For more than a century, gravity has been the immovable backdrop of modern physics, a force that can be described and ...

An engineer who once worked with NASA says he has built a machine that can push against gravity without burning a drop of ...

Air engines are a common occurrence here on Hackaday. They’re relatively novel and reasonably easy to 3D print without requiring any fluids or supporting machinery. For example, [Tom Stanton] took a ...