In this episode of my live Q&BA chat session, I answered a question about how "gravity slingshots" work. This is the process of using the gravity of a planet to accelerate (or decelerate) space probes so they can more easily get to the inner and outer planets. It turns out gravity is not the only process at work here.
This technique is used all the time for spacecraft, and engineers are pretty good about nailing them perfectly, too. Sometimes the probes pass by Earth and take amazing pictures of us, like when Rosetta did in 2009, and in 2007, or when it passed Mars in 2007.
Be sure to check out all my other Q&BA videos!