Pluto probe survives encounter, phones home

Jul 15, 2015

by Irene Klotz

LAUREL, Md., July 14 (Reuters) – A U.S. spacecraft sailed past the tiny planet Pluto in the distant reaches of the solar system on Tuesday, capping a journey of 3 billion miles (4.88 billion km) that began nine and a half years ago.

NASA’s New Horizons spacecraft passed by the ice-and-rock planetoid and its entourage of five moons at 7:49 a.m. EDT (1149 GMT). The event culminated an initiative to survey the solar system that the space agency embarked upon more than 50 years ago.

“Pluto just had its first visitor,” President Obama posted on Twitter. “Thanks NASA. It’s a great day for discovery and American leadership.”

About 13 hours after its closest approach to Pluto, the last major unexplored body in the solar system, New Horizons phoned home, signaling that it had survived its 31,000 miles per hour(49,000 km per hour) blitz through the Pluto system.

Managers had estimated there was a 1-in-10,000 chance a debris strike could destroy New Horizons as it soared just 7,750 miles (12,472 km) – about the distance from New York to Mumbai – from Pluto.

But right on time, New Horizons made radio contact with flight controllers at the Johns Hopkins University Applied Physics Lab outside Baltimore, sparking a wave of shouts and applause from an overflow crowd gathered to watch the drama unfold.

With 99 percent of the data gathered during the encounter still on the spaceship, New Horizons’ survival was critical to the mission.

“This is a tremendous moment in human history,” said John Grunsfeld, NASA’s associate administrator for science.

New Horizons spent more than eight hours after its closest approach looking back at Pluto for a series of experiments to study the planet’s atmosphere and photograph its night-side using light reflected off its primary moon Charon.

Sending back its first post-flyby signal took another four-and-a-half hours, the time it takes radio signals, traveling at light speed, to travel the 3 billion miles (4.88 billion km) back to Earth.

Already, the trickle of images and measurements relayed from New Horizons before Tuesday’s pass by Pluto has changed scientists’ understanding of this diminutive world, which is smaller than Earth’s moon.

Once considered an icy, dead world, the planetoid has yielded signs of geological activity, with evidence of past and possibly present-day tectonics, or movements of its crust.

“This is clearly a world where both geology and atmosphere climatology play a role,” said Alan Stern, New Horizons lead scientist, with the Southwest Research Institute in Boulder, Colorado. He noted that it appears that nitrogen and methane snow fall on Pluto.


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31 comments on “Pluto probe survives encounter, phones home

  • The images of Pluto and Charon show spheroid structures which are quite different to the irregular shapes of moons of Mars.

    This is why the category “Dwarf Planet” is important to distinguish those bodies where the gravity has produced the spheroid shape.

    I suspect that out in the Kuiper belt and Oort Cloud, it will be difficult to distinguish planets from moons, as with the low gravitational effects of forces of the distant Sun and the inner planets, combined with very long orbital periods, trajectories will be difficult to plot.

    We already know that some of Saturn’s shepherd moons swap orbits from time to times as they interact with the rings and each other.

    http://www.planetary.org/blogs/emily-lakdawalla/2006/janus-epimetheus-swap.html



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  • It’s depressing that in most news outlets this story ranked somewhere below the latest goings on of the Kardashians (or similar). People should be agog with awe at the fact that humans can do this but so many would shrug and say “So what?”

    On a related note re: what the media/public consider a story, glad to see that everyone on the team got the memo about appropriate shirts.



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  • paulmcuk
    Jul 15, 2015 at 3:01 pm

    It’s depressing that in most news outlets this story ranked somewhere below the latest goings on of the Kardashians (or similar). People should be agog with awe at the fact that humans can do this but so many would shrug and say “So what?”

    Apparently in the UK it is all Greek to the news outlets!!



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  • RICARDO
    Jul 15, 2015 at 5:09 pm

    Is Pluto so dense that, contrary to our Moon, it has an atmosphere?

    I don’t think so.
    I think it is a matter of the weakness of the Sun’s gravity and radiation this far out in the Solar System.
    Temperatures are extremely low, and even the weak gravity of a dwarf planet can retain an atmosphere. – In contrast, on Mercury for example, even heavy elements are vaporised and swept off in a comet-like tail by the solar wind.
    Mercury, being close to the Sun’s strong gravity, cannot retain any moons, whereas Pluto has several.



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  • Welcome to Iceworld: Stunning first hi-def image of Pluto reveals huge 11,000 foot mountains made of water ice and a geologically active surface

    Image of Pluto with 10 times the resolution of anything ever seen before has being unveiled by Nasa
    It shows evidence of geological activity, water ice and mountains that formed 100 million years ago
    Nasa also unveiled an image of Charon showing a canyon that’s six miles deep, and a new view of Hydra

    http://www.dailymail.co.uk/sciencetech/article-3162894/11-000-foot-high-mountains-ice-geologically-active-surface-Stunning-image-surface-Pluto-revealed.html

    *The first ever high-resolution image of Pluto has been beamed back to Earth revealing 11,000ft (3,350 metre) mountains made of water ice.

    The remarkable image, released alongside new pictures of Pluto’s moons Charon and Hydra, provides evidence that geological activity is still taking place on the icy world.

    Scientists were shocked to see mountains as high as those in the Rockies that likely formed 100 million years ago – mere youngsters relative to the 4.56-billion-year age of the solar system. Nasa says they may still be in the process of building.



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  • First there is a LOT of data to download to Earth, but then there is the question of continuing the mission.

    http://www.nasaspaceflight.com/2015/07/new-horizons-pluto-historic-kuiper-encounter/

    .Pre-mission planning hoped that New Horizons would be able to fly by at least one and possibly two additional Kuiper Belt Objects (KBOs) after the Pluto encounter.

    2015-07-12-210144However, since the entirety of the mission was based on the successful encounter with Pluto, any KBO visited afterword would have to fall within 1 degree of New Horizons’ trajectory at the time of the Pluto encounter and fall within an orbital boundary of 55 AU.

    The restriction of 1 degree from New Horizons’ trajectory is because of the minimal amount of hydrazine fuel that will remain within the probe following the Pluto campaign.

    The restriction to 55 AU has to do with the probe’s communications and power abilities.

    Beyond 55 AU, New Horizons’ communications link will become too weak to support a flyby.

    Likewise, New Horizons’ power source (its RTG wattage) will have decayed too much to allow for scientific observations of objects beyond 55 AU.

    Moreover, the New Horizons team hoped that any KBO visited after Pluto would be more than 50 km (31 miles) in diameter, neutral in color, and, if possible, have a moon.

    2015-07-12-210219By 15 October 2014, the Hubble Space Telescope had revealed three potential KBO targets for New Horizons post-Pluto.

    All three objects fell within an estimated diameter range of 30-55 km and were observed at distances from the Sun between 43 and 44 AU.

    Of the three objects identified as PT1, PT2, and PT3, estimates for fuel probability of reaching these objects were found to be 100%, 7%, and 97%, respectively.

    Moreover, all three KBOs are low-inclination and low-eccentricity classical KBOs that are quite different from Pluto.

    If PT1 is chosen for flyby (the object with a 100% probability of enough fuel for flyby), New Horizons will reach it in January 2019.

    2015-07-12-210304However, PT3 (the object with a 97% probability of enough fuel for flyby) might be more preferable since it is brighter and therefore probably larger than PT1.

    As of writing, PT2 is no longer in consideration for flyby, and PT1, with a diameter now estimated at 40–70 km, is the preferred flyby target.

    .A final decision on which object to take New Horizons to after Pluto will be made in August 2015.

    After this proposed flyby of a KBO, New Horizons will join the Voyager probes in their exploration of the outer realm of the solar system, specifically in the mapping of the heliosphere.

    It is currently estimated that New Horizons will end its mission based on RTG plutonium decay in 2026, thus resulting in intermittent heliosphere data collection if instrument power-sharing is required – as is currently done on the Voyager probes.

    If, like the Voyager probes, New Horizons is still functioning when it reaches the outer heliosphere, it is expected that the probe will encounter the heliopause in 2047 and join Voyager 1 (and by that point, Voyager 2) in the interstellar medium between the stars.



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  • I’m not smart enough to comment on the elements of the solar system.
    However, I find it incredible, almost beyond belief, that man has achieved this, only 85yrs after the planet ‘Pluto’ was discovered.



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  • @OP – About 13 hours after its closest approach to Pluto, the last major unexplored body in the solar system, New Horizons phoned home, signaling that it had survived its 31,000 miles per hour(49,000 km per hour) blitz through the Pluto system.

    Media science writers should not be making up foot-in-mouth comments like this!!

    Those viewing my link on dwarf planets (above) will see that the unexplored dwarf planet ERIS is a similar size to Pluto – not to mention that there could well be many more yet-to-be-dicovered dwarf planets in the Solar-System!

    It is another example of the sloppy journalism I mentioned here!

    https://www.richarddawkins.net/2015/07/nasas-new-horizons-spacecraft-zips-past-pluto-in-flyby/#li-comment-183039



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  • 16
    cmirana says:

    This great Universe!
    One stands humbled!
    Congratulations NASA; leading the world from the shackles of ignorance to the freedom of scientific discovery.



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  • 17
    NearlyNakedApe says:

    I can’t help thinking how unfortunate it is that Carl Sagan isn’t alive to witness this great landmark in the exploration of the solar system. He would have been 80 years old and most likely just as excited about this amazing mission as he was about the Mariner and Voyager missions of his younger days.

    Incidentally, the year 2016 will mark the 20th aniversary of his passing.



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  • Alan4discussion
    Jul 15, 2015 at 7:14 pm

    Likewise, New Horizons’ power source (its RTG wattage) will have decayed too much to allow for scientific observations of objects beyond 55 AU.

    Only this type of RTG or a nuclear reactor, can provide electrical power in the outer Solar-System, where the light is too weak to use solar-cells.

    https://en.wikipedia.org/wiki/Multi-Mission_Radioisotope_Thermoelectric_Generator

    The MMRTG is powered by 8 Pu-238 dioxide GPHS modules, provided by the Department of Energy. Initially, these 8 GPHS modules generate about 2 kW thermal power.

    The MMRTG design incorporates PbTe/TAGS thermoelectric couples (from Teledyne Energy Systems). The MMRTG is designed to produce 125 W electrical power at the start of mission, falling to about 100 W after 14 years.[5] With a mass of 45 kg[6] the MMRTG provides about 2.8 W/kg of electrical power at beginning of life.

    Radioisotope power has been used on 8 Earth orbiting missions, 8 missions travelling to each of the outer planets as well as each of Apollo missions following 11 to Earth’s moon. Some of the outer Solar System missions are the Pioneer, Voyager, Ulyssess, Galileo, Cassini and Pluto New Horizons missions. The RTGs on Voyager 1 and 2 have been operating since 1977. Similarly, Radioisotope Heat Units (RHUs) were used to provide heat to critical components on Apollo 11 as well as the first two generations of Mars rovers.[7] In total, over the last four decades, 26 missions and 45 RTGs have been launched by the United States.



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  • Patience is going to be required by those wishing to see more details, as the probe is still busy collecting data and does not have the capacity to transmit much existing data while doing so!

    http://www.bbc.co.uk/news/science-environment-33570131

    The American space agency will release more pictures later from the New Horizons flyby of Pluto.

    Scientists promise to show further close-ups of the dwarf planet, and talk about some of the other types of data acquired during Tuesday’s close pass.

    Already, there are strong indications that Pluto and its main moon, Charon, have been active in the recent past.

    Meanwhile, the probe itself continues to monitor the diminutive world and its five satellites.

    Even though it has gone more than three million km beyond the Pluto system, there is still much to learn by looking in “the rear-view mirror”.

    New Horizons is attempting to study the crescent Pluto, to see if there are hazes and even clouds in its tenuous atmosphere.

    It is also hunting for rings. It is possible Pluto is surrounded by concentric circles of dusty, icy particles, and these would scatter sunlight in a way that might be easier to detect from “behind” the dwarf planet.

    On Thursday Nasa released another view of Charon, as a tease ahead of Friday’s briefing.

    This zoomed in on a rectangular area approximately 390km long.

    The terrain has relatively few craters, but what really catches the eye is a large mountain that sits in a depression – like a castle surrounded by a moat.

    “This is a feature that has geologists stunned and stumped,” said Jeff Moore, a Nasa scientist who leads New Horizons’ geology, geophysics and imaging team.

    The probe has so far sent back only a tiny amount of its stored flyby data.

    The vast distance to Pluto (4.7 billion km) and the modest transmitter/antenna system (12W) onboard makes for very slow bit rates – an average of one kilobit (125 bytes) per second.

    The three-axis stabilised spacecraft can boost this if it switches off its power-hungry inertial measurement unit and spins itself up to maintain a steady orientation. However, it cannot do this and take images at the same time.

    Not until the probe has observed Pluto for another two full rotations will it make this change.

    And given that a “Pluto day” is 6.4 Earth days, this means the command to stop imaging and spin-up is at least a fortnight away.



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  • “This is a feature that has geologists stunned and stumped,” said Jeff Moore, a Nasa scientist who leads New Horizons’ geology, geophysics and imaging team.

    Jeff Moore, affectionately called “Big Mac Jeff” by colleagues, also discovered strange geologic features he describes as “Golden Arches.” “I can’t imagine why I coined the phrase just before lunchtime,” Moore told reporters.



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  • “Golden Arches”

    A certain slumping fast-food restaurant will love the free publicity. As long as Mr. Moore doesn’t “phone home” his coinage [i.e.] argh(!) that shop worn phrase, please jettison it to infinity and beyond.

    Hm, Saturn onion rings?



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  • I see NASA has now released pictures of Pluto’s frozen plains.

    http://www.nasa.gov/press-release/nasa-s-new-horizons-discovers-frozen-plains-in-the-heart-of-pluto-s-heart

    In the latest data from NASA’s New Horizons spacecraft, a new close-up image of Pluto reveals a vast, craterless plain that appears to be no more than 100 million years old, and is possibly still being shaped by geologic processes. This frozen region is north of Pluto’s icy mountains, in the center-left of the heart feature, informally named “Tombaugh Regio” (Tombaugh Region) after Clyde Tombaugh, who discovered Pluto in 1930.

    “This terrain is not easy to explain,” said Jeff Moore, leader of the New Horizons Geology, Geophysics and Imaging Team (GGI) at NASA’s Ames Research Center in Moffett Field, California. “The discovery of vast, craterless, very young plains on Pluto exceeds all pre-flyby expectations.”

    This fascinating icy plains region — resembling frozen mud cracks on Earth — has been informally named “Sputnik Planum” (Sputnik Plain) after the Earth’s first artificial satellite. It has a broken surface of irregularly-shaped segments, roughly 12 miles (20 kilometers) across, bordered by what appear to be shallow troughs. Some of these troughs have darker material within them, while others are traced by clumps of hills that appear to rise above the surrounding terrain. Elsewhere, the surface appears to be etched by fields of small pits that may have formed by a process called sublimation, in which ice turns directly from solid to gas, just as dry ice does on Earth.

    Scientists have two working theories as to how these segments were formed. The irregular shapes may be the result of the contraction of surface materials, similar to what happens when mud dries. Alternatively, they may be a product of convection, similar to wax rising in a lava lamp. On Pluto, convection would occur within a surface layer of frozen carbon monoxide, methane and nitrogen, driven by the scant warmth of Pluto’s interior.

    Pluto’s icy plains also display dark streaks that are a few miles long. These streaks appear to be aligned in the same direction and may have been produced by winds blowing across the frozen surface.



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  • Georg Wilhelm Friedrich Hegel said philosophy was a greater path to the truth than science. He said that although the definition of planets have changed since the ancients, philosophically there can only be 7 planets!



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  • cbrown
    Jul 19, 2015 at 1:02 am

    Georg Wilhelm Friedrich Hegel said philosophy was a greater path to the truth than science.

    In the science illiterates, the perceptions of the aether and souls, are still strong – as is their confidence in their perceptions of “TRRrroooof”!!!

    Fancy scientists not recognising that planets are powered by the minions of heaven turning celestial spheres – and god-did-it!! !!!

    https://en.wikipedia.org/wiki/Dynamics_of_the_celestial_spheres



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  • 25
    NearlyNakedApe says:

    Georg Wilhelm Friedrich Hegel said philosophy was a greater path to the truth than science.

    I suspect that Hegel meant HIS philosophical ideas when he made this statement. And if that’s the case, then it seems to me that he wasn’t much inclined to make that “truth” widely understood to the rest of the world.

    Here’s an excerpt from Wikipedia:

    “Bertrand Russell stated in his Unpopular Essays (1950) and A History of Western Philosophy (1945) that Hegel was “the hardest to understand of all the great philosophers”.”

    “Karl Popper wrote that “there is so much philosophical writing (especially in the Hegelian school) which may justly be criticized as meaningless verbiage”.”

    So if Hegel truly believed that he was on the path to the truth, he also seemed quite happy to be the only one on that path… along with the handful of individuals who pretended to understand what he was talking about.

    Science OTOH is all about making its discoveries and knowledge widely shared and as well understood as possible through clarity of explanation, consistent documentation, examples and demonstrations. As Alan4 wrote, Hegel was comparing philosophy with something about which he probably knew next to NOTHING and probably didn’t care for either.

    Furthermore….

    “Popper further proposed that Hegel’s philosophy served not only as an inspiration for communist and fascist totalitarian governments of the 20th century, whose dialectics allow for any belief to be construed as rational simply if it could be said to exist.”

    Hmmm… now what does that kind of thinking remind me of?… Small wonder Karl Bath described Hegel as the “Protestant Thomas Aquinas”.



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  • NearlyNakedApe
    Jul 19, 2015 at 11:34 am

    Hegel was comparing philosophy with something about which he probably knew next to NOTHING and probably didn’t care for either.

    From time immemorial, there have been navel-gazers impressed and inebriated by their own verbosity – sometimes sharing their delusions of profundity, with a bandwagon of followers.



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  • NASA is now getting more images sent back to Earth, with more expected on Friday.

    https://www.nasa.gov/image-feature/nasa-s-new-horizons-finds-second-mountain-range-in-pluto-s-heart
    NASA’s New Horizons Finds Second Mountain Range in Pluto’s ‘Heart’

    A newly discovered mountain range lies near the southwestern margin of Pluto’s Tombaugh Regio (Tombaugh Region), situated between bright, icy plains and dark, heavily-cratered terrain. This image was acquired by New Horizons’ Long Range Reconnaissance Imager (LORRI) on July 14, 2015 from a distance of 48,000 miles (77,000 kilometers) and sent back to Earth on July 20. Features as small as a half-mile (1 kilometer) across are visible.

    Pluto’s icy mountains have company. NASA’s New Horizons mission has discovered a new, apparently less lofty mountain range on the lower-left edge of Pluto’s best known feature, the bright, heart-shaped region named Tombaugh Regio (Tombaugh Region).

    These newly-discovered frozen peaks are estimated to be one-half mile to one mile (1-1.5 kilometers) high, about the same height as the United States’ Appalachian Mountains. The Norgay Montes (Norgay Mountains) discovered by New Horizons on July 15 more closely approximate the height of the taller Rocky Mountains.

    The new range is just west of the region within Pluto’s heart called Sputnik Planum (Sputnik Plain). The peaks lie some 68 miles (110 kilometers) northwest of Norgay Montes.

    This newest image further illustrates the remarkably well-defined topography along the western edge of Tombaugh Regio.

    “There is a pronounced difference in texture between the younger, frozen plains to the east and the dark, heavily-cratered terrain to the west,” said Jeff Moore, leader of the New Horizons Geology, Geophysics and Imaging Team (GGI) at NASA’s Ames Research Center in Moffett Field, California. “There’s a complex interaction going on between the bright and the dark materials that we’re still trying to understand.”



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  • Alan4D

    Interesting alternative theory as to formation of Pluto and its moons. Dr Andrew Prentice is an astronomer and planetary scientist at Monash University. He proposes a fusion method of formation (Not Nuclear) instead of the collision theory.

    http://www.abc.net.au/science/articles/2015/07/22/4278762.htm

    You may find the article of interest.

    Can the fission hypothesis explain the mysterious heart-shaped region, now named Tombaugh Regio in honour of Pluto’s discoverer Clyde Tombaugh? What about mountains of ice that and the icy plains of Sputnik Planum within the Heart that are made up of polygonal segments, and separated by dark lines and hillocks?

    It is my belief that the huge bright white region that makes up Tombaugh Regio is the launch site of the material that made Charon and the small moonlets of Pluto. When fission of proto-Pluto took place, the crust of Pluto would have ruptured at its weakest point.

    The huge mass of ejected liquid that formed Pluto’s moons then shot off into space, leaving behind a gaping gash. Liquids would have continued to spill out onto the surface for many hours after that cataclysmic event occurred and then later froze over to form the heart-shaped patch that we see today.



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  • David R Allen
    Jul 23, 2015 at 2:40 am

    Interesting alternative theory as to formation of Pluto and its moons.

    @ link – In a paper published in the Australian Journal of Astronomy in 1993, I proposed that Pluto and Charon were once part of a single body, called proto-Pluto.

    I think the date is quite telling on this notion.

    This body had formed by the gravitational accumulation of a swarm of smaller bodies of ice and rock that had existed in a gas ring cast off from the equator of the primitive Sun, some 4.56-billion years ago.

    I think it more likely that it formed from the accretion disk like most of the other bodies. The comet probes confirm that in the building of comets and proto-planets they form from aggregating small spheroid planetesimals.

    This far out in the Solar System, gravity is weak so unlike Earth, a small body like Pluto was unlikely to retain forcibly ejected material in orbit. The absence of craters, indicating young geology next to older cratered areas, suggests the dating and sequence in this hypothesis is wrong.

    In the outer Solar-System small bodies in proximity to each other gently drift together, attracted by their weak gravity. There are plenty of bodies in the Kuiper Belt to bunch together orbiting each other.
    Impacts come from orbit crossing bodies hitting each other at tangents – hence the contrast in velocities causing impact craters.



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  • There are now further images available:-

    http://www.independent.co.uk/news/science/nasa-new-horizons-team-reveal-stunning-new-images-of-pluto-10415229.html

    New Pluto images: Nasa New Horizons team reveal stunning pictures of ‘glacier-like’ flowing ice

    A few hours after making a close approach, the probe turned its camera back towards Pluto, capturing rays of sunlight streaming through its atmosphere, creating an eerie eclipse effect.

    The image shows two distinct layers of haze, miles above the surface, that makes up Pluto’s alien atmosphere.

    After studying the fascinating images, Grunsfeld sad the team saw “flowing ices, exotic surface chemistry, mountain ranges,” and a “diversity of planetary geology that is truly thrilling.”

    The ‘ice’ that has been spotted on Pluto’s surface is not made from water, but is a frozen mix of nitrogen, carbon monoxide and methane ices.

    At a temperature of -234 degrees celsius, Pluto is more than capable of freezing most chemicals that we know as gases here on earth.

    As well as this frozen mixture, scientists also spotted revealing signs of recent geologic activity – something that researchers had hoped to spot but didn’t expect.

    This image show the complexity of Pluto – including its icy plains, two mountain ranges, and areas where ancient craters have been overrun by newer ice deposits (see link).



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