A mysterious blotch that appeared along the horizon in a photo from the surface of Mars stirred speculation about what it might be, as two hours later it was gone.

One image from the Curiosity rover as it landed on the fourth planet from the sun showed a "faint but distinctive" image on the horizon, the Los Angeles Times reported. However, a subsequent batch of images sent from the unmanned rover two hours later showed no trace of the blotch.

One theory put forth by space enthusiasts in the L.A. Times story is that Curiosity had somehow snapped a photo of part of the spacecraft that escorted the rover through the Martian atmosphere crash-landing a distance away.

[Slideshow: Latest images from Mars]

But to capture that image "would be an insane coincidence," one engineer told the newspaper.

Others say more feasible possibilities would be simply dirt on the lens, or maybe a dust devil twisting far in the distance.

But as more images start to pour into NASA, more is being learned about the rover's pinpoint landing.

In what some are dubbing the "crime scene" photo of the landing zone taken by another satellite, Curiosity is seen on the ground along with pieces of the spacecraft that broke apart as planned on the way to the surface. The photo reveals the heat shield that protected the rover as it entered the atmosphere and the parachute that helped ease the vehicle onto Mars. Also seen are parts of the "sky crane," the spacecraft that carried the rover to the planet, the article noted.

Could the sky crane crashing be the blotch? From another L.A. Times story:

The crime scene photo showed that the sky crane had crash-landed, as designed, about 2,000 feet away—and in the same direction that Curiosity's camera was pointed when it snapped the first photo showing the blotch. The new satellite photo also showed that the sky crane, when it crash-landed, kicked up a violent wave of dirt that had scarred the surface of Mars.

Curiosity mission manager Michael Watkins told the Times if it were the case, "it would be incredibly cool. ... A crazy, serendipitous thing."

Story continues

Images from Mars have always fueled curiosity.

Remember what folks thought was a huge face on Mars? An image from Viking 1 in 1976 that appeared to show a rock formation with eyes, a nose and a mouth? Later high-resolution imaging and side-by-side analysis proved the "face" to be a mesa, like the flat-topped natural formations found in the southwestern U.S.

As the Curiosity rover readies to begin the scientific discovery part of the mission, maybe more interesting things will be revealed.