In the first of a new series, Kate answers your questions from the comments sections. If nitrogen triiodide is so unstable, how do you make it in the first place? How many dimensions are there? And why doesn’t the Earth fall into the sun? Kate has the answers. Subscribe for regular science videos: http://bit.ly/RiSubscRibe Have more questions you’d like Kate to answer? Stick them in the comments section below! Watch the videos featured: Slow Motion Contact Explosive - Nitrogen Triiodide: https://youtu.be/DFfRqoIdArM?list=PLbnrZHfNEDZyfUXqroIlSf2hOznnThqM0 The Story of Spacetime – with Fay Dowker: https://youtu.be/XtptrdsToXU?list=PLbnrZHfNEDZz256ho3Q4gt7YrF2xApo5g Four Dimensional Maths: Things to See and Hear in the Fourth Dimension with Matt Parker https://youtu.be/1wAaI_6b9JE?list=PLbnrZHfNEDZz256ho3Q4gt7YrF2xApo5g Subscribe for regular science videos: http://bit.ly/RiSubscRibe The Ri is on Twitter: http://twitter.com/ri_science and Facebook: http://www.facebook.com/royalinstitution and Tumblr: http://ri-science.tumblr.com/ Our editorial policy: http://www.rigb.org/home/editorial-policy Subscribe for the latest science videos: http://bit.ly/RiNewsletter