First Good Look at Pluto’s Small Moon Nix

Homing in on the small satellite Nix, New Horizons Long Range Reconnaissance Imager captured this image, which shows features as small as 4 miles or 6 kilometers across. Mission scientists believe we are looking at one end of an elongated body about 25 miles or 40 kilometers in diameter. The image was acquired on July 13 from a distance of about 360,000 miles or 590,000 kilometers. Credits: NASA/JHUAPL/SWRI

The New Horizons science team released the latest image of Nix, one of Pluto’s small moons, during a media briefing on July 17. The image was captured by the Long Range Reconnaissance Imager (LORRI) aboard NASA’s New Horizons spacecraft on July 13 from a distance of about 590,000 kilometres (360,000 miles). Pixelated as it may be, the image resolves features as small as 6 kilometres (4 miles) across. A mere three months ago we didn’t have images of Pluto that were this good. This newest image of Nix also contains twice as many pixels as the best Earth-based views of Pluto.

In the image, we are looking down one end of an elongated body some 40 kilometres (25 miles) in diameter.

Nix is an odd little moon. It is the third moon out from Pluto and orbits the dwarf planet in about 24.9 days. It was discovered along with Hydra back in 2005 by a team that included Alan Stern, Principal Investigator for New Horizons. Recent findings published in the journal Nature on June 4, also revealed that Nix (along with the outermost moon Hydra), wobble and spin unpredictable as they orbit. If you lived on Nix, you’d never know which direction the sun will rise each day.

This set of computer modelling illustrations of Pluto’s moon Nix shows how the orientation of the moon changes unpredictably as it orbits the “double planet” Pluto-Charon. Credits: NASA/ESA/M. Showalter (SETI)/G. Bacon (STScI)

Discovery images of Plutonian satellites Nix and Hydra.

The best images of Nix are yet to come. Of all of Pluto’s four smallest moons, New Horizons will image Nix with the highest resolution, as high as 330 metres per pixel or 18 times higher than the best current image.

Nix was named after the Greek goddess of darkness and night. She is the mother of Charon, the ferryman of Hades, who takes the souls of the newly deceased down the river Styx to the underworld. In mythology, Nix is found in the shadows of the world and only ever seen in glimpses. But thanks to New Horizons, we will be getting an unprecedented view of this mysterious moon.