Rover photographs perfectly round ball on Mars surface

NASA's Curiosity Rover has sent back a photo from Mars of a perfectly round object that looks like a ball.

But sad news for conspiracy theorists: No one has been playing golf on the Red Planet.

Instead, experts told Discovery.com they believe the ball is an example of a geological process called concretion — when a mass of minerals embeds in a "host" sedimentary rock.

NASA said the sphere, which was photographed Sept. 11, is likely one centimetre wide.

It's not the first time a rover has photographed a similar phenomenon on Mars. In 2004, the rover Opportunity relayed images of a small grouping of concretions that looked similar to blueberries. The existence of the spheres suggests that area of Mars had groundwater at one point, the scientists said in a paper in Nature in June 2004.

NASA Curiosity Rover Drills its First Hole at Mount Sharp

NASA's Curiosity rover has reached the ultimate destination in its science mission on Mars and has officially broken the ground at Mount Sharp.

According to Space.com, Curiosity drilled about 2.6 into the base of the mountain in the middle of the Gale Crater, the rover's landing spot. The one-ton rover collected pieces of powdered rock for future analysis.

Curiosity has been on a track to reach Mount Sharp, which stands about 3.4 miles high, since landing on the Red Planet in Aug. 2012.

"This drilling target is at the lowest part of the base layer of the mountain, and from here we plan to examine the higher, younger layers exposed in the nearby hills," Ashwin Vasavada, Curiosity deputy project scientist at NASA's Jet Propulsion Laboratory (JPL), said in a press release. "This first look at rocks we believe to underlie Mount Sharp is exciting because it will begin to form a picture of the environment at the time the mountain formed, and what led to its growth."

Curiosity took its time to get from Yellow Knife Bay to Mount Sharp, about a five-mile trek. In 15 months, Curiosity plodded along while making various stops to collect samples and examine them. Thanks to the rover, NASA mission managers have enjoyed a wealth of information that have changed the way many people look at Mars.

"We're putting on the brakes to study this amazing mountain," Jennifer Trosper, Curiosity deputy project manager at JPL, said in the release. "Curiosity flew hundreds of millions of miles to do this."

Curiosity will now take its time with analyzing the sample because the results could determine whether or not it is safe for filtration and delivery to the rover's internal lab.