How to build a dark matter detector – By Jenna Saffin

https://ed.ted.com/lessons/how-to-build-a-dark-matter-detector-jenna-saffin

I hope you didn’t expect that after four and a half minutes you could actually build a dark matter detector. They are very expensive to build and can take forever. We learn that perhaps 25% of matter in the universe is dark and doesn’t emit or interact with light. How come we don’t just bump into it? I guess that they are incredibly small. I guess that’s why we haven’t encountered it yet.