Artist's impression of New Horizons' close encounter with the Pluto–Charon system. Credit: NASA/JHU APL/SwRI/Steve Gribben
On July 14th, 2015, the New Horizons probe made history by accomplishing the first flyby of Pluto and its largest satellite, Charon. The stunning images this mission took of these icy worlds have helped scientists address some of the key questions about Pluto and its massive moon, which have been shrouded in mystery for decades (owing to their great distance from Earth). One of the biggest mysteries that scientists have contemplated since Charon was first discovered in 1978 is how it came together with Pluto in the first place.
For decades, astronomers suspected that Pluto and Charon formed through a process similar to Earth and the Moon. This theory, known as the Giant Impact Hypothesis, states that roughly 4.5 billion years ago, primordial Earth was struck by a Mars-sized body named Theia. In a new study, a team of researchers from the University of Arizona challenged this assumption and offered an alternate theory known as “kiss and capture.” Their findings could help scientists better understand how planetary bodies in the outer Solar System form and evolve.
Pluto may have been downgraded from full-planet status, but that doesn’t mean it doesn’t hold a special place in scientist’s hearts. There are practical and sentimental reasons for that – Pluto has tantalizing mysteries to unlock that New Horizons, the most recent spacecraft to visit the system, only added to. To research those mysteries, a multidisciplinary team from dozens of universities and research institutes has proposed Persephone – a mission to the Pluto system that could last 50 years.
An SwRI-led team detected carbon dioxide and hydrogen peroxide spectral signatures on Pluto’s largest moon Charon using Webb telescope observations (white), which extend the wavelength coverage of previous New Horizons flyby measurements (pink). Credit: SwRI
The James Webb Space Telescope (JWST) has revealed magnificent things about the Universe. Using its sophisticated infrared optics, it has peered deeper into space (and farther back in time) than any observatory to date, gathering data on the first galaxies to form in our Universe. It has also obtained spectra from exoplanets, revealing things about the chemical composition of their atmospheres. In addition, Webb has provided some stunning views of objects within our Solar System, like Jupiter and its auroras, Saturn’s rings and moons, and Neptune and its satellites.
Recently, a team led by researchers from Southwest Research Institute (SwRI) used Webb Near-Infrared Spectrograph (NIRSpec) to closely examine the Pluto-Charon system. Their observations detected frozen carbon dioxide and hydrogen peroxide on the surface of Pluto’s largest moon for the first time. These discoveries add to what scientists learned about Charon’s chemical inventory from ground-based telescopes and the New Horizons mission. It also reveals more about the chemical composition of the many objects that make up the Kuiper Belt.
Color-enhanced image of Pluto's largest moon, Charon, taken by NASA's New Horizons spacecraft on July 14, 2015. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)
In a recent study scheduled to be published in the journal Icarus in March 2023, a team of researchers led by the Southwest Research Institute (SwRI) modeled a potential correlation between an ancient freezing ocean with cryovolcanic flows and surface canyons on Pluto’s largest moon, Charon. Their hypothesis was that when Charon’s interior ocean froze long ago, the significant stress put on the icy outer shell from the addition of more ice to the bottom of the existing shell could have been responsible for the cryovolcanic flows on the surface.
Pluto’s largest moon, Charon, started off as a beautiful, smooth red grape until someone came along, mostly peeled it, tried to smoosh it, then just gave up and walked away, leaving the poor moon to look like the absolute travesty that it is. Okay, so maybe that’s not exactly what happened, but Charon just looks like a mess and scientists want to know why. Never mind its smooshed equator, but what’s the deal with its red cap? Where did it come from and why is it red?
Far left: Pluto and it's heart-shaped feature
called “Tombaugh Regio” in honor of astronomer Clyde Tombaugh, who discovered
the dwarf planet. The bright expanse of the western lobe of Pluto’s “heart” is
informally called Sputnik Planum. Above left: Pluto’s surface sports a remarkable
range of landforms that have their own distinct colors, telling a complex geological
and climatological story.
Credit: Courtesy NASA / JHUAPL / SwRI
Table of Contents page
2015 Annual Report
Division: (15)
NASA’s New Horizons mission taught us a lot about Pluto, the ice dwarf planet. But the spacecraft sped past Pluto so quickly, we only got high-resolution images of one side of the planet, the so-called “encounter side.” New Horizons gave us a big leap in understanding, but in a way, it asked more questions than it answered.
The next step is clearly an orbiter, and now NASA is starting to seriously consider one.
New Horizons image of the small craters on Pluto's moon Charon. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
In 2015, the New Horizons mission became the first robotic spacecraft to conduct a flyby of Pluto. In so doing, the probe managed to capture stunning photos and valuable data on what was once considered to be the ninth planet of the Solar System (and to some, still is) and its moons. Years later, scientists are still poring over the data to see what else they can learn about the Pluto-Charon system.
For instance, the mission scienceteam at the Southwest Research Institute (SwRI) recently made an interesting discovery about Pluto and Charon. Based on images acquired by the New Horizons spacecraft of some small craters on their surfaces, the team indirectly confirmed something about the Kuiper Belt could have serious implications for our models of Solar System formation.
Welcome to the 558th Carnival of Space! The Carnival is a community of space science and astronomy writers and bloggers, who submit their best work each week for your benefit. We have a fantastic roundup today, so now, on to this week’s stories! Continue reading “Carnival of Space #558”
Map projection of Charon, the largest of Pluto’s five moons, annotated with its first set of official feature names. With a diameter of about 1215 km, the France-sized moon is one of largest known objects in the Kuiper Belt, the region of icy, rocky bodies beyond Neptune. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
In 2015, the New Horizons mission made history by being the first spacecraft to conduct a flyby of Pluto. In addition to revealing things about the planet’s atmosphere, its geology and system of moons, the probe also provided the first clear images of the surface of Pluto and its largest moon, Charon. Because of this, scientists are now able to study Pluto and Charon’s many curious surface features and learn more about their evolution.
Another interesting thing that has resulted from this surface imaging has been the ability to name these features. Recently, the IAU Working Group for Planetary System Nomenclatureofficially approved of a dozen names that had been proposed by NASA’s New Horizons team. These names honor legendary explorers and visionaries, both real and fictitious, and include science fiction authors Octavia Butler and Arthur C. Clarke.
Aside from being Pluto’s largest moon, Charon is also one of the larger bodies in the Kuiper Belt. Because of its immense size, Charon does not orbit Pluto in the strictest sense. In truth, the barycenter of the Pluto-Charon system is outside Pluto, meaning the two bodies almost orbit each other. The moon also has a wealth of features, which include valleys, crevices, and craters similar to what have been seen on other moons.
Artist’s impression of New Horizons’ close encounter with the Pluto–Charon system. Credit: NASA/JHU APL/SwRI/Steve Gribben
For some time, the New Horizons team has been using a series of informal names to describe Charon’s many features. The team gathered most of them during the online public naming campaign they hosted in 2015. Known as “Our Pluto“, this campaign consisted of people from all over the world contributed their suggestions for naming features on Pluto and Charon.
The New Horizons team also contributed their own suggestions and (according to the IAU) was instrumental in moving the new names through approval. As Dr. Alan Stern, the New Horizon team leader, told Universe Today via email: “We conduced a public feature name bank process in 2015 before flyby. Once flyby was complete our science team created a naming proposal for specific features and sent it to IAU.”
A similar process took place last year, where the IAU officially adopted 14 place names that were suggested by the New Horizons team – many of which were the result of the online naming campaign. Here too, the names were those that the team had been using informally to describe the many regions, mountain ranges, plains, valleys and craters that were discovered during the spacecraft’s flyby.
The names that were ultimately selected honored the spirit of epic exploration, which the New Horizons mission demonstrated by being the first probe to reach Pluto. As such, the names that were adopted honored travelers, explorers, scientists, pioneering journeys, and mysterious destinations. For example, Butler Mons honors Octavia E. Butler, a celebrated author and the first science fiction writer to win a MacArthur fellowship.
Global map of Pluto’s moon Charon pieced together from images taken at different resolutions. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Similarly, Clarke Montes honors Sir Arthur C. Clarke, the prolific writer and futurist who co-wrote the screenplay for 2001: A Space Odyssey (which he later turned into a series of novels). Stanley Kubrik, who produced and directed 2001: A Space Odyssey, was also honored with the feature Kubrik Mons. Meanwhile, several craters were named in honor of fictional characters from famous stories and folklore.
The Revati Crater is named after the main character in the Hindu epic narrative Mahabharata while the Nasreddin Crater is named for the protagonist in thousands of folktales told throughout the Middle East, southern Europe and parts of Asia. Nemo Crater honors the captain of the Nautilus in Jule’s Verne’s novels Twenty Thousand Leagues Under the Sea (1870) and The Mysterious Island (1874).
The Pirx Crater is name after the main character in a series of short stories by Polish sci-fi author Stanislaw Lem, while the Dorothy Crater takes its name from the protagonist in The Wizard of Oz, one of several children’s stories by L. Frank Baum that was set in this magical land.
As Rita Schulz, chair of the IAU Working Group for Planetary System Nomenclature, commented, “I am pleased that the features on Charon have been named with international spirit.” Dr. Alan Stern expressed similar sentiments. When asked if he was happy with the new names that have been approved, he said simply, “Very.”
Artist’s impression of NASA’s New Horizons spacecraft encountering 2014 MU69 (Ultima Thule), a Kuiper Belt object that orbits 1.6 billion km (1 billion mi) beyond Pluto, on Jan. 1st, 2019. Credits: NASA/JHUAPL/SwRI/Steve Gribben
Even though the encounter with the Pluto system happened almost three years ago, scientists are still busy studying all the information gathered during the historic flyby. In addition, the New Horizons spacecraft will be making history again in the not-too-distant future. At present, the spacecraft is making its way farther into the outer Solar System with the intention of rendezvousing with two Kuiper Belt Objects.
On Jan. 1st, 2019, it will rendezvous with its first destination, the KBO known as 2014 MU69 (aka. “Ultima Thule“). This object will be the most primitive object ever observed by a spacecraft, and the encounter will the farthest ever achieved in space exploration. Before this intrepid exploration mission is complete, we can expect that a lot more of the outer Solar System will be mapped and named.
