The Sun in 3-D

On Monday, NASA’s Jet Propulsion Laboratory released the first 3-D images of the sun from a pair of spacecraft called Stereo. The spacecraft, which were launched last October, are helping astronomers study and predict gigantic eruptions from the sun. (See “Better Predictions of Space Weather.”) Currently, the nature and causes of these explosions of high-energy particles and magnetic storms are poorly understood. And being able to predict them farther in advance will help prevent damage to satellites orbiting the earth.

In the past, astronomers have been able to look at these solar storms, called coronal mass ejections, only from the earth. This made it impossible to predict the storms in advance. But by sending up the pair of spacecraft, one orbiting the sun in front of the earth and the other behind, researchers have gained a far better view of the solar storms and will be able to predict them sooner.

The spacecraft, which carry multiple instruments, including 3-D imagers and particle and magnetic-field detectors, have not yet helped predict any storms because the sun has been relatively calm. But that could soon change: the number of coronal mass ejections is expected to peak within the next few years.