These maps of water ice on Pluto's surface were created using data captured by NASA's New Horizons spacecraft during its flyby of the dwarf planet on July 14, 2015. The map at left is an early effort; the one at right used modeling techniques to achieve greater sensitivity.
Hubble (left): NASA, ESA, and J. Parker (Southwest Research Institute); Dawn (right): NASA/JPL-Caltech/UCLA/MPS/DLR/IDA; edit: Ian O'Neill/Discovery News
The term "dwarf planet" wasn't defined until the infamous International Astronomical Union (IAU) vote in 2006, but this year, 9 years later, we are beginning to get our first ever close-up views of two of our solar system's most famous dwarf planets: Pluto and Ceres.VIDEO: Pluto Flyby and Black Holes: Top Space Events for 2015
Currently spiraling in on Ceres, the innermost dwarf planet inhabiting the asteroid belt between the orbits of Mars and Jupiter, NASA's Dawn spacecraft is slowly revealing a cratered and complex world, details of which that have so far eluded even Hubble's powerful vision. Dawn is scheduled to make final orbital insertion around Ceres in March 2015 where it is destined to remain after its fuel runs out as a permanent human-made satellite of Ceres. A comparison image of the Hubble and Dawn views of Ceres is shown above.ANALYSIS: NASA Spacecraft Ready to Unlock Ceres' Mysteries
But Dawn is just the first dwarf planet encounter of 2015. In July, NASA's New Horizons mission will flyby Pluto and its system of moons, exploring the mysterious Kuiper Belt. Between Hubble's blurry observations of Ceres and Pluto and this year's NASA encounters, many artists' impressions of these enigmatic worlds have guessed at what lies in store for our robotic explorers. But how do they measure up now we are beginning to see Ceres' and Pluto's surfaces?
Walter Myers/Stocktrek Images/Corbis
This artist's impression of Ceres shows NASA's Dawn spacecraft in orbit around the dwarf planet. As opposed to an ice encrusted world, this visualization shows a cratered, moon-like surface.NEWS: Tantalizing Detail Seen on Mysterious Dwarf Planet
Walter Myers/Stocktrek Images/Corbis
Again with Dawn in view, this artist's impression shows an active Ceres complete with water vapor escaping from a possible sub-surface ocean. Water vapor was detected in the vicinity of Ceres by Hubble, so Dawn will be on the look-out for any trace of geysers venting water.ANALYSIS: Water Plume 'Unequivocally' Detected at Dwarf Planet Ceres
NASA, ESA, J. Parker (Southwest Research Institute), L. McFadden (University of Maryland)
As seen by Hubble from afar, curious white patches and possible variations in Ceres' surface composition can be seen. However, any detail in these images have so far prevented planetary scientists from fully understanding the dwarf planet's true nature.NEWS: What is That Mysterious White Blob on Ceres?
But now, as Dawn fast approaches orbital insertion, we're being treated to a bounty of data that shows a possibly ancient, rocky surface. Those curious white patches originally spied by Hubble are also snapping into view -- but what are they? Theories abound, but they may be tentative signs of subsurface water escaping to space and freezing on the surface. These are all signs of cryovolcanism, a dynamic that may dominate dwarf planet surface morphology.NEWS: Dwarf Planet's Puzzling Landscape Snaps into View
From afar, NASA's Dawn mission is able to watch Ceres rotate, as this series of observations on Feb. 4 shows.ANALYSIS: Craters Pop as NASA’s Dawn Probe Approaches Ceres
As Dawn gets up-close and personal with Ceres, the drama in the outer solar system is only just beginning to unfold. After 9 years of flying toward Pluto, NASA's New Horizons mission has begun approach preparations for its flyby in July.VIDEO: Pluto Getting Bigger in New Horizons Probe's Window
From ground-based and Hubble observations, there at tantalizing clues that this frozen world has a surprisingly dynamic surface with a thin atmosphere that changes during Pluto's 248 year orbit around the sun. In this artist's impression of New Horizons flying over Pluto, an atmosphere has been included with cryovolcanos -- the latter of which planetary scientists hope to confirm in July.
Ron Miller/Stocktrek Images/Corbis
Pluto has a system of known moons, the largest of which, Charon, may be considered to be Pluto's binary partner. As Charon orbits Pluto, its powerful gravitational field tugs the dwarf planet off center, a dynamic that New Horizons has observed as it approaches.ANALYSIS: NASA Probe Captures First Pluto Approach Photos
Mark Garlick/Science Photo Library/Corbis
This artist's conception shows Pluto's moon Charon eclipsing the dwarf planet. Twice every orbit around the sun, each world eclipses the other.NEWS: Tally-Ho on Targets for New Horizons After Pluto
When Hubble spies on Pluto, it can see the different shades of the dwarf planet's surface rotate. As shown here in these blotchy images, little detail is obvious, but large regions with differing albedo (reflectiveness) may reveal huge craters, vast plains or mountains. But until New Horizons gets close, these regions will remain a mystery.
William Radcliffe/Science Faction/Corbis
In this digital illustration rendered from 3-D NASA data of Pluto, an attempt has been made at matching observations with possible surface features.
NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
In July 2014, NASA's New Horizons looked ahead and spied its ultimate goal: Pluto and Charon. Although tiny pinpricks of light, the pair can be seen orbiting one another in a binary dance that shifts Pluto off center. Both masses actually orbit an invisible point in space, above Pluto's surface, known as the Pluto-Charon barycenter. These observations have increased calls for Pluto to be redefined (yet again) as a 'binary planet.'MORE: Can We Call Pluto and Charon a 'Binary Planet' Yet?
NASA/Johns Hopkins APL/Southwest Research Institute
Having spotted Charon months ago, New Horizons is now beginning to see Pluto's wider family of moons pop into view. Shown here are moons Nix (yellow diamond) and Hydra (orange diamond).MORE: Pluto's Tiny Moons Spied by Incoming NASA Probe
Once NASA's New Horizons mission careens through the Pluto-Charon system, assuming it doesn't hit any debris on its way through, its mission in the Kuiper Belt has only just begun. Hubble is currently being used to identify possible icy targets
the spacecraft's Pluto encounter. Shown here is an artist's impression of another dwarf planet, Eris, that was discovered in 2005. Originally thought to be the
planet of the solar system, its discovery led to the IAU's decision to reclassify these small worlds as dwarf planets, demoting Pluto in the process, leaving us with 8 planets. But as we approach Pluto and begin to understand Ceres, just because they are dwarf planets doesn't mean they're not rich and dynamic places to explore. Our voyage of dwarf planet discovery has only just begun and regardless of our need to classify celestial objects, Pluto and Ceres hold some fascinating clues to planetary formation and solar system evolution.
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Water ice is surprisingly abundant on Pluto's surface, a new map of the dwarf planet reveals.
Scientists created the map using data collected by NASA's New Horizons spacecraft during its epic flyby of Pluto last July.
The new map is more sensitive than an earlier version also produced using flyby observations, and thus shows more water ice — the dwarf planet's bedrock material — cropping up across Pluto's surface than had been seen previously, NASA officials said.
"But despite its much greater sensitivity, the map still shows little or no water ice in the informally named places called Sputnik Planum (the left or western region of Pluto’s 'heart') and Lowell Regio (far north on the encounter hemisphere)," NASA officials wrote in a statement Thursday (Jan. 28). "This indicates that at least in these regions, Pluto's icy bedrock is well hidden beneath a thick blanket of other ices such as methane, nitrogen and carbon monoxide."
New Horizons zoomed within just 7,800 miles (12,550 kilometers) of Pluto on July 14, 2015, returning history's first up-close looks at the dwarf planet and its five moons.
The new and old water-ice maps were both made using infrared-light observations captured by New Horizons' Ralph/Linear Etalon Imaging Spectral Array (LEISA) instrument, at a distance of about 67,000 miles (108,000 km) from Pluto, NASA officials said.
New Horizons is currently zooming toward a small object about 1 billion miles (1.6 billion km) beyond Pluto called 2014 MU69. If NASA approves and funds a proposed extended mission, the spacecraft will study 2014 MU69 up close on Jan. 1, 2019.
New Horizons is also still beaming home the many photos and measurements it captured during the July 14 flyby. All of the close-encounter data should be on the ground by this coming fall, mission team members have said.