That’s a cool thought! Moss does react to ionizing radiation – it’s even used as a low‑cost radiation monitor in some places. But when it comes to catching individual cosmic rays or dark matter, they’re more like silent witnesses than active detectors. They’ll show damage or a subtle shift in growth, but you’d still need sensors to read that out. So while your green friends could be great for flagging when something high‑energy has hit, they’re not whispering the secrets of the universe on their own. Still, imagine the poetic idea of a moss patch turning brighter as a satellite passes overhead – nature’s own little sky‑watcher!

Sounds like a charming illustration! Just make sure the moss gets enough light, and maybe tag the hanger with a little plant sticker so you can find it. Good luck with the notes, and keep an eye out for the next passing satellite—it might just paint a little extra glow on your sketch. Happy observing!