There might be some extraterrestrial dust on your roof, at least that’s what scientists in Europe found in Norway. Researchers discovered extraterrestrial dust particles, also known as micrometeorites on rooftop debris.

The material was analyzed and the findings were published on the journal Geology.

Micrometeorites, which survive atmospheric entry and reach our planet’s surface, are thought to include material from asteroids and comets. There was a popular belief that micrometeorites could be found on urban roofs, but now it seems to be true.

Scientists analyzed 500 micrometeorites collected among particles obtained from roof gutters in Oslo, Norway and one from Paris by a group called Project Stardust. Out of the collected material, which weighed a total of about 661 lbs, 48 of the particles were found to be “cosmic spherules.” Cosmic spherules are micrometeorites formed by extensive melting during atmospheric entry heating. Researchers said the cosmic spherules analyzed “represent the youngest large” micrometeorites yet recovered (however, you’ll still need a microscope to see them).

Project Stardust shares pictures of meteorites, here’s one of them:

Every year, more than 100 billion micrometeorites are believed to fall to Earth, but until now scientists believed the extraterrestrial material be found only in the cleanest environments, such as the Antarctic. This means you might be able to find some micrometeorites on your roof.

“The discovery demonstrates that, contrary to current belief, micrometeorites can be collected from urban environments,” scientists concluded.