The sun is much less active and has fewer sunspots than comparable stars. This is evident from scientific research published Thursday in the journal Science. According to the scientists, that’s good news.
Scientists at the Max Planck Institute for Solar System Research in Göttingen, Germany, have concluded that our sun has a “dull personality” after examining 396 stars of the same size, rotation speed and surface temperature as the sun. On average, they show five times more variations in brightness.
The variation is due to the presence of sunspots on the surface that influence the brightness of the light due to the rotation of the sun. Sunspots are caused by strong magnetic fields that prevent hot plasma from entering the interior of a star from the outside, creating cool spots. Sunspots disappear after a while.
A dull sun is good news
It came as a surprise to scientists that comparable stars are so much more active. They compared data from NASA’s Kepler space telescope and ESA’s Gaia telescope with some 400 years of observations from our own sun and 9,000 years of data obtained from tree rings and ice cores.
But a “dull” sun is good news for us, the researchers say. “A much more active sun would have had an impact on geological timescales and on climate development over the centuries. An overly active star would certainly have changed the conditions for life on Earth, so a dull sun is not the worst option.”
Sunspots affect how satellites work
By measuring the number of sunspots, you measure the activity of a star. Then there are brief explosions of energy that release charged particles: solar flares and solar storms. When they reach Earth, they provide the Polar Light, among other things, but can also affect the operation of satellites and communications with astronauts.
The sun, a hot ball of hydrogen and helium 1.4 million kilometers across, is a medium-sized star that originated about 4.5 billion years ago and is halfway through its life cycle. The surface temperature of the sun is about 5,500 degrees Celsius and the sun rotates on its axis in about 24.5 days.
The scientists do not rule out the possibility that the sun will become more active again in the (distant) future.