General Relativity – The Conversation

Physicists know a lot about the most fundamental properties of the universe, but they certainly don’t know everything. 2021 was a big year for physics – what was learned and what’s coming next?

Black holes could take us to the future, and maybe even the past. The hard part would be surviving the trip.

The speed of light is the fastest anything can travel. What happens to a photon from a galaxy 25 million light years away on its journey toward Earth?

Space-time isn’t an actual object or event, it’s a conceptual framework for understanding reality.

Cutting-edge theories of physics suggest time may not be real – but even if they’re right, life can still go on as usual.

Science fiction imagines wormholes as shortcuts through spacetime. But the original idea suggests they could be something far stranger.

Our two best theories of nature, quantum mechanics and general relativity, are incompatible with each other in many ways – leaving physicists to dig deeper.

Such a mission could be developed soon, allowing astrophysicists to take selfies of the solar system and use the Sun’s gravity as a lens to peer deep into space.

Bright, flickering galaxies called quasars were thought to pose a problem for our understanding of the cosmos – but new research shows Einstein was right yet again.

Physicists often say space-time “exists,” but what does that really mean? A hidden confusion between happening and being could be warping our view of reality.

What’s the most impressive natural phenomenon known to humankind? Probably a solar eclipse! Here’s a brief overview ahead of this summer’s big celestial event.

Your experience of time is relative because it depends on motion – more specifically, your speed and acceleration.

Physicists long believed time was a basic feature of the universe. But it may just emerge from cosmic information.

Is time real, or an illusion? The best answer may be neither: Both physics and philosophy suggest that time is a projection of the mind onto a timeless reality.

Astronomers watched a pair of pulsars for 16 years to test the theory of general relativity, which has stood unchallenged for over a century.