Dermoscopy is a useful technique for diagnosing melanocytic nevi, along with patient-related factors, and the 4 x 4 x 6 "rule" may help clinicians evaluate pigmented lesions.

Crowded globular star clusters like this one, called 47 Tucanae, may be the best place to search for signs of interstellar alien civilizations, scientists say. The relative close proximity of ...

Globular clusters can have between 1,000 and one million stars packed into a cube 3.2 light years on a side. Breathtaking Hubble Telescope images 39 photos ...