When the sun puts its power on display, we often can't see it all or predict it in advance, but the effects can be world-changing. A massive solar storm could wipe out almost all of our modern technology without warning.
Our nearest star, the Sun, is essential for life on Earth. It is an unusually well-behaved star, but solar storms and the solar wind can negatively impact the performance and reliability of not only our space-based technology, but also our ground-based technology. Satellites can be disabled, radio communications wiped out worldwide, and voltages sent soaring to dangerous levels in power transformers and oil pipelines by a solar storm. When aimed at Earth, strong solar flares and eruptions can supercharge the Earth's aurora displays over the poles. The most powerful solar storms can also pose a risk to astronauts and satellites in space and even completely impair power grids on Earth's surface as well as interfere with communication and navigation signals. How would all this affect our medical care? (http://solarstorms.org/) Keep in mind: Solar storms not only can kill satellites, they can kill astronauts.