We look at the sun rising every day. It's bright, it's big and it warms us up. Our sun happens to be the brightest object in our universe and it has captured our curiosity and imaginations throughout history.
Our sun is very dynamic and its turbulent surface produces some of the largest eruptions in the solar system. Called coronal mass ejections, these eruptions can cause serious damage when they reach our planet by disrupting satellites and other communication devices. Our TV may not work, our cell phones will be down, a high speed train may run loose and if an astronaut happens to be on the moon at the time when the sun erupts, he or she would be in great danger.
NASA uses satellites such as the Solar and Heliospheric Observatory (SOHO), to predict these events so that we have a warning of at least 2-3 days to protect our expensive communication devices during a solar eruption. SOHO is just one of the instruments that NASA uses to help scientists understand our sun better along with other satellites and large observatories on Earth.