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 ...

Fragments of energy may be the fundamental building blocks of the universe. The theory combines the ideas of particles and waves into a concentration of energy that flows throughout space and time.

A null boundary carries a degenerate signature (0++) metric, which is obtained by taking the pull-back of the four-dimensional line element to the boundary. Credit: Classical and Quantum Gravity (2025 ...

The discovery in 1998 that the Universe is expanding faster over time shook the foundations of cosmology. This finding challenged deep-seated assumptions about how space behaves on the grandest scales ...

110 years ago today, Albert Einstein published his General Theory of Relativity, which redefined the relationship between matter and gravity. Suddenly, our mysterious universe made a little more sense ...

Einstein's theory of general relativity suggests that the "memory" of ancient events, such as black hole mergers, may be etched into the fabric of space-time by gravitational waves. New research shows ...

Energy-momentum distribution remains a fundamental yet challenging aspect of theoretical physics. In general relativity, the localisation of gravitational energy is obscured by the equivalence ...

A record-breaking gravitational wave signal let scientists "listen" to a distant black hole merger and put Einstein's gravity ...