Looking back at an overexposed Charon and Plutoshine. Credit: NASA/JPL/New Horizons
Sometimes, its not the eye candy aspect of the image, but what it represents. A recent image of Pluto’s large moon Charon courtesy of New Horizons depicting what could only be termed ‘Plutoshine’ caught our eye. Looking like something from the grainy era of the early Space Age, we see a crescent Charon, hanging against a starry background…
So what, you say? Sure, the historic July 14th , 2015 flyby of New Horizons past Pluto and friends delivered images with much more pop and aesthetic appeal. But look closely, and you’ll see something both alien and familiar, something that no human eye has ever witnessed, yet you can see next week.
We’re talking about the reflected ‘Plutoshine‘ on the dark limb of Charon. This over-exposed image was snapped from over 160,000 kilometers distant by New Horizons’ Ralph/Multispectral imager looking back at Charon, post flyby. For context, that’s just shy of half the distance between the Earth and the Moon. “Bigger than Texas” (Cue Armageddon), Charon is about 1200 kilometers in diameter and 1/8th the mass of Pluto. Together, both form the only true binary (dwarf) planetary pair in the solar system, with the 1/80th Earth-Moon pair coming in at a very distant second.
Earthshine on the Moon. Credit: Dave Dickinson
We see reflected sunlight coming off of a gibbous Pluto which is just out of frame, light that left the Sun 4 hours ago and took less than a second to make the final Pluto-Charon-New Horizons bounce. You can see a similar phenomenon next week, as Earthshine or Ashen Light illuminates the otherwise dark nighttime side of the Earth’s Moon, fresh off of passing New phase this weekend. Snow and cloud cover turned Moonward can have an effect on how bright Earthshine appears. One ongoing study based out of the Big Bear Solar observatory in California named Project Earthshine seeks to characterize long-term climate variations looking at this very phenomenon.
The view on the evening of January 28th looking west at dusk. Credit: Stellarium.
Standing on Pluto, you’d see a 3.5 degree wide Charon, 7 times larger than our own Full Moon. Of course, you’d need to be standing in the right hemisphere, as Pluto and Charon are tidally locked, and keep the same face turned towards each other. It would be a dim view, as the Sun shines at -20 magnitude at 30 AU distant, much brighter than a Full Moon, but still over 600 times fainter than sunny Earth. Dim Plutoshine on the nightside of Charon would, however, be easily visible to the naked eye.
A small 6 cm instrument, Ralph images in the visual to near-infrared range. Ralph compliments New Horizons larger LORRI instrument, which has a diameter and very similar optical configuration to an amateur 8-inch Schmidt-Cassegrain telescope.
Charon as seen from Pluto. Credit: Starry Night.
Don’t look for Pluto now; it just passed solar conjunction on the far side of the Sun on January 7th, 2017. Pluto reaches opposition and favorable viewing for 2017 on July 10th, one of the 101 Astronomical Events for 2017 that you’ll find in our free e-book, out from Universe Today.
And for an encore, New Horizons will visit the 45 kilometer in diameter Kuiper Belt Object 2014 MU69 on New Year’s Day 2019. From there, New Horizons will most likely chronicle the environs of the the distant solar system, as it joins Pioneer 10 and 11 and Voyagers 1 and 2 as human built artifacts cast adrift along the galactic plane.
A pretty pair: Pluto and Charon. Credit: NASA/JPL/New Horizons
And to think, it has taken New Horizons about 18 months for all of its flyby data to trickle back to the Earth. Enjoy, as it’ll be a long time before we visit Pluto and friends again.
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!
Alan Stern’s 2006 Nissan 350Z and Percival Lowell’s 1912 car in front of the Lowell Observatory. Percival Lowell’s car nicknamed his car “Big Red,” and Stern’s car is nicknamed “New Red.” Credit: Lowell Observatory
Many of the rocket and space flight enthusiasts I know are also car buffs. If you fit into that category, here’s an opportunity you won’t want to miss: a chance to own the car that New Horizons principal investigator Alan Stern drove all the way to Pluto.
Well, technically, he drove his shiny red Nissan 350Z the entire time the New Horizons’ spacecraft was making a beeline for the icy dwarf planet. But Stern has now donated this car to the Lowell Observatory, the facility where Pluto was discovered. The car is being auctioned off on eBay, with proceeds going to support “Lowell’s mission of scientific research and education.” You can make your bid now, as bids are being accepted from December 15-24, and the winner will not only have the privilege of owning the car, but also enjoy a dinner with Stern.
New Horizons Principal Investigator Alan Stern and the Nissan sports car he has donated to the Lowell Observatory for a fundraiser. Credit: Lowell Observatory.
Stern bought the car in 2006, the year New Horizons launched (it has a bumper sticker that says “My other vehicle is on its way to Pluto”) and he continued driving it until earlier this year, well past the spacecraft’s flyby of Pluto in July 2015.
It is a two-door model with red exterior and carbon interior, and has just over 77,000 miles on it, which, as Stern points out, is almost 10 times fewer miles than New Horizons clocked on its first day of flight. A November 9, 2016 appraisal states the vehicle is in excellent shape and has a life expectancy of 300,000 miles.
“It was Percival Lowell’s perseverance and dedication that resulted in the discovery of Pluto and, ultimately, resulted in the flight of New Horizons to explore this distant, small planet,” Stern said in a press release from the Lowell Observatory. “New Horizons was, and is, the best aspect of my career so far, so I wanted to donate this car to Lowell Observatory as a fundraising vehicle to recognize the fact that New Horizons could not have happened without the historic and pioneering work that took place at Lowell Observatory early in the last century.”
Bumper sticker on Alan Stern’s car. Credit: Lowell Observatory.
Stern was the impetus behind New Horizons, billed as the fastest spacecraft ever launched, so he calls the Nissan 350Z his “second fastest vehicle.” He still oversees the New Horizons mission, as the spacecraft continues on its journey through the Kuiper Belt. It will fly past another object, named 2014 MU69, which Stern said is an ancient KBO that formed where it orbits now.
“It’s the type of object scientists have been hoping to study for decades, and this will be the most distant world we’ve ever been able to see up close,” Stern told me during an interview for my upcoming book, “Incredible Stories From Space.” Chapter 1 tells the stories of the New Horizons mission, including many stories from Stern.
With a penchant for both creating and driving state-of-the-art vehicles, Stern revealed earlier this year that his new car is a Tesla.
Lowell director Jeff Hall said, “It’s been a real pleasure working with Alan over the past few years leading up to and past the Pluto flyby. He’s been tremendously supportive of Lowell, and his donation of his car for us to auction is a sterling example of this. We’re thrilled by this gesture, and we look forward to meeting the lucky winner.”
The Lowell Observatory was founded in 1894 by Percival Lowell and has been home to many important discoveries including the detection of the large recessional velocities (redshift) of galaxies by Vesto Slipher in 1912-1914 (a result that led to the realization the universe is expanding), and the discovery of Pluto by Clyde Tombaugh in 1930. Today, Lowell’s 14 astronomers use ground-based telescopes around the world, telescopes in space, and NASA planetary spacecraft to conduct research in astronomy and planetary science. Lowell is a private, non-profit research institution and is located near Flagstaff, Arizona.
New Horizon's July 2015 flyby of Pluto captured this iconic image of the heart-shaped region called Tombaugh Regio. Credit:
NASA/JHUAPL/SwRI.
The evidence keeps growing for a large subsurface ocean at Pluto, which also provides clues how the iconic ‘heart’ of Pluto was formed.
We reported in early October that thermal models of Pluto’s interior and tectonic evidence suggest an ocean may exist beneath Pluto’s heart-shaped Sputnik Planitia. Now, new research on data from the New Horizons mission shows more indications of an ocean just below Pluto’s surface that consists of a slushy, viscous liquid, kept warm from Pluto’s interior and a hint of anti-freeze.
“As far as we can tell, there’s no tidal heating helping to keep the ocean liquid,” Francis Nimmo from UC Santa Cruz told Universe Today. He is the first author of a paper on the new findings published today in Nature. “The main heat source keeping the ocean liquid is radioactive decay in Pluto’s rocky interior, although it certainly helps if there is an ‘antifreeze’ present.”
This cutaway image of Pluto shows a section through the area of Sputnik Planitia, with dark blue representing a subsurface ocean and light blue for the frozen crust. Artwork by Pam Engebretson, courtesy of UC Santa Cruz.
Nimmo said he suspects the ocean is mostly water with ammonia acting as an antifreeze. This subsurface ocean is also bulging, similar to the ‘mascons’ on the Moon, putting stress on Pluto’s icy outer shell, causing fractures consistent with features seen in the New Horizons images.
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 fractures and faulted mountain blocks, to the textured surface of the vast basin informally called Sputnik Planitia. Credit: NASA/JHUAPL/SWRI
Sputnik Planitia forms one side of the prominent heart-shaped feature seen in some of the first close-up images from New Horizons July 2015 flyby. It was likely created by the impact of a giant meteorite, which would have blasted away a huge amount of Pluto’s icy crust.
But a deep basin is just a “big, elliptical hole in the ground,” Nimmo said, that would not provide the extra mass needed to cause that kind of reorientation. “So, the extra weight must be hiding somewhere beneath the surface. And an ocean is a natural way to get that.”
These schematic diagrams show how the gravity anomaly at Sputnik Planitia is affected by an uplifted ocean and the thickness of the nitrogen layer. Either a nitrogen layer more than 40 km thick (panel b) or an uplifted ocean (panel c) could result in a present-day positive gravity anomaly at Sputnik Planitia; otherwise, the gravity anomaly will be strongly negative (panel a). (Image from Nimmo et al., Nature, 2016)
But Pluto is cold, with temperatures ranging from -387 to -369 Fahrenheit (-233 to -223 Celsius). How could there be an ocean?
“Pluto is small enough that it’s just about almost cooled off but still has a little heat, and it’s about 2 percent the heat budget of the Earth, in terms of how much energy is coming out,” said co-author Richard Binzel, from MIT. “So we calculated Pluto’s size with its interior heat flow, and found that underneath Sputnik Planitia, at those temperatures and pressures, you could have a zone of water-ice that could be at least viscous. It’s not a liquid, flowing ocean, but maybe slushy. And we found this explanation was the only way to put the puzzle together that seems to make any sense.”
The massive basin also appears extremely bright relative to the rest of the planet, and the data from New Horizons suggest it is filled with frozen nitrogen ice.
Previous research from the the mission showed evidence that the liquid nitrogen may be constantly refreshing, or convecting, as a result of a weak spot at the bottom of the basin, and this weak spot may let heat rise through Pluto’s interior to continuously refresh the ice.
Additionally, the extra weight of an underground ocean could help explain the longstanding question of why Pluto’s heart aligns almost exactly opposite from Charon. Nimmo said this alignment is “suspicious” and that the likelihood of this being just a coincidence is only 5 percent. Therefore, the alignment suggests that extra mass in that location interacted with tidal forces between Pluto and Charon to reorient Pluto, putting Sputnik Planitia directly opposite the side facing Charon.
A thick, heavy ocean, the new data suggest, may have served as a “gravitational anomaly,” which would factor heavily in Pluto and Charon’s gravitational tug-of-war, the researchers said. Over millions of years, the planet would have spun around, aligning its subsurface ocean and the heart-shaped region above it, almost exactly opposite along the line connecting Pluto and Charon.
While scientists are still studying the data from New Horizons, it is safe to say that Pluto keeps surprising everyone, even the scientists who know it best.
“Pluto is hard to fathom on so many different levels,” said Binzel.
New Horizon's July 2015 flyby of Pluto captured this iconic image of the heart-shaped region called Tombaugh Regio. Credit:
NASA/JHUAPL/SwRI.
Finally, the New Horizons team has their entire “pot of gold.” 15 months after the mission’s flyby of the Pluto system, the final bits of science data from the historic July 2015 event has been safely transmitted to Earth.
“The New Horizons mission has required patience for many years, but we knew the results would be well worth the wait,” New Horizons project scientists Hal Weaver told me earlier this year.
Because of New Horizons’ great distance from Earth and the spacecraft’s low power output (the spacecraft runs on just 2-10 watts of electricity), it has a relatively low ‘downlink’ rate at which data can be transmitted to Earth, just 1-4 kilobits per second. That’s why it has taken so long to get all the science data back to Earth.
“This is what we came for – these images, spectra and other data types that are going to help us understand the origin and the evolution of the Pluto system for the first time,” New Horizons principal investigator Alan Stern said a few months ago during an interview. “We’re seeing that Pluto is a scientific wonderland. The images have been just magical. It’s breathtaking.”
Because it was a flyby, and the spacecraft had just one chance at gathering data from Pluto, New Horizons was designed to gather as much data as it could, as quickly as it could – taking about 100 times more data on close approach to Pluto and its moons than it could have sent home before flying onward. The spacecraft was programmed to send select, high-priority datasets home in the days just before and after close approach, and began returning the vast amount of remaining stored data in September 2015.
New Horizons is now over 3.1 billion miles (5 billion km) away from Earth as it continues its journey through the Kuiper Belt. That translates to a current radio signal delay time of five hours, eight minutes at light speed.
The science team created special software to keep track of all the data sets and schedule when they would be returned to Earth.
New Horizons was about 3.7 million miles (6 million kilometers) from Pluto and Charon when it snapped this portrait late on July 8, 2015. Credits: NASA-JHUAPL-SWRI
The final item that was received was a portion of a Pluto-Charon observation sequence taken by the Ralph/LEISA imager. It arrived at New Horizons’ mission operations at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, at 5:48 a.m. EDT on Oct. 25. The downlink came via NASA’s Deep Space Network station in Canberra, Australia. It was the last of the 50-plus total gigabits of Pluto system data transmitted to Earth by New Horizons over the past 15 months.
“We have our pot of gold,” said Mission Operations Manager Alice Bowman, of APL.
Bowman also said the team will conduct a final data-verification review of New Horizons two onboard recorders before sending commands to erase all the data on the spacecraft. New Horizons has more work to do, so erasing the “old” data will clear space for new data to be taken during its Kuiper Belt Extended Mission (KEM). The spacecraft will do a series of distant Kuiper Belt object observations as well as perform a close encounter flyby with with a small Kuiper Belt object, 2014 MU69, on Jan. 1, 2019.
“There’s a great deal of work ahead for us to understand the 400-plus scientific observations that have all been sent to Earth,” said Stern. “And that’s exactly what we’re going to do—after all, who knows when the next data from a spacecraft visiting Pluto will be sent?”
This image of haze layers above Pluto’s limb was taken by the Ralph/Multispectral Visible Imaging Camera (MVIC) on NASA’s New Horizons spacecraft. About 20 haze layers are seen; the layers have been found to typically extend horizontally over hundreds of kilometers, but are not strictly parallel to the surface. For example, scientists note a haze layer about 3 miles (5 kilometers) above the surface (lower left area of the image), which descends to the surface at the right. Credit: NASA/JHUAPL/SwRI.
By the end of this week, all the data gathered by the New Horizons spacecraft during its July 2015 flyby of the Pluto system will have finished downloading to Earth and be in the hands of the science team. Bonnie Buratti, a science team co-investigator said they have gone from being able to look at the pretty pictures to doing the hard work required to study the data. During today’s press briefing from the Division of Planetary Sciences conference, the New Horizons team shared a few interesting and curious findings they’ve found in the data so far.
While the famous global view of Pluto appears to show a cloud-free dwarf planet, Principal investigator Alan Stern said the team has now take a closer look and found handful of potential clouds in images taken with New Horizons’ cameras.
“Clouds are common in the atmospheres of the solar system,” Stern said during the briefing, “ and a natural question was whether Pluto, with a nitrogen atmosphere, has any clouds.”
Stern said they’ve known since flyby that Pluto has haze layers, as seen in the backlit lead image above, as New Horizons flew away from Pluto. “They stretch more than 200 km into the sky, and we’ve counted over two dozen concentric layers,” he said.
While hazes are not clouds, Stern said they have identified candidates for clouds in high-phase images from the Long Range Reconnaissance Imager and the Multispectral Visible Imaging Camera.
Candidates for possible clouds on Pluto, in images from the New Horizons Long Range Reconnaissance Imager and Multispectral Visible Imaging Camera, during the spacecraft’s July 2015 flight through the Pluto system. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
“The seven candidates are all similar in that they are very low altitude,” Stern said, and they are all low-lying, isolated small features, so no broad cloud decks or fields. When we map them over the surface, they all lie near the terminator, so they occur near dawn or dusk. This is all suggestive they are clouds because low-lying regions and dawn or dusk provide cooler conditions where clouds may occur.”
Stern told Universe Today that these possible, rare condensation clouds could be made of ethane, acetylene, hydrogen cyanide or methane under the right conditions. Stern added these clouds are probably short-lived phenomena – again, likely occurring only at dawn or dusk. A day on Pluto is 6.4 days on Earth.
“But if there are clouds, it would mean the weather on Pluto is even more complex than we imagined,” Stern said.
Disappointingly, the New Horizons team has no way of confirming if these are clouds or not. “None of them can be confirmed as clouds because they are very low lying and we don’t have stereo images to tell us more,” Stern said, adding that the only way to confirm if there are condensation clouds on Pluto would be to return with an orbiter mission.
Landslides on Charon
Signs of a long run-out landslide on Pluto’s largest moon, Charon. This perspective view of Charon’s informally named Serenity Chasm shows a 200-meter thick lobate landslide that runs up against a 6 km high ridge. The images were taken by New Horizons, Long Range Reconnaissance Imager (LORRI) and Multispectral Visible Imaging Camera (MVIC) during the spacecraft’s July 2015 flyby of the Pluto system. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
While Pluto shows many kinds of activity, one surface process scientists haven’t seen on the dwarf planet is landslides. Surprisingly, though, they have been spotted on Pluto’s largest moon, Charon.
“We’ve seen similar landslides on other rocky and icy planets, such as Mars and Saturn’s moon Iapetus, but these are the first landslides we’ve seen this far from the sun, in the Kuiper Belt,” said Ross Beyer, a science team researcher from Sagan Center at the SETI Institute and NASA Ames Research Center, California. “The big question is will they be detected elsewhere in the Kuiper Belt?”
Long runout landslides seen on Charon’s Serenity Chasm shows a 200-meter thick lobate landslide that runs up against a 6 km high ridge.
“With our images, we can just resolve a smooth apron and the deposit as a whole,” said Beyer, “we can’t see individual grains. But given the cold conditions on Charon, the deposit likely made of boulders of ice and rock.”
Beyer said earthquakes or an impact could have jump started the landslide on regions that were ready to slide. “The boulders may have melted and the edges and got slippery enough to begin to slide down the slope,” he said.
The images of Serenity Chasma were taken by New Horizons’ Long Range Reconnaissance Imager (LORRI) on July 14, 2015, from a distance of 48,912 miles (78,717 kilometers).
Beyer added that while Pluto doesn’t have landslides, it does have material that appears to be moving downhill as rock falls and glacier-like flows.
Scientists from NASA’s New Horizons mission have spotted signs of long run-out landslides on Pluto’s largest moon, Charon. Arrows mark indications of landslide activity. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.
Bright and active
New Horizons data shows that portions of Pluto’s large heart-shaped region, Sputnik Planitia, are among the most reflective in the solar system. “That brightness indicates surface activity,” said Buratti, “similar to how Saturn’s moon Enceladus is very reflective, about 100% reflective, and is very active with plumes and geysers. Because we see a pattern of high surface reflectivity equating to activity, we can infer that the dwarf planet Eris, which is known to be highly reflective, is also likely to be active.”
Next Target
New Horizons is now making a beeline for its next target, KBO 2014 MU69. Cameras on the New Horizons spacecraft have been taking long range images and MU69 is the smallest KBO to have its color measured: it has a reddish tint. Scientists have used that data to confirm this object is part of the so-called cold classical region of the Kuiper Belt, which is believed to contain some of the oldest, most prehistoric material in the solar system.
“The reddish color tells us the type of Kuiper Belt object 2014 MU69 is,” said Amanda Zangari, a New Horizons post-doctoral researcher from Southwest Research Institute. “The data confirms that on New Year’s Day 2019, New Horizons will be looking at one of the ancient building blocks of the planets.”
Zangari added that they will be using the Hubble Space Telescope to better understand MU69.
“We would like to use Hubble to its find rotation rate and better understand its shape, as far as planning,” she said. “We would like to know ahead of time, if it is oblong, we would like to fly when the longest point is facing the telescope.”
Several times during the briefing, Stern indicated how having a future mission that orbited Pluto would answer so many outstanding questions the team has. He outlined one potential mission that is in the very earliest stages of study where a spacecraft could be launched on NASA’s upcoming Space Launch System (SLS) and the spacecraft could have an RTG-powered ion engine that would allow a fast-moving spacecraft the ability to slow down and go into orbit (unlike New Horizons). This type of architecture would allow for a flight time of 7.5 years to Pluto, quicker than New Horizons’ nearly 9.5 years.
New Horizon's July 2015 flyby of Pluto captured this iconic image of the heart-shaped region called Tombaugh Regio. Credit:
NASA/JHUAPL/SwRI.
What lies beneath Pluto’s icy heart? New research indicates there could be a salty “Dead Sea”-like ocean more than 100 kilometers thick.
“Thermal models of Pluto’s interior and tectonic evidence found on the surface suggest that an ocean may exist, but it’s not easy to infer its size or anything else about it,” said Brandon Johnson from Brown University. “We’ve been able to put some constraints on its thickness and get some clues about composition.”
Research by Johnson and his team focused Pluto’s “heart” – a region informally called Sputnik Planum, which was photographed by the New Horizons spacecraft during its flyby of Pluto in July of 2015.
New Horizons’ Principal Investigator Alan Stern called Sputnik Planum “one of the most amazing geological discoveries in 50-plus years of planetary exploration,” and previous research showed the region appears to be constantly renewed by current-day ice convection.
Like a cosmic lava lamp, a large section of Pluto’s icy surface in Sputnik Planum is being constantly renewed by a process called convection that replaces older surface ices with fresher material. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.
The heart is a 900 km wide basin — bigger than Texas and Oklahoma combined — and at least the western half of it appears to have been formed by an impact, likely by an object 200 kilometers across or larger.
Johnson and colleagues Timothy Bowling of the University of Chicago and Alexander Trowbridge and Andrew Freed from Purdue University modeled the impact dynamics that created a massive crater on Pluto’s surface and also looked at the dynamics between Pluto and its moon Charon.
The two are tidally locked with each other, meaning they always show each other the same face as they rotate. Sputnik Planum sits directly on the tidal axis linking the two worlds. That position suggests that the basin has what’s called a positive mass anomaly — it has more mass than average for Pluto’s icy crust. As Charon’s gravity pulls on Pluto, it would pull proportionally more on areas of higher mass, which would tilt the planet until Sputnik Planum became aligned with the tidal axis.
So instead of being a hole in the ground, the crater actually has been filled back in. Part of it has been filled in by the convecting nitrogen ice. While that ice layer adds some mass to the basin, it isn’t thick enough on its own to make Sputnik Planum have positive mass.
The Mountainous Shoreline of Sputnik Planum on Pluto. Great blocks of Pluto’s water-ice crust appear jammed together in the informally named al-Idrisi mountains. Some mountain sides appear coated in dark material, while other sides are bright. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.
The rest of that mass, Johnson said, may be generated by a liquid lurking beneath the surface.
Johnson and his team explained it like this:
Like a bowling ball dropped on a trampoline, a large impact creates a dent on a planet’s surface, followed by a rebound. That rebound pulls material upward from deep in the planet’s interior. If that upwelled material is denser than what was blasted away by the impact, the crater ends up with the same mass as it had before the impact happened. This is a phenomenon geologists refer to as isostatic compensation.
Water is denser than ice. So if there were a layer of liquid water beneath Pluto’s ice shell, it may have welled up following the Sputnik Planum impact, evening out the crater’s mass. If the basin started out with neutral mass, then the nitrogen layer deposited later would be enough to create a positive mass anomaly.
“This scenario requires a liquid ocean,” Johnson said. “We wanted to run computer models of the impact to see if this is something that would actually happen. What we found is that the production of a positive mass anomaly is actually quite sensitive to how thick the ocean layer is. It’s also sensitive to how salty the ocean is, because the salt content affects the density of the water.”
The models simulated the impact of an object large enough to create a basin of Sputnik Planum’s size hitting Pluto at a speed expected for that part in the solar system. The simulation assumed various thicknesses of the water layer beneath the crust, from no water at all to a layer 200 kilometers thick.
The scenario that best reconstructed Sputnik Planum’s observed size depth, while also producing a crater with compensated mass, was one in which Pluto has an ocean layer more than 100 kilometers thick, with a salinity of around 30 percent.
“What this tells us is that if Sputnik Planum is indeed a positive mass anomaly —and it appears as though it is — this ocean layer of at least 100 kilometers has to be there,” Johnson said. “It’s pretty amazing to me that you have this body so far out in the solar system that still may have liquid water.”
Johnson he and other researchers will continue study the data sent back by New Horizons to get a clearer picture Pluto’s intriguing interior and possible ocean.
Artist view of New Horizons passing Pluto and three of its moons.. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Now more than a year after its historic flyby of Pluto, the New Horizons spacecraft continues to speed through the Kuiper Belt. It’s currently on a beeline towards its next target of exploration, a KBO called 2014 MU69. But during its travels, New Horizons spotted another KBO, one of Pluto’s pals, Quaoar.
This animated sequence shows composite images of the Kuiper Belt object Quaoar, taken by New Horizons’ Long Range Reconnaissance Imager (LORRI). Click on the image to animate. Credit: NASA/JHUAPL/SwRI.
When these images were taken (in July 2016), Quaoar was approximately 4 billion miles (6.4 billion kilometers) from the Sun and 1.3 billion miles (2.1 billion kilometers) from New Horizons.
The animated sequence, above, (click the image if it isn’t animating in your browser) shows composite images taken by New Horizons’ Long Range Reconnaissance Imager (LORRI) at four different times over July 13-14: “A” on July 13 at 02:00 Universal Time; “B” on July 13 at 04:08 UT; “C” on July 14 at 00:06 UT; and “D” on July 14 at 02:18 UT. The New Horizons team explained that each composite includes 24 individual LORRI images, providing a total exposure time of 239 seconds and making the faint object easier to see.
Quaoar ( pronounced like “Kwa-war”) is about 690 miles or 1,100 kilometers in diameter, about half the size of Pluto. It was discovered on June 4, 2002 by astronomers Mike Brown and Chad Trujillo from Caltech, and at the time of its discovery, it was the largest object found in the Solar System since the discovery of Pluto. Quaoar’s discovery was one of the things that spurred the discussion of whether Pluto should continue to be classified as a planet or not.
But Quaoar is an interesting object in its own right and the New Horizons team said the oblique views of it that New Horizons can see – where LORRI sees only a portion of Quaoar’s illuminated surface — is very different from the nearly fully illuminated view of it that is visible from Earth. Comparing Quaoar from the two very different perspectives gives mission scientists a valuable opportunity to study the light-scattering properties of Quaoar’s surface.
If you’re thinking, “Why don’t we send a mission to Quaoar, or Sedna or Eris?” you aren’t alone. New Horizons team member Alex Parker has obviously been thinking about it. Parker tweeted that for a New Horizons-like mission it would take about 13 and a half years to reach Quaoar if it could be launched in December 2016. “Otherwise, we have to wait another 11 years for the next Jupiter assist window,” he said.
Um, NASA, can we put this on the schedule for 2027?
In the meantime, the images and data that New Horizons gathered during the Pluto flyby in July 2015 are still trickling back to Earth. The image below is a stunning view of Pluto’s methane snowcaps, visible at the terminator, showing the region north of Pluto’s dark equatorial band informally named Cthulhu Regio, and southwest of the vast nitrogen ice plains informally named Sputnik Planitia. This image was taken about 45 minutes before New Horizons’ closest approach to Pluto on July 14, 2015.
This area is south of Pluto’s dark equatorial band informally named Cthulhu Regio, and southwest of the vast nitrogen ice plains informally named Sputnik Planitia. North is at the top; in the western portion of the image, a chain of bright mountains extends north into Cthulhu Regio. New Horizons compositional data indicate the bright snowcap material covering these mountains isn’t water, but atmospheric methane that has condensed as frost onto these surfaces at high elevation. Between some mountains are sharply cut valleys – indicated by the white arrows. These valleys are each a few miles across and tens of miles long. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.
See all of the latest photos sent back from our robot in the outer reaches of our Solar System at the New Horizons website.
New Horizons trajectory and the orbits of Pluto and 2014 MU69.
New Horizons trajectory and the orbits of Pluto and 2014 MU69.
In an ‘Independence Day’ gift to a slew of US planetary research scientists, NASA has granted approval to nine ongoing missions to continue for another two years this holiday weekend.
The biggest news is that NASA green lighted a mission extension for the New Horizons probe to fly deeper into the Kuiper Belt and decided to keep the Dawn probe at Ceres forever, rather than dispatching it to a record breaking third main belt asteroid.
And the exciting extension news comes just as the agency’s Juno probe is about to ignite a do or die July 4 fireworks display to achieve orbit at Jupiter – detailed here.
“Mission approved!” the researchers gleefully reported on the probes Facebook and Twitter social media pages.
“Our extended mission into the #KuiperBelt has been approved. Thanks to everyone for following along & hopefully the best is yet to come.
Dwarf planet Ceres is shown in this false-color renderings, which highlight differences in surface materials. The image is centered on Ceres brightest spots at Occator crater. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
The New Horizons spacecraft will now continue on course in the Kuiper Belt towards an small object known as 2014 MU69, to carry out the most distant close encounter with a celestial object in human history.
“Here’s to continued success!”
The spacecraft will rendezvous with the ancient rock on New Year’s Day 2019.
Researchers say that 2014 MU69 is considered as one of the early building blocks of the solar system and as such will be invaluable to scientists studying the origin of our solar system how it evolved.
It was almost exactly one year ago on July 14, 2015 that New Horizons conducted Earth’s first ever up close flyby and science reconnaissance of Pluto – the most distant planet in our solar system and the last of the nine planets to be explored.
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.com
The immense volume of data gathered continues to stream back to Earth every day.
“The New Horizons mission to Pluto exceeded our expectations and even today the data from the spacecraft continue to surprise,” said NASA’s Director of Planetary Science Jim Green at NASA HQ in Washington, D.C.
“We’re excited to continue onward into the dark depths of the outer solar system to a science target that wasn’t even discovered when the spacecraft launched.”
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
While waiting for news on whether NASA would approve an extended mission, the New Horizons engineering and science team already ignited the main engine four times to carry out four course changes in October and November 2015, in order to preserve the option of the flyby past 2014 MU69 on Jan 1, 2019.
Green noted that mission extensions into fiscal years 2017 and 2018 are not final until Congress actually passes sufficient appropriation to fund NASA’s Planetary Science Division.
“Final decisions on mission extensions are contingent on the outcome of the annual budget process.”
Tough choices were made even tougher because the Obama Administration has cut funding for the Planetary Sciences Division – some of which was restored by a bipartisan majority in Congress for what many consider NASA’s ‘crown jewels.’
NASA’s Dawn asteroid orbiter just completed its primary mission at dwarf planet Ceres on June 30, just in time for the global celebration known as Asteroid Day.
“The mission exceeded all expectations originally set for its exploration of protoplanet Vesta and dwarf planet Ceres,” said NASA officials.
The Dawn science team had recently submitted a proposal to break out of orbit around the middle of this month in order to this conduct a flyby of the main belt asteroid Adeona.
Green declined to approve the Dawn proposal, citing additional valuable science to be gathered at Ceres.
The long-term monitoring of Ceres, particularly as it gets closer to perihelion – the part of its orbit with the shortest distance to the sun — has the potential to provide more significant science discoveries than a flyby of Adeona,” he said.
The funding required for a multi-year mission to Adeona would be difficult in these cost constrained times.
However the spacecraft is in excellent shape and the trio of science instruments are in excellent health.
Dawn arrived at Ceres on March 6, 2015 and has been conducting unprecedented investigation ever since.
Dawn is Earth’s first probe in human history to explore any dwarf planet, the first to explore Ceres up close and the first to orbit two celestial bodies.
The asteroid Vesta was Dawn’s first orbital target where it conducted extensive observations of the bizarre world for over a year in 2011 and 2012.
The mission is expected to last until at least later into 2016, and possibly longer, depending upon fuel reserves.
Due to expert engineering and handling by the Dawn mission team, the probe unexpectedly has hydrazine maneuvering fuel leftover.
Dawn will remain at its current altitude at the Low Altitude Mapping Orbit (LAMO) for the rest of its mission, and indefinitely afterward, even when no further communications are possible.
Green based his decision on the mission extensions on the biannual peer review scientific assessment by the Senior Review Panel.
Dawn was launched in September 2007.
The other mission extensions – contingent on available resources – are: the Mars Reconnaissance Orbiter (MRO), Mars Atmosphere and Volatile EvolutioN (MAVEN), the Opportunity and Curiosity Mars rovers, the Mars Odyssey orbiter, the Lunar Reconnaissance Orbiter (LRO), and NASA’s support for the European Space Agency’s Mars Express mission.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
This mosaic of Pluto's surface was created from images taken by the New Horizons probe just 23 minutes before its closest approach. Credit: NASA/JHUAPL/SwRI
The New Horizons mission, which its conducted its historic flyby on July 14th, 2015, has yielded a wealth of scientific data about Pluto. This has included discoveries about Pluto’s size, its mountainous regions, its floating ice hills, and (more recently) how the dwarf planet interacts with solar wind – a discovery which showed that Pluto is actually more planet-like than previously thought.
But beyond revelations about the planet’s size, geography and surface features, it has also provided the most breathtaking, clear, and inspiring images of Pluto and its moons to date. And with this latest release of images taken by the New Horizon‘s Long Range Reconnaissance Imager (LORRI), people here on Earth are being treated to be the best close-up of Pluto yet.
These images, which were taken while the New Horizon’s probe was still 15,850 km (9,850 mi) away from Pluto (just 23 minutes before it made its closest approach), extend across the hemisphere that the probe was facing as it flew past. It shows features ranging from the cratered northern uplands and the mountainous regions in Voyager Terra before slicing through the flatlands of “Pluto’s Heart” – aka. Tombaugh Regio – and ending up in another stretch of rugged highlands.
Informal names given to Pluto’s surface features. Credit: earthsky.org
The width of the strip varies as the images pass from north to south, from more than 90 km (55 mi) across at the northern end to about 75 km (45 mi) at its southern point. The perspective also changes, with the view appearing virtually horizontal at the northern end and then shifting to an almost top-down view onto the surface by the end.
The crystal clear photographs that make up the mosaic – which have a resolution of about 80 meters (260 feet) per pixel – offer the most detailed view of Pluto’s surface ever. With this kind of clarity, NASA scientists are able to discern features that were never before visible, and learn things about the kinds of geological processes which formed them.
This includes the chaotic nature of the mountains in the northern hemisphere, and the varied nature of the icy nitrogen plains across Tombaugh Regio – which go from being cellular, to non-cellular, to a cross-bedding pattern. These features are a further indication that Pluto’s surface is the product of a combination of geological forces, such as cryovolcanism, sublimation, geological activity, convection between water and nitrogen ice, and interaction between the surface and atmosphere.
Images snapped by New Horizons’ Long Range Reconnaissance Imager (LORRI) while the probe was still on approach to Pluto were combined with color data from the Ralph instrument to create this global view of Pluto. Credits: NASA/JHUAPL/SwRI
Alan Stern, the principal investigator of the New Horizons mission and the Associate Vice President of Research and Development at the Southwest Research Institute, was especially impressed with this latest find. As he told Universe Today via email:
“This new high resolution image mosaic is the complete highest resolution strip of images New Horizons obtained, and its both eye candy gorgeous and scientifically rich. Think about it— one flyby and we have this mosaic, plus so much more; no dataset like this existed on Mars until we’d flown half a dozen missions there!”
The most distant flyby in the history of space exploration, and yet we’ve obtained more from this one mission than multiple flybys were able to provide from one of Earth’s closest neighbors. Fascinating! And what’s more, new information is expected to be coming from the New Horizons probe until this coming October. To top it off, our scientists are still not finished analyzing all the information the mission collected during its flyby.
The full-resolution image can be viewed here, and be sure to enjoy this NASA video of the mosaic:
