An artist's concept shows the Solar Maximum Mission spacecraft in orbit. It was launched on February 14, 1980, to measure the peak of the Sun's 11-year magnetic cycle. Such peaks are accompanied by large numbers of sunspots as well as eruptions from the Sun's surface. Solar Max failed in late 1980, but was repaired by space shuttle astronauts in 1984. [NASA]
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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 airlines to re-route flights, and even knock out power grids on the ground.
You might expect that the Sun would be dimmest when it’s covered with more sunspots, but Solar Max found otherwise. The sunspots are surrounded by hot, bright rings, which more than make up for the dimming effect of the spots themselves.
That and other findings provided a more complete picture of the active Sun — a picture that astronomers are still refining today.
Script by Damond Benningfield, Copyright 2014