The Hidden Hemisphere of the Sun

2000/05/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Astronomia

When we look at the Sun, each time we see the only hemisphere of the star, the one in front. We do not know what remains on the opposite side. The researchers have used the SOHO space telescope to see what happens in the Solar Hemisphere that is out of sight.

To do this they have used the tool called MDI (Michelson Doppler Imager) to see or, rather, listen to the hemisphere of the hidden Sun. The technique, called helioseismatic holography, detects sound waves that cross the Sun side by side. The technique has been used to predict solar storms and forecasts have been checked when the hemisphere has become visible. Observation times are 24 hours, not very long, and prediction can be made two weeks in advance.

The prediction of solar storms is very valuable, as such storms can cause great damage to satellites, probes or spacecraft.