http://www.guardian.co.uk/science/2011/feb/06/first-panoramic-view-sun
The identical, refrigerator-sized probes, which were launched in 2006, follow the Earth's orbit around the sun, one leading far ahead of the other. Today [yesterday], the probes became directly aligned on either side of the star, giving scientists a unique opportunity to see it from every angle.
It is hoped the probes will help scientists understand coronal mass ejections (CMEs) – violent eruptions on the sun that can hurl a billion tonnes of particles at Earth at speeds of up to 450,000mph.
Satellites such as the Solar and Heliospheric Observatory give scientists an hour's warning of CMEs heading for Earth. The Stereo mission aims to increase the warning time to more than two days.

http://en.wikipedia.org/wiki/Serendipity
Serendipity is a propensity for making fortunate discoveries while looking for something unrelated.