Observations show the universe appears flat, yet its true size and global shape beyond the observable horizon may remain forever unknown.

Is the universe infinite? It's one of the most profound questions we can ask, and here's the short answer: We don't know. While we have learned a great deal about the universe, a portion of the cosmos ...

The question of whether the cosmos goes on forever is no longer just a late night thought experiment, it is a live research problem that cuts to the heart of modern physics. Astrophysicists are using ...