Some astronomers call it the Big Quiet – the absence of sunspots during what is supposed to be a period of heightened magnetic activity on our sun.

For past four or more days, telescopes pointed at the sun have detected only a handful of sunspots, sometimes none at all, in a “very weird” development that is baffling scientists, said Alan Duffy, an astrophysicist at Swinburne University.

Almost spotless: the sun on July 18. Credit:NASA

“Sunspots can change all the time, but when you should be seeing many dozens at any one point of time, it’s quite strange that we’re not seeing any at all,” Dr Duffy said. “We don’t have any idea why that is.”

Sunspots have been studied for centuries and are one gauge of the solar cycle – a roughly 11-year period of above- or below-average magnetic activity. During maximum periods, such as the current one, observations of sunspots and solar flares being fired by the sun should be more common.