WASHINGTON - Scientists are predicting that the sun is heading into an unusual and extended super quiet mode. Around 2020, sunspots may disappear for years, maybe decades.

A handout picture shows the Sun as viewed by the Solar Dynamics Observatory on June 9, 2011.[Photo/Agencies]

Scientists say there is nothing to worry about. Effects from a calmer sun are mostly good. There would be fewer disruptions of satellites and power systems. And it might mean a little less increase in global warming.

It has happened before, but not for a couple of centuries.

Scientists at a solar physics conference in New Mexico revealed their prediction based on sunspot activity, magnetic field strength and a disappearing solar jet stream.

The prediction is specifically aimed at the solar cycle starting in 2020, but experts say the sun already has been unusually quiet for about four years.