Friday, October 16, 2015

A (Woefully Late) New Horizons Update! Our Awesome, Intrepid, Little Explorer Reveals Amazing Pluto In All Its Stunning Complexity

**This entry was posted on Oct. 16, 2015.**

The Norgay and Hillary Mountains of Pluto as seen from 11,000 miles away by our awesome New Horizons space probe minutes after its closest approach on July 14, 2015.

Those are 11,000 foot solid nitrogen ice mountains. Ponder that.

NASA Caption: Closer Look: Majestic Mountains and Frozen Plains: Just 15 minutes after its closest approach to Pluto on July 14, 2015, NASA’s New Horizons spacecraft looked back toward the sun and captured this near-sunset view of the rugged, icy mountains and flat ice plains extending to Pluto’s horizon. The smooth expanse of the informally named Sputnik Planum (right) is flanked to the west (left) by rugged mountains up to 11,000 feet (3,500 meters) high, including the informally named Norgay Montes in the foreground and Hillary Montes on the skyline. The backlighting highlights more than a dozen layers of haze in Pluto’s tenuous but distended atmosphere. The image was taken from a distance of 11,000 miles (18,000 kilometers) to Pluto; the scene is 230 miles (380 kilometers) across. Credits: NASA/JHUAPL/SwRI) Source here.

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My previous astronomical-themed entry brought to mind the fact that I am WOEFULLY (as in 3 months) behind on posting information on the Pluto system flyby by our awesome and wonderful little New Horizons space probe.

NASA Caption: This synthetic perspective view of Pluto, based on the latest high-resolution images to be downlinked from NASA’s New Horizons spacecraft, shows what you would see if you were approximately 1,100 miles (1,800 kilometers) above Pluto’s equatorial area, looking northeast over the dark, cratered, informally named Cthulhu Regio toward the bright, smooth, expanse of icy plains informally called Sputnik Planum. The entire expanse of terrain seen in this image is 1,100 miles (1,800 kilometers) across. The images were taken as New Horizons flew past Pluto on July 14, 2015, from a distance of 50,000 miles (80,000 kilometers). Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute. Source here.

We were really lucky that the Tombaugh Regio happened to rotate into view during the actual flyby.

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Of course, during that time, New Horizons mission control has analyzed tremendous amounts of data and released incredible pictures that have brought home just how amazing is Pluto and at least Charon (the other moons did not get as much analysis).

Let's start out with another APOD, namely, the Oct 6, 2015 APOD that involves New Horizons' flyby of Pluto last July ...



APOD caption (without links): What would it look like to fly past Pluto? The robotic New Horizons spacecraft did just this in late July and continues to return stunning pictures of the dwarf planet. Some well-chosen flyby images have now been digitally sequenced to create the featured video. The animation begins by showing New Horizon's approach to the Pluto system, with Pluto and its largest moon Charon orbiting a common center of mass. As the spacecraft bears down on Pluto uniquely, surprising surface features are nearly resolved that, unfortunately, quickly rotate out of view. New Horizons then passes just above and near a large, fascinating, light-colored, heart-shaped, and unusually smooth region now known as Tombaugh Regio. The spacecraft then pivots to look back at Pluto's night side, seeing an encompassing atmospheric haze. Finally, Pluto fades away in a final sequence illustrated with the orbits of many of Pluto's smaller moons. Although humanity has no current plans to return to Pluto, the New Horizons spacecraft may well be directed next to fly past an asteroid currently known only as 2014 MU69.

(I don't have a NASA or New Horizons mission page link for this video but rather it is on the APOD YouTube channel.)

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NASA caption: This animation combines various observations of Pluto over the course of several decades. The first frame is a digital zoom-in on Pluto as it appeared upon its discovery by Clyde Tombaugh in 1930 (image courtesy Lowell Observatory Archives). The other images show various views of Pluto as seen by NASA's Hubble Space Telescope beginning in the 1990s and NASA's New Horizons spacecraft in 2015. The final sequence zooms in to a close-up frame of Pluto released on July 15, 2015. Source here.

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We now know that Pluto is a highly diverse ice world that must also be geologically active. Nitrogen ice dominates with small amounts of methane and carbon monoxide ice. Pluto has both Rocky Mountain-sized mountains of nitrogen ice rising above extensive, craterless plains of nitrogen ice dusted in frozen reddish-brown tholins.

A labeled map of the Sputnik Planum lobe of the Tombaugh Regio of Pluto using the names bestowed by the New Horizons Mission. The names are not as yet "official" via the International Astronomical Union.

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The astonishing heart-shaped Tombaugh Regio -- named for Pluto's discoverer, the wonderful Clyde Tombaugh -- includes the western lobe called Sputnik Planum, itself bounded by the Hillary and Norgay Montes regions (named for, yes, Sir Edmund Hillary and Tenzing Norgay).

The nitrogen and methane chemical compounds in the extremely tenuous Plutonian atmosphere creates the tholins that actually cause preferential blue scattering of the very distant sunlight creating, yes, a blue sky (likely a very dark blue).

This colorized image shows it well ...

Pluto as seen from New Horizons on July 15, 2015 (or shortly after midnight UTC on July16, 2015) a day after the closest approach in a colorized image.

The NASA caption reads: Pluto's haze layer shows its blue color in this picture taken by the New Horizons Ralph/Multispectral Visible Imaging Camera (MVIC). The high-altitude haze is thought to be similar in nature to that seen at Saturn’s moon Titan. The source of both hazes likely involves sunlight-initiated chemical reactions of nitrogen and methane, leading to relatively small, soot-like particles (called tholins) that grow as they settle toward the surface. This image was generated by software that combines information from blue, red and near-infrared images to replicate the color a human eye would perceive as closely as possible. Source here and here.

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Now this isn't to say there are no craters on Pluto. This image attests to the fact that it definitely does:

Complex geological terrain of a portion of Pluto as seen by New Horizons on its July 14, 2015 flyby.

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A close-up of the ice mountains of Pluto near the terminator line as by New Horizons flyby on July 14, 2015. For more information, see here.

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As for New Horizons, it is presently (as I write this) 111.6 million kilometers from Pluto and receding fast from it. The little probe is en route to this tiny Kuiper Belt object as it heads out forever from Earth, eventually into interstellar space.

Once again, that now-iconic "true colors" picture of Pluto with its nothing-less-than-joy-inspiring heart shape in full view as seen by New Horizons shortly before its closest encounter...

Pluto global mosaic image from New Horizons taken on July 14, 2015 from about 280,000 miles away. This is a combined LORRI and Ralph set of images that gives Pluto's approximate true color (to the human eye).

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Tremendous additional info is available on the New Horizons news website and the NASA New Horizons mission website including as well on Pluto's moons.

WE LOVE PLUTO, AND WE LOVE YOU, NEW HORIZONS! You did us so proud at Pluto.
 
Still more wonderful worlds await you, New Horizons! Go, little one, go!

--Regulus

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