Tag Archives: pluto

Charon’s Cracks Formed During Ancient Near-Misses With Other Worlds

Ever since the gargantuan cracks on Plutos moon Charon were first spotted, astronomers have been baffled as to what may have formed them, with explanations ranging from giant impacts to an active, hot mantle.

A new paper, due to be published in the journal Icarus, has come up with an alternative, and arguably more compelling, explanation:Based on a series of computer simulations, it appears that a long history of near-misses by other massive objects, and not plate tectonics, may be responsible for forging mountains and canyons on this distant world.

I was inspired by computer graphics code in how to model the icy moons, Alice Quillen, a professor of physics and astronomy at the University of Rochester and lead author of the study, said in a statement. The inside of the moons is similar to how blood splatter is modeled in games and the outer, icy crust is similar to modeling clothes and how they move.

The computer simulations of the close tidal encounters. Alice Quillen via YouTube

Earth’s Moon may be small, but it’s still sufficiently sizable to be able to generate tides on Earth with its gravitational pull, both at the surface and within the liquid outer core. This mechanism is known as tidal forcing, and the authors of this new study hypothesizedthat this phenomenon may have once acted on the surfaces of icy worlds and moons like Charon when similarlysized worlds drifted close by in the Solar System, although they don’t specify when this would have happened.

The researchers decided to use an N-body simulation, which models objects as having multiple internal regions interconnected by springs. Its commonly used by astrophysicists to model the effect of gravity on planets and stars, but this is the first time it has been applied to a moon.

A massive perturber forming cracks on a Charon-like icy world. Alice Quillen via YouTube

In multiple virtual experiments, simulated icy moons were kept stationary as similar mass objects flew by them, and the team watched as they became deformed.

As it turns out, such close encounters exert enough of a tidal force on the icy moons to cause their surface to fracture in a brittle manner and on surprisingly huge scales. This means that the giant cracks and complex fault structures on the icy moons of Dione and Tethys (of Saturn), Ariel (of Uranus), and Charon (of Pluto) at the very least may be caused by this mechanism.

A close-up of the tectonic belt on Charon. NASA/JHUAPL/SwRI

We know that Earths internal heat escapes through both volcanoes and, significantly, convection currents in the mantle; these move around tectonic plates, which create mountains, faults, canyons, ocean basins, and continents. This process is known as plate tectonics, and its been happening on Earth for at least 3 billion years, but theres little evidence that it has happened anywhere else in the Solar System.

Icy moons like Charon are thought to be too small to still contain any heat left over from their presumably violent formation, so its unlikely that plate tectonics ever managed to effectively operate on them in the same way they did, and still do, on Earth. Perhaps this new study has finally solved the conundrum of where the ginormous alien crevasses come from or, as another recent study suggested, these vast canyons may have instead formed as the icy moon cooled and contracted.

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Read more: http://www.iflscience.com/space/charons-cracks-formed-during-ancient-near-misses-other-worlds

Scientists Think Rivers Of Liquid Nitrogen Once Flowed On Pluto

There are tropics on Pluto. While this may sound counterintuitive, its climate means that there are warmer parts of the world relative to its colder, arctic regions. As new research presented at the 2016 Lunar and Planetary Science Conferencethis week reveals, this diverse climate means that rivers and lakes of liquid nitrogen are likely to form at the surface.

Even with less than half of New Horizons data, scientists are unravelling more and more secrets about the dwarf planet by the day. The latest comes by way of researchers at NASAwho confirm that Pluto despite being on average 5.9 billion kilometers (3.7 billion miles) away from the Sun has seasons.

The central tropical region of Pluto, from 60 north to 60 south, experiences the Sun passing directly overhead. Its arctic region above 30 north experiences prolonged sunlight in the summer months, whilst the arctic region beneath 30 south is utterly frigid in a simultaneous winter.

Pluto is tipped over on its rotational axis at 120, rather wonky compared to Earths 23 tilt. As a result of this, during a northern arctic summer, the region receiving the most heat is its north pole.

Go home Pluto, youre drunk: The extreme axial tilt of the dwarf planet. NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

The dwarf planet wobbles and shakes on its axis as it orbits the Sun just like Earth does, meaning that these arctic regions advance and retreat over cycles of hundreds of thousands of years. One region, however, never experiences arctic climates.

This band, between 13 N and 13 S, appears to have been gouged out, in that theres a dark, deep stripe compared to the rest of the planet. The researchers think that the constant warm band here means that ice and volatiles compounds that evaporate at low temperatures couldnt accumulate here under the Suns constant bombardment.

The dark equatorial band. NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Incidentally, the icy worlds elliptical orbit means that it moves between 50 Earth-Sun distances at its furthest point from the Sun and 30 Earth-Sun distances at its nearest point. Consequently, the temperature difference between a distant summer and a closer summer are more extreme than almost anywhere else.

This is all still relative, mind you: a summertime peak temperature is still around -200C (-330F). As Pluto takes 248 Earth years to rotate around the Sun, these summers and winters last for more than a century.

A second paper presented at the conference reveals that Plutos atmospheric pressure has varied wildly over its history, driven by these long-term orbital and rotational changes. It has ranged from about one-ten-thousandth right up to up to one-fifth of Earths.

These enormous changes in atmospheric pressure would have a distinct effect on the surface of the world; at higher pressures, the abundant nitrogen at the surface would remain a liquid instead of a gas. This means rivers, floods and lakes of liquid nitrogen may haved existed on Pluto.

Researchers noted that these features would be relatively common around 800,000 years ago, when temperatures were hot enough to lead to widespread melting. There may be some still around today near the equatorial region, although they have yet to be spotted. Frozen lakes, however, have been seen, and these ice reservoirs were almost certainly once liquid.

An enhanced color image of Pluto highlighting its wildly varying geological features. NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Pluto is the gift that just keeps on giving, it seems. A plethora of papers have recently revealed that Plutos atmosphere isnt disintegrating as much as we previously thought, and most significantly, the surface is active essentially meaning that mountain building and perhaps cryovolcanism is still happening on this distant, icy sphere.

Above is a video of the research presented from the LPSC.

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Read more: http://www.iflscience.com/space/pluto-has-rivers-liquid-nitrogen-extreme-seasons-and-chaotic-atmosphere

Stunning New Mosaic Of Pluto Reveals Battered Surface

Each week, we look forward to new and exciting Pluto announcements, and this week is definitely no exception. Just five months ago we were on the edge of our seats, anticipating the first-ever up-close views of the icy world.

Now, with less than half of the data collected by New Horizons beamed back to Earth, we are just beginning to understand it.

Along with these incredible new images are detailed scientificfindings revealing the secrets of Plutos geography, atmosphere and moons. The research was presented today during the American Geophysical Unions Fall Meeting.

Weve seen Pluto resemble the Earth in remarkable ways. This week, scientists presented evidence for hanging valleys like the ones in Wyomings Yellowstone National Park. The presence of these eroded valleys are geological evidence indicating there was widespread glacial activity both in Plutos past and its present.

Alan Howard, a scientific collaborator with the New Horizons Geology, Geophysics and Imaging team, said in a statement:Pluto has greatly exceeded our expectations in diversity of landforms and processes processes that continue to the present.

As New Horizons principal investigator Alan Stern has said previously that what we knew about Pluto when New Horizons “could fit on one sheet of paper,” and soon we will be able to “write the textbook. However, before we can write the book, we need to understand the processes taking place on this icy world. Scientists believe the key to understanding Plutos geological activity is to understand the role of nitrogen and other volatile ices.

Pluto has a heart as seen in the iconic post-flyby image with two very different lobes. The left side is a vast, icy basin covering an area 1,000 kilometers (620 miles) wide. Unofficially dubbed Sputnik Planum, after the first satellite launched into space, the region is littered with icy polygonal features and covered in nitrogen ice. New numerical models show that thermal convection is taking place within the icy layers of the planum and are the driving source behind the unusual polygons. The models show this area is still being transformed today by glacial flows of nitrogen ice, erasing any evidence of craters or scarring.

Unlike the smooth icy plains of Sputnik Planum, the right side of Plutos frozen heart is covered in strange pits and rougher terrain. Unofficially named Tombaugh Regio after the man who discovered Pluto, Clyde Tombaugh, the region appears to be older than the neighboring planum.This region of Pluto is scarred by vast chasms and chock full of impact craters and even mountains that tower above the surface basically tons of interesting surface features to stare at. The new images show details resolve features as small as 500 meters (1,640 feet) across, revealing Plutos contrasting surface in stunning detail.

Adjacent to Tombaugh Regio in Plutos western hemisphereis Wright Mons,one of two potential cryovolcanoes on Pluto. Similar to the shield volcanoes we see on Earth, Wright Mons and Piccard Mons have a broad, circular basin with a deep depression at the summit. However, instead of lava and ash, cryovolcanoes would spew a melted slurry of water ice, ammonia and other volatiles.

Also included in the latest image release is a new view of Nix, Plutos third largest moon. This is one of the best images we have of Plutos potato-shaped moon and shows a heavily cratered surface. The image was taken on the day of the flyby, July 14, and at a distance of 23,000 kilometers (14,000 miles).

Image in text: The full new mosaic of Pluto.NASA/JHUAPL/SwRI

Read more: http://www.iflscience.com/stunning-new-mosaic-pluto

Pluto’s Moons Behave Like Spinning Tops

We know that Pluto is unlike anything we ever imagined, and its family of moons is no exception. Before arriving at the Pluto system, scientists made some predictions about Plutos small moons based on data collected by the Hubble Space Telescope and other observatories. Some were pretty spot on, and others were way off. Lets take a look at what weve learned so far about this incredibly interesting and dynamic system.

The Pluto system is composed of the binary pair of Pluto and its largest moon Charon, with four smaller moons Nix, Styx, Hydra, and Kerberos orbiting the duo. Since Pluto and Charon orbit a common barycenter, its better to think of Pluto and Charon as a pair rather than a planet and a large moon. Prior to its closest approach, data from the Hubble Space Telescope predicted that Plutos small moons orbit in a chaotic fashion.

The vast majority of moons in the Solar System are very well-behaved: orbiting in synchronous rotation and tidally locked with their planet, keeping the same face toward the planet all the time. As the science team analyzes the New Horizons data, we are seeing time and time again that Pluto’s small moons do not play by these rules; they write their own.

During a briefing at the 47th annual meeting for the Division of Planetary Science, Mark Showalter of the SETI Institute said, Weve gone from dots to details in less than 10 years. Its amazing what we have learned so far. Its not chaos in this system, its pandemonium.

New data from the New Horizons spacecraft reveals the small satellites are spinning much faster than first predicted. For example Hydra, the most distant moon, spins a whopping 89 times in one single orbit. Hydra is acting like a typical Kuiper Belt Object, Showalter said. It spins 89 times in one time around Pluto; flaunting everything we know about objects in the Solar System, Hal Weaver, New Horizons project scientist added.

Our first response to this might be to ask why Hydra is spinning so fast, but the better question is Why hasnt it slowed down? The science team doesnt quite understand all the dynamics of the Pluto system yet, but one hypothesis is that Charon exerts a strong torque on the smaller satellites, preventing them from slowing down and settling into a synchronous rotation.

Nix, Plutos innermost, potato-shaped moon could arguably be the most fascinating of the small moons. Spanning 48 kilometers by 32 kilometers (29 miles by 19 miles) roughly the surface area of Los Angeles the surface is void of any boulders or fractures, but we do see a fewrecognizable craters and a few potential craters that we cant quite resolve. The wobbly potato moon also rotates backwards, and even increased its spin rate by as much as 10percent between 2012 and2014.

The small moons of Pluto behave like spinning tops. Credit: Nasa/Youtube

Styx and Kerberos are so small and low mass that its no wonder our predictions for Kerberos were completely off. Originally scientists believed the moon to be darker than the others, but recently returned data from New Horizons shows the tiny moons surface to be just as reflective as the rest.

Images of the small moons indicate that at least two of them Kerberos and Hydra appear to be dual-lobed and could have formed as a result of two different bodies merging together. This suggests that at one time Pluto may have had more moons. Showalter and Alan Stern, New Horizons principal investigator, suspect that the small moons formed during the sameimpact that created Charon.

Scientistscombined data collected from New Horizons with computer models and concluded that an object smaller than Pluto but larger than Charon had to have struck the protoplanet Pluto in order to create the two bodies we see today. The data also indicates this impact had to have taken place a very long time ago, not long after the formation of the original body.

Read more: http://www.iflscience.com/space/plutos-moons-behave-spinning-tops-ke-editing

New Horizons Begins Life After Pluto By Studying Distant Solar System Object

After the New Horizons spacecraft made its historic flyby of Pluto in July 2015, the plan was always to send it further out of the Solar System to study other objects. Now, the spacecraft has returned the first science from such observations.

New Horizons observed a Kuiper Belt object (KBO) on two separate occasions called 1994 JR1, which measures 145 kilometers (90 miles) across. KBOs are remnants of the early Solar System, in the form of icy comets and asteroids, so studying them could reveal important clues about our beginnings.

These observations werent comparable with the Pluto flyby though, when New Horizons flew just a few tens of thousands of kilometers above the surface. Instead, New Horizons snapped the KBO from a distance of 111 million kilometers (69 million miles) in early April, following preliminary observations from more than twice as far away in November 2015.

But this post-Pluto science is important, because it helps New Horizons practice for a more ambitious mission in 2019. On January 1 of that year, mission scientists will send New Horizons flying past a KBO called 2014 MU69 closer than it came to Pluto, although the exact flyby distance is not known yet.

As for JR1, well, we did actually learn a bit from these views. First, scientists were able to pinpoint its location to within 1,000 kilometers (621miles), the most accurate for any small KBO. This allowed them to rule out a theory that JR1 might be a distant satellite of Pluto. They were also able to work out JR1s rotation speed, clocking it at one rotation every 5.4 Earth hours.

Above, an animation of JR1 moving from two of 20 observations made in April 2016. Top left is an internal camera reflection, which NASA calls “a kind of selfie.”NASA/JHUAPL/SwRI

Thats relatively fast for a KBO, said science team member John Spencer, from the Southwest Research Institute (SwRI) in Colorado, in a statement. This is all part of the excitement of exploring new places and seeing things never seen before.

Before New Horizons reaches 2014 MU69, it willstudy about 20 more KBOs, pending approval for this extended mission from NASA (which seems a done deal at the moment). Pluto may have been impressive, but these endeavors will tell us even more about the outer Solar System than ever before.

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Read more: http://www.iflscience.com/new-horizons-begins-life-after-pluto

NASA’s New Horizons Readies for This Summer’s Pluto Flyby

After traveling nearly five billion kilometers over nine years, NASA’s New Horizons spacecraft has just entered the first phase of approach in its upcoming epic encounter with Pluto. The series of several planned approaches will culminate on July 14 with the first ever close-up flyby of Pluto—a dwarf planet 7.5 billion kilometers (4.67 billion miles) from Earth.  

New Horizons, launched into space on January 19, 2006, is the first mission to the former ninth planet. The spacecraft woke up from its final hibernation period just last month to English tenor Russell Watson’s “Where My Heart Will Take Me.” Since 2007, the piano-sized probe has spent 1,873 days (or two-thirds of its flight time) largely unpowered over the course of 18 separate hibernation periods to reduce wear and tear. 

“We’ve completed the longest journey any spacecraft has flown from Earth to reach its primary target, and we are ready to begin exploring,” New Horizons principal investigator Alan Stern from Southwest Research Institute says in a news release

The plan is to head into the orbit of one of Pluto’s five known moons. And in preparation for this summer’s close encounter, scientists have been configuring the probe for distant observations of Pluto, including a long-range photo shoot beginning January 25 and continuing through the next few months. Images taken by the on-board Long-Range Reconnaissance Imager will help navigate the probe across the last 220 million kilometers (135 million miles).

“We need to refine our knowledge of where Pluto will be when New Horizons flies past it,” says Mark Holdridge of Johns Hopkins University’s Applied Physics Laboratory. “The flyby timing also has to be exact, because the computer commands that will orient the spacecraft and point the science instruments are based on precisely knowing the time we pass Pluto—which these images will help us determine.” 

This first approach phase will run until the spring, and various instruments on New Horizons will be gathering interplanetary data continuously, including measurements of high-energy particles streaming from the sun and the concentrations of dust particles in the Kuiper Belt, an unexplored area in the outer region of our solar system that could contain thousands of small icy, rocky planets.

Then in the springtime, cameras and spectrometers aboard the spacecraft will begin capturing high-resolution images that’ll help map Pluto and its moons more accurately than ever before. “We really are on Pluto’s doorstep,” Stern says.

Read more: http://www.iflscience.com/space/nasas-new-horizons-readies-summers-pluto-flyby