Clean water ice discovered on Pluto's Moon Hydra

The latest in the series of findings from NASA’s New Horizons spacecraft is the first even data about the four moons of Pluto. The fresh data reveals a really interesting fact that pristine water ice dominates the surface of Pluto’s moon Hydra. The crystalline water ice also dominates Charon, the largest moon of Pluto.

The spectrum of Hydra is similar to that of Charon. However, the water-ice absorption bands of Hydra are even deeper than that of Charon’s. This suggests that the ice grains on the surface of Hydra are larger. These ice grains reflect more light at certain angles than the ones on Charon.

Hydra, which is the outermost small moon of Pluto, is believed to have originated some four billion years ago in an debris disk. Scientists are trying to find out why the ice of Hydra seems to be cleaner than Charon’s.

“Perhaps micrometeorite impacts continually refresh the surface of Hydra by blasting off contaminants,” said Simon Porter, New Horizons science team member from Southwest Research Institute in Boulder, Colorado.

“This process would have been ineffective on the much larger Charon, whose much stronger gravity retains any debris created by these impacts,” he said in a NASA statement.

The science team of New Horizons is now planning to obtain similar spectra of Pluto’s other small moons in order to compare them with Hydra and Charon. New Horizons gathered the new data from a distance of 240,000 km on July 14 last year.