This mosaic of Pluto's surface was created from images taken by the New Horizons probe just 23 minutes before its closest approach. Credit: NASA/JHUAPL/SwRI
The New Horizons mission, which its conducted its historic flyby on July 14th, 2015, has yielded a wealth of scientific data about Pluto. This has included discoveries about Pluto’s size, its mountainous regions, its floating ice hills, and (more recently) how the dwarf planet interacts with solar wind – a discovery which showed that Pluto is actually more planet-like than previously thought.
But beyond revelations about the planet’s size, geography and surface features, it has also provided the most breathtaking, clear, and inspiring images of Pluto and its moons to date. And with this latest release of images taken by the New Horizon‘s Long Range Reconnaissance Imager (LORRI), people here on Earth are being treated to be the best close-up of Pluto yet.
These images, which were taken while the New Horizon’s probe was still 15,850 km (9,850 mi) away from Pluto (just 23 minutes before it made its closest approach), extend across the hemisphere that the probe was facing as it flew past. It shows features ranging from the cratered northern uplands and the mountainous regions in Voyager Terra before slicing through the flatlands of “Pluto’s Heart” – aka. Tombaugh Regio – and ending up in another stretch of rugged highlands.
Informal names given to Pluto’s surface features. Credit: earthsky.org
The width of the strip varies as the images pass from north to south, from more than 90 km (55 mi) across at the northern end to about 75 km (45 mi) at its southern point. The perspective also changes, with the view appearing virtually horizontal at the northern end and then shifting to an almost top-down view onto the surface by the end.
The crystal clear photographs that make up the mosaic – which have a resolution of about 80 meters (260 feet) per pixel – offer the most detailed view of Pluto’s surface ever. With this kind of clarity, NASA scientists are able to discern features that were never before visible, and learn things about the kinds of geological processes which formed them.
This includes the chaotic nature of the mountains in the northern hemisphere, and the varied nature of the icy nitrogen plains across Tombaugh Regio – which go from being cellular, to non-cellular, to a cross-bedding pattern. These features are a further indication that Pluto’s surface is the product of a combination of geological forces, such as cryovolcanism, sublimation, geological activity, convection between water and nitrogen ice, and interaction between the surface and atmosphere.
Images snapped by New Horizons’ Long Range Reconnaissance Imager (LORRI) while the probe was still on approach to Pluto were combined with color data from the Ralph instrument to create this global view of Pluto. Credits: NASA/JHUAPL/SwRI
Alan Stern, the principal investigator of the New Horizons mission and the Associate Vice President of Research and Development at the Southwest Research Institute, was especially impressed with this latest find. As he told Universe Today via email:
“This new high resolution image mosaic is the complete highest resolution strip of images New Horizons obtained, and its both eye candy gorgeous and scientifically rich. Think about it— one flyby and we have this mosaic, plus so much more; no dataset like this existed on Mars until we’d flown half a dozen missions there!”
The most distant flyby in the history of space exploration, and yet we’ve obtained more from this one mission than multiple flybys were able to provide from one of Earth’s closest neighbors. Fascinating! And what’s more, new information is expected to be coming from the New Horizons probe until this coming October. To top it off, our scientists are still not finished analyzing all the information the mission collected during its flyby.
The full-resolution image can be viewed here, and be sure to enjoy this NASA video of the mosaic:
This artist's impression shows the New Horizons spacecraft encountering a Pluto-like object in the distant Kuiper Belt. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Steve Gribben)
Even the most curmudgeonly anti-space troll has to admit that the New Horizons mission to Pluto has been an overwhelming success.
It’s not like New Horizons discovered life or anything, but it did bring an otherwise cold, distant lump to life for humanity. Vivid images and detailed scientific data revealed Pluto as a dynamic, changing world, with an active surface and an atmosphere. And we haven’t even received all of the data from New Horizons’ mission to Pluto yet.
Fresh off its historic visit to Pluto, New Horizons is headed for the Kuiper Belt, and just sent back its first science on one of the denizens of the distant belt of objects. The target in this case is 1994 JR1, a 145 km (90 mi.) wide Kuiper Belt Object (KBO). that orbits the Sun at a distance greater than 5 billion km. (3 billion mi.) New Horizons has now observed 1994 JR1 twice, and the team behind the mission has garnered new insights into this KBO based on these observations.
The spacecraft’s Long Range Reconnaissance Imager (LORRI) captured images of 1994 JR1 on April 7th-8th from a distance of 111 million km. (69 million mi.). That’s far closer than the images New Horizons captured in November 2015 from a distance of 280 million km (170 million miles).
This image, taken with the LORRI instrument aboard New Horizons, shows 2 of the 20 images captured in April. The moving dots are 1994 JR1, shown against a backdrop of stationary stars. The circular object in the top left of the image is a reflective artifact of the camera itself, showing LORRI’s three support arms. Image: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
New Horizons science team member Simon Porter, of the Southwest Research Institute (SwRI) in Boulder Colorado, commented on the importance of these images. “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,” Porter said.
Porter added that this accurate measurement of the KBO’s orbit allows New Horizons science team members to quash the idea that JR1 is a quasi-satellite of Pluto.
The team was also able to determine, by measuring the light reflected from the surface, that JR1’s rotational period is only 5.4 hours. That’s fast for a KBO. John Spencer, another New Horizons science team member from SwRI, said “This is all part of the excitement of exploring new places and seeing things never seen before.”
Variations in the brightness of light reflected from the surface of 1994 JR1 allowed science team members to pinpoint the object’s rotation period at 5.4 hours. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
KBOs are ancient remnants of the early days of the Solar System. Whereas the inner regions of the Solar System were largely swept clean as the planets formed, the Kuiper Belt remained mostly as it is, untouched by the gravity of the planets.
There are trillions of objects in this cold, distant part of the Solar System. The Kuiper Belt itself spans a distance that is 30 to 50 times greater than the distance from the Earth to the Sun. It’s similar to the asteroid belt between Mars and Jupiter, but Kuiper Belt objects are icy, whereas asteroid belt objects are rocky, for the most part.
The New Horizons team has requested a mission extension, and if that extension is approved, the target is already chosen. In August 2015, NASA selected the KBO 2014 MU69, which resides in an orbit almost a billion miles beyond Pluto. There were two potential destinations for the spacecraft after it departed Pluto, and 2014 MU69 was recommended by the New Horizons team, and chosen by NASA.
If New Horizons’ mission is extended, this is the path it will take to its next destination, 2014 MU69. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Alex Parker)
Choosing New Horizons’ next target early was important for fuel use. Fuel conservation allows the spacecraft to perform the maneuvers necessary to reach 2014 MU69. If all goes well, New Horizons should reach its next target by January 2019.
According to Alan Stern, New Horizons Principal Investigator, there are good reasons to visit 2014 MU69. “2014 MU69 is a great choice because it is just the kind of ancient KBO, formed where it orbits now, that the Decadal Survey desired us to fly by,” he said. “Moreover, this KBO costs less fuel to reach [than other candidate targets], leaving more fuel for the flyby, for ancillary science, and greater fuel reserves to protect against the unforeseen.”
The Decadal Survey in 2003 strongly recommended that flybys of Pluto and small KBOs should be conducted. The KBO is an unexplored region, and these flybys will allow us to sample the diversity of objects in the belt.
If New Horizons makes it to its next target, 2014 MU69, and delivers the types of results it has so far in its journey, it will be an unprecedented success. The kind of success that will make it harder and harder to be a curmudgeonly anti-space troll.
New Horizon's July 2015 flyby of Pluto captured this iconic image of the heart-shaped region called Tombaugh Regio. Credit:
NASA/JHUAPL/SwRI.
Pluto can’t seem to catch a break lately. After being reclassified in 2006 by the International Astronomical Union, it seemed that what had been the 9th planet of the Solar System was now relegated to the status of “dwarf planet” with the likes of Ceres, Eris, Haumea, and Makemake. Then came the recent announcements that the title of “Planet 9” may belong to an object ten times the mass of Earth located 700 AU from our Sun.
And now, new research has been produced that indicates that Pluto may need to be reclassified again. Using data provided by the New Horizons mission, researchers have shown that Pluto’s interaction with the Sun’s solar wind is unlike anything observed in the Solar System thus far. As a result, it would seem that the debate over how to classify Pluto, and indeed all astronomical bodies, is not yet over.
NASA’s New Horizons mission science team has produced this updated panchromatic (black-and-white) global map of Pluto. Credits: NASA/JHUAPL/SWRI
NASA’s New Horizons mission science team has produced this updated panchromatic (black-and-white) global map of Pluto. Credits: NASA/JHUAPL/SWRI
The science team leading NASA’s New Horizons mission that unveiled the true nature of Pluto’s long hidden looks during the history making maiden close encounter last July, have published a fresh global map that offers the sharpest and most spectacular glimpse yet of the mysterious, icy world.
The newly updated global Pluto map is comprised of all the highest resolution images transmitted back to Earth thus far and provides the best perspective to date.
Click on the lead image above to enjoy Pluto revealed at its finest thus far. Click on this link to view the highest resolution version.
Prior to the our first ever flyby of the Pluto planetary system barely 8 months ago, the planet was nothing more than a fuzzy blob with very little in the way of identifiable surface features – even in the most powerful telescopic views lovingly obtained from the Hubble Space Telescope (HST).
Dead center in the new map is the mesmerizing heart shaped region informally known as Tombaugh Regio, unveiled in all its glory and dominating the diminutive world.
The panchromatic (black-and-white) global map of Pluto published by the team includes the latest images received as of less than one week ago on April 25.
The images were captured by New Horizons’ high resolution Long Range Reconnaissance Imager (LORRI).
The science team is working on assembling an updated color map.
During its closest approach at approximately 7:49 a.m. EDT (11:49 UTC) on July 14, 2015, the New Horizons spacecraft swoop to within about 12,500 kilometers (nearly 7,750 miles) of Pluto’s surface and about 17,900 miles (28,800 kilometers) from Charon, the largest moon.
The map includes all resolved images of Pluto’s surface acquired in the final week of the approach period ahead of the flyby starting on July 7, and continuing through to the day of closest approach on July 14, 2015 – and transmitted back so far.
The pixel resolutions are easily seen to vary widely across the map as you scan the global map from left to right – depending on which Plutonian hemisphere was closest to the spacecraft during the period of close flyby.
They range from the highest resolution of 770 feet (235 meters), at center, to 18 miles (30 kilometers) at the far left and right edges.
The Charon-facing hemisphere (left and right edges of the map) had a pixel resolution of 18 miles (30 kilometers).
“This non-encounter hemisphere was seen from much greater range and is, therefore, in far less detail,” noted the team.
However the hemisphere facing New Horizons during the spacecraft’s closest approach on July 14, 2015 (map center) had a far higher pixel resolution reaching to 770 feet (235 meters).
Coincidentally and fortuitously the spectacularly diverse terrain of Tombaugh Regio and the Sputnik Planum area of the hearts left ventricle with ice flows and volcanoes, mountains and river channels was in the region facing the camera and sports the highest resolution imagery.
See below a newly released shaded relief map of Sputnik Planum.
This new 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 are “floating” in the bright deposits of softer, denser solid nitrogen. Credits: NASA/JHUAPL/SwRI
“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,” according to the team.
Even more stunning images and groundbreaking data will continue streaming back from New Horizons until early fall, across over 3 billion miles of interplanetary space.
Thus the global map of Pluto will be periodically updated.
Its taking over a year to receive the full complement of some 50 gigabits of data due to the limited bandwidth available from the transmitter on the piano-shaped probe as it hurtled past Pluto, its largest moon Charon and four smaller moons.
Pluto is the last planet in our solar system to be visited in the initial reconnaissance of planets by spacecraft from Earth since the dawn of the Space Age.
This new global mosaic view of Pluto was created from the latest high-resolution images to be downlinked from NASA’s New Horizons spacecraft and released on Sept. 11, 2015. The images were taken as New Horizons flew past Pluto on July 14, 2015, from a distance of 50,000 miles (80,000 kilometers). This new mosaic was stitched from over two dozen raw images captured by the LORRI imager and colorized. Annotated with informal place names. Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Marco Di Lorenzo/Ken Kremer/kenkremer.com
New Horizons remains on target to fly by a second Kuiper Belt Object (KBO) on Jan. 1, 2019 – tentatively named PT1, for Potential Target 1. It is much smaller than Pluto and was recently selected based on images taken by NASA’s Hubble Space Telescope.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
The varying brightness in Pluto's atmosphere is caused by atmospheric gravity waves, or buoyancy waves. Image: NASA/New Horizons/Johns Hopkins APL/SWRI
New Horizons’ historic journey to Pluto and beyond continues to provide surprises. As data from the spacecraft’s close encounter with Pluto and its moons arrives at Earth, scientists are piecing together an increasingly intriguing picture of the dwarf planet. The latest discovery is centred around Pluto’s atmosphere, and what are called ‘atmospheric gravity waves.’
Atmospheric gravity waves are a different phenomenon than the gravity waves that were detected for the first time in February, 2016. Those gravity waves are ripples in the fabric of space time, first predicted by Albert Einstein back in 1916. After years of searching, the LIGO instrument detected gravity waves that resulted from two black holes colliding. The discovery of what you might call ‘Einsteinian Gravity Waves’ may end up revolutionizing astronomy.
New Horizons has revealed surprise after surprise in its study of Pluto. Its atmosphere has turned out to be much more complex than anybody expected. It’s composed of 90% nitrogen, with extensive haze layers. Scientists have discovered that Pluto’s atmosphere can vary in brightness depending on viewpoint and illumination, while the vertical structure of the layered haze remains unchanged.
Scientists studying the New Horizons’ data think that atmospheric gravity waves, also called buoyancy waves, are responsible. Atmospheric gravity waves are known to exist on only two other planets; Earth and Mars. They are typically caused by wind flowing over obstructions like mountain ranges.
The layers in Pluto’s atmosphere, and their varying brightness, are most easily seen when they are backlit by the Sun. This was the viewpoint New Horizons had when it captured these images on its departure from Pluto on July 14, 2015. The spacecraft’s Long Range Reconnaissance Imager (LORRI) captured them, using time intervals of 2 to 5 hours. What they show is the brightness of the layers changing by 30% without any change in their height above the surface of the planet.
LORRI, as its name suggests, is a long range image capture instrument. It also captures high resolution geologic data, and was used to map Pluto’s far side. The principal investigator for LORRI is Andy Cheng, from the Applied Physics Laboratory at Johns Hopkins University, in Maryland. “Pluto is simply amazing,” said Andy Cheng. “When I first saw these images and the haze structures that they reveal, I knew we had a new clue to the nature of Pluto’s hazes. The fact that we don’t see the haze layers moving up or down will be important to future modelling efforts.”
Overall, Pluto and its system of moons has turned out to be a much more dynamic place than previously thought. A geologically active landscape, possible ice volcanoes, eroding cliffs made of methane ice, and more, have woken us up to Pluto’s complexity. But its atmosphere has turned out to be just as complex and puzzling.
New Horizons has departed the Pluto system now, and is headed for the Kuiper Belt. The Kuiper Belt is considered a relic of the early Solar System. New Horizons will visit another icy world there, and hopefully continue on to the edge of the heliosphere, the same way the Voyage probes have. New Horizons has enough energy to last until approximately the mid-2030’s, if all goes well.
The solar wind data collected by New Horizons will help create more accurate models of the space environment in our Solar System. Image: NASA's Goddard Space Flight Center Scientific Visualization Studio, the Space Weather Research Center (SWRC) and the Community-Coordinated Modeling Center (CCMC), Enlil and Dusan Odstrcil (GMU)
Anybody with an ounce of intellectual curiosity (and an internet connection) has seen the images of Pluto and its system taken by the New Horizons probe. The images and data from New Horizons have opened the door to Pluto’s atmosphere, geology, and composition. But New Horizons wasn’t entirely dormant during its 9 year, billion-plus mile journey to Pluto.
New Horizons returned 3 years worth of data on the solar wind that sweeps through the near-emptiness of space. The solar wind is the stream of particles that is released from the upper atmosphere of the Sun, called the corona. The Sun’s solar wind is what creates space weather in our solar system, and the wind itself varies in temperature, speed, and density.
The solar wind data from New Horizons, which NASA calls an “unprecedented set of observations,” is filling in a gap in our knowledge. Observatories like the Solar Dynamics Observatory (SDO) and the Solar and Heliospheric Observatory (SOHO) are studying the Sun up close, and the Voyager probes have sampled the solar wind near the edge of the heliosphere, where the solar wind meets interstellar space, but New Horizons is giving us our first look at the solar wind in Pluto’s region of space.
This solar wind data should shed some light on a number of things, including the dangerous radiation astronauts face when in space. There is a type of particle with extreme energy levels called anomalous cosmic rays. When travelling close to Earth, these high-velocity rays can be a serious radiation hazard to astronauts.
The data from New Horizons reveals particles that pick up an acceleration boost, which makes them exceed their initial speed. It’s thought that these particles could be the precursors to anomalous cosmic rays. A better understanding of this might lead to a better way to protect astronauts.
These same rays have other effects further out in space. It looks like they are partly responsible for shaping the edge of the heliosphere; the region in space where the solar wind meets the interstellar medium.
New Horizons has also told us something about the structure of the solar wind the further it travels from the Sun. Close to the Sun, phenomena like coronal mass ejections (CMEs) have a clearly discernible structure. And the differences in the solar wind, in terms of velocity, density, and temperature, are also discernible. They’re determined by the region of the Sun they came from. New Horizons found that far out in the solar system, these structures have changed.
“At this distance, the scale size of discernible structures increases, since smaller structures are worn down or merge together,” said Heather Elliott, a space scientist at the Southwest Research Institute in San Antonio, Texas, and the lead author of a paper to be published in the Astrophysical Journal. “It’s hard to predict if the interaction between smaller structures will create a bigger structure, or if they will flatten out completely.”
The Voyager probes measured the solar wind as they travelled through our Solar System into the interstellar medium. They’ve told us a lot about the solar wind in the more distant parts of our system, but their instruments aren’t as sensitive and advanced as New Horizons’. This second data set from New Horizons is helping to fill in the blanks in our knowledge.
The amazing stereo view of a broad area informally named Tartarus Dorsa combines two images from the Ralph/Multispectral Visible Imaging Camera (MVIC) taken about 14 minutes apart on July 14, 2015. The first was taken when New Horizons was 16,000 miles (25,000 kilometers) away from Pluto, the second when the spacecraft was 10,000 miles (about 17,000 kilometers) away. Credits: NASA/JHUAPL/SwRI
The amazing stereo view of a broad area informally named Tartarus Dorsa combines two images from the Ralph/Multispectral Visible Imaging Camera (MVIC) taken about 14 minutes apart on July 14, 2015. The first was taken when New Horizons was 16,000 miles (25,000 kilometers) away from Pluto, the second when the spacecraft was 10,000 miles (about 17,000 kilometers) away. Credits: NASA/JHUAPL/SwRI
It’s time to whip out your 3-D glasses to enjoy and scrutinize the remarkable detail of spectacular terrain revealed in a new high resolution stereo image of Pluto – King of the Kuiper Belt! – taken by NASA’s New Horizons spacecraft.
The amazing new stereo Plutonian image focuses on an area dominated by a mysterious feature that geologists call ‘bladed’ terrain – seen above – and its unlike anything seen elsewhere in our solar system.
Its located in a broad region of rough highlands informally known as Tartarus Dorsa – situated to the east of the Pluto’s huge heart shaped feature called Tombaugh Regio. The best resolution is approximately 1,000 feet (310 meters).
The stereo view combines a pair of images captured by New Horizons Ralph/Multispectral Visible Imaging Camera (MVIC) science instruments. They were taken about 14 minutes apart on during history making first ever flyby of the Pluto planetary system on July 14, 2015.
The first was taken when New Horizons was 16,000 miles (25,000 kilometers) away from Pluto, the second when the spacecraft was 10,000 miles (about 17,000 kilometers) away.
The blades align from north to south, typically reach up to about 550 yards (500 meters) high and are spaced about 2-4 miles (3-5 kilometers). Thus they are among the planets steepest features. They are “perched on a much broader set of rounded ridges that are separated by flat valley floors,” according to descriptions from the New Horizons science team.
This color image of Pluto taken by NASA’s New Horizons spacecraft shows rounded and bizarrely textured mountains, informally named the Tartarus Dorsa, rise up along Pluto’s terminator and show intricate but puzzling patterns of blue-gray ridges and reddish material in between. This view, roughly 330 miles (530 kilometers) across, combines blue, red and infrared images taken by the Ralph/Multispectral Visual Imaging Camera (MVIC) on July 14, 2015, and resolves details and colors on scales as small as 0.8 miles (1.3 kilometers). Credits: NASA/JHUAPL/SWRI
Mission scientists have also noted that the bladed terrain has the texture of “snakeskin” owing to their “scaly raised relief.”
In the companion global image from NASA (below), the bladed terrain is outlined in red and shown to extend quite far to the east of Tombaugh Regio.
The composite image was taken on July 13, 2015, the day before the closest approach flyby, when the probe was farther away thus shows lower resolution. It combines a pair of images from two of the science instruments – a Ralph/Multispectral Visible Imaging Camera (MVIC) color scan and an image from the Long Range Reconnaissance Imager (LORRI).
This global view of Pluto combines a Ralph/Multispectral Visible Imaging Camera (MVIC) color scan and an image from the Long Range Reconnaissance Imager (LORRI), both obtained on July 13, 2015 – the day before New Horizons’ closest approach. The red outline marks the large area of mysterious, bladed terrain extending from the eastern section of the large feature informally named Tombaugh Regio. Credits: NASA/JHUAPL/SwRI
The MVIC scan was taken from a range of 1 million miles (1.6 million kilometers), at a resolution of 20 miles (32 kilometers) per pixel. The corresponding LORRI image was obtained from roughly the same range, but has a higher spatial resolution of 5 miles (8 kilometers) per pixel, say officials.
Scientists have developed several possible theories about the origins of the bladed terrain, including erosion from evaporating ices or deposition of methane ices.
Measurements from the Linear Etalon Imaging Spectral Array (LEISA) instrument reveal that that this region “is composed of methane (CH4) ice with a smattering of water,” reports New Horizons researcher Orkan Umurhan.
He speculates that “the material making up the bladed terrain is a methane clathrate. A clathrate is a structure in which a primary molecular species (say water, or H2O) forms a crystalline ‘cage’ to contain a guest molecule (methane or CH4, for example).”
But the question of whether that methane ice is strong enough to maintain the steep walled snakeskin features, will take much more research to determine a conclusive answer.
Umurhan suggests that more research could help determine if the “methane clathrates in the icy moons of the outer solar system and also in the Kuiper Belt were formed way back before the solar system formed – i.e., within the protosolar nebula – potentially making them probably some of the oldest materials in our solar system.”
Pluto continues to amaze and surprise us as the data streams back to eagerly waiting scientists on Earth over many more months to come – followed by years and decades of painstaking analysis.
This new global mosaic view of Pluto was created from the latest high-resolution images to be downlinked from NASA’s New Horizons spacecraft and released on Sept. 11, 2015. The images were taken as New Horizons flew past Pluto on July 14, 2015, from a distance of 50,000 miles (80,000 kilometers). This new mosaic was stitched from over two dozen raw images captured by the LORRI imager and colorized. Annotated with informal place names. Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Marco Di Lorenzo/Ken Kremer/kenkremer.com
During New Horizons flyby on July 14, 2015, it discovered that Pluto is the biggest object in the outer solar system and thus the ‘King of the Kuiper Belt.”
The Kuiper Belt comprises the third and outermost region of worlds in our solar system.
Pluto is the last planet in our solar system to be visited in the initial reconnaissance of planets by spacecraft from Earth since the dawn of the Space Age.
New Horizons remains on target to fly by a second Kuiper Belt Object (KBO) on Jan. 1, 2019 – tentatively named PT1, for Potential Target 1. It is much smaller than Pluto and was recently selected based on images taken by NASA’s Hubble Space Telescope.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
Learn more about NASA Mars rovers, Orion, SLS, ISS, Orbital ATK, ULA, SpaceX, Boeing, Space Taxis, NASA missions and more at Ken’s upcoming outreach events:
Apr 9/10: “NASA and the Road to Mars Human Spaceflight programs” and “Curiosity explores Mars” at NEAF (NorthEast Astronomy and Space Forum), 9 AM to 5 PM, Suffern, NY, Rockland Community College and Rockland Astronomy Club – http://rocklandastronomy.com/neaf.html
Apr 12: Hosting Dr. Jim Green, NASA, Director Planetary Science, for a Planetary sciences talk about “Ceres, Pluto and Planet X” at Princeton University; 7:30 PM, Amateur Astronomers Assoc of Princeton, Peyton Hall, Princeton, NJ – http://www.princetonastronomy.org/
Apr 17: “NASA and the Road to Mars Human Spaceflight programs”- 1:30 PM at Washington Crossing State Park, Nature Center, Titusville, NJ – http://www.state.nj.us/dep/parksandforests/parks/washcros.html
Data from New Horizons supports the theory that Pluto's 4 small moons were formed as a result of a collision. Image by NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
The high albedo (reflectivity) of some of Pluto’s moons supports the theory that those moons were formed as a result of a collision, rather than being Kuiper Belt Objects (KBOs) that wandered too close and were captured by Pluto’s gravity. Data supporting the collision theory came from NASA’s New Horizons spacecraft as it flew by Pluto in July 2015.
The Pluto system is a complex one. Pluto has 5 moons: Charon, Styx, Nix, Kerberos, and Hydra. Charon is the only moon that is tidally locked with Pluto, and the two are sometimes called a double dwarf planet. The system’s barycenter lies between Pluto and Charon, though much closer to Pluto. The objects in the system move in near-circular orbits, rather than ellipses.
Pluto and Charon were thought to have formed the same way the other planets formed in the Solar System; by coalescing out of a ring of debris left over after the Sun formed. Then, it was thought, the other Plutonian moons were captured from the Kuiper Belt. Pluto resides in the Kuiper Belt, so this made sense. Some of the other moons in our Solar System, like Neptune’s Triton and Saturn’s Phoebe, are also thought to be captured Kuiper Belt Objects (KBOs).
A competing theory for the formation of the Pluto system is the collision theory. This theory states that Pluto and Charon did indeed coalesce out of the ring of debris around the Sun, and that Charon was itself a dwarf planet. But a collision occurred after that, about 4 or 4.5 billion years ago, between Pluto and an object about the same size as Pluto.
This collision left Pluto and Charon in their binary state, but created a circumbinary disk of debris out of which the other 4 moons formed. There are competing versions of these theories, one of which suggests that all of Pluto’s 5 moons were formed by this collision, and none coalesced out of the circumstellar disk of debris that the other planets were formed from.
New Horizons has delivered measurements and data showing that the albedo of Pluto’s 4 smallest moons is much too high for captured KBOs. Their surface reflectivity is highly suggestive of a water-ice composition. Measured KBOs have a geometric albedo of less than .20, while Styx, Nix, Hydra, and Kerberos have values of .40, .57, .56, and .45 respectively. This points to the idea that the object that collided with Pluto 4 to 4.5 billion years ago had at least some icy surface layers.
Pluto’s 4 small moons, Styx, Nix, Kerberos, and Hydra, are all non-spheroidal. This also points to their origins as conglomerated objects which formed from a collision-induced debris disk, rather than as captured Kuiper Belt objects.
These results were published in the journal Science, on March 18th, 2016. They were gathered using the Long-Range Reconnaissance Imager (LORRI), and the Multispectral Visible Imaging Camera (MVIC) instruments on board New Horizons.
Half of the data from New Horizons’ visit to Pluto is yet to arrive, including data from the Linear Etalon Imaging Spectral Array (LEISA). Scientists are hopeful that this data, and all the existing data which together will take years to analyze, will answer some of the questions surrounding the formation of the Pluto system.
The New Horizons team used "principal component analysis" to get this false-color image that highlights the different regions of Pluto. Image: NASA/New Horizons/JHAPL
The New Horizons probe revealed the surface features of Pluto in rich detail when it reached the dwarf planet in July 2015. Some of the features look like snapshots of rivers and lakes that are locked firmly in place by Pluto’s frigid temperatures. But now scientists studying the data coming back from New Horizons think that those frozen lakes and rivers could once have been liquid nitrogen.
Pluto has turned out be a surprisingly active place. New Horizons has shown us what might be clouds in Pluto’s atmosphere, mountains that might be ice volcanoes, and cliffs made of methane ice that melt away into the plains. If there were oceans and rivers of liquid nitrogen on the surface of Pluto, that would fit in with our evolving understanding of Pluto as a much more active planet than we thought.
Richard Binzel, a New Horizons team member from MIT, thinks that lakes of liquid nitrogen could have existed some 800 or 900 million years ago. It all stems from Pluto’s axial tilt, which at 120 degrees is much more pronounced than Earth’s relatively mild 23 degree tilt. And computer modelling suggests that this tilt could have even been more extreme many millions of years ago.
The result of this extreme tilt is that much more of Pluto’s surface would have been exposed to sunlight. That may have warmed Pluto enough to allow liquid nitrogen to flow over the planet’s surface. These kinds of changes to a planet’s axial tilt, (and precession and eccentricity) affect a planet’s climate in what are called Milankovitch cycles. The same cycles are thought to have a similar effect on Earth’s climate, though not as extreme as on Pluto.
According to Binzel, Pluto could be somewhere in between its temperature extremes, meaning that if Pluto will ever be warm enough for liquid nitrogen again, it could be hundreds of millions of years from now. “Right now, Pluto is between two extreme climate states,” Binzel says.
Alan Stern is a planetary scientist at the Southwest Research Institute, and New Horizons’ Principal Investigator. He thinks that these long-cycle climate changes could have a very pronounced effect on Pluto, which has a nitrogen-rich atmosphere. In ancient times, Pluto’s atmosphere could have been more dense than Mars’. “This opens up the possibility that liquid nitrogen may have once or even many times flowed on Pluto’s surface,” he said.
More data from New Horizons is still on its way. About half is yet to arrive. That data, and further analysis, might discredit the fledgling idea that Pluto had and will have again lakes of liquid nitrogen. “We are just beginning to understand the long-term climate of Pluto,” said Binzel.
This week is the 47th Lunar and Planetary Science Conference (LPSC) in Houston. Members of the New Horizons team will be presenting almost 40 reports on Pluto and its system of moons at this conference. Stern’s lecture, titled “The Exploration of Pluto,” will be archived online at http://livestream.com/viewnow/LPSC2016.
This image of Pluto taken by the New Horizons spacecraft shows the blue color of Pluto's high-altitude haze. Image: NASA/New Horizons.
The New Horizons team is releasing their first set of five research papers on Pluto and its moons. What the team is calling a “comprehensive set of papers” is the result of the New Horizons spacecraft’s close encounter with Pluto and its moons last summer. New Horizons has been transmitting data from the encounter that time, and will be sending data back for months to come.
We can tell from images that Pluto is not what we thought it was. Images and data show that Pluto is a much more active planet than we thought, and its surface shows a diversity of landscapes and geological processes. There’s been a lot of discussion about Pluto and its moons, and a lot of educated guesses about what’s going on there, but the 5 papers released by the team will take the discussion to a new level.
“These five detailed papers completely transform our view of Pluto – revealing the former ‘astronomer’s planet’ to be a real world with diverse and active geology, exotic surface chemistry, a complex atmosphere, puzzling interaction with the sun and an intriguing system of small moons,” said Alan Stern, New Horizons principal investigator from the Southwest Research Institute (SwRI), Boulder, Colorado.
The surface of Pluto is a constantly changing palette, shaped by the interactions between the volatile compounds nitrogen, methane, and carbon monoxide ices with the much sturdier and more predictable water ice. The evaporation and condensation of these compounds shapes the surface of Pluto. “These cycles are a lot richer than those on Earth, where there’s really only one material that condenses and evaporates – water,” said Will Grundy of the Lowell Observatory, Flagstaff, Arizona.
The New Horizons team used “principal component analysis” to get this false-color image of Pluto that highlights the different regions of Pluto. Image: NASA/New Horizons/JHAPL
Images from New Horizons showed that Pluto’s moons are highly reflective, much more reflective than other bodies in the Kuiper Belt. This led scientists to believe that rather than being captured from the Kuiper Belt and drawn into orbit around Pluto, the moons may have been a result of a collision that formed the Pluto system.
The New Horizons team has found evidence to support this, and evidence that the surface ages of some moons are at least 4 billion years old. “These latter two results reinforce the hypothesis that the small moons formed in the aftermath of a collision that produced the Pluto-Charon binary system,” said Hal Weaver, New Horizons project scientist from the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland.
There’s a lot of material in these papers, and I direct interested readers to a summary here: Top New Horizons Findings.
