In the local Universe, this is not a major constraint, as the time delays that light imposes are relatively manageable. The delays even to communicate with New Horizons, at the very outskirts of ...

The universe follows predictable rules, behaving classically according to Einstein’s theory of general relativity. So, what ...

What would really happen if you fell into a black hole? This mind-bending journey explores the terrifying beauty and strange physics behind one of the universe’s most mysterious objects. As you ...

But Gödel's rotating universe is simply a matter of observational test, not a fundamental break with known physics. We could have found ourselves in a rotating universe just as easily as we find ...

This empty, expanding universe, called a “de Sitter” space-time, has a horizon, beyond which space expands so quickly that no signal from there will ever reach an observer in the center of the space.

A theoretical astrophysicist uses his protractor to measure the universe. From a sheet of paper to the cosmos. Lots of pictures! This post is from Observer Short List—an email of three favorite ...

The 2012 Hubble Space Telescope Advent Calendar is a fantastic tradition; it reveals a new image of the universe every day until Tuesday, December 25. This post is from Observer Short List—an ...