The latest from New Horizons reveals a shocking truth about Pluto's tiny moon, Hydra.
NASA’s New Horizons space probe has long since passed Pluto, but the tiny craft continues to send information about the strange world and its satellites back to Earth. According to a report from Discovery News, the most recent transmission reveals a fascinating truth about Pluto’s tiny, oddball moon, Hydra.
Hydra was first discovered in 2005, and is the outermost moon orbiting Pluto. Scientists believe that it broke off of a bigger planetary body nearly four billion years ago, creating both Pluto and its larger moon Charon. Hydra measures just 31 miles across, and appeared bright and clear in New Horizons’ lenses as the probe blasted past the outer rim of the solar system last summer.
Using the Linear Etalon Imaging Spectral Array, or LEISA instrument on New Horizons, scientists confirmed that Hydra is coated in a layer of pure water ice. Researchers believed this was the case before New Horizons arrived, but the recent transmission reveals that this assumption was indeed correct.
The spectral signature measured on Hydra was even more indicative of pure water ice than what was previously found on Charon, Pluto’s largest moon. This suggests that Hydra lacks the dusty, dark particles that characterize the ice on Charon.
According to Simon Porter, a New Horizons team member working out of the Southwest Research Institute in Boulder, CO, “Perhaps micrometeorite impacts continually refresh the surface of Hydra by blasting off contaminants. This process would have been ineffective on the much larger Charon, whose much stronger gravity retains any debris created by these impacts.”
Before New Horizons relayed this data to scientists back on Earth, not much was known about Hydra. The discovery offers unique insight into the early days of the solar system, confirming that water molecules are abundant to the very outer edges – even if they are frozen.
A press release from NASA describing the details of the discovery can be found here.