For more than half a century, the idea that light or radio waves could suddenly reverse in time sounded like a thought experiment, not a laboratory result. Now, a series of meticulous experiments has ...

For centuries, ever since we realized that every star we can see in the night sky is a Sun just like our own ⁠— with possibly its own solar system, planets, and possibly even life ⁠— humanity has ...

Researchers at Osaka University demonstrate the relativistic contraction of an electric field produced by fast-moving charged particles, as predicted by Einstein’s theory, which can help improve ...

An underground vat of liquid xenon in Italy may have just detected a new particle, born in the heart of the sun. If that's indeed what happened, it could upend laws of physics that have held fast for ...

Many lab classes will now have students perform online simulations or watch videos of professors and TAs completing the labs. Credit: Melanie Hilman On Monday, Penn students attended class virtually ...