A new thought experiment indicates that quantum mechanics doesn’t work without strange numbers that turn negative when squared.
Since they can’t prod actual universes as they inflate and bump into each other in the hypothetical multiverse, physicists are studying digital and physical analogs of the process.
For decades, astronomers debated whether a particular smudge was close-by and small, or distant and huge. A new X-ray map supports the massive option.
Physicists plan to leave no stone unturned, checking whether dark matter tickles different types of detectors, nudges starlight, warms planetary cores or even lodges in rocks.
Physicists have reached a long-sought goal. The catch is that their room-temperature superconductor requires crushing pressures to keep from falling apart.
Renormalization has become perhaps the single most important advance in theoretical physics in 50 years.
Cosmologists have concluded that the universe doesn’t appear to clump as much as it should. Could both of cosmology’s big puzzles share a single fix?