The dwarf planet Pluto has kept on puzzling scientists, although New Horizons keeps on gathering data about the tiny planet but it does not mean that it’s every mystery is unfolded. Recently images sent by the craft shocked scientists when they saw that the heart-shaped region on Pluto is covered with pits.

According to NASA, the craft took these images on July 14 but it too long for them to receive them. The pits on Tombaugh Regio are each hundreds of yards across and 10 or more yards deep.

The pits appear to be large in number and well aligned with each other. Scientists think that the pits might have been formed from ice fracturing and evaporating relatively recently.

The top-left part of the photo shows the border between the relatively smooth Sputnik Planum ice sheet and the pitted area, with a series of hills forming slightly inside the unusual ‘shoreline’, NASA added.

Researchers hope that studying the pattern and the varying depths of these pits can help them to get some clues about how he surface of the planet has changed in recent years and at what rate have these changes occurred.

The agency told that some more high-resolution images from the craft are on its way to reach earth. More may be expected as soon as NASA and its partners have a chance to process and present them.

The images captured are part of a sequence taken by New Horizons’ Long Range Reconnaissance Imager (LORRI) as the spacecraft passed within 9,550 miles (15,400 kilometers) of Pluto's surface, just 13 minutes before the time of closest approach.