Astronomers use many methods to determine this number, including gravitational lensing, the universe’s expansion rate, and more.

In a recent piece for my column The Universe, I wrote about the biggest black holes in the cosmos. Black holes are rather ...

You can measure objects on an iPhone using Apple's Measure app. The app is free and works with specific versions of the iPhone, iPad, and iPod. You may be able to ...

An actively feeding black hole surrounds itself with a disk of hot gas and dust that flickers like a campfire. Astronomers have now found that monitoring changes in those flickers can reveal something ...

A new study has attempted to pin down the properties of interstellar comet 3I/Atlas, finding it is "anomalously massive" at around 33 billion tons.