Weekly Space Hangout – April 17, 2015: Amy Shira Teitel and “Breaking the Chains of Gravity”

Host: Fraser Cain (@fcain)
Special Guest: Amy Shira Teitel (@astVintageSpace) discussing space history and her new book Breaking the Chains of Gravity
Guests:
Morgan Rehnberg (cosmicchatter.org / @MorganRehnberg )

This Week’s Stories:
Falcon 9 launch and (almost!) landing
NASA Invites ESA to Build Europa Piggyback Probe
Bouncing Philae Reveals Comet is Not Magnetised
Astronomers Watch Starbirth in Real Time
SpaceX Conducts Tanking Test on In-Flight Abort Falcon 9
Rosetta Team Completely Rethinking Comet Close Encounter Strategy
Apollo 13 Custom LEGO Minifigures Mark Mission’s 45th Anniversary
LEGO Launching Awesome Spaceport Shuttle Sets in August
New Horizons Closes in on Pluto
Work Platform to be Installed in the Vehicle Assembly Building at NASA’s Kennedy Space Center in Florida.
Watching the Sunsets of Mars Through Robot Eyes: Photos
NASA Invites ESA to Build Europa Piggyback Probe
ULA Plans to Introduce New Rocket One Piece at a Time
Two Mysterious Bright Spots on Dwarf Planet Ceres Are Not Alike
18 Image Montage Show Off Comet 67/P Activity
ULA’s Next Rocket To Be Named Vulcan
NASA Posts Huge Library of Space Sounds And You’re Free to Use Them
Explaining the Great 2011 Saturn Storm
Liquid Salt Water May Exist on Mars
Color Map Suggests a Once-Active Ceres
Diverse Destinations Considered for New Interplanetary Probe
Paul Allen Asserts Rights to “Vulcan” Trademark, Challenging Name of New Rocket
First New Horizons Color Picture of Pluto and Charon
NASA’s Spitzer Spots Planet Deep Within Our Galaxy
Icy Tendrils Reaching into Saturn Ring Traced to Their Source
First Signs of Self-Interacting Dark Matter?
Anomaly Delays Launch of THOR 7 and SICRAL 2
Nearby Exoplanet’s Hellish Atmosphere Measured
The Universe Isn’t Accelerating As Fast As We Thought
Glitter Cloud May Serve As Space Mirror
Cassini Spots the Sombrero Galaxy from Saturn
EM-1 Orion Crew Module Set for First Weld Milestone in May
Special Delivery: NASA Marshall Receives 3D-Printed Tools from Space
The Roomba for Lawns is Really Pissing Off Astronomers
Giant Galaxies Die from the Inside Out
ALMA Reveals Intense Magnetic Field Close to Supermassive Black Hole
Dawn Glimpses Ceres’ North Pole
Lapcat A2 Concept Sup-Orbital Spaceplane SABRE Engine Passed Feasibility Test by USAF Research Lab
50 Years Since the First Full Saturn V Test Fire
ULA CEO Outlines BE-4 Engine Reuse Economic Case
Certification Process Begins for Vulcan to Carry Military Payloads
Major Advance in Artificial Photosynthesis Poses Win/Win for the Environment
45th Anniversary [TODAY] of Apollo 13’s Safe Return to Earth
Hubble’s Having A Party in Washington Next Week (25th Anniversary of Hubble)

Don’t forget, the Cosmoquest Hangoutathon is coming soon!

We record the Weekly Space Hangout every Friday at 12:00 pm Pacific / 3:00 pm Eastern. You can watch us live on Google+, Universe Today, or the Universe Today YouTube page.

You can join in the discussion between episodes over at our Weekly Space Hangout Crew group in G+, and suggest your ideas for stories we can discuss each week!

The Moment We’ve been Waiting For: First New Images of Pluto from New Horizons

Pluto and Charon, the largest of Pluto's five known moons, seen Jan. 25 and 27, 2015, through the telescopic Long-Range Reconnaissance Imager (LORRI) on NASA's New Horizons spacecraft. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.

Here we go! New Horizons is now on approach and today – on the anniversary of Pluto discoverer Clyde Tombaugh’s birth – the spacecraft has sent back its first new images of the Pluto system. The images aren’t Earth-shattering (Pluto-shattering?) but they do represent the mission is closing in on its target, and will allow the New Horizons engineers to precisely aim the spacecraft as it continues its approach.

The photos were taken with the telescopic Long-Range Reconnaissance Imager (LORRI) on January 25 and 27, 2015.

“Pluto is finally becoming more than just a pinpoint of light,” said Hal Weaver, New Horizons project scientist. “LORRI has now resolved Pluto, and the dwarf planet will continue to grow larger and larger in the images as New Horizons spacecraft hurtles toward its targets. The new LORRI images also demonstrate that the camera’s performance is unchanged since it was launched more than nine years ago.”

A comparison of images of Pluto and its large moon Charon, taken in July 2014 and January 2015. Between takes, New Horizons had more than halved its distance to Pluto, from about 264 million miles (425 million kilometers) to 126 million miles (203 million kilometers). Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.
A comparison of images of Pluto and its large moon Charon, taken in July 2014 and January 2015. Between takes, New Horizons had more than halved its distance to Pluto, from about 264 million miles (425 million kilometers) to 126 million miles (203 million kilometers). Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.

New Horizons was about 203 million kilometers (126 million miles) away from Pluto when it began taking images. Pluto appears as a pixelated smudge, and New Horizons is only close enough so that just Pluto and its largest moon, Charon are visible. In this current view from LORRI, Pluto is about 2 pixels and Charon is 1, compared to 1 pixel and 0.5 pixels last July. The images were magnified four times to make Pluto and Charon more visible.

NASA says that over the next few months, LORRI will take hundreds of pictures of Pluto, against a starry backdrop, to refine the team’s estimates of New Horizons’ distance to Pluto. As in these first images, the Pluto system will resemble little more than bright dots in the camera’s view until late spring. However, mission navigators can still use such images to design course-correcting engine maneuvers to direct the spacecraft for a more precise approach. The first such maneuver based on these optical navigation images, or OpNavs, is scheduled for March 10.

The image of Pluto and its moon Charon, taken by NASA’s New Horizons spacecraft, was magnified four times to make the objects more visible. Over the next several months, the apparent sizes of Pluto and Charon, as well as the separation between them, will continue to expand in the images. Image Credit:  NASA/JHU APL/SwRI
The image of Pluto and its moon Charon, taken by NASA’s New Horizons spacecraft, was magnified four times to make the objects more visible. Over the next several months, the apparent sizes of Pluto and Charon, as well as the separation between them, will continue to expand in the images.
Image Credit:
NASA/JHU APL/SwRI

Closest approach for the spacecraft will be on July 14.

These first images represent a milestone.

“These images of Pluto, clearly brighter and closer than those New Horizons took last July from twice as far away, represent our first steps at turning the pinpoint of light Clyde saw in the telescopes at Lowell Observatory 85 years ago, into a planet before the eyes of the world this summer,” said Alan Stern, New Horizons principal investigator. “This is our birthday tribute to Professor Tombaugh and the Tombaugh family, in honor of his discovery and life achievements — which truly became a harbinger of 21st century planetary astronomy.”

During its flyby, New Horizons will be characterizing the global geology and topography of Pluto and Charon, mapping their surface compositions and temperatures, examining Pluto’s atmospheric composition and structure, studying Pluto’s smaller moons, and searching for new moons and rings.

Sources: NASA, JHUAPL

The Solar System’s ‘Yearbook’ is About to Get Filled In

The 33 largest objects in our Solar System, ordered by mean radius, using the best images available as of January, 2015. Credit and copyright: Radu Stoicescu.

Lined up like familiar faces in your high school yearbook, here are images of the 33 largest objects in the Solar System, ordered in size by mean radius. Engineer Radu Stoicescu put this great graphic together, using the highest resolution images available for each body. Nine of these objects have not yet been visited by a spacecraft. Later this year, we’ll visit three of them and be able to add better images of Ceres, Pluto and Charon. It might be a while until the remaining six get closeups.

“This summer, for the first time since 1989,” Stoicescu noted on reddit, “we will add 3 high resolution pictures to this collection, then, for the rest of our lives, we are not going to see anything larger than 400 km in high definition for the first time. It is sad and exciting at the same time.”

Dawn will enter orbit at Ceres approximately March 6, 2015, four months before New Horizons flies past Pluto and Charon.

But a comprehensive Solar System yearbook might never be completed. Not only will there likely be new dwarf planets discovered in the Kuiper Belt, uUnless things change in the budgetary and planetary missions departments for any of the world’s space agencies, the remaining six unvisited objects in the graphic above will likely remain as “fuzzy dots” for the rest of our lives.

If you like the graphic above, you can see more imagery and space discussions at Stoicescu’s reddit page.

For more Solar System yearbook-like imagery, Emily Lakdawalla has also created some wonderful graphics/montages of our Solar System, like this one:

Every round object in the solar system under 10,000 kilometers in diameter, to scale. Montage by Emily Lakdawalla. Data from NASA / JPL and SSI, processed by Gordan Ugarkovic, Ted Stryk, Bjorn Jonsson, and Emily Lakdawalla.
Every round object in the solar system under 10,000 kilometers in diameter, to scale. Montage by Emily Lakdawalla. Data from NASA / JPL and SSI, processed by Gordan Ugarkovic, Ted Stryk, Bjorn Jonsson, and Emily Lakdawalla.

As Emily wrote in the accompanying blog post, “Just look at all of these worlds, and think about how much of the solar system we have yet to explore. Think about how much we have to learn by orbiting, and maybe even landing on, those planet-sized moons. Think about how Pluto isn’t the end of the planets, it’s the start of a whole new part of the solar system that we’ve never seen before, and how seeing Charon is going to clue us in to what’s happening on a dozen other similar-sized, unvisitably far worlds.”

‘Death Star’ Ocean? Seven Moons That Could Host Huge Hidden Liquid Reservoirs

A view of Mimas from the Cassini spacecraft. Credit: NASA/JPL/Space Science Institute

Could there be an ocean hidden somewhere in that Death Star-like picture? This is an image of Mimas, a moon of Saturn, and just yesterday (Oct. 15) newly released data from the Cassini spacecraft suggests there are big liquid reservoirs underneath its surface.

“The amount of the to-and-fro motion indicates that Mimas’ interior is not uniform. These wobbles can be produced if the moon contains a weirdly shaped, rocky core or if a sub-surface ocean exists beneath its icy shell,” said Cornell University in a press release. More flybys with the Cassini spacecraft will be required to learn more about what lies beneath.

You can read more about the study (led by Cornell astronomy research associate Radwan Tajeddine) in Science, where it was published. Below, learn more about other worlds in the Solar System that could host oceans under their surface.

Enceladus

Recent Cassini images of Saturn's moon Enceladus backlit by the sun show the fountain-like sources of the fine spray of material that towers over the south polar region. This image was taken looking more or less broadside at the "tiger stripe" fractures observed in earlier Enceladus images. It shows discrete plumes of a variety of apparent sizes above the limb (edge) of the moon. This image was acquired on Nov. 27, 2005.   Image Credit:   NASA/JPL/Space Science Institute
Cassini images of Saturn’s moon Enceladus backlit by the sun show the fountain-like sources of the fine spray of material that towers over the south polar region. This image was taken looking more or less broadside at the “tiger stripe” fractures observed in earlier Enceladus images. It shows discrete plumes of a variety of apparent sizes above the limb (edge) of the moon. This image was acquired on Nov. 27, 2005. Image Credit: NASA/JPL/Space Science Institute

After nearly a decade of speculation, this year the Cassini spacecraft returned gravity data suggesting Enceladus (another moon of Saturn) does have a large subsurface ocean near its south pole, if not a global ocean. If confirmed, that could help explain why scientists see water gushing out of fractures in that area. As this recent paper by Cassini scientists shows, Enceladus is a promising location for habitability.

Titan

A halo of light surrounds Saturn's moon Titan in this  backlit picture, showing its atmosphere. Credit: NASA/JPL/Space Science Institute
A halo of light surrounds Saturn’s moon Titan in this backlit picture, showing its atmosphere. Credit: NASA/JPL/Space Science Institute

By the way, anyone noticed that we still haven’t even left Saturn’s system? Titan is usually high on astrobiology wish lists for researchers because its hydrocarbon chemistry could be precursors to how life evolved. What’s not talked about as much, though, is at least two research findings pointing to evidence of a hidden ocean. Evidence comes from Titan’s tidal flexing from interacting with Saturn — which is 10 times more than what would be expected with a solid core — and the way that it moves on its own axis as well as around Saturn.

Europa

Rendering showing the location and size of water vapor plumes coming from Europa's south pole. Credit: NASA/ESA/L. Roth/SWRI/University of Cologne
Rendering showing the location and size of water vapor plumes coming from Europa’s south pole. Credit: NASA/ESA/L. Roth/SWRI/University of Cologne

That Minecraft-looking object floating beside Europa there is a rendering showing where water vapor erupted from the Jovian moon, spotted by the Hubble Space Telescope in 2013. We were lucky enough to have a close-up view of Europa in the 1990s and early 2000s courtesy of NASA’s Galileo spacecraft. What we know for sure is there’s thick ice on Europa. What’s underneath is not known, but there’s long been speculation that it could be a subsurface ocean that may have more water than our own planet.

Io

Jupiter's volcanic moon Io , imaged by the Galileo spacecraft in 1997. Credit: NASA/JPL/University of Arizona
Jupiter’s volcanic moon Io , imaged by the Galileo spacecraft in 1997. Credit: NASA/JPL/University of Arizona

Still flying around Jupiter here, we now turn our attention to Io — a place that is often remarked upon because of its blotchy appearance as well as all of the volcanoes on its surface. A newer analysis of Galileo data in 2011 — looking at some of the lesser-understood magnetic field data signatures — led one research team to conclude there could be a magma ocean lurking underneath that violence.

Triton

A glimpse of Triton from the Voyager 2 spacecraft, which flew by the Neptunian moon in August 1989. Credit: NASA/JPL
A glimpse of Triton from the Voyager 2 spacecraft, which flew by the Neptunian moon in August 1989. Credit: NASA/JPL

Little is known about Triton because only one spacecraft whizzed by it — Voyager 2, which took a running pass through the Neptune system in August 1989. An Icarus paper two years ago speculated that the world could host a subsurface ocean, but more data is needed. The energy of Neptune (which captured Triton long ago) could have melted its interior through tidal heating, possibly creating water from the ice in its crust.

Charon

Hubble image of Pluto and some of its moons, Charon, Nix and Hydra. Image Credit: NASA, ESA, H. Weaver (JHU/APL), A. Stern (SwRI), and the HST Pluto Companion Search Team
Hubble image of Pluto and some of its moons, Charon, Nix and Hydra. Image Credit: NASA, ESA, H. Weaver (JHU/APL), A. Stern (SwRI), and the HST Pluto Companion Search Team

We don’t have any close-up pictures of this moon of Pluto yet, but just wait a year. The New Horizons spacecraft will zoom past Charon and the rest of the system in July 2015. In the meantime, however, findings based on a model came out this summer in Icarus suggesting Charon — despite being so far from the Sun — might have had a subsurface ocean in the past. Or even now. The key is its once eccentric orbit, which would have produced tidal heating while interacting with Pluto. The science team plans to look for cracks that could be indicative of “the structure of the moon’s interior and how easily it deforms, and how its orbit evolved,” stated Alyssa Rhoden of NASA’s Goddard Space Flight Center in Maryland, who led the research.

Watch Pluto and Charon Engage in Their Orbital Dance

Animation of Pluto and Charon showing nearly a full rotation (NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)

Now here’s something I guarantee you’ve never seen before: a video of the dwarf planet Pluto and its largest moon Charon showing the two distinctly separate worlds actually in motion around each other! Captured by the steadily-approaching New Horizons spacecraft from July 19–24, the 12 images that comprise this animation were acquired with the Long Range Reconnaissance Imager (LORRI) instrument from distances of 267 million to 262 million miles (429 million to 422 million km) and show nearly a full orbital rotation. Absolutely beautiful!

For a close-up video of the two worlds in motion, click below:

Pluto and Charon rotation movie from New Horizons (enlarged view)
Pluto and Charon rotation movie from New Horizons (enlarged view)

Pluto and Charon are seen circling a central gravitational point known as the barycenter, which accounts for the wobbling motion. Since Charon is 1/12th the mass of Pluto the center of mass between the two actually lies a bit outside Pluto’s radius, making their little gravitational “dance” readily apparent.

(The same effect happens with the Earth and Moon too, but since the barycenter lies 1,700 km below Earth’s surface it’s not nearly as obvious.)

“The image sequence showing Charon revolving around Pluto set a record for close range imaging of Pluto—they were taken from 10 times closer to the planet than the Earth is,” said New Horizons mission Principal Investigator Alan Stern, of the Southwest Research Institute. “But we’ll smash that record again and again, starting in January, as approach operations begin.”

Fastest Spacecraft
Artist concept of the New Horizons spacecraft. Credit: NASA

Launched January 19, 2006, New Horizons is now in the final year of its journey to the Pluto system. On August 25 it will pass the orbit of Neptune – which, coincidentally, is 25 years to the day after Voyager 2’s closest approach – and then it’s on to Pluto and Charon, which New Horizons will become the first spacecraft to fly by on July 14, 2015, at distances of 10,000 and 27,000 km respectively. Find out where New Horizons is right now here.

Source: New Horizons

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Where Exactly Is Pluto? Pinpoint Precision Needed For New Horizons Mission

Artist's conception of the Pluto system from the surface of one of its moons. Credit: NASA, ESA and G. Bacon (STScI)

When you have a spacecraft that takes the better part of a decade to get to its destination, it’s really, really important to make sure you have an accurate fix on where it’s supposed to be. That’s true of the Rosetta spacecraft (which reached its comet today) and also for New Horizons, which will make a flyby past Pluto in 2015.

To make sure New Horizons doesn’t miss its big date, astronomers are using the Atacama Large Millimeter/submillimeter Array (ALMA) to figure out its location and orbit around the Sun. You’d think that we’d know where Pluto is after decades of observations, but because it’s so far away we’ve only tracked it through one-third of its 248-year orbit.

“With these limited observational data, our knowledge of Pluto’s position could be wrong by several thousand kilometers, which compromises our ability to calculate efficient targeting maneuvers for the New Horizons spacecraft,” stated Hal Weaver, a New Horizons project scientist at Johns Hopkins University Applied Physics Laboratory in Maryland.

Pluto’s moon Charon moves around the dwarf planet in this animated image based on the data from the Atacama Large Millimeter/submillimeter Array (ALMA). Credit: B. Saxton (NRAO/AUI/NSF)

As ALMA is a radio/submillimeter telescope, the array picked up Pluto and its largest moon, Charon, by looking at the radio emission from their surfaces. They examined the objects in November 2013, in April 2014 and twice in July. More observations are expected in October.

“By taking multiple observations at different dates, we allow Earth to move along its orbit, offering different vantage points in relation to the Sun,” stated Ed Fomalont, an astronomer with the National Radio Astronomy Observatory who is assigned to ALMA’s operations support facility in Chile. “Astronomers can then better determine Pluto’s distance and orbit.”

New Horizons will reach Pluto in July 2015, and Universe Today is planning a series of articles about the dwarf planet. We’ll need your support to get it done, though. Check out the details here.

Source: National Radio Astronomy Observatory

New Horizons Wakes Up for the Summer

New Horizons
Artist's impression of the New Horizons spacecraft. Image Credit: NASA

While many kids in the U.S. are starting their school summer vacations, New Horizons is about to get back to work! Speeding along on its way to Pluto the spacecraft has just woken up from hibernation, a nap it began five months (and 100 million miles) ago.

The next time New Horizons awakens from hibernation in December, it will be beginning its actual and long-awaited encounter with Pluto! But first the spacecraft and its team have a busy and exciting summer ahead.

New Horizons Tweeted about its Father's Day wakeup call
New Horizons tweeted about its Father’s Day wakeup call

After an in-depth checkout of its onboard systems and instruments, the New Horizons team will “track the spacecraft to refine its orbit, do a host of instrument calibrations needed before encounter, carry out a small but important course correction, and gather some cruise science,” according to principal investigator Alan Stern in his June 11 update, aptly titled “Childhood’s End.”

What’ll be particularly exciting for us space fans is an animation of Pluto and Charon in motion around each other, to be made from new observations to be acquired in July. Because of New Horizons’ position, the view will be from a perspective not possible from Earth.

New Horizons LOng Range Reconnaissance Imager (LORRI) composite image showing the detection of Pluto’s largest moon, Charon, cleanly separated from Pluto itself. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)
New Horizons LOng Range Reconnaissance Imager (LORRI) image of Pluto and Charon from July 2013 (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)

The next major milestone for New Horizons will be its crossing of Neptune’s orbit on August 25. (This just happens to fall on the 25th anniversary of Voyager 2’s closest approach in 1989.) “After that,” Stern says, “we’ll be in ‘Pluto space!'”

Read more: An Ocean on Pluto’s Moon?

Launched on Jan. 19, 2006, New Horizons will make its closest approach to Pluto on July 14, 2015 at 11:49 UTC. Traveling nearly 35,000 mph (55,500 km/h) it’s one of the fastest vehicles ever built, moving almost 20 times faster than a bullet. 

Read more from Alan Stern in his latest “PI Perspective” article on the New Horizons web site here, and check out NASA’s mission page here for the latest news as well.

“There is a lot to tell you about over the next 12 weeks, and this is just the warm-up act. Showtime — the start of the encounter — begins in just six months. This is what New Horizons was built for, and what we came to do. In a very real sense, the mission is emerging into its prime.”

– Alan Stern, New Horizons principal investigator

Also, check out a video on Pluto and the New Horizons mission here.

An Ocean On Pluto’s Moon? Hopeful Scientists Will Keep An Eye Out For Cracks

Artist impression of Pluto and Charon (NASA)

It’s a lot of speculation right now, but the buzz in a new NASA study is Pluto’s largest moon (Charon) could have a cracked surface.

If the New Horizons mission catches these cracks when it whizzes by in 2015, this could hint at an ocean underneath the lunar surface — just like what we talk about with Europa (near Jupiter) and Enceladus (near Saturn). But don’t get too excited — it’s also possible Charon had an ocean, but it froze out over time.

“Our model predicts different fracture patterns on the surface of Charon depending on the thickness of its surface ice, the structure of the moon’s interior and how easily it deforms, and how its orbit evolved,” stated Alyssa Rhoden of NASA’s Goddard Space Flight Center in Maryland, who led the research.

“By comparing the actual New Horizons observations of Charon to the various predictions, we can see what fits best and discover if Charon could have had a subsurface ocean in its past, driven by high eccentricity.”

It seems an unlikely proposition given that Pluto is so far from the Sun — about 29 times further away than the Earth is. Its surface temperature is -380 degrees Farhenheit (-229 degrees Celsius), which — to say the least — would not be a good environment for liquid water on the surface.

But it could happen with enough tidal heating. To back up, both Europa and Enceladus are small moons fighting gravity from their much larger gas giant planets, not to mention a swarm of other moons. This “tug-of-war” not only makes their orbits eccentric, but creates tides that change the interior and the surface, causing the cracks. Perhaps this might have kept subsurface oceans alive on these moons.

Encaladus, a moon of Saturn, as shown in this Voyager 1 image. Credit: NASA
Encaladus, a moon of Saturn, as shown in this Voyager 1 image. Credit: NASA

Since Charon once had an eccentric orbit, perhaps it also had tidal heating. Scientists think that the moon was created after a large object smacked into Pluto and created a chain of debris (similar to the leading theory for how our Moon was formed). The proportionally huge Charon — it’s one-eighth Pluto’s mass — would have been close to its parent planet, causing gravity to tug on both objects and creating friction inside their interiors.

“This friction would have also caused the tides to slightly lag behind their orbital positions,” NASA stated. “The lag would act like a brake on Pluto, causing its rotation to slow while transferring that rotational energy to Charon, making it speed up and move farther away from Pluto.”

But this friction would have ceased long ago, given that observations show Charon orbits in a stable circle further away from Pluto, and there are no extraneous tugs on its path today. So another possibility is there was an ocean beneath the moon’s surface that today is a block of ice.

The study was published in April in the journal Icarus. And by the way, some have even speculated that Pluto itself could have an ocean.

Source: NASA

A Crash Put Pluto’s Moons Into Odd Orbits: Study

Pluto's solar system in a 2012 artist's conception. P4 and P5 are now called Kerberos and Styx, respectively. Credit: NASA/John Hopkins University Applied Physics Laboratory

A smash-up that created Pluto’s largest moon, Charon, likely sprayed debris four billion years ago that formed the genesis of the other moons scientists are spotting today, a new study concludes.

The find could explain why the satellites Styx, Nix, Kereberos and Hydra have orbital periods that are, respectively, just about exactly 3, 4, 5 and 6 times longer than Charon’s, scientists said.

“Any initially surviving satellites would likely be destroyed in collisions, but these shattered moons wouldn’t be lost; rather, their remains would stay in the Pluto/Charon system and become the starting point for building new satellites,” stated the Southwest Research Institute (SWRI), which led the study.

Artist's impression of New Horizons' encounter with Pluto and Charon. Credit: NASA/Thierry Lombry
Artist’s impression of New Horizons’ encounter with Pluto and Charon. Credit: NASA/Thierry Lombry

“In modeling the destruction of the satellites, the SWRI study found that there may be a method for moving them, or their building blocks, outward, due to the competing effects of Charon’s gravitational kicks and collisions among the debris of the disrupted satellites.”

Given Charon’s large size relative to Pluto (it’s a tenth of the dwarf planet’s size, compared to the Earth-Moon 81: 1 ratio), its large mass could easily perturb these smaller moons if they got close. Also, collisions between the debris could alter the orbits “to keep things away from Charon”, the scientists said.

Hopefully we will learn more when the NASA New Horizons spacecraft arrives at Pluto in 2015.

The findings were presented yesterday (Oct. 9) at the American Astronomical Association’s division of planetary sciences meeting in Denver; information on whether the results are peer-reviewed was not immediately available.

Source: Southwest Research Institute

New Horizons: I Spy Pluto and Charon!

New Horizons LOng Range Reconnaissance Imager (LORRI) composite image showing the detection of Pluto’s largest moon, Charon, cleanly separated from Pluto itself. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)

The New Horizons spacecraft is still about 880 million kilometers (550 million miles) from Pluto, but on July 1 and 3, 2013, the spacecraft’s LOng Range Reconnaissance Imager (LORRI) was able to detect not only Pluto, but its largest moon, Charon, visible and cleanly separated from Pluto itself. Charon orbits about 19,000 kilometers (12,000 miles) away from Pluto, and seen from New Horizons, that’s only about 0.01 degrees away.

“The image itself might not look very impressive to the untrained eye, but compared to the discovery images of Charon from Earth, these ‘discovery’ images from New Horizons look great!” said New Horizons Project Scientist Hal Weaver. “We’re very excited to see Pluto and Charon as separate objects for the first time from New Horizons.”

The frame on the left in the grouping of images above is an average of six different LORRI images, each taken with an exposure time of 0.1 second. The frame to the right is the same composite image but with Pluto and Charon circled; Pluto is the brighter object near the center and Charon is the fainter object near its 11 o’clock position. The circles also denote the predicted locations of the objects, showing that Charon is where the team expects it to be, relative to Pluto. No other Pluto system objects are seen in these images.

These images are just a hint of what’s to come when New Horizons gets closer to the Pluto system. On July 14, 2015, the spacecraft is scheduled to pass just 12,500 kilometers (7,750 miles) above Pluto’s surface, where LORRI will be able to spot features about the size of a football field.

“We’re excited to have our first pixel on Charon,” said New Horizons Principal Investigator Alan Stern, “but two years from now, near closest approach, we’ll have almost a million pixels on Charon –and I expect we’ll be about a million times happier too!”

Pluto has five known moons (and naming them has been a bit controversial). Will New Horizons find even more?

Source: New Horizons