Nasa's Curiosity rover has snapped a photo of a mysterious object on the surface of Mars, which conspiracy theorists believe could be evidence of aliens.
The high-definition image appears to show the object glinting against Mars' rocky landscape, according to the Daily Mail.
While many people believe that the object is made by aliens, others have suggested that it is merely the rover's own entry debris.
The image was taken in March, but was posted on Reddit this week, sparking a huge online debate about what it shows.
Prosaic Origin, the Reddit user who posted the image, wrote: "Uh Nasa? UFO caught on Mars Rover mission? Is this real?"
His post has received 79 replies, many of which back up his thoughts that it could be aliens.
EdisonVonneZula said: "Looks like light glimmering off of a genuine spaceship on an alien planet in outer space."
And Crazylegs99 wrote: "They forgot to Photoshop that one out. Love how skeptical the mods are.
"You could have aliens waving hi through the windshield and it would be flagged as a likely prosaic."
But not everyone is convinced.
OnceReturned suggested the image could merely show debris from the rover's landing craft.
The user wrote: "We know that the Rover was taking pictures of its own entry debris at that time.
"There's nothing particularly alien about the object in question - it could easily be entry debris, at least in my opinion."
And Nigel Watson, author of the UFO Investigations Manual told MailOnline: "It might look like a spaceship, but as usual the picture is out-of-focus and there is no guide to tell the viewer how big or small this object is.
"One explanation is that the object is a piece of debris from the Mars Rover itself or from its sky crane landing system.
"Unless we get more detailed information this is another case of wishful thinking."
This isn't the first time that conspiracy theorists have claimed that images taken by the Curiosity rover show aliens.
Yesterday, alien hunters claimed that the rover had taken images of thigh bones protruding from the red planet's surface.
The pictures were presented in a video from conspiracy theorist group Martian Archaeology alongside several other Curiosity images that appear to show 'signs of life'.
These include reported signs of lichen and fungi and other biological life growing on Mars.
Fans of the video have posted their views in the comment section.
TJ Devereaux wrote: "After years of research and study, I'm convinced now, more then ever, that there much more to Mars then what Nasa admits to.
"I'm certain life, including water, and intelligent life forms, once occupied the planet, and... big leap here... that both still exist, in much smaller quantities."