The sun has "flipped upside down", with its north and south poles reversed to reach the midpoint of Solar Cycle 24, Nasa has said.
Now, the magnetic fields will once again started moving in opposite directions to begin the completion of the 22 year long process which will culminate in the poles switching once again.
"A reversal of the sun’s magnetic field is, literally, a big event," said Nasa’s Dr. Tony Phillips.
"The domain of the sun’s magnetic influence (also known as the ’heliosphere’) extends billions of kilometers beyond Pluto. Changes to the field’s polarity ripple all the way out to the Voyager probes, on the doorstep of interstellar space."
To mark the event, Nasa has released a visualisation of the entire process.