Dear Mayo Clinic: What’s the difference between a cluster headache and a migraine? Is there a way to treat severe headaches without prescription medication? There are various differences between ...

Star clusters are groups of stars formed from the same material. Globular clusters are old, spherical, and contain many stars. Open clusters are younger, less dense, and have irregular shapes.

Migraine is a complex neurological disease that affects people in many different ways. But as painful and disabling as it can be, it's not the only headache disorder that can bring people to their ...