The New Horizons spacecraft, hurtling toward a rendezvous with Pluto, is slowly bringing into focus an unexpected number of complicated "faces" from the dwarf planet.

Just one month away from its planned flyby of the orbiting solar system outlier, New Horizons has captured a 360-degree panorama of the tiny world's surface.

The images "show an increasingly complex surface with clear evidence of discrete equatorial bright and dark regions — some that may also have variations in brightness," said mission principal investigator Alan Stern of the Southwest Research Institute. "We can also see that every face of Pluto is different, and that Pluto's northern hemisphere displays substantial dark terrains."

However, both the brightest and the darkest regions of the dwarf planet appear to be clustered around its equator —something scientists cannot yet account for.

 "Why this is so is an emerging puzzle," Stern said.

The Hubble Space Telescope and earlier New Horizons images taken from father away had already shown both light and dark spots, but the latest images suggest a planetary surface more complex and nuanced than was previously apparent.

In the weeks before the spacecraft's closest approach on July 14, spectroscopic data may help provide insights into Pluto's many faces, researchers said.

New Horizons has travelled some 2.9 billion miles from Earth — a journey that has taken almost 10 years. NASA said it's now just a little more than 20 million miles from Pluto, hustling along at more than 36,000 mph.

When the spacecraft launched in 2006, Pluto was still considered a full member of the solar system's planetary family — nine in all. Later that same year, the International Astronomical Union agreed on a new definition of a planet, which Pluto failed to meet — leading to its being kicked to the cosmic curb as a "dwarf planet."

New Horizons' close encounter with the tiny, reclassified world will be carried live by NASA TV, starting at 7 a.m. ET July 14, with the exact moment of its closest approach estimated to occur at 7:49 a.m.

Meanwhile, scientists have the new images – the best ever captured of Pluto and its surrounding moons – to pore over.

"We're squeezing as much information as we can out of these images, and seeing details we've never seen before," said New Horizons Project Scientist Hal Weaver.