New Horizons Spots Pluto's Elusive Moons

It's been only 85 years since Pluto was first discovered, but in that time it's been celebrated, wondered at, and even argued about. Now NASA's spacecraft New Horizons is quickly approaching the small and icy world and already offering us a never-before-seen perspective - namely surprising new imagery of Pluto's moons.

In a series of images snapped between Jan. 27 and Feb. 8, at distances ranging from 125 million to 115 million miles (201 million to 186 million kilometers) away, New Horizons was able to capture the moons Nix and Hydra orbiting their host planet. This is providing scientists their first intended look at Hydra and a first-ever direct view of Nix. Previously, the moon's presence was only known thanks to measurements of gravitational pull and light.

"It's thrilling to watch the details of the Pluto system emerge as we close the distance to the spacecraft's July 14 encounter," New Horizons science team member John Spencer, from Southwest Research Institute, said in a statement. "This first good view of Nix and Hydra marks another major milestone, and a perfect way to celebrate the anniversary of Pluto's discovery."

Pluto was discovered by Clyde Tombaugh on February 18 back in 1930, making Wednesday an ideal time to release these new and historic images. (Scroll to read on...)

NASA reports that the images, assembled into the seven-frame movie above, are the first of a series of long-exposure images to be taken by New Horizon's Long-Range Reconnaissance Imager (LORRI) through early March.

They will help astronomers better understand the moons' orbits, and more should come into view as the spacecraft draws closer. As things stand, the moons Styx and Kerberos are hidden behind the glare of Pluto and its largest moon Charon - which caused a spike of overexposure (as can been seen in the images). That glare should diminish as New Horizons changes angles and prepares for its close-encounter with the planetoid.

Interestingly, Nix and Hydra are reltively new to the astronomer scene, only being desciovered by Hubble scientists back in 2005. Each moon is thought to be between 25 and 95 miles (approximately 40- 150 kilometers) in diameter, but scientists won't know their sizes more precisely until New Horizons obtains close-up pictures of both of them in July.

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