The more we understand about dwarf planet Pluto, the more confusing it becomes. New set of data sent by NASA’s New Horizons spacecraft revealed that the distant planet had lakes on its surface in the past. Before this, it was thought that Pluto only has an ocean under its frozen surface.

The data collected by the spacecraft during its flyby of Pluto last year in July also suggested that the planet in the Kuiper belt may have a nitrogen lake on its surface in future. NASA has released a new image confirming that there were liquid channels on the surface of Pluto millions or billions of years ago.

The photo captured by New Horizons during the flyby also shows smooth patch on Pluto’s rocky landscape. From the picture, it seems that a lake was surrounded by hills and mountains in the past.

Sunlight falling on the distant planet has an impact on its atmosphere, said Alan Stern, a researcher from the Southwest Research Institute and lead scientist of New Horizons mission. “We find that Pluto’s atmospheric pressure today is atypically low and that in the past it could have been 1,000 to 10,000 times higher, exceeding the pressure of Mars by up to 40 times”, Stern added.

Astronomers used computer models to study the impact of changes in temperature and atmospheric pressure on the planet and found that high temperature and atmospheric pressure are apt for liquid nitrogen.

During the last year flyby, the spacecraft clicked some high-resolution images showing some features that astronomers think are carved by liquids. The photos also showed a frozen lake that could be 20 miles across at its widest point, as per New Horizons team. The lake’s widest point may be present just north of Sputnik Planum on Pluto.