NASA's Cassini spacecraft is currently spending its last year on its mission to observe the ringed planet Saturn. Surprisingly, a comparison of old and new photographs of Saturn's North Pole revealed its changing colors.

Cassini has been sending a ton of information about Saturn and its moons, including Titan. But today, the spacecraft shifted the focus from Saturn's moons to its North Pole, which appears to be changing in color as time passes by.

The breathtaking image of Saturn's mysterious changing of colors on its hexagonal North Pole was seen in a comparison of images released by NASA. The changing colors may be attributed to the planet's changing weather and wind systems, some experts suggest.

The images were sent back to Earth for study by the Cassini spacecraft. Comparing images four years apart, one image was taken last 2012 and the other one taken this year, 2016, revealed the colorful discovery. The photographs show there is an obvious change in the color of the North Pole.

In 2012, the hexagonal North Pole appeared to be bluish, but today, it appears to be lighter in color with a hint of golden tint, which could be attributed to changing weather patters, according to a report.

Read: Saturn's Moon Dione Hiding a Watery Secret Beneath Icy Exterior

Not only were the scientists surprised with the discovery, it also posed a deeper question: what could have caused the changing color in Saturn's North Pole? The changing weather system remains a hypothesis until further investigations are launched to dig deeper into the phenomenon.

The hexagon jet stream on the Northern hemisphere of Saturn could have been playing a big role in this phenomenon. Scientists believe that the pattern on top of Saturn prevents outside materials from entering the planet. A study suggests that the planet experiences seven-year winter. However, after the equinox on the planet in Aug. 2009, there is an observable continuous sunlight. Aerosols are also believed to be forming inside the hexagon, making the atmosphere look lazy.

But experts are not dispelling the possibility of other factors causing the change in color of Saturn's North Pole. Experts say it could be atmosphere circulation that is causing the phenomenon.