Category Archives: New Horizons

Shores of Pluto

plutoterrain

 

Those “pits” are very intriguing, need to know more about them.

New Horizons:

This enhanced color view from NASA’s New Horizons spacecraft zooms in on the southeastern portion of Pluto’s great ice plains, where at lower right the plains border rugged, dark highlands informally named Krun Macula. (Krun is the lord of the underworld in the Mandaean religion, and a ‘macula’ is a dark feature on a planetary surface.)

Pluto is believed to get its dark red color from tholins, complex molecules found across much of the surface. Krun Macula rises 1.5 miles (2.5 kilometers) above the surrounding plain – informally named Sputnik Planum – and is scarred by clusters of connected, roughly circular pits that typically reach between 5 and 8 miles (8 and 13 kilometers) across, and up to 1.5 miles (2.5 kilometers) deep.

At the boundary with Sputnik Planum, these pits form deep valleys reaching more than 25 miles (40 kilometers) long, 12.5 miles (20 kilometers) wide and almost 2 miles (3 kilometers) deep – almost twice as deep as the Grand Canyon in Arizona – and have floors covered with nitrogen ice.  New Horizons scientists think these pits may have formed through surface collapse, although what may have prompted such a collapse is a mystery.

This scene was created using three separate observations made by New Horizons in July 2015. The right half of the image is composed of 260 feet- (80 meter-) per-pixel data from the Long Range Reconnaissance Imager (LORRI), obtained at 9,850 miles (15,850 kilometers) from Pluto, about 23 minutes before New Horizons’ closest approach.  The left half is composed of 410 feet- (125 meter-) per-pixel LORRI data, obtained about six minutes earlier, with New Horizons 15,470 miles (24,900 kilometers) from Pluto.

These data respectively represent portions of the highest- and second-highest-resolution observations obtained by New Horizons in the Pluto system. The entire scene was then colorized using 2,230 feet- (680 meter-) per-pixel data from New Horizons’ Ralph/Multispectral Visual Imaging Camera (MVIC), obtained at 21,100 miles (33,900 kilometers) from Pluto, about 45 minutes before closest approach.

Credits: NASA/JHUAPL/SwRI

Active Pluto

plutolavalamp

Hard to imagine that a (dwarf) planet so far from the Sun would be as active as Pluto is!

The New Horizon’s caption:
Like a cosmic lava lamp, a large section of Pluto’s icy surface is being constantly renewed by a process called convection that replaces older surface ices with fresher material.

Scientists from NASA’s New Horizons mission used state-of-the-art computer simulations to show that the surface of Pluto’s informally named Sputnik Planum is covered with churning ice “cells” that are geologically young and turning over due to a process called convection. The scene above, which is about 250 miles (400 kilometers) across, uses data from the New Horizons Ralph/Multispectral Visible Imaging Camera (MVIC), gathered July 14, 2015. Their findings are published in the June 2, 2016, issue of the journal Nature.

Image: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Peering Through Pluto’s Atmosphere

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New findings from New Horizons:

New Horizons succeeded in observing the first occultations of Pluto’s atmosphere by ultraviolet stars, an important goal of the mission’s Pluto encounter. This illustration shows how New Horizons’ Alice ultraviolet spectrometer instrument “watched” as two bright ultraviolet stars passed behind Pluto and its atmosphere. The light from each star dimmed as it moved through deeper layers of the atmosphere, absorbed by various gases and hazes.

The observations were made approximately four hours after New Horizons made its closest approach to Pluto on July 14, 2015, when the spacecraft was about 200,000 miles (320,000 kilometers) beyond Pluto.

Much like the solar occultation that Alice had observed a few hours before – when it used sunlight to make similar measurements – these stellar occultations provided information about the composition and structure of Pluto’s atmosphere. Both stellar occultations revealed ultraviolet spectral fingerprints of nitrogen, hydrocarbons like methane and acetylene, and even haze, just as the solar occultation had done earlier.

The results from the solar and stellar occultations are also consistent in terms of vertical pressure and temperature structure of Pluto’s upper atmosphere. This means that the upper atmosphere vertical profiles of nitrogen, methane, and the observed hydrocarbons are similar over many locations on Pluto.

These results confirm findings from the Alice solar occultation that the upper atmospheric temperature is as much as 25 percent colder and thus more compact than what scientists predicted before New Horizons’ encounter. This also confirms, albeit indirectly, the result from analysis and modeling of the Alice solar observation that the escape rate of nitrogen is about 1,000 times lower than expected before the flyby.

Image: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Post Pluto

mystery

The first of many “post-Pluto” observations from New Horizons. I have to smile because missions like this answer so many questions and ask about twice as many – that’s the fun of science.

From New Horizons:

Warming up for a possible extended mission as it speeds through deep space, NASA’s New Horizons spacecraft has now twice observed 1994 JR1, a 90-mile-wide (145-kilometer-wide) Kuiper Belt object (KBO) orbiting more than 3 billion miles (5 billion kilometers) from the sun. Science team members have used these observations to reveal new facts about this distant remnant of the early solar system.

Taken with the spacecraft’s Long Range Reconnaissance Imager (LORRI) on April 7-8 from a distance of about 69 million miles (111 million kilometers), the images shatter New Horizons’ own record for the closest-ever views of this KBO in November 2015, when New Horizons detected JR1 from 170 million miles (280 million kilometers) away.

Simon Porter, a New Horizons science team member from Southwest Research Institute (SwRI) in Boulder, Colorado, said the observations contain several valuable findings. “Combining the November 2015 and April 2016 observations allows us to pinpoint the location of JR1 to within 1,000 kilometers (about 600 miles), far better than any small KBO,” he said, adding that the more accurate orbit also allows the science team to dispel a theory, suggested several years ago, that JR1 is a quasi-satellite of Pluto.

From the closer vantage point of the April 2016 observations, the team also determined the object’s rotation period, observing the changes in light reflected from JR1’s surface to determine that it rotates once every 5.4 hours (or a JR1 day). “That’s relatively fast for a KBO,” said science team member John Spencer, also from SwRI. “This is all part of the excitement of exploring new places and seeing things never seen before.”

Spencer added that these observations are great practice for possible close-up looks at about 20 more ancient Kuiper Belt objects that may come in the next few years, should NASA approve an extended mission. New Horizons flew through the Pluto system on July 14, 2015, making the first close-up observations of Pluto and its family of five moons. The spacecraft is on course for an ultra-close flyby of another Kuiper Belt object, 2014 MU69, on Jan. 1, 2019.

Credits: NASA/JHUAPL/SwRI

Hydra

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We are beginning to get a bit of compositional data on Pluto’s four small moons.   The moon shown here is Hydra and it appears to be made mostly of water ice.

New Horizons:

The new data – known as infrared spectra – show the unmistakable signature of crystalline water ice: a broad absorption from 1.50 to 1.60 microns and a narrower water-ice spectral feature at 1.65 microns. The Hydra spectrum is similar to that of Pluto’s largest moon, Charon, which is also dominated by crystalline water ice. But Hydra’s water-ice absorption bands are even deeper than Charon’s, suggesting that ice grains on Hydra’s surface are larger or reflect more light at certain angles than the grains on Charon. Hydra is thought to have formed in an icy debris disk produced when water-rich mantles were stripped from the two bodies that collided to form the Pluto-Charon binary some 4 billion years ago. Hydra’s deep water bands and high reflectance imply relatively little contamination by darker material that has accumulated on Charon’s surface over time.

hydracomposite

~click~

Mission scientists are investigating why Hydra’s ice seems to be cleaner than Charon’s. “Perhaps micrometeorite impacts continually refresh the surface of Hydra by blasting off contaminants,” said Simon Porter, a 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.”

The New Horizons science team is looking forward to obtaining similar spectra of Pluto’s other small moons, for comparison to Hydra and Charon.

Credits: NASA/JHUAPL/SwRI

Elevation Map from Pluto

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The New Horizon’s team released this elevation map of Sputnik Planum, the heart shaped feature on Pluto.

From New Horizons
This shaded relief view of the region surrounding the left side of Pluto’s heart-shaped feature – informally named Sputnik Planum – shows that the vast expanse of the icy surface is on average 2 miles (3 kilometers) lower than the surrounding terrain. Angular blocks of water ice along the western edge of Sputnik Planum can be seen “floating” in the bright deposits of softer, denser solid nitrogen.

Topographic maps of Pluto are produced from digital analysis of New Horizons stereo images acquired during the July 14, 2015 flyby. Such maps are derived from digital stereo-image mapping tools that measure the parallax – or the difference in the apparent relative positions – of individual features on the surface obtained at different times. Parallax displacements of high and low features are then used to directly estimate feature heights.

These topographic maps are works in progress and artifacts are still present in the current version. The map is artificially illuminated from the south, rather than the generally northern solar lighting of landscape during the time of the flyby. One of the many advantages of digital terrain maps is that they can be illuminated from any direction to best bring out different features. North is up and the total relief in the scene is approximately 4 miles (6 kilometers) from the lowest to the highest features.

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Ice Spider on Pluto

spiderpluto

No, not some science fiction movie, but close, Pluto is very strange.

Credit: NASA / John Hopkins APL / SwRI

From New Horizons:

Sprawling across Pluto’s icy landscape is an unusual geological feature that resembles a giant spider.

“Oh, what a tangled web Pluto’s geology weaves,” said Oliver White, a member of the New Horizons geology team from NASA Ames Research Center, Mountain View, California. “The pattern these fractures form are like nothing else we’ve seen in the outer solar system, and shows once again that anywhere we look on Pluto, we see something different.”

As shown in the enhanced color image below – obtained by NASA’s New Horizons spacecraft on July 14, 2015 – this feature consists of at least six extensional fractures (indicated by white arrows in this annotated version) converging to a point near the center. The longest fractures are aligned roughly north-south, and the longest of all, the informally named Sleipnir Fossa, is more than 360 miles (580 kilometers) long.  The fracture aligned east-west is shorter and reaches less than 60 miles (100 kilometers) long.  To the north and west, the fractures extend across the mottled, rolling plains of the high northern latitudes, and to the south, they intercept and cut through the bladed terrain informally named Tartarus Dorsa.

Curiously, the spider’s “legs” noticeably expose red deposits below Pluto’s surface.

New Horizons scientists think fractures seen elsewhere on Pluto, which tend to be aligned parallel to each other in long belts – rather than intersecting with one another at a nexus, as this feature does – are caused by global-scale extension of Pluto’s water–ice crust.  However, given the curious radiating pattern of the fractures forming the “spider,” it may instead be caused by a focused source of stress in the crust under the point where the fractures converge – for example, due to material welling up from under the surface.  The spider somewhat resembles “radially fractured centers” on Venus called novae (http://photojournal.jpl.nasa.gov/catalog/PIA00150) seen by NASA’s Magellan spacecraft, as well as the Pantheon Fossae formation seen by NASA’s MESSENGER spacecraft on Mercury (http://photojournal.jpl.nasa.gov/catalog/PIA19410).

This image was obtained by New Horizons’ Ralph/Multispectral Visible Imaging Camera (MVIC).  The image resolution is approximately 2,230 feet (680 meters) per pixel.  It was obtained at a range of approximately 21,100 miles (33,900 kilometers) from Pluto, about 45 minutes before New Horizons’ closest approach on July 14, 2015.