NASA’s New Horizons sent back a second close-up image of Pluto this week, giving us another detailed look at the dwarf planet’s diverse terrain. Like the other high resolution picture, the image reveals a surface that ranges from deep canyons to towering mountains. Features as small as a half-mile are visible; it looks positively frightening, an alien wasteland that’s becoming more mysterious by the day.

Scientists estimate the these newly discovered peaks around roughly one-half mile to one mile high, which is about the same height as the Appalachian Mountains in the U.S.

“There is a pronounced difference in texture between the younger, frozen plains to the east and the dark, heavily-cratered terrain to the west,” said Jeff Moore, leader of the New Horizons Geology, Geophysics and Imaging Team. “There’s a complex interaction going on between the bright and the dark materials that we’re still trying to understand.”

What’s interesting is what the picture tells us about Pluto’s age. The darker region in the image is estimated to date back billions of years; Sputnik Planum, which is east of the new mountain range, is estimated to be about 100 million years old.

For comparison, we’ve also included the image NASA released last week, which showed off a different mountainous region said to be over 11,000 feet tall.