When an object moves extremely fast—close to the speed of light—certain basic assumptions that we take for granted no longer apply. This is the central consequence of Albert Einstein's special theory ...

A clock aboard a fast-moving spacecraft does not break, lag or malfunction. It ticks normally for everyone inside.

Albert Einstein’s general theory of relativity is one of the towering achievements of 20th-century physics. Published in 1916, it explains that what we perceive as the force of gravity in fact arises ...

In this video, we explore Albert Einstein's theory of general relativity, focusing on his insights into gravity and acceleration. Initially ridiculed, Einstein developed key concepts after observing a ...

BOULDER- Black holes, time travel and E= mc^2. They are all related to Albert Einstein's Theory of Relativity. How many of us, though, can actually explain any of it? This year, Einstein's theory ...

Relativity Space is shifting its strategy in an attempt to accelerate work on the reusable rocket it's developing. It's adjusting its manufacturing approach to blend its 3D-printing-first approach ...

Relativity Space made a flurry of announcements on Wednesday about its past and future. The company is going bigger, and it has already started to do so. In an interview with Ars, the company’s chief ...