The universe has a speed limit, and it's the speed of light. Nothing can travel faster than light — not even our best spacecraft — according to the laws of physics. So, what is the speed of light?

On one hand, the speed of light is just a number: 299,792,458 meters per second. And on the other, it’s one of the most important constants that appears in nature and defines the relationship of ...

During a meeting with the Mars Exploration Program Analysis Group, an internal NASA working crew dedicated to supporting missions to Mars included a pitch from Elon Musk's SpaceX to deploy Starlink ...

Chris Impey receives funding from the National Science Foundation and the Hearst Foundation. Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, ...