A HUGE section of Saturn’s surface appears to have changed colour.

Stargazers have spotted a mysterious hexagon shape at the northern pole of the planet has changed from blue to gold.

2 This NASA image shows the marked change in the colour of Saturn's 'hexagon'

Images captured by NASA’s Cassini spacecraft, which has been observing the planet since 2004, shows how Saturn’s surface gradually changed its tone between November 2012 and September this year.

The hexagon essentially looks like a rotating cloud pattern and it’s believed the shape may be produced by differences in the speeds of Saturn’s winds (seen in the image above).

Saturn is the sixth planet from the Sun and the second-largest in the Solar System, behind Jupiter.

Like Jupiter, Saturn is a giant gas planet and is composed of similar gases including hydrogen, helium and methane.

The change in its colour is thought to be a result of the changing seasons on the planet and the result of the greater level of sunlight producing aerosols in the atmosphere.

Related Stories LIFE ON MARS Elon Musk says one MILLION people will soon be living in glass domes on Mars l'Espace odyssey Toulouse is a medieval French city full of a space age adventure for families with tech-loving teenagers ONE SMALL STEP BACK FOR MANKIND Panic in space as NASA Juno probe to Jupiter suffers mysterious shutdown Video 'ALIEN MISSILE' OR HOAX? Mysterious UFO spotted in NASA photo of Moon taken on Neil Armstrong’s Apollo 11 mission MARTIAN DISASTER European Mars probe 'crashed and exploded' on surface of Red Planet DEEP SPACE NINE Mysterious 'ice planet' discovered that could hold clue to existence of fabled 'Planet Nine'

“In particular, the change from a bluish colour to a more golden hue may be due to the increased production of photochemical hazes in the atmosphere as the north pole approaches summer solstice in May 2017,” NASA said.

According to the US space agency, the hexagon shape might act as a kind of protective shell with the “six-sided jetstream” working to prevent particles produced outside the planet from entering.

Whatever its purpose, it sure looks pretty cool — and we now know it comes in both blue and gold.

This story originally appeared on news.com.au.