It's official: The mystery of a strange rock on Mars that suddenly appeared in front of NASA's Opportunity rover has warped into the final frontier. Even "Star Trek" actor William Shatner wants to know what's going on with the stone, which looks like a jelly doughnut.

Shatner, who portrayed Captain James Kirk of the Starship Enterprise on "Star Trek," asked NASA about the strange Mars rock found by Opportunity via Twitter during a press conference on Opportunity's latest discoveries last month.

A comparison of two raw Pancam photographs from sols 3528 and 3540 of Opportunity's mission (a sol is a Martian day). Notice the "jelly doughnut"-sized rock in the center of the photograph to the right. Minor adjustments for brightness and contrast.
A comparison of two raw Pancam photographs from sols 3528 and 3540 of Opportunity's mission (a sol is a Martian day). Notice the "jelly doughnut"-sized rock in the center of the photograph to the right. Minor adjustments for brightness and contrast.
Credit: NASA/JPL-Caltech

"We've got another question from Twitter, this one from William Shatner," NASA spokesman Guy Webster said in the Jan. 23 event. "He'd like to know if you've ruled out the Martian rock throwers in the case of the jelly doughnut."

You can watch Shatner's question being asked in this NASA video. It appears two minutes and 32 seconds into the video.

Mars rover lead scientist Steve Squyres of Cornell University in Ithaca, N.Y., was happy to oblige Shatner. Squyres spoke during a press conference to celebrate the 10-year anniversary of Opportunity on Mars.

"I think Martian rock throwers are unlikely, though we'll keep our eyes open for those," Squyres said. "We did actually have another scenario which we're still thinking about. It's the 'smoking hole in the ground hypothesis' as I've called it. We cannot yet rule out the possibility with certainty that there wasn't a freshly formed impact crater nearby, and that this is a piece of stuff that was thrown out by a small impact. "

The origin of the Mars rock in Opportunity's photos has sparked other wild theories on what the object is, including some claims that it is a candidate for life (it's actually just a rock, Squyres and other scientists stress). One supporter of the life claim has even filed a lawsuit against NASA regarding the Mars mystery rock.

This before-and-after pair of images of the same patch of ground in front of NASA's Mars Rover Opportunity 13 days apart documents the arrival of a strange, bright rock at the scene. The rock, called "Pinnacle Island," is seen in the right image on Jan. 8, 2014. The image at left was taken on Dec. 26, 2013.
This before-and-after pair of images of the same patch of ground in front of NASA's Mars Rover Opportunity 13 days apart documents the arrival of a strange, bright rock at the scene. The rock, called "Pinnacle Island," is seen in the right image on Jan. 8, 2014. The image at left was taken on Dec. 26, 2013.
Credit: NASA/JPL-Caltech/Cornell Univ./Arizona State Univ.

In the Jan. 23 event, Squyres went on to reiterate what he views as the most plausible explanation for the weird Martian rock's sudden appearance in Opportunity's camera views. Scientists have since taken to calling the object "Pinnacle Rock" in NASA descriptions. 

"We think the most likely scenario is that that rock wasn't thrown, it wasn't kicked out of a crater. It was flicked out by one of our wheels," Squyres said. "And we're going to take a close look at that hypothesis just in the upcoming days."

NASA's Opportunity rover landed on Mars on Jan. 24, 2004, just a few weeks after its robotic twin Spirit. The two rovers far outlasted their original 90-day mission, with Spirit going silent in 2010 while Opportunity continues to explore the Red Planet to this day.

Email Tariq Malik at tmalik@space.com or follow him @tariqjmalik and Google+. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.