Back in February, I spent a few hours crawling around on my hands and knees on a rooftop in Brooklyn, New York. What I was looking for was smaller than the period at the end of this sentence: nearly invisible micrometeorites that may — or may not — have fallen from space. Surprisingly, I actually found some. I think.

With the help of a powerful neodymium magnet, some plastic sandwich bags, and a lot of patience, I was able to scrounge up about fifteen cosmic candidates — a process that we documented in our first micrometeorite video.

But finding the samples ultimately proved to be the easy part. Trying to verify their origin turned out to be an entirely different ordeal. Here at Verge Science, we simply didn’t have the capacity to reach a definitive conclusion, so we turned to the micrometeorite experts at NASA.

With a few of our most promising samples, and a bonus sample gifted to us by the world’s foremost micrometeorite hunter, we took a trip to Johnson Space Center in Houston to visit the Astromaterials Research and Exploration Science division. There, we were finally able to get to the bottom of our months-long hunt for a real micrometeorite, and we learned a few things about the universe along the way.

Be sure to check out the full video above for part two of our hunt for micrometeorites.