Check out the math & physics courses that I mentioned (many of which are free!) and support this channel by going to https://brilliant.org/Sabine/ where you can create your Brilliant account. The first 200 will get 20% off the annual premium subscription. Why do we have both positive and negative electric charges, but not both positive and negative masses? Could there be negative masses out there which anti-gravitate? How much such anti-gravitating matter behave? Why don't physicists look for it? Could anti-matter anti-gravitate? So many questions! At the end of today's video you will know all that physicists know about this. You can support our channel on Patreon: https://www.patreon.com/Sabine 0:00 Intro 0:31 Newton's law vs Coulomb's law 3:53 Does anti-matter anti-gravitate? 6:55 How would anti-gravitating matter behave? 8:27 Does anti-gravity explain dark matter or dark energy? 11:42 Sponsor message #physics #universe