The Sun looks constant and steady, but it’s not. It goes through an 11-year cycle that produces dramatic changes on its surface and in its hot outer atmosphere. These changes can have a direct impact on daily life here on Earth — especially on our technology. So a better understanding of this cycle can help keep things running smoothly. To that end, NASA launched a satellite to study the peak of the solar cycle 35 years ago today. Known as the Solar Maximum Mission — Solar Max for short — it needed a little help to get the job done. The craft failed less than a year after launch. But in 1984, space shuttle astronauts repaired it in orbit, giving it five more years of life. The peak of the solar cycle produces a lot of dark sunspots, which are magnetic storms on the Sun’s surface that are big enough to swallow Earth. But it also produces giant explosions known as solar flares, as well as massive eruptions of hot gas. When these outbursts reach Earth, they can zap satellites, force airli
