The new Pluto photos reveal complex features that 'rival anything we've seen in the solar system'

NASA just released the latest photos of Pluto, and they reveal more complex features and diversity on the surface than scientists could have ever hoped to imagine.

Here's one of the newest photos that shows the heart-shaped feature, informally named Tombaugh Regio, in the upper right portion of the dwarf planet:

The dwarf planet Pluto might be 4.6 billion miles from Earth, but last July, NASA flew their New Horizons spacecraft to get a better look at just 7,800 miles above the Plutonian surface - about 500,000 times closer than Earth.

And some of the first photos it snapped and transmitted to Earth told a mysterious tale of this icy world that still has scientists scratching their heads. Mountains of water ice and nitrogen snow are just a couple of the perplexing possibilities on Pluto.

Now, New Horizons has sent back some of the most detailed photos yet of Pluto's surface that have doubled the amount of Pluto's surface that we can see in super-fine detail.

"Pluto is showing us a diversity of landforms and complexity of processes that rival anything we've seen in the solar system," said New Horizons Principal Investigator Alan Stern, in a NASA statement. "If an artist had painted this Pluto before our flyby, I probably would have called it over the top - but that's what is actually there."

These latest shots reveal the most heavily cratered portion of Pluto ever seen. Because other features on Pluto are surprisingly smooth - which suggests a younger surface smoothed over time by geological activity - this heavily cratered region is the oldest region of Pluto observed, so far, NASA said.

The oldest region boarders one of the youngest on Pluto, informally named Sputnik Planum, which is the left lobe of the heart-shaped feature. Here's where on Pluto we're looking:

Scientists suspect the smooth, light color in Sputnik Planum could be from nitrogen snow. Here's a close-up of Sputnik Planum, with the heavily cratered section shown in black toward the bottom. This photo covers about 1,000 miles left-to-right:

And here's an even closer look at that same old, cratered section. This photo, taken while New Horizons was 50,000 miles from Pluto, covers a much smaller region that is just 220-miles wide.

It includes "dark, ancient heavily cratered terrain, bright, smooth geologically young terrain; assembled masses of mountains; and an enigmatic field of dark, aligned ridges that resemble dunes," NASA described.

One of the more "wild" theories concerning this portion of Pluto is that some of those hill-like features toward the top of the above photo could be "dark wind-blown dunes," NASA said.

"Seeing dunes on Pluto - if that is what they are - would be completely wild, because Pluto's atmosphere today is so thin," said William B. McKinnon, in the NASA statement. "Either Pluto had a thicker atmosphere in the past, or some process we haven't figured out is at work. It's a head-scratcher."

What caused this region to remain so unchanged over billions of year while its neighbor, Sputnik Planum, grew a mysteriously smooth, young surface is still under debate.

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