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

The catastrophic collision of a black hole and a neutron star sent ripples across the universe. New analysis of those ripples ...

I live near a few volcanoes. One of them – Mount St. Helens – is bubbling with molten material that will probably gush out as lava someday. I asked my friend Johannes Hämmerli about lava. He’s an ...

The surface of Earth is finite. We can measure it. If it was expanding, then its size would grow with time. And once again, good ol' Earth helps us understand what the universe might be doing beyond ...

A rare gravitationally lensed supernova called SN 2025wny appears in five separate images due to the gravity of two ...

Earth and the entire Milky Way galaxy might be sitting inside an enormous, mysterious void—a giant cosmic hole making our universe expand faster right here than anywhere else. This unusual idea, ...

Blue oceans, green forests, a cozy blanket of oxygen. Our planet is a super comfy home. It’s hard to imagine there was ever a time it didn’t exist. I asked my friend Julie Ménard how Earth formed. She ...