The latest high-resolution images of the planet Pluto have revealed a snakeskin-like pattern on its surface.
The revealing photographs were taken from Nasa's New Horizons spacecraft - the first ever to visit the dwarf planet.
The clearest image was taken near the line that separates day from night, capturing a vast rippling landscape of strange, aligned linear ridges that Nasa said astonished New Horizons team members.
"It's a unique and perplexing landscape stretching over hundreds of miles," said William McKinnon, New Horizons Geology, Geophysics and Imaging (GGI) team deputy.
"It looks more like tree bark or dragon scales than geology. This'll really take time to figure out; maybe it's some combination of internal tectonic forces and ice sublimation driven by Pluto's faint sunlight."
Life on Pluto?
Scientists aren't sure what causes the pattern, but theories include the impact of plate tectonics rippling the surface, or frozen gasses that are released when surface temperatures increase.
The spacecraft also captured the highest-resolution colour view yet of Pluto, as well as detailed spectral maps and other high-resolution images. The new 'extended colour' view of Pluto shows its extraordinarily rich colour palette.
These images reveal features that resemble dunes, the older shoreline of a shrinking glacial ice lake, and fractured, angular water ice mountains with sheer cliffs.
TV's Professor Brian Cox said: "(This) means - if our understanding of life on Earth is even slightly correct - that you could have living things there."