Thursday marked the 300th day of astronaut Scott Kelly's historic year-long stay on the International Space Station, and he celebrated in suitably spacey style: bouncing a sphere of water around like a ping pong ball.
The paddles are etched with a special hydrophobic pattern, then covered in teflon — causing water droplets like this one to bounce right off instead of making the paddles wet. As Kelly demonstrates, this means a droplet can be bounced back and forth with ease.
This interesting phenomenon was filmed in ultra-high definition or 4K, with four times the pixels as a normal 1080p video. So if you've got a 4K TV, you're in for a treat — everyone else will have to make do with ordinary full HD.
Kelly and cosmonaut Mikhail Kornienko are both spending a full year on the ISS, affording researchers an excellent chance to perform long-term experiments on them. Weather and other factors permitting, the ISS's longest-term residents will return to Earth in early March.