Color mosaic map of Pluto's surface, created from the New Horizons many photographs. Credit: NASA/JHUAPL/SwRI
On July 14th, 2015, the New Horizons mission made history by conducting the first flyby of Pluto. This represented the culmination of a nine year journey, which began on January 19th, 2006 – when the spacecraft was launched from the Cape Canaveral Air Force Station. And before the mission is complete, NASA hopes to send the spacecraft to investigate objects in the Kuiper Belt as well.
To mark the 11th anniversary of the spacecraft’s launch, members of the New Horizons team took part in panel a discussion hosted by the Johns Hopkins University Applied Physics Laboratory (JHUAPL) located in Laurel, Maryland. The event was broadcasted on Facebook Live, and consisted of team members speaking about the highlights of the mission and what lies ahead for the NASA spacecraft.
The live panel discussion took place on Thursday, Sept. 19th at 4 p.m. EST, and included Jim Green and Alan Stern – the director the Planetary Science Division at NASA and the principle investigator (PI) of the New Horizons mission, respectively. Also in attendance was Glen Fountain and Helene Winters, New Horizons‘ project managers; and Kelsi Singer, the New Horizons co-investigator.
Artist’s concept of the New Horizons spacecraft encountering a Kuiper Belt object, part of an extended mission after the spacecraft’s July 2015 Pluto flyby. Credits: NASA/JHUAPL/SwRI
In the course of the event, the panel members responded to questions and shared stories about the mission’s greatest accomplishments. Among them were the many, many high-resolution photographs taken by the spacecraft’s Ralph and Long Range Reconnaissance Imager (LORRI) cameras. In addition to providing detailing images of Pluto’s surface features, they also allowed for the creation of the very first detailed map of Pluto.
Though Pluto is not officially designated as a planet anymore – ever since the XXVIth General Assembly of the International Astronomical Union, where Pluto was designated as a “dwarf planet” – many members of the team still consider it to be the ninth planet of the Solar System. Because of this, New Horizons‘ historic flyby was of particular significance.
As Principle Investigator Alan Stern – from the Southwestern Research Institute (SwRI) – explained in an interview with Inverse, the first phase of humanity’s investigation of the Solar System is now complete. “What we did was we provided the capstone to the initial exploration of the planets,” he said. “All nine have been explored with New Horizons finishing that task.”
Other significant discoveries made by the New Horizons mission include Pluto’s famous heart-shaped terrain – aka. Sputnik Planum. This region turned out to be a young, icy plain that contains water ice flows adrift on a “sea” of frozen nitrogen. And then there was the discovery of the large mountain and possible cryovolcano located at the tip of the plain – named Tombaugh Regio, (in honor of Pluto’s discovered, Clyde Tombaugh).
New Horizons path from the inner Solar System to Pluto and the Kuiper Belt. Credit: NASA/JHUAPL
The mission also revealed further evidence of geological activity and cryovolcanism, the presence of hyrdocarbon clouds on Pluto, and conducted the very first measurements of how Pluto interacts with solar wind. All told, over 50 gigabits of data were collected by New Horizons during its encounter and flyby with Pluto. And the detailed map which resulted from it did a good job of capturing all this complexity and diversity. As Stern explained:
“That really blew away our expectations. We did not think that a planet the size of North America could be as complex as Mars or even Earth. It’s just tons of eye candy. This color map is the highest resolution we will see until another spacecraft goes back to Pluto.”
After making its historic flyby of Pluto, the New Horizons team requested that the mission receive an extension to 2021 so that it could explore Kuiper Belt Objects (KBOs). This extension was granted, and for the first part of the Kuiper Belt Extended Mission (KEM), the spacecraft will perform a close flyby of the object known as 2014 MU69.
This remote KBO – which is estimated to be between 25 – 45 km (16-28 mi) in diameter – was one of two objects identified as potential targets for research, and the one recommended by the New Horizons team. The flyby, which is expected to take place in January of 2019, will involve the spacecraft taking a series of photographs on approach, as well as some pictures of the object’s surface once it gets closer.
Before the extension ends in 2021, it will continue to send back information on the gas, dust and plasma conditions in the Kuiper Belt. Clearly, we are not finished with the New Horizons mission, and it is not finished with us!
Artist's concept of the hypothetical "Planet Nine." Could it have moons? Credit: NASA/JPL-Caltech/Robert Hurt
Artistic rendering shows the distant view from theoretical Planet Nine back towards the sun. The planet is thought to be gaseous, similar to Uranus and Neptune. Hypothetical lightning lights up the night side. Credit: Caltech/R. Hurt (IPAC)
The astronomer known worldwide for vigorously promoting the demotion of Pluto from its decades long perch as the 9th Planet, has now found theoretical evidence for a new and very distant gas giant planet lurking way beyond Pluto out to the far reaches of our solar system.
“X” marks the spot in this image transmitted to Earth on Dec. 24, 2015 from the Long Range Reconnaissance Imager (LORRI) from NASA’s New Horizons’ showing the highest-resolution swath of Pluto at the center of Sputnik Planum, the informally named plain that forms the left side of Pluto’s “heart.” The pattern of polygonal cells stems from the slow thermal convection of the nitrogen-dominated ices. Also visible is a a dirty block of water ice “floating” in denser solid nitrogen. Credits: NASA/JHUAPL/SwRI
“X” marks the spot that’s illustrative of “convective churning” resulting from subsurface planetary heating, as seen in a fascinating new super high resolution image received from NASA’s New Horizons spacecraft on Christmas Eve, Dec. 24, 2015. Its situated at the very center of the left ventricle of Pluto’s huge “heart” – an icy flow plain that’s informally named “Sputnik Planum.”
The “X” feature – see image above – is located in an area of intersecting cells, shaped like polygons, on the plains of “Sputnik Planum” which are mostly comprised of frozen nitrogen ices.
Reconstruction of Voyager 2 images showing the Great Black spot (top left), Scooter (middle), and the Small Black Spot (lower right). Credit: NASA/JPL
Neptune is a truly fascinating world. But as it is, there is much that people don’t know about it. Perhaps it is because Neptune is the most distant planet from our Sun, or because so few exploratory missions have ventured that far out into our Solar System. But regardless of the reason, Neptune is a gas (and ice) giant that is full of wonder!
Below, we have compiled a list of 10 interesting facts about this planet. Some of them, you might already know. But others are sure to surprise and maybe even astound you. Enjoy!
Ice Volcanoes on Pluto? The informally named feature Wright Mons, located south of Sputnik Planum on Pluto, is an unusual feature that’s about 100 miles (160 kilometers) wide and 13,000 feet (4 kilometers) high. It displays a summit depression (visible in the center of the image) that's approximately 35 miles (56 kilometers) across, with a distinctive hummocky texture on its sides. The rim of the summit depression also shows concentric fracturing. New Horizons scientists believe that this mountain and another, Piccard Mons, could have been formed by the 'cryovolcanic' eruption of ices from beneath Pluto's surface. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Ice Volcanoes on Pluto?
The informally named feature Wright Mons, located south of Sputnik Planum on Pluto, is an unusual feature that’s about 100 miles (160 kilometers) wide and 13,000 feet (4 kilometers) high. It displays a summit depression (visible in the center of the image) that’s approximately 35 miles (56 kilometers) across, with a distinctive hummocky texture on its sides. The rim of the summit depression also shows concentric fracturing. New Horizons scientists believe that this mountain and another, Piccard Mons, could have been formed by the ‘cryovolcanic’ eruption of ices from beneath Pluto’s surface. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute[/caption]
The possible discovery of a pair of recently erupting ice volcanoes on Pluto are among the unexpected “astounding” findings just unveiled by perplexed scientists with NASA’s New Horizons spacecraft, barely four months after the historic first flyby of the last unexplored planet in our solar system.
“Nothing like this has been seen in the deep outer solar system,” said Jeffrey Moore, New Horizons Geology, Geophysics and Imaging team leader from NASA Ames Research Center, Moffett Field, California, as the results so far were announced at the 47th Annual Meeting of the Division for Planetary Sciences (DPS) of the American Astronomical Society (AAS) this week in National Harbor, Maryland.
“The Pluto system is baffling us,” said mission Principal Investigator Alan Stern of the Southwest Research Institute, Boulder, Colorado, at a news media briefing on Nov. 9.
Two large mountainous features tens of miles across and several miles high, have been potentially identified by the team as volcanoes.
Scientists using New Horizons images of Pluto’s surface to make 3-D topographic maps have discovered that two of Pluto’s mountains, informally named Wright Mons and Piccard Mons, could possibly be ice volcanoes. The color is shown to depict changes in elevation, with blue indicating lower terrain and brown showing higher elevation; green terrains are at intermediate heights. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
They were found in terrain located south of Sputnik Planum – a vast area of smooth icy plains located within Pluto’s huge heart shaped region informally known as Tombaugh Regio. It may have formed very recently resulting from geologic activity within the past 10 million years.
The possible ice volcanoes, or cryovolcanoes, were found at two of Pluto’s most distinctive mountains and identified from images taken by New Horizons as it became Earth’s first emissary to hurtle past the small planet on July 14, 2015.
“All of our flyby plans succeeded,” Stern stated at the briefing.
“All of the data sets are spectacular.
Scientists created 3-D topographic maps from the probes images and discovered the possible ice volcanoes – informally named Wright Mons and Piccard Mons.
Wright Mons, pictured above, is about 100 miles (160 kilometers) wide and 13,000 feet (4 kilometers) high.
Both mountains appear to show summit depressions “with a large hole” visible in the center, similar to volcanoes on Earth. Scientists speculate “they may have formed by the ‘cryovolcanic’ eruption of ices from beneath Pluto’s surface.”
The erupting Plutonian ices might be composed of a melted slurry of water ice, nitrogen, ammonia and methane.
The depression inside Wright Mons is approximately 35 miles (56 kilometers) across and exhibits a “distinctive hummocky texture on its sides. The rim of the summit depression also shows concentric fracturing.”
“These are big mountains with a large hole in their summit, and on Earth that generally means one thing—a volcano,” said Oliver White, New Horizons postdoctoral researcher with NASA Ames, in a statement.
The team is quick to caution that the “interpretation of these features as volcanoes is tentative” and requires much more analysis.
“If they are volcanic, then the summit depression would likely have formed via collapse as material is erupted from underneath. The strange hummocky texture of the mountain flanks may represent volcanic flows of some sort that have travelled down from the summit region and onto the plains beyond, but why they are hummocky, and what they are made of, we don’t yet know.”
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. Right side inset from New Horizons team focuses on Tombaugh Regio heart shaped feature. Annotated with informal place names. Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Marco Di Lorenzo/Ken Kremer/kenkremer.com
More than 50 papers about the Pluto system are being presented at the AAS meeting this week.
So far New Horizon has transmitted back only about 20 percent of the data gathered, according to mission Principal Investigator Alan Stern.
“It’s hard to imagine how rapidly our view of Pluto and its moons are evolving as new data stream in each week. As the discoveries pour in from those data, Pluto is becoming a star of the solar system,” said Stern.
“Moreover, I’d wager that for most planetary scientists, any one or two of our latest major findings on one world would be considered astounding. To have them all is simply incredible.”
Locations of more than 1,000 craters mapped on Pluto by NASA’s New Horizons mission indicate a wide range of surface ages, which likely means that Pluto has been geologically active throughout its history. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
The piano shaped probe gathered about 50 gigabits of data as it hurtled past Pluto, its largest moon Charon and four smaller moons.
Stern says it will take about a year for all the data to get back. Thus bountiful new discoveries are on tap for a long time to come.
With 20 percent of the data now returned and more streaming back every day, the team is excited to debate what is all means.
“This is when the debates begin,” said Curt Niebur, New Horizons program scientist at NASA Headquarters, at the missions Nov 9 media briefing. “This is when the heated discussions begin. This is when the entire science community starts staying up throughout the night.”
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
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 – shown in this colorized rendition. The smooth expanse of the informally named icy plain 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. To the right, east of Sputnik, rougher terrain is cut by apparent glaciers. 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 780 miles (1,250 kilometers) wide. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute. Colorized/Annotated: Marco Di Lorenzo/Ken Kremer/kenkremer.com
Artist's impression of NASA's 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 though the New Horizons spacecraft hasn’t officially been approved to do a flyby of a distant Kuiper Belt Object in about 3 years, the engineering team has now performed two maneuvers in a series of four to direct the spacecraft towards an ancient and distant KBO named 2014 MU69.
“Second of four engine burns to target our KBO was completed successfully!! Go New Horizons! Go NASA!” said Principal Investigator Alan Stern on Facebook.
Two more burns will occur within the next 8 days.
The 25-minute burn on October 25 was the largest propulsive maneuver ever conducted by New Horizons. The team said that the spacecraft is in excellent health as it continues to transmit data from the Pluto system flyby in July. It is currently zooming through deep space at more than 52,000 km/hr (32,000 miles per hour) and it is now about 122 million kilometers (76 million miles) past Pluto and 5.09 billion kilometers (3.16 billion miles) from Earth.
Projected path of NASA’s New Horizons spacecraft toward 2014 MU69, which orbits in the Kuiper Belt about 1 billion miles beyond Pluto. Planets are shown in their positions on Jan. 1, 2019, when New Horizons is projected to reach the small Kuiper Belt object. NASA must approve an extended mission for New Horizons to study MU69. Credit: New Horizons team.
New Horizons must travel about a billion miles to get to 2014 MU69, which is also nicknamed “PT1” (for “Potential Target 1”) and if all continues to go well, the spacecraft is expected to reach the KBO on January 1, 2019.
“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,” Stern said back in August 2015 when the target was announced. “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 2003 National Academy of Sciences’ Planetary Decadal Survey recommended that the first mission to the Kuiper Belt include flybys of Pluto and small KBOs, in order to sample the diversity of objects in that previously unexplored region of the solar system. PT1 is a completely different class of KBO than Pluto.
New Horizons has hydrazine-fueled thrusters, and it carries enough fuel for the flyby, but the team really wants to have the other two maneuvers carried out as scheduled on Oct. 28 and Nov. 4, in order to make the fuel last as long as possible.
The New Horizons team will submit a formal proposal to NASA for the KBO flyby in early 2016. NASA officials have said the discussions on whether to approve this extended mission will take place in the larger context of the planetary science portfolio, i.e., to see if it fits in the budget.
Given the success of the Pluto system flyby, and the success so far of the maneuvers to send the spacecraft to PT1, it would be a grave mistake not to take advantage of this opportunity.
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
Data from that priceless, once in a lifetime flyby is now trickling back to Earth.
The ‘snakeskin’ feature on Pluto’s utterly bizarre surface was unveiled to “astonished” scientists scrutinizing the latest data dump received over the past week, that included images taken by the Ralph instruments Multispectral Visual Imaging Camera (MVIC).
Features as small as 0.8 miles (1.3 kilometers) are resolved in detail.
The MVIC image stretches about 330 miles (530 kilometers) across the ‘snakeskin’ like landscape composed of rounded and bizarrely textured mountains that are informally named Tartarus Dorsa and that borders the bodies day-night terminator.
It shows intricate patterns of blue-gray ridges and reddish material in between that are puzzling researchers.
“It’s a unique and perplexing landscape stretching over hundreds of miles,” said William McKinnon, New Horizons Geology, Geophysics and Imaging (GGI) team deputy lead from Washington University in St. Louis.
“It looks more like tree bark or dragon scales than geology. This’ll really take time to figure out; maybe it’s some combination of internal tectonic forces and ice sublimation driven by Pluto’s faint sunlight.”
The Ralph/MVIC image is actually a composite of blue, red and infrared images.
The image of Tartarus Dorsa reveals a “multitude of previously unseen topographic and compositional details. It captures a vast rippling landscape of strange, aligned linear ridges that has astonished New Horizons team members,” say officials.
NASA’s New Horizons spacecraft captured this high-resolution enhanced color view of Pluto on July 14, 2015. The image combines blue, red and infrared images taken by the Ralph/Multispectral Visual Imaging Camera (MVIC). Pluto’s surface sports a remarkable range of subtle colors, enhanced in this view to a rainbow of pale blues, yellows, oranges, and deep reds. Many landforms have their own distinct colors, telling a complex geological and climatological story that scientists have only just begun to decode. The image resolves details and colors on scales as small as 0.8 miles (1.3 kilometers). The viewer is encouraged to zoom in on the image on a larger screen to fully appreciate the complexity of Pluto’s surface features. Credit: NASA/JHUAPL/SwRI
Another wider angle global view of Pluto downlinked on Sept. 19 shows a new “extended color” view of Pluto with an the extraordinarily rich color palette of the planet.
“We used MVIC’s infrared channel to extend our spectral view of Pluto,” said John Spencer, a GGI deputy lead from Southwest Research Institute (SwRI) in Boulder, Colorado.
“Pluto’s surface colors were enhanced in this view to reveal subtle details in a rainbow of pale blues, yellows, oranges, and deep reds. Many landforms have their own distinct colors, telling a wonderfully complex geological and climatological story that we have only just begun to decode.”
The image resolves details and colors on scales as small as 0.8 miles (1.3 kilometers).
High-resolution images of Pluto taken by NASA’s New Horizons spacecraft just before closest approach on July 14, 2015, reveal features as small as 270 yards (250 meters) across, from craters to faulted mountain blocks, to the textured surface of the vast basin informally called Sputnik Planum. Enhanced color has been added from the global color image. This image is about 330 miles (530 kilometers) across. For optimal viewing, zoom in on the image on a larger screen. Credits: NASA/JHUAPL/SWRI
Beyond MVIC, additional new images taken by New Horizons’ narrow-angle Long Range Reconnaissance Imager (LORRI) during the July 14 were downlinked on Sept. 20.
They focus on the Sputnik Planum ice plains on the left side of the famous heart shaped Tombaugh Regio feature and are the highest resolution yet – as seen below. The team added color based on the global MVIC map shown above.
High-resolution images of Pluto taken by NASA’s New Horizons spacecraft just before closest approach on July 14, 2015, are the sharpest images to date of Pluto’s varied terrain—revealing details down to scales of 270 meters. In this 75-mile (120-kilometer) section of the taken from a larger, high-resolution mosaic, the textured surface of the plain surrounds two isolated ice mountains. Credits: NASA/JHUAPL/SWRI
Barely 5 or 6 percent of the 50 gigabits of data captured by New Horizons has been received by ground stations back on Earth.
“With these just-downlinked images and maps, we’ve turned a new page in the study of Pluto beginning to reveal the planet at high resolution in both color and composition,” added New Horizons Principal Investigator Alan Stern, of SwRI.
“I wish Pluto’s discoverer Clyde Tombaugh had lived to see this day.”
Stern says it will take about a year for all the data to get back. Thus bountiful new discoveries are on tap.
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 mosaic was stitched from over two dozen raw images captured by the LORRI imager and colorized. Right side mosaic comprises twelve highest resolution views of Tombaugh Regio heart shaped feature and shows objects as small as 0.5 miles (0.8 kilometers) in size. Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/ Ken Kremer/kenkremer.com/Marco Di Lorenzo
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
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 – shown in this colorized rendition. The smooth expanse of the informally named icy plain 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. To the right, east of Sputnik, rougher terrain is cut by apparent glaciers. 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 780 miles (1,250 kilometers) wide. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute. Colorized/Annotated: Marco Di Lorenzo/Ken Kremer/kenkremer.com
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. Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Marco Di Lorenzo/Ken Kremer/kenkremer.com
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. Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Marco Di Lorenzo/Ken Kremer/kenkremer.com
See annotated version and new hi res Tombaugh Regio mosaic below[/caption]
But because of limited bandwidth the new image data sets were stored onboard the probe until days ago when they were transmitted back to Earth and released by the New Horizons team late in the day on Friday, Sept. 11.
This best yet view of far flung Pluto comes from raw images taken as New Horizons conducted the history making first flyby past Pluto on July 14, 2015, at a distance of 50,000 miles (80,000 kilometers).
The global Pluto mosaic was generated from over two dozen raw images captured by New Horizons’ Long Range Reconnaissance Imager (LORRI) and stitched together by the image processing team of Marco Di Lorenzo and Ken Kremer.
See also our expanded hi res Tombaugh Regio mosaic below showing features as small as 0.5 miles (0.8 kilometers) in size.
After transmitting carefully selected high priority images and science measurements across over 3 billion miles (about 5 billion kilometers) of interplanetary space in the days around the history making flyby, the team elected to temporarily pause the transmission of new images for several weeks in favor of sending other data important for helping place the entire Pluto planetary system into context.
Altogether, over 50 gigabits of data were collected during the July 14 encounter and flyby periods of the highest scientific activity – which includes the most critical hours before and after the spacecrafts closest approach to Pluto, its largest moon Charon and its quartet of smaller moons.
Highest resolution mosaic of ‘Tombaugh Regio’ shows the heart-shaped region on Pluto including ice flows and plains of ‘Sputnik Planum’ (center) and icy mountain ranges of ‘Hillary Montes’ and ‘Norgay Montes.’ This new mosaic combines the eleven highest resolution images captured by NASA’s New Horizons LORRI imager during history making closest approach flyby on July 14, 2015. It shows features as small as 0.5 miles (0.8 kilometers) in size. Credit: NASA/JHUAPL/SWRI/Ken Kremer/kenkremer.com/Marco Di Lorenzo
Data from the flyby continues streaming back to Earth, but rather slowly due to limited bandwidth amounting to an average “downlink” of only about 2 kilobits per second via its two transmitters.
New Horizon’s unveiled Pluto as a surprising vibrant and geologically active “icy world of wonders” as it barreled past the Pluto-Charon double planet system on July 14 at over 31,000 mph (49,600 kph) and collected unprecedented high resolution imagery and spectral measurements of the utterly alien worlds.
Since the flyby, the team has been busy analyzing the science data returned thus far and “making some discoveries” said New Horizons Principal Investigator Alan Stern of the Southwest Research Institute, Boulder, Colorado, during the Weekly Space Hangout on Sept 11.
The team is ecstatic with all the new images and created what they call a synthetic global view of a portion of Pluto.
“We created a synthetic global mosaic view of more than a dozen frames from the LORRI camera, and wrapped it on a sphere and then projected the view as if you were suspended about a thousand miles above the planet – looking back.”
Each LORRI frame is about 400 km across.
This new mosaic of Pluto is from the latest high-resolution images sent to Earth from the 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). Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
“It gives a breathtaking view of how diverse the geology is and also how diverse the seasonal volatile transport must be across the surface.”
“It’s just absolutely magical and breathtaking. There is a lot going on there.”
“The big bright area on the left side of the heart shaped feature is informally called Sputnik Planum after the first spacecraft – Sputnik. Surrounding the Texas sized plain are steep mountain ranges that are as tall as the Rockies in Colorado.”
What are Pluto’s plains and mountains comprised of?
“We know that the mountain ranges are not made of the same stuff as the planum, or plains. The plains are made of nitrogen. But nitrogen is too soft a material to build mountains out of, even in Pluto’s weak gravity.”
“So the mountains must be made of something else stronger. Rock and water ice are the two most likely possibilities. But they are most likely water ice, the lighter stuff. Because the rock has almost certainly sunk to the center of Pluto and the ice has floated to the top and formed the mantle and perhaps the crust of Pluto.”
“So we think the volatiles like the nitrogen, methane and carbon monoxide you see there and that shifts around with the seasons and interacts with the atmosphere – is just a veneer. It’s just a coating on the surface. And in some places its very thin and looks like it is breaking up on the margins. In other places it may be quite thick, maybe even kilometers thick.”
“We’ll see when we have more data!” exclaimed Stern.
“The data downlink will take over a year to get all the data to the ground [on Earth].”
“Over 50 gigabits of science data from the Pluto system needs to be sent back. The Pluto flyby took place on the 50th anniversary of NASA’s first flyby of Mars by Mariner IV. New Horizons dataset amounted to several thousand times more data collected compared to what Mariner IV sent back during its first flyby of Mars,” Stern elaborated.
“The surface of Pluto is every bit as complex as that of Mars,” says Jeff Moore, leader of the New Horizons Geology, Geophysics and Imaging (GGI) team at NASA’s Ames Research Center in Moffett Field, California. “The randomly jumbled mountains might be huge blocks of hard water ice floating within a vast, denser, softer deposit of frozen nitrogen within the region informally named Sputnik Planum.”
How much data has been returned so far varies by instrument.
“The average across all the entire science payload is only about 5 or 6 percent so far,” Stern explained.
“All the flyby data from the two plasma instruments – PEPSI and SWAP – and the Student Dust Counter instrument is back on the ground, because they were small datasets.”
“But less than 3% of the ALICE UV spectrometer data is back so far. And for the other imaging instruments its similar.”
“So it’s going to take about another year to send all the data back!”
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
Stern informed that the team has submitted a paper to the journal Science and plans a large series of technical scientific presentations at upcoming meetings, including the Division of Planetary Sciences Meeting in Washington in November.
And New Horizons is in excellent shape to get those 50 gigabits of data back to the eagerly waiting researchers since all the spacecraft systems are operating normally.
“The spacecraft is doing very well,” said Alice Bowman, New Horizons Mission Operations Manager of the Johns Hopkins University Applied Physics Laboratory (APL), during the Weekly Space Hangout.
“It’s very healthy and we are getting back gobs of data – causing a flurry of emails among the science team.”
“It’s been a good ride and we had a good flyby of Jupiter too [along the way].”
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 mosaic was stitched from over two dozen raw images captured by the LORRI imager and colorized. Right side mosaic comprises twelve highest resolution views of Tombaugh Regio heart shaped feature and shows objects as small as 0.5 miles (0.8 kilometers) in size. Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/ Ken Kremer/kenkremer.com/Marco Di Lorenzo
New Horizons also discovered that Pluto is the largest known body beyond Neptune – and thus reigns as the “King of the Kuiper Belt!”
As of today, Sept. 14, New Horizons is 2 months past the Pluto flyby and already over 73 million kilometers ( over 45 million miles) beyond Pluto and continuing its journey into the Kuiper Belt, the third realm of worlds in our solar system.
The science team plans to target New Horizons to fly by another much smaller Kuiper Belt Object (KBO) in 2019 after recently selecting the object dubbed PT1, for Potential Target 1, based on images taken by NASA’s Hubble Space Telescope.
“Since the flyby, we have been planning for the extended mission which we will propose to NASA next year,” Stern explained. NASA will then decide whether to approve and fund the new KBO mission proposal.
“We expect to do an engine burn for that [new KBO target] next month [in October]. The KBO flyby will take place about a billion miles beyond Pluto at about 44 AU.”
The actual flyby distance of New Horizons from the KBO is yet to be determined. Stern thinks it could perhaps be much closer, but all those details still need to be worked out.
NASA Associate Administrator for the Science Mission Directorate John Grunsfeld, left, New Horizons Principal Investigator Alan Stern of Southwest Research Institute (SwRI), Boulder, CO, second from left, New Horizons Mission Operations Manager Alice Bowman of the Johns Hopkins University Applied Physics Laboratory (APL), second from right, and New Horizons Project Manager Glen Fountain of APL, right, are seen at the conclusion of a press conference after the team received confirmation from the spacecraft that it has completed the flyby of Pluto, Tuesday, July 14, 2015 at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland. Credit: Ken Kremer/kenkremer.com
Watch for Ken’s continuing coverage of the Pluto flyby. He was onsite reporting live on the flyby and media briefings for Universe Today from the Johns Hopkins University Applied Physics Laboratory (APL), in Laurel, Md.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
Pluto Explored at Last
The New Horizons mission team celebrates successful flyby of Pluto in the moments after closest approach at 7:49 a.m. EDT on July 14, 2015. New Horizons Principal Investigator Alan Stern of Southwest Research Institute (SwRI), Boulder, CO., left, Johns Hopkins University Applied Physics Laboratory (APL) Director Ralph Semmel, center, and New Horizons Co-Investigator Will Grundy Lowell Observatory hold an enlarged print of an U.S. stamp with their suggested update after Pluto became the final planet in our solar system to be explored by an American space probe (crossing out the words ‘not yet’) – at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland. Credit: Ken Kremer/kenkremer.comHighest resolution mosaic of ‘Tombaugh Regio’ shows the heart-shaped region on Pluto focusing on ice flows and plains of ‘Sputnik Planum’ at top and icy mountain ranges of ‘Hillary Montes’ and ‘Norgay Montes’ below. This new mosaic combines the seven highest resolution images captured by NASA’s New Horizons LORRI imager during history making closest approach flyby on July 14, 2015. Inset at right shows global view of Pluto with location of mosaic and huge heart-shaped region in context. Annotated with place names. Credit: NASA/JHUAPL/SWRI/ Marco Di Lorenzo/Ken Kremer/kenkremer.comThis 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. Right side inset from New Horizons team focuses on Tombaugh Regio heart shaped feature. Annotated with informal place names. Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Marco Di Lorenzo/Ken Kremer/kenkremer.com
Tenth planet? Artists concept of the view from Eris with Dysnomia in the background, looking back towards the distant sun. Credit: Robert Hurt (IPAC)
Ask a person what Dysnomia refers to, and they might venture that it’s a medical condition. In truth, they would be correct. But in addition to being a condition that affects the memory (where people have a hard time remembering words and names), it is also the only known moon of the distant dwarf planet Eris.
In fact, the same team that discovered Eris a decade ago – a discovery that threw our entire notion of what constitutes a planet into question – also discovered a moon circling it shortly thereafter. As the only satellite that circles one of the most distant objects in our Solar System, much of what we know about this ball of ice is still subject to debate.
Discovery and Naming:
In January of 2005, astronomer Mike Brown and his team discovered Eris using the new laser guide star adaptive optics system at the W. M. Keck Observatory in Hawaii. By September, Brown and his team were conducting observations of the four brightest Kuiper Belt Objects – which at that point included Pluto, Makemake, Haumea, and Eris – and found indications of an object orbiting Eris.
Provisionally, this body was designated S/2005 1 (2003 UB³¹³). However, in keeping with the Xena nickname that his team was already using for Eris, Brown and his colleagues nicknamed the moon “Gabrielle” after Xena’s sidekick. Later, Brown selected the official name of Dysnomia for the moon, which seemed appropriate for a number of reasons.
For one, this name is derived from the daughter of the Greek god Eris – a daemon who represented the spirit of lawlessness – which was in keeping with the tradition of naming moons after lesser gods associated with the primary god. It also seemed appropriate since the “lawless” aspect called to mind actress Lucy Lawless, who portrayed Xena on television. However, it was not until the IAU’s resolution on what defined a planet – passed in August of 2006 – that the planet was officially designated as Dysnomia.
Size, Mass and Orbit:
The actual size of Dysnomia is subject to dispute, and estimates are based largely on the planet’s albedo relative to Eris. For example, the IAU and Johnston’s Asteroids with Satellites Database estimate that it is 4.43 magnitudes fainter than Eris and has an approximate diameter of between 350 and 490 km (217 – 304 miles)
However, Brown and his colleagues have stated that their observations indicate it to be 500 times fainter and between 100 and 250 km (62 – 155 miles) in diameter. Using the Herschel Space Observatory in 2012, Spanish astronomer Pablo Santo Sanz and his team determined that, provided Dysnomia has an albedo five times that of Eris, it is likely to be 685±50 km in diameter.
Eris and its moon, Dysnomia, as imaged by the W.M. Keck Observatory in Hawaii. Credits:NASA/ESA and M. Brown/Caltech
In 2007, Brown and his team also combined Keck and Hubble observations to determine the mass of Eris, and estimate the orbital parameters of the system. From their calculations, they determined that Dysnomia’s orbital period is approximately 15.77 days. These observations also indicated that Dysnomia has a circular orbit around Eris, with a radius of 37350±140 km. In addition to being a satellite of a dwarf planet, Dysnomia is also a Kuiper Belt Object (KBO) like Eris.
Composition and Origin:
Currently, there is no direct evidence to indicate what Dysnomia is made of. However, based on observations made of other Kuiper Belt Objects, it is widely believed that Dysnomia is composed primarily of ice. This is based largely on infrared observations made of Haumea (2003 EL61), the fourth largest object in the Kuiper Belt (after Eris, Pluto and Makemake) which appears to be made entirely of frozen water.
Astronomers now know that three of the four brightest KBOs – Pluto, Eris and Haumea – have one or more satellites. Meanwhile, of the fainter members, only about 10% are known to have satellites. This is believed to imply that collisions between large KBOs have been frequent in the past. Impacts between bodies of the order of 1000 km across would throw off large amounts of material that would coalesce into a moon.
Artist’s concept of Kuiper Belt Object Eris and its tiny satellite Dysnomia. The Hubble Space Telescope and Keck Observatory took images of Dysnomia’s movement from which astronomer Mike Brown (Caltech) precisely calculated Eris to be 27 percent more massive than Pluto. Credit: NASA/ESA/Adolph Schaller (for STScI)
This could mean that Dysnomia was the result of a collision between Eris and a large KBO. After the impact, the icy material and other trace elements that made up the object would have evaporated and been ejected into orbit around Eris, where it then re-accumulated to form Dysnomia. A similar mechanism is believed to have led to the formation of the Moon when Earth was struck by a giant impactor early in the history of the Solar System.
Since its discovery, Eris has lived up to its namesake by stirring things up. However, it has also helped astronomers to learn many things about this distant region of the Solar System. As already mentioned, astronomers have used Dysnomia to estimate the mass of Eris, which in turn helped them to compare it to Pluto.
While astronomers already knew that Eris was bigger than Pluto, but they did not know whether it was more massive. This they did by measuring the distance between Dysnomia and how long it takes to orbit Eris. Using this method, astronomers were able to discover that Eris is 27% more massive than Pluto is.
With this knowledge in hand, the IAU then realized that either Eris needed to be classified as a planet, or that the term “planet” itself needed to be refined. Ergo, one could make that case that it was the discovery of Dysnomia more than Eris that led to Pluto no longer being designated a planet.
Pluto was re-classified as a dwarf planet based on our growing understanding of its nature. Will Schlaufman's new study help us more accurately classify gas giants and brown dwarfs? NASA's New Horizons spacecraft captured this high-resolution enhanced color view of Pluto on July 14, 2015. Credit: NASA/JHUAPL/SwRI
After being officially discovered by Clyde Tombaugh in 1930, Pluto spent close to a century being thought of as the ninth planet of our Solar System. In 2006, it was reclassified as a “dwarf planet” due to the discovery of other Trans-Neptunian Objects (TNOs) of comparable size. However, that does not change its significance one bit. In addition to being the largest TNO, it is the largest and second-most massive dwarf planet in our Solar System.
As a result, a great deal of time and study has been devoted to this former planet. And with the successful flyby of the New Horizons mission this month, we finally have a clear picture of what it looks like. As scientists pour over the voluminous amounts of data being sent back, our understanding of this world at the edge of our Solar System has grown by leaps and bounds.
Discovery:
The existence of Pluto was predicted before it was observed. In the 1840s, French mathematician Ubrain Le Verrier used Newtonian mechanics to predict the position of Neptune (which had not yet been discovered) based on the perturbation of Uranus. By the late 19th century, subsequent observations of Neptune led astronomers to believe that a planet was perturbing its orbit as well.
In 1906, Percival Lowell – an American mathematician and astronomer who founded the Lowell Observatory in Flagstaff, Arizona, in 1894 – initiated a project to locate “Planet X”, the possible ninth planet of the Solar System. Unfortunately, Lowell died in 1916 before a confirmed discovery was made. But unbeknownst to him, his surveys had captured two faint images of Pluto (March 19th and April 7th, 1915), which were not recognized for what they were.
The discovery photographs of Pluto, dated January 23rd and 29th , 1930. Credit: Lowell Observatory Archives
After Lowell’s death, the search did not resume until 1929, at which point the director of the Lowell Observatory (Vesto Melvin Slipher) entrusted the job of locating Planet X to Clyde Tombaugh. A 23 year-old astronomer from Kansas, Tombaugh spent the next year photographing sections of the night sky and then analyzing the photographs to determine if any objects had shifted position.
On February 18th, 1930, Tombaugh discovered a possible moving object on photographic plates taken in January of that year. After the observatory obtained further photographs to confirm the existence of the object, news of the discovery was telegraphed to the Harvard College Observatory on March 13th, 1930. The mysterious Planet X had finally been discovered.
Naming:
After the discovery was announced, the Lowell Observatory was flooded with suggestions for names. The name Pluto, based on the Roman god of the underworld, was proposed by Venetia Burney (1918–2009), a then eleven-year-old schoolgirl in Oxford, England. She suggested it in a conversation with her grandfather who passed the name on to astronomy professor Herbert Hall Turner, who cabled it to colleagues in the United States.
Pluto’s surface as viewed from the Hubble Space Telescope in several pictures taken in 2002 and 2003. Credit: NASA/Hubble
The object was officially named on March 24th, 1930, and it came down to a vote between three possibilities – Minerva, Cronus, and Pluto. Every member of the Lowell Observatory voted for Pluto, and the name was announced on May 1st, 1930. The choice was based on part on the fact that the first two letters of Pluto – P and L – corresponded to the initials of Percival Lowell.
The name quickly caught on with the general public. In 1930, Walt Disney was apparently inspired by it when he introduced a canine companion for Mickey Mouse named Pluto. In 1941, Glenn T. Seaborg named the newly created element plutonium after Pluto. This was in keeping with the tradition of naming elements after newly discovered planets – such as uranium, which was named after Uranus, and neptunium, which was named after Neptune.
Size, Mass, and Orbit:
With a mass of 1.305±0.007 x 1o²² kg – which is the equivalent of 0.00218 Earths and 0.178 Moons – Pluto is the second most-massive dwarf planet and the tenth-most-massive known object directly orbiting the Sun. It has a surface area of 1.765×107 km, and a volume of 6.97×109 km3.
Map of Pluto’s surface features, with (informal) names for some of the largest surface features. Credit: NASA/JHUAPL
Pluto has a moderately eccentric and inclined orbit, which ranges from 29.657 AU (4.4 billion km) at perihelion to 48.871 AU (7.3 billion km) at aphelion. This means that Pluto periodically comes closer to the Sun than Neptune, but a stable orbital resonance with Neptune prevents them from colliding.
Pluto has an orbital period of 247.68 Earth years, meaning it takes almost 250 years to complete a single orbit of the Sun. Meanwhile, its rotation period (a single day) is equal to 6.39 Earth days. Like Uranus, Pluto rotates on its side, with an axial tilt of 120° relative to its orbital plane, which results in extreme seasonal variations. At its solstices, one-fourth of its surface is in continuous daylight, whereas another fourth is in continuous darkness.
Composition and Atmosphere:
With a mean density of 1.87 g/cm3, Pluto’s composition is differentiated between an icy mantle and a rocky core. The surface is composed of more than 98% nitrogen ice, with traces of methane and carbon monoxide. The surface is very varied, with large differences in both brightness and color. A notable feature is a large, pale area nicknamed the “Heart”.
The theoretical structure of Pluto, consisting of 1. Frozen nitrogen 2. Water ice 3. Rock. Credit: NASA/Pat Rawlings
Scientists also suspect that Pluto’s internal structure is differentiated, with the rocky material having settled into a dense core surrounded by a mantle of water ice. The diameter of the core is believed to be approximately 1700 km, 70% of Pluto’s diameter. Thanks to the decay of radioactive elements, it is possible that Pluto contains a subsurface ocean layer that is 100 to 180 km thick at the core–mantle boundary.
Pluto has a thin atmosphere consisting of nitrogen (N2), methane (CH4), and carbon monoxide (CO), which are in equilibrium with their ices on Pluto’s surface. However, the planet is so cold that during part of its orbit, the atmosphere congeals and falls to the surface. The average surface temperature is 44 K (-229 °C), ranging from 33 K (-240 °C) at aphelion to 55 K (-218 °C) at perihelion.
Satellites:
Pluto has five known satellites. The largest, and closest in orbit to Pluto, is Charon. This moon was first identified in 1978 by astronomer James Christy using photographic plates from the United States Naval Observatory (USNO) in Washington, D.C. Beyond Charon lies the four other circumbinary moons – Styx, Nix, Kerberos, and Hydra, respectively.
Nix and Hydra were discovered simultaneously in 2005 by the Pluto Companion Search Team using the Hubble Space Telescope. The same team discovered Kerberos in 2011. The fifth and final satellite, Styx, was discovered by the New Horizons spacecraft in 2012 while capturing images of Pluto and Charon.
Artist’s concept comparing the scale and brightness of the moons of Pluto. Credit: NASA/ESA/M. Showalter
Charon, Styx and Kerberos are all massive enough to have collapsed into a spheroid shape under their own gravity. Nix and Hydra, meanwhile, are oblong in shape. The Pluto-Charon system is unusual, since it is one of the few systems in the Solar System whose barycenter lies above the primary’s surface. In short, Pluto and Charon orbit each other, causing some scientists to claim that it is a “double-dwarf system” instead of a dwarf planet and an orbiting moon.
In addition, it is unusual in that each body is tidally locked to the other. Charon and Pluto always present the same face to each other; and from any position on either body, the other is always at the same position in the sky, or always obscured. This also means that the rotation period of each is equal to the time it takes the entire system to rotate around its common center of gravity.
In 2007, observations by the Gemini Observatory of patches of ammonia hydrates and water crystals on the surface of Charon suggested the presence of active cryo-geysers. This would seem indicate that Pluto does have a subsurface ocean that is warm in temperature, and that the core is geologically active. Pluto’s moons are believed to have been formed by a collision between Pluto and a similar-sized body early in the history of the Solar System. The collision released material that consolidated into the moons around Pluto.
Classification:
From 1992 onward, many bodies were discovered orbiting in the same area as Pluto, showing that Pluto is part of a population of objects called the Kuiper Belt. This placed its official status as a planet in question, with many asking whether Pluto should be considered separately or as part of its surrounding population – much as Ceres, Pallas, Juno and Vesta, which lost their planet status after the discovery of the Asteroid Belt.
On July 29h, 2005, the discovery of a new Trans-Neptunian Object (TNO), Eris, was announced, which was thought to be substantially larger than Pluto. Initially referred to the as the Solar System’s “tenth planet”, there was no consensus on whether or not Eris constituted the planet. What’s more, others in the astronomic community considered its discovery the strongest argument for reclassifying Pluto as a minor planet.
The debate came to a head on August 24th, 2006 with an IAU resolution that created an official definition for the term “planet”. According to the XXVI General Assembly of the International Astronomical Union, a planet must meet three criteria: it needs to be in orbit around the Sun, it needs to have enough gravity to pull itself into a spherical shape, and it needs to have cleared its orbit of other objects.
Pluto fails to meet the third condition, because its mass is only 0.07 times that of the mass of the other objects in its orbit. The IAU further decided that bodies that do not meet criterion 3 would be called dwarf planets. On September 13th, 2006, the IAU included Pluto, and Eris and its moon Dysnomia, in their Minor Planet Catalog.
The IAUs decision was met with mixed reactions, especially from within the scientific community. For instance, Alan Stern, the principal investigator with NASA’s New Horizons mission to Pluto, and Marc W. Buie – an astronomer with the Lowell Observatory – have both openly voiced dissatisfaction with the reclassification. Others, such as Mike Brown – the astronomer who discovered Eris – have voiced their support.
Our evolving understanding of Pluto, represented by images taken by Hubble in 2002-3 (left), and images taken by New Horizons in 2015 (right). Credit: theguardian.com
On August 14th – 16th, 2008, in what came to be known as “The Great Planet Debate“, researchers on both sides of the issue gathered at Johns Hopkins University Applied Physics Laboratory. Unfortunately, no scientific consensus was reached; but on June 11th 2008, the IAU announced in a press release that the term “plutoid” would henceforth be used to refer to Pluto and other similar objects.
Exploration:
Pluto presents significant challenges for spacecraft because of its small mass and great distance from Earth. In 1980, NASA began to contemplate sending the Voyager 1 spacecraft on a flyby of Pluto. However, the controllers opted instead for a close flyby of Saturn’s moon Titan, resulting in a trajectory incompatible with a Pluto flyby.
Voyager 2 never had a plausible trajectory for reaching Pluto, but it’s flyby Neptune and Triton in 1989 led scientists to once again begin contemplating a mission that would take a spacecraft to Pluto for the sake of studying the Kuiper Belt and Kuiper Belt Objects (KBOs). This led to the formation of the Pluto Kuiper Express mission proposal, and NASA instructing the JPL to being planning for a Pluto, Kuiper Belt flyby.
By 2000, the program had been scrapped due to apparent budget concerns. After much pressure had been brought to bear by the scientific community, a revised mission to Pluto, dubbed New Horizons, was finally granted funding from the US government in 2003. New Horizons was launched successfully on January 19th, 2006.
From September 21st-24th, 2006, New Horizons managed to capture its first images of Pluto while testing the LORRI instruments. These images, which were taken from a distance of approximately 4,200,000,000 km (2.6×109 mi) or 28.07 AU and released on November 28th, confirmed the spacecraft’s ability to track distant targets.
Distant-encounter operations at Pluto began on January 4th, 2015. Between January 25th to 31st, the approaching probe took several images of Pluto, which were released by NASA on February 12th. These photos, which were taken at a distance of more than 203,000,000 km (126,000,000 mi) showed Pluto and its largest moon, Charon.
Pluto and Charon, captured by the New Horizons spacecraft from January 25th to 31st. Credit: NASA
The New Horizons spacecraft made its closest approach to Pluto at 07:49:57 EDT (11:49:57 UTC) on July 14th, 2015, and then Charon at 08:03:50 EDT (12:03:50 UTC). Telemetries confirming a successful flyby and the health of the spacecraft reached Earth on 20:52:37 EDT (00:52:37 UTC).
During the flyby, the probe captured the clearest pictures of Pluto to date, and full analyses of the data obtained is expected to take years to process. The spacecraft is currently traveling at a speed of 14.52 km/s (9.02 mi/s) relative to the Sun and at 13.77 km/s (8.56 mi/s) relative to Pluto.
Though the New Horizons mission has shown us much about Pluto – and will continue to do so as scientists pour over all the data collected by the probe’s instruments – we still have much to learn about this distant and mysterious world. In time, and with more missions to the outer Solar System, we may eventually be able to unlock some of its deeper mysteries.
Artist’s impression of the New Horizons spacecraft in orbit around Pluto (Charon is seen in the background). Credit: NASA/JPL
Until then, we offer all information that is currently available on Pluto. We hope that you find what you are looking for in the links below and, as always, enjoy your research!
