Astronomers are discovering that magnetic fields permeate much of the cosmos. If these fields date back to the Big Bang, they could solve a major cosmological mystery.
By chewing on the problems posed by “extremal” black holes, physicists have exposed a surprising and universal connection between energy and entropy.
The laws of physics imply that the passage of time is an illusion. To avoid this conclusion, we might have to rethink the reality of infinitely precise numbers.
Sometimes a mirror that reflects 99.9999% of light isn’t good enough.
In a new paper, physicists argue that hypothetical particles called axions could explain why the universe isn’t empty.