Comets

While observing the Halley-type comet 12P/Pons-Brooks with ALMA and NASA's Infrared Telescope Facility, researchers determined that the comet's water is strikingly similar to the water on Earth.

New Hubble Telescope imagery of the interstellar interloper comet 3I/ATLAS reveals a dusty coma and the beginning of a tail.

A controversial new paper questions whether the interstellar object 3I/ATLAS is a potentially dangerous alien probe, similar to claims made about 'Oumuamua. But experts have called it "nonsense".

Astronomers unveiled a striking view of the new interstellar visitor 3I/ATLAS on its journey toward the inner solar system.

The scientific and cultural impact of 3I/ATLAS over the coming months and years will serve as an exemplar of what astronomy can learn and why it matters.

The European Southern Observatory has captured the clearest images yet of the interstellar visitor 3I/ATLAS as it moves inward through the solar system.

How do we know 3I/ATLAS, also called comet C/2025 N1 (ATLAS), is interstellar? Will it strike Earth? Can we visit it? Here are all of your questions answered.

3I/ATLAS is the third-ever interstellar object discovered.

Here's an observers' guide to the newly discovered Comet 2025 F2 (SWAN), which is visible in northern skies right now.

The striking Comet C/2025 F2 (SWAN) photograph was captured by astrophotographer Josh Dury at 4:50 a.m. local time on April 9.