Galaxy clusters are formed by a dense packing of many galaxies, making them the most massive structures in the universe.

An international team of astronomers led by Canadian researchers has found something the universe wasn't supposed to have: a ...

A galaxy cluster can be thought of as a slow-built machine: gravity assembles the parts, time warms the coolant, and only later does the system settle into the kind of hot, stable “atmosphere” seen in ...

Scientists have detected a surprisingly hot galaxy cluster dating back to the universe’s infancy. The cluster formed far earlier and burned far hotter than current models predict. Researchers believe ...

Using the Anglo-Australian Telescope (AAT), astronomers have observed a nearby galactic globular cluster known as NGC 6569.

Cluster headaches are a series of relatively short but very painful headaches that happen every day for weeks or months at a time. You tend to get them at the same time each year, such as in the ...

Here’s a guide to why this type of weapon is controversial and widely banned — and why Kyiv wants it. By Victoria Kim Gaya Gupta and John Ismay The United States agreed on Friday to provide Ukraine ...

NPR's Leila Fadel talks to Mary Wareham of Human Rights Watch about the Cluster Munition Coalition report which says there were 987 casualties from the weapons in 2022 — mostly Ukrainian civilians. We ...

Over the past year, cluster munitions—weapons banned by a majority of the world’s countries—have killed or injured hundreds of civilians in Ukraine. Their use, which began the first day of Russia’s ...

The United States is providing Ukraine with cluster bombs it says have a failure rate of 2.35%. But past use suggests "failure rates of 10% to 30%," according to a report prepared for Congress.

Cluster headaches are severely painful headaches that occur in clusters. You experience cycles of headache attacks, followed by headache-free periods. The frequency of your headaches during these ...