NASA’s New Horizons spacecraft is speeding through our solar system and is now just three weeks from reaching the most distant object and former ninth planet in our Solar System: Pluto. But what will it find once it gets there?

Scientists don’t know yet — after all, why send a spacecraft if you do? — but all that will change once New Horizons arrives at the icy rock, and early images are sending some rather strange indications already, according to a National Geographic report.

The photos reveal a bright spot at Pluto’s polar cap, and Charon, the dwarf planet’s moon, has a strange dark spot. Pluto also has weird smaller moons that are rotating in a chaotic fashion, and one of them is extremely dark.

Those are just a few of the many mysteries New Horizons will hopefully unravel for NASA, and one of the biggest ones could be a giant mountain range that runs along the planet, a feature that has so far been only found on Saturn’s moon Iapetus. Iapetus has a two-toned surface that is similar to Pluto’s, and that means it could potentially feature a similar mountain range.

On Iapetus, this mountain range only runs along three-quarters of the moon’s equator, but why? Scientists don’t know, and perhaps Pluto could better help them understand.

The Cassini spacecraft first observed the mountain range on Iapetus back in 2004, and these mountains are huge: they are far taller even than Mount Everest on Earth.

The theory is that the ridges came about when a moon of Iapetus — a moon-moon, if you will — got to close and collided with Iapetus, creating a big deposit of material along the equator.

Whatever scientists find once New Horizons arrive in a few weeks’ time, it will most certainly be interesting.