Researchers have revealed that mysterious, steep-sided pits discovered by the Rosetta spacecraft on the surface of comet 67P/Churyumov-Gerasimenko appear to be sinkholes. Researchers said the sinkholes are caused by weaknesses in the ground beneath the comet's surface.

The findings of the study have opened the doors for researches to figure out the age of the comet.

The pits were spotted by researchers after Rosetta became the first probe in history to orbit a comet last summer. However, researchers could not pay much attention to them because of being too engrossed in mapping the comet's craggy surface.

Planetary scientist Jean-Baptiste Vincent, of the Max Planck Institute for Solar System Research in Göttingen, Germany, said they had no idea about what they were that time.

The pits have been explained in a paper published in the journal Nature. According to Vincent, chances are slim for this or the others to become impact craters as steep-sided holes would not be created by incoming meteorites.

Also, it is unlikely for subsurface ice being warmed by the sun and exploding outward to have created the pits. It's true that this happens on Rosetta, but the scale is too low to create these enormous pits.

"We can see jets of dust and gas coming from inside some of the pits, and we measured how much dust was coming out. It was minor. It would have taken forever to create the pits this way", said Vincent.

According to space physicist Paul Weissman, with NASA's Jet Propulsion Laboratory in California, there is high possibility for the pits to be sinkholes.