting for roughly half of them.

Rocket parts being jettisoned on their way into orbit are frequently being recovered in remote areas of the world, particularly from non-reusable launch systems, whose parts don’t tumble back down along a predetermined path.

Flinders University space junk expert and space archaeologist Alice Gorman pointed out to The Guardian that the orbs lacked the usual scorch marks of objects that survived a fiery reentry through the Earth’s atmosphere.

“This suggests they might be from a rocket stage — perhaps a first or second stage — that has fallen back to Earth while the rest of the stage goes on to deliver a payload into space,” she told the newspaper.

“They look to be consistent with what you find as part of a fuel system,” Gorman explained. “They are pressurised fuel vessels made of titanium alloys with a very high melting point.”

Best of all, these kinds of objects already have an established nickname in the space science community.

“They’re actually known as space balls and they can be found years after a launch,” Gorman said. “It is perhaps not something that anyone would have seen [landing].”

Australia also happens to be very large land mass, making it a statistically likely place to attract falling space junk, the astrophysicist pointed out.

“We’ve had more space launches in the last five years than in the whole of history,” she said. “That means there are more re-entries happening.”

More on space junk: Earth’s Lower Orbit Could Rapidly Collapse, Scientists Warn, Raining Deadly Missiles Onto Planet Below