New Horizons reaches Pluto

The first close-up images of Pluto and its moon Charon have been sent back to Earth by the New Horizons spacecraft following its historic flyby. The probe passed the dwarf planet at 11:49:57 UT on 14 July and began transmitting data back a few days later. Though only a handful of images have made it back to Earth so far, they have already thrown up a couple of surprises.

Several large areas of both Pluto and Charon are free of impact craters, suggesting that some mechanism is renewing the surface. A heart-shaped feature, informally named the Tombaugh Regio after the planet’s discoverer, covers a large portion of the planet’s southern hemisphere, the surface of which only appears to be around 100 million years old.

“This terrain is not easy to explain,” says Jeff Moore of New Horizons’ geology, geophysics and imaging team. “The discovery of vast, craterless, very young plains on Pluto exceeds all pre-flyby expectations.” The early images have also revealed mountains far larger than researchers can easily explain and an icy haze around the planet. It is hoped that the full dataset from the flyby, which will be downloaded over the next 16 months, will supply some answers. “After nearly 15 years of planning, building, and flying the New Horizons spacecraft across the Solar System, we’ve reached our goal,” says the mission’s project manager Glen Fountain. “The bounty of what we’ve collected is about to unfold.”