From VRubinObs@astrodon.social on Mastodon: What's mysterious, invisible, and permeates the Universe? That's right, dark matter! ....oh, and Halloween spirits too. Happy # DarkMatterDay and a spooky # Halloween , a day to celebrate the stuff we can't see 🌌🎃 At ~85% of the total matter in our Universe, dark matter a big mystery for scientists to solve. Learn how Rubin Observatory will change our understanding of dark matter at http:// rubinobservatory.org/explore/s cience-goals/dark-matter 📷: NASA/ESA