New Photos Show a Two-Faced Pluto
As we anticipate the July 14 New Horizons Pluto flyby, in new images published by the mission team on Wednesday, the small world has revealed it has two faces.
As we anticipate the July 14 Pluto flyby - as NASA's New Horizons spacecraft zips through the dwarf planet's system of moons - in new images published by the mission team on Wednesday, the small world has revealed it has two faces.
Beginning to look like a fuzzy, slightly paler version of Mars, Pluto seems to have a huge diversity of surface features, even from a distance of over 9.5 million miles (15 million kilometers) and it's beginning to look like the dwarf planet has two very distinct hemispheres. One "face" is smooth, with large dark features; the opposite side appears to have a peculiar series of spots spanning Pluto's equator, all roughly the same size, around 300 miles (480 kilometers) in diameter.
"It's a real puzzle - we don't know what the spots are, and we can't wait to find out," said Alan Stern, New Horizons' principal investigator at the Southwest Research Institute, in Boulder, Colo. "Also puzzling is the longstanding and dramatic difference in the colors and appearance of Pluto compared to its darker and grayer moon Charon."
Indeed, the difference in color is becoming more pronounced on every image release. Pluto has a ruddy yellow hue, whereas Charon's color appears to have more in common with our moon than Pluto. It is worth noting, however, that these images are still very early in the flyby game, so we'll need to be patient until we start drawing any conclusions about surface composition or whether Pluto possesses clouds in its thin exosphere.
In other news from the Kuiper Belt, the New Horizons infrared spectrometer is online and has detected frozen methane on Pluto's surface. Astronomers have known about the spectroscopic signature of methane on Pluto since 1976, but the mission will study the distribution of this molecule around the dwarf planet to see how it varies.
"We already knew there was methane on Pluto, but these are our first detections," said Will Grundy, New Horizons Surface Composition team leader with the Lowell Observatory in Flagstaff, Ariz. "Soon we will know if there are differences in the presence of methane ice from one part of Pluto to another."
The study of methane on Pluto will provide us with more clues as to the composition of the nebula from which our sun and the planets were born from 4.5 billion years ago. In short, this primordial chemical is an open book from the beginning of planetary formation.
As New Horizons continues to approach Pluto, the world is getting bigger, as shown in this awesome series of images captured from May 28 to June 25, 2015:
Pluto shows two remarkably different sides in these color images of the planet and its largest moon Charon taken by New Horizons on June 25 and June 27. The images were made from black-and-white images combined with lower-resolution color data.
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.
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.
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?
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.
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.
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.
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.
From afar, NASA's Dawn mission is able to watch Ceres rotate, as this series of observations on Feb. 4 shows.
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.
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.
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.
This artist's conception shows Pluto's moon Charon eclipsing the dwarf planet. Twice every orbit around the sun, each world eclipses the other.
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.
In this digital illustration rendered from 3-D NASA data of Pluto, an attempt has been made at matching observations with possible surface features.
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.'
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).
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.
For more, regularly check on the
mission web sites.