An international team of astronomers that includes NCAR’s Savita Mathur has observed mixed waves—a mixture of acoustic and gravity waves—that run all the way to the cores of red giant stars. Astronomers already knew that such waves (known as stellar oscillations) existed, but until now had only observed pure acoustic waves traveling through the outer parts of stars.

A finely textured cloud leads to an informal investigation and a lively scientific debate over how it formed.

The return of sunlight in polar spring means ozone destruction above the Antarctic—and, in 2011, above the Arctic.

One of the most enduring mysteries in solar physics is why the Sun’s outer atmosphere, or corona, is millions of degrees hotter than its surface. Now scientists believe they have discovered a major source of hot gas that replenishes the corona.

Like a creature from a hydrologic horror flick, Devils Lake, North Dakota, has been expanding off and on for 70 years, most dramatically from the mid-1990s onward. Some of its tendrils have blocked rail lines and roadways for years.