The sun's magnetic field is about to turn round in the next few months, NASA said.
The Sun's polarity changes every 11 years, when the north and south end change places. During this flip, the sunspots become fewer. A complete solar cycle occurs every 22 years.
The next reversal- in about 3 to 4 months time- marks a half of Solar Cycle 24.
"It looks like we're no more than three to four months away from a complete field reversal," said solar physicist Todd Hoeksema of Stanford University. "This change will have ripple effects throughout the solar system."
The period of high solar activity is called solar maximum. It is during this time that there is an increase in sunspots. The period of lower activity and fewer sunspots is called solar minimum.
"The sun's polar magnetic fields weaken, go to zero and then emerge again with the opposite polarity. This is a regular part of the solar cycle," said Solar physicist Phil Scherrer, also at Stanford.
The "current sheet" is often talked about during solar reversals. This sheet is a surface within the solar system where the polarity changes. A small electric current about 10-10 A/m² flows within the sheet. The thickness of the sheet is about 10,000 km near the Earth's orbit.
The current sheet becomes wavy during the solar reversal. As the Earth moves in an out of this sheet, it experiences changes in space weather, NASA said. A wavy current sheet will deflect cosmic rays- the high-energy particles that accelerate to light's speed by supernova explosion. Cosmic rays are known to damage space probes.
Galileo Galilei, back in 1612, observed that the sunspots seem to move directly across the disk of the sun.