Awesome Blue Skies and Red Surface Ice Found at Pluto – The Other Red Planet

Much to the amazement and delight of scientists, the latest findings about Pluto reveal it possesses hazy blue skies and numerous red colored patches of water ice exposed on the surface of a world also now known as “The Other Red Planet.”

With each passing day, significant discoveries about Pluto continue piling up higher and higher as more and more data gathered and stored from this past summer’s historic flyby by NASA’s New Horizons reaches ground stations back here on Earth.

“Blue skies–Pluto is awesome!” says Alan Stern, New Horizons principal investigator from Southwest Research Institute (SwRI), Boulder, Colorado.

The bluish tint to Pluto’s skies were unexpectedly discovered after researchers examined the first color images of the high altitude atmospheric hazes returned by New Horizons last week that were taken by the probes Ralph/Multispectral Visible Imaging Camera (MVIC).

“Who would have expected a blue sky in the Kuiper Belt?” Stern said in a NASA statement.

During New Horizons flyby on July 14, 2015, it discovered that Pluto is the biggest object in the outer solar system and thus the ‘King of the Kuiper Belt.”

The Kuiper Belt comprises the third and outermost region of worlds in our solar system.

“It’s gorgeous!” exclaims Stern.

Moreover, the source of Pluto’s blue haze is different from Earth’s and more related to Titan, Saturn’s largest moon – currently being explored by NASA’s Cassini mission orbiting Saturn since 2004.

On Earth, the blue sky is caused by light scattering off tiny particles of nitrogen molecules. Whereas on Titan its related to soot-like particles called tholins.

Tholins are generated by a series of very complex sunlight-initiated chemical reactions between nitrogen and methane (CH4) high in the atmosphere. This eventually produces relatively small, soot-like particles of complex hydrocarbons.

“That striking blue tint tells us about the size and composition of the haze particles,” said New Horizons science team researcher Carly Howett, of SwRI, in a statement.

“A blue sky often results from scattering of sunlight by very small particles. On Earth, those particles are very tiny nitrogen molecules. On Pluto they appear to be larger — but still relatively small — soot-like particles we call tholins.”

As the tholins rain down on Pluto, they add to the widespread red surface coloring.

The Ralph instrument was also key in another discovery announced by New Horizons researchers.

Numerous small, exposed regions of water ice on Pluto’s surface were discovered by combining measurements from the Ralph MVIC spectral composition mapper and infrared spectroscopy from the Linear Etalon Imaging Spectral Array (LEISA) instrument.

The strongest signatures of water ice were found in the Virgil Fossa and Viking Terra regions berby the western edge of Pluto’s huge heart-shaped Tombaugh Regio feature – see image below.

Water Ice on Pluto: Regions with exposed water ice are highlighted in blue in this composite image from New Horizons' Ralph instrument, combining visible imagery from the Multispectral Visible Imaging Camera (MVIC) with infrared spectroscopy from the Linear Etalon Imaging Spectral Array (LEISA). The strongest signatures of water ice occur along Virgil Fossa, just west of Elliot crater on the left side of the inset image, and also in Viking Terra near the top of the frame. A major outcrop also occurs in Baré Montes towards the right of the image, along with numerous much smaller outcrops, mostly associated with impact craters and valleys between mountains. The scene is approximately 280 miles (450 kilometers) across. Note that all surface feature names are informal.  Credits: NASA/JHUAPL/SwRI
Water Ice on Pluto: Regions with exposed water ice are highlighted in blue in this composite image from New Horizons’ Ralph instrument, combining visible imagery from the Multispectral Visible Imaging Camera (MVIC) with infrared spectroscopy from the Linear Etalon Imaging Spectral Array (LEISA). The strongest signatures of water ice occur along Virgil Fossa, just west of Elliot crater on the left side of the inset image, and also in Viking Terra near the top of the frame. A major outcrop also occurs in Baré Montes towards the right of the image, along with numerous much smaller outcrops, mostly associated with impact craters and valleys between mountains. The scene is approximately 280 miles (450 kilometers) across. Note that all surface feature names are informal. Credits: NASA/JHUAPL/SwRI

Water ice is only found in certain zones of Pluto for reasons yet to be understood. There may also be a relationship to the tholins, that likewise is yet to be gleaned.

“I’m surprised that this water ice is so red,” says Silvia Protopapa, a science team member from the University of Maryland, College Park. “We don’t yet understand the relationship between water ice and the reddish tholin colorants on Pluto’s surface.”

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
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

As of today, New Horizons remains healthy and is over 3.1 billion miles (5 billion kilometers) from Earth.

The team hopes to fire up the thrusters later this fall to propel the spacecraft toward a second Kuiper Belt Object (KBO) in 2019 tentativley named PT1, for Potential Target 1. It is much smaller than Pluto and was recently selected based on images taken by NASA’s Hubble Space Telescope.

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer

Adventures With Starblinker

Observational astronomy is a study in patience. Since the introduction of the telescope over four centuries ago, steely-eyed observers have watched the skies for star-like or fuzzy points of light that appear to move. Astronomers of yore discovered asteroids, comets and even the occasional planet this way. Today, swiftly moving satellites have joined the fray. Still other ‘new stars’ turn out to be variables or novae.

Now, a new and exciting tool named Starblinker promises to place the prospect of discovery in the hands of the backyard observer.

Image credit:
Tombaugh’s mechanical ‘steampunk starblinker’ on display at the Lowell observatory. Image credit: Dave Dickinson

The advent of photography in the late 19th century upped the game… you’ll recall that Clyde Tombaugh used a blink comparator to discover Pluto from the Lowell Observatory in 1930. Clyde’s mechanical shutter device looked at glass plates in quick sequence. Starblinker takes this idea a step further, allowing astro-imagers to compare two images in rapid sequence in a similar ‘blink comparator’ fashion. You can even quickly compare an image against one online from, say, the SDSS catalog or Wikipedia or an old archival image. Starblinker even automatically orients and aligns the image for you. Heck, this would’ve been handy during a certain Virtual Star Party early last year hosted by Universe Today, making the tale of the ‘supernova in M82 that got away’ turn out very differently…

Often times, a great new program arises simply because astrophotographers find a need where no commercial offering exists. K3CCD Tools, Registax, Orbitron and Deep Sky Stacker are all great examples of DIY programs that filled a critical astronomy need which skilled users built themselves.

Image credit
M81 via Starblinker. Image credit: Marco Lorrai

“I started to code the software after the mid of last month,” Starblinker creator Marco Lorrai told Universe Today. “I knew there was a plugin for MaximDL to do this job, but nothing for people like me that make photos just with a DSLR… I own a 250mm telescope, and my images go easily down to magnitude +18 so it is not impossible to find something interesting…”

Starblinker is a free application, and features a simple interface. Advanced observers have designed other programs to sift through video and stacks of images in the past, but we have yet to see one with such a straight-forward user interface with an eye toward quick and simple  use in the field.

Image credit:
Starblinker screenshot.  Image credit: Marco Lorrai

“The idea came to me taking my astrophotos: many images are so rich with stars, why not analyze (them) to check if something has changed?” Lorrai said. “I started to do this check manually, but the task was very thorny, because of differences in scale and rotation between the two images. Also, the ‘blinking’ was done loading two alternating windows containing two different images… not the best! This task could be simplified if someone already has a large set of images for comparison with one old image (taken) with the same instrument… a better method is needed to do this check, and then I started to code Starblinker.”

Why Starblinker

I can see a few immediate applications for Starblinker: possible capture of comets, asteroids, and novae or extragalactic supernovae, to name a few. You can also note the variability of stars in subsequent images. Take images over the span of years, and you might even be able to tease out the proper motion of nearby fast movers such as 61 Cygni, Kapteyn’s or even Barnard’s Star, or the orbits of double stars.  Or how about capturing lunar impacts on the dark limb of the Moon? It may sound strange, but it has been done before… and hey, there’s a lunar eclipse coming right up on the night of September 27/28th. Just be careful to watch for cosmic ray hits, hot pixels, satellite and meteor photobombs, all of which can foil a true discovery.

Image credit:
The Dumbell Nebula (M27). Note the (possible) variable star (marked). Image credit: Marco Lorrai

“A nice feature to add could be the support for FITS images and I think it could be very nice that… the program could retrieve automatically a comparison image, to help amateurs that are just starting (DSLR imaging).” Lorrai said.

And here is our challenge to you, the skilled observing public. What can YOU do with Starblinker? Surprise us… as is often the case with any hot new tech, ya just never know what weird and wonderful things folks will do with it once it’s released in the wild. Hey, discover a comet, and you could be immortalized with a celestial namesake… we promise that any future ‘Comet Dickinson’ will not be an extinction level event, just a good show…

Image credit:
Not Starblinker… but it could be. Do you see the dwarf planet Makemake? Image credit: Mike Weasner/Cassiopeia observatory
Image credit: Mike Weasner/Cassiopeia observatory
Image credit: Mike Weasner/Cassiopeia observatory

Download Starblinker here.

Think you’ve discovered a comet? Nova? A new asteroid? Inbound alien invasion fleet? OK, that last one might be tweet worthy, otherwise, here’s a handy list of sites to get you started, with the checklist of protocols to report a discovery used by the pros:

How to Report New Variable Star Discoveries  to the American Association of Variable Star Observers (AAVSO)

-The Central Bureau of Astronomical Telegrams (they take emails, too!)

How to Report a Comet by veteran comet hunter David Levy

How to Report a Discovery via the International Astronomical Union

-And be sure to send in those Starblinker captures to Universe Today.

NASA and New Horizons team pick post-Pluto target … and serve up an awesome video

NASA and the science team behind the New Horizons mission to Pluto and beyond have settled on the popular choice for the spacecraft’s next flyby: It’s 2014 MU69, an icy object a billion miles beyond Pluto that’s thought to be less than 30 miles (45 kilometers) wide.

That’s 10 times bigger than, say, the comet targeted by the European Space Agency’s Rosetta probe – but on the order of 1 percent as wide as Pluto. The New Horizons team suspects that 2014 MU69 represents a primordial object in the Kuiper Belt, the vast ring of icy material that lies beyond the orbit of Neptune.

Studying such a Kuiper Belt object, or KBO, should satisfy the mission’s post-Pluto objective of documenting the diversity of worlds at the solar system’s edge. “It is just the kind of ancient KBO, formed where it orbits now, that the Decadal Survey desired us to fly by,” New Horizons principal investigator Alan Stern said Friday in a NASA news release.

This chart shows the path of NASA’s New Horizons spacecraft toward its next potential target, the Kuiper Belt object 2014 MU69, also known as PT1. Other dwarf planets are indicated on the chart as well. (Credit: Alex Parker / NASA / JHUAPL / SwRI)
This chart shows the path of NASA’s New Horizons spacecraft toward its next potential target, the Kuiper Belt object 2014 MU69, also known as PT1. Other dwarf planets are indicated on the chart as well. (Credit: Alex Parker / NASA / JHUAPL / SwRI)

2014 MU69, also known as Potential Target 1 or PT1, was one of three objects identified after a months-long search that drew upon the observing power of the Hubble Space Telescope. Although an alternate target known as PT3 was somewhat brighter and probably bigger, PT1 was favored because there’s a 100 percent chance of reaching it with the fuel that was left on the New Horizons spacecraft after last month’s big Pluto flyby.

The New Horizons team has planned a series of four maneuvers in October and November to send the piano-sized probe toward 2014 MU69, but NASA won’t be able to give the final go-ahead for the extended mission until the team makes a formal proposal in 2016. If NASA gives the green light, the flyby is due to take place on Jan. 1, 2019.

In the meantime, New Horizons is continuing to send back imagery and other data that have been stored up since it flew past Pluto on July 14. New pictures should be released starting in a week or so.

This month, views from the Pluto flyby were mashed together with animations to produce a glorious time-lapse video. Check out this masterpiece by Southwest Research Institute’s Stuart Robbins on YouTube:

NASA’s New Horizons Makes Major Discoveries: Young Ice Mountains on Pluto and Crispy Young Chasms on Charon

New close-up images of a region near Pluto’s equator reveal a giant surprise — a range of youthful mountains rising as high as 11,000 feet (3,500 meters) above the surface of the icy body. Credits: NASA/JHU APL/SwRI
Story/photos expanded[/caption]

APPLIED PHYSICS LABORATORY, LAUREL, MD – Scientists leading NASA’s historic New Horizons mission to the Pluto system announced the first of what is certain to be a tidal wave of new discoveries, including the totally unexpected finding of young ice mountains at Pluto and crispy clear views of young fractures on its largest moon Charon, at a NASA media briefing today (July 15) at the Applied Physics Laboratory (APL) in Laurel, Maryland.

A treasure trove of long awaited data has begun streaming back to Mission Control at Johns Hopkins University Applied Physics Laboratory to the mouth watering delight of researchers and NASA.

With the first ever flyby of Pluto, America completed the initial up close reconnaissance of the planets in our solar system. Pluto was the last unexplored planet, building on missions that exactly started 50 years ago in 1965 when Mariner IV flew past Mars.

“Pluto New Horizons is a true mission of exploration showing us why basic scientific research is so important,” said John Grunsfeld, associate administrator for NASA’s Science Mission Directorate in Washington.

“The mission has had nine years to build expectations about what we would see during closest approach to Pluto and Charon. Today, we get the first sampling of the scientific treasure collected during those critical moments, and I can tell you it dramatically surpasses those high expectations.”

Crisp new view of Pluto’s largest moon, Charon shows a swath of cliffs and troughs stretches about 600 miles (1,000 kilometers) from left to right, suggesting widespread fracturing of Charon’s crust, likely a result of internal processes. At upper right, along the moon’s curving edge, is a canyon estimated to be 4 to 6 miles (7 to 9 kilometers) deep.  Credit: NASA-JHUAPL-SwRI
Crisp new view of Pluto’s largest moon, Charon shows a swath of cliffs and troughs stretches about 600 miles (1,000 kilometers) from left to right, suggesting widespread fracturing of Charon’s crust, likely a result of internal processes. At upper right, along the moon’s curving edge, is a canyon estimated to be 4 to 6 miles (7 to 9 kilometers) deep. Credit: NASA-JHUAPL-SwRI

Today the team announced that New Horizons has already made a totally unexpected discovery showing clear evidence of ice mountains on Pluto’s surface in the bright area informally known as the ‘big heart of Pluto.’

The new close-up image released today showed an icy mountain range near the base of the heart with peaks jutting as high as 11,000 feet (3,500 meters) above the surface, announced John Spencer, New Horizons science team co-investigator at the media briefing.

“It’s a very young surface, probably formed less than 100 million years old,’ said Spencer. “It may be active now.”

Spencer also announce that the heart shaped region will now be named “Tombaugh Reggio” in honor of Clyde Tombaugh, the American astronomer who discovered Pluto in 1930.

“We are seeing water ice.”

“I never would have imagined this!” Spencer exclaimed.

“And I’m very surprised that there are no craters in the first high resolution images.”

The large, heart-shaped region is front and center. Several craters are seen and much of the surface looks reworked rather than ancient. Credit: NASA
Pluto nearly fills the frame in this image from the Long Range Reconnaissance Imager (LORRI) aboard NASA’s New Horizons spacecraft, taken on July 13, 2015 when the spacecraft was 476,000 miles (768,000 kilometers) from the surface. This is the last and most detailed image sent to Earth before the spacecraft’s closest approach to Pluto on July 14. The large, heart-shaped region is front and center. Several craters are seen and much of the surface looks reworked rather than ancient. Credit: NASA-JHUAPL-SwRI

The finding of ice mountains has major scientific implications.

Unlike the icy moons of giant planets, Pluto cannot be heated by gravitational interactions with a much larger planetary body. Some other process must be generating the mountainous landscape, said the team.

“This may cause us to rethink what powers geological activity on many other icy worlds,” says Spencer of SwRI.

NASA announces discovery of icy mountain ranges on Pluto at July 15 media briefing at Johns Hopkins University Applied Physics Laboratory. Credit: Ken Kremer/kenkremer.com
NASA announces discovery of icy mountain ranges on Pluto at July 15 media briefing at Johns Hopkins University Applied Physics Laboratory. Credit: Ken Kremer/kenkremer.com

“Pluto may have internal activity. There may be geysers or cryovolcanoes,” New Horizons principal investigator Alan Stern of the Southwest Research Institute, Boulder, Colorado, said during the media briefing. However there is no evidence for them yet.

Additional high resolution images for “Tombaugh Reggio” area are being transmitted back to Earth today and will continue.

“Finding a mountain range of ice is a complete surprise,” Stern noted.

After a nine year voyage through interplanetary space, New Horizons barreled past the Pluto system on Tuesday, July 14 for a history making first ever flyby at over 31,000 mph (49,600 kph), and survived the passage by swooping barely 7,750 miles (12,500 kilometers) above the planet’s amazingly diverse surface.

The team had to wait another 12 hours for confirmation that the spacecraft lived through the daring encounter when signals were reacquired as planned at 8:53 p.m. EDT last night. Since New Horizons swung past Pluto to continue its voyage, the probe is now more than million miles outbound just 24 hours later.

NASA Associate Administrator for the Science Mission Directorate John Grunsfeld, left, New Horizons Principal Investigator Alan Stern of Southwest Research Institute (SwRI), Boulder, CO, second from left, New Horizons Mission Operations Manager Alice Bowman of the Johns Hopkins University Applied Physics Laboratory (APL), second from right, and New Horizons Project Manager Glen Fountain of APL, right, are seen at the conclusion of a press conference after the team received confirmation from the spacecraft that it has completed the flyby of Pluto, Tuesday, July 14, 2015 at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland. Credit:  Ken Kremer/kenkremer.com
NASA Associate Administrator for the Science Mission Directorate John Grunsfeld, left, New Horizons Principal Investigator Alan Stern of Southwest Research Institute (SwRI), Boulder, CO, second from left, New Horizons Mission Operations Manager Alice Bowman of the Johns Hopkins University Applied Physics Laboratory (APL), second from right, and New Horizons Project Manager Glen Fountain of APL, right, are seen at the conclusion of a press conference after the team received confirmation from the spacecraft that it has completed the flyby of Pluto, Tuesday, July 14, 2015 at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland. Credit: Ken Kremer/kenkremer.com

The New Frontiers spacecraft was built by a team led by Stern and included researchers from SwRI and the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland. APL also operates the New Horizons spacecraft and manages the mission.

NASA Administrator Charles Bolden congratulates the New Horizons team after successful Pluto flyby on July 14, 2015, to cheering crowd at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland, during  live NASA TV media briefing. Credit: Ken Kremer/kenkremer.com
NASA Administrator Charles Bolden congratulates the New Horizons team after successful Pluto flyby on July 14, 2015, to cheering crowd at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland, during live NASA TV media briefing. Credit: Ken Kremer/kenkremer.com

Watch for Ken’s continuing onsite coverage of the Pluto flyby on July 14 from the Johns Hopkins University Applied Physics Laboratory (APL).

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer

New Horizons science team co-investigator John Spencer examines print of the newest Pluto image taken on July 13, 2015 after the successful Pluto flyby. Credit: Ken Kremer/kenkremer.com
New Horizons science team co-investigator John Spencer examines print of the newest Pluto image taken on July 13, 2015 after the successful Pluto flyby. Credit: Ken Kremer/kenkremer.com

New Horizons Phones Home, Flyby a Success


Watch Pluto grow in this series of photos taken during New Horizons’ approach

Whew! We’re out of the woods. On schedule at 9 p.m. EDT, New Horizons phoned home telling the mission team and the rest of the on-edge world that all went well. The preprogrammed “phone call” —  a 15-minute series of status messages beamed back to mission operations at the Johns Hopkins University Applied Physics Laboratory in Maryland through NASA’s Deep Space Network — ended a tense 21-hour waiting period. 

The team deliberately suspended communications with New Horizons until it was beyond the Pluto system, so the spacecraft could focus solely on data gathering. With a mountain of information now queued up, it’s estimated it will take 16 months to get it all back home. As the precious morsels arrive bit by byte, New Horizons will sail deeper into the Kuiper Belt looking for new targets until it ultimately departs the Solar System.

After Pluto, NASA hopes to send New Horizons to another asteroid or two in the Kuiper Belt and perform a flyby and reconnaissance similar to the Pluto mission. Credt: Alex Parker / SwRI
After Pluto, NASA hopes to send New Horizons to another asteroid or two in the Kuiper Belt to perform a flyby and reconnaissance similar to the Pluto mission. Credit: Alex Parker / SwRI

Assuming NASA funds a continuing mission, the team hopes to direct the spacecraft to one or two additional Kuiper Belt objects (KBO) over the next five to seven years. There are presently three possible targets – PT1, PT2, and PT3. (PT = potential target). PT1, imaged by the Hubble Space Telescope, looks like the best option at the moment and could by reached by January 2019. If you thought Pluto was small, PT 1 is only about 25 miles (40 km) across. Much lies ahead.

The image at left shows a KBO at an estimated distance of approximately 4 billion miles from Earth. Its position noticeably shifts between exposures taken approximately 10 minutes apart. The image at right shows a second KBO at roughly a similar distance.
The image at left shows a KBO at an estimated distance of approximately 4 billion miles from Earth. Its position noticeably shifts between exposures taken approximately 10 minutes apart. The image at right shows a second KBO at roughly a similar distance. Credit: NASA, ESA, SwRI, JHU/APL, and the New Horizons KBO Search Team

Pluto’s Time to Shine Just Hours Away – A Guide and Timetable

Countdown to discovery! Not since Voyager 2’s flyby of Neptune in 1989 have we flung a probe into the frozen outskirts of the Solar System. Speeding along at 30,800 miles per hour New Horizons will pierce the Pluto system like a smartly aimed arrow. 

Pluto as seen from New Horizons on July 11, 2015. Credits: NASA/JHUAPL/SWRI
Newest view of Pluto seen from New Horizons on July 11, 2015 shows a world that continues to grow more fascinating and look stranger every day. See annotated version below.
Credits: NASA/JHUAPL/SWRI
On July 11, 2015, New Horizons captured a world that is growing more fascinating by the day. For the first time on Pluto, this view reveals linear features that may be cliffs, as well as a circular feature that could be an impact crater. Rotating into view is the bright heart-shaped feature that will be seen in more detail during New Horizons’ closest approach on July 14. The annotated version includes a diagram indicating Pluto’s north pole, equator, and central meridian. Credits: NASA/JHUAPL/SWRI
For the first time on Pluto, this view reveals linear features that may be cliffs, as well as a circular feature that could be an impact crater. Rotating into view is the bright heart-shaped feature that will be seen in more detail during New Horizons’ closest approach on July 14. The annotated version includes a diagram indicating Pluto’s north pole, equator, and central meridian.
Credits: NASA/JHUAPL/SWRI

Edging within 7,800 miles of its surface at 7:49 a.m. EDT, the spacecraft’s long-range telescopic camera will resolve features as small as 230 feet (70 meters). Fourteen minutes later, it will zip within 17,930 miles of Charon as well as image Pluto’s four smaller satellites — Hydra, Styx, Nix and Kerberos.

This image shows New Horizons' current position (3 p.m. EDT July 12) along its planned Pluto flyby trajectory. The green segment of the line shows where New Horizons has traveled; the red indicates the spacecraft's future path. The Pluto is tilted up like a target because the planet's axis is tipped 123° to the plane of its orbit. Credit: NASA/JHUAPL/SWRI
This image shows New Horizons’ current position (3 p.m. EDT July 12) along its planned Pluto flyby trajectory. The green segment of the line shows where New Horizons has traveled; the red indicates the spacecraft’s future path. The Pluto system is tilted on end because the planet’s axis is tipped 123° to the plane of its orbit. Credit: NASA/JHUAPL/SWRI

After zooming past, the craft will turn to photograph Pluto eclipsing the Sun as it looks for the faint glow of rings or dust sheets illuminated by backlight. At the same time, sunlight reflecting off Charon will faintly illuminate Pluto’s backside. What could be more romantic than Charonshine?

Six other science instruments will build thermal maps of the Pluto-Charon pair, measure the composition of the surface and atmosphere and observe Pluto’s interaction with the solar wind. All of this will happen autopilot. It has to. There’s just no time to send a change instructions because of the nearly 9-hour lag in round-trip communications between Earth and probe.

Instruments New Horizons will use to characterize Pluto are REX (atmospheric composition and temperature; PEPSSI (composition of plasma escaping Pluto's atmosphere); SWAP (solar wind); LORRI (close up camera for mapping, geological data); Star Dust Counter (student experiment measuring space dust during the voyage); Ralph (visible and IR imager/spectrometer for surface composition and thermal maps and Alice (composition of atmosphere and search for atmosphere around Charon). Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Instruments New Horizons will use to characterize Pluto are REX (atmospheric composition and temperature); PEPSSI (composition of plasma escaping Pluto’s atmosphere); SWAP (solar wind studies); LORRI (close up camera for mapping, geological data); Star Dust Counter (student experiment measuring space dust during the voyage); Ralph (visible and IR imager/spectrometer for surface composition and thermal maps) and Alice (composition of atmosphere and search for atmosphere around Charon). Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Want to go along for the ride? Download and install NASA’s interactive app Eyes on Pluto and then click the launch button on the website. You’ll be shown several options including a live view and preview. Click preview and sit back to watch the next few days of the mission unfold before your eyes.

American astronomer Clyde Tombaugh discovered Pluto in 1903 from Lowell Observatory. Tombaugh died in 1997, but an ounce of his ashes, affixed to the spacecraft in a 2-inch aluminum container. "Interned herein are remains of American Clyde W. Tombaugh, discoverer of Pluto and the solar system's 'third zone.' Adelle and Muron's boy, Patricia's husband, Annette and Alden's father, astronomer, teacher, punster, and friend: Clyde Tombaugh (1906-1997)"
American astronomer Clyde Tombaugh discovered Pluto in 1930 from Lowell Observatory. Tombaugh died in 1997, but an ounce of his ashes, affixed to the spacecraft in a 2-inch aluminum container. “Interned herein are remains of American Clyde W. Tombaugh, discoverer of Pluto and the solar system’s ‘third zone.’ Adelle and Muron’s boy, Patricia’s husband, Annette and Alden’s father, astronomer, teacher, punster, and friend: Clyde Tombaugh (1906-1997)”

Like me, you’ve probably wondered how daylight on Pluto compares to that on Earth. From 3 billion miles away, the Sun’s too small to see as a disk with the naked eye but still wildly bright. With NASA’s Pluto Time, select your city on an interactive map and get the time of day when the two are equal. For my city, daylight on Pluto equals the gentle light of early evening twilight six minutes after sunset. An ideal time for walking, but step lightly. In Pluto’s gentle gravity, you only weigh 1/15 as much as on Earth.

Pluto and its cohorts in the icy-asteroid-rich Kuiper Belt beyond the orbit of Neptune. Credit: NASA
Pluto and its inclined orbit are highlighted among the hundreds of thousands of icy asteroids in the Kuiper Belt beyond Neptune. Credit: NASA

New Horizons is the first mission to the Kuiper Belt, a gigantic zone of icy bodies and mysterious small objects orbiting beyond Neptune. This region also is known as the “third” zone of our solar system, beyond the inner rocky planets and outer gas giants. Pluto is its most famous member, though not necessarily the largest. Eris, first observed in 2003, is nearly identical in size. It’s estimated there are hundreds of thousands of icy asteroids larger than 61 miles (100 km) across along with a trillion comets in the Belt, which begins at 30 a.u. (30 times Earth’s distance from the Sun) and reaches to 55 a.u.

During its fleeting flyby, New Horizons will slice across the Pluto system, turning this way and that to photograph and gather data on everything it can. Crucial occultations are shown that will be used to determine the structure and composition of Pluto’s (and possibly Charon’s) atmosphere. Credit: NASA with additions by the author
During its fleeting flyby, New Horizons will slice across the Pluto system, turning this way and that to photograph and gather data on everything it can. Crucial occultations are shown that will be used to determine the structure and composition of Pluto’s (and possibly Charon’s) atmosphere. Sunlight reflected from Charon will also faintly illuminate Pluto’s backside. Credit: NASA with additions by the author

Below you’ll find a schedule of events in Eastern Time. (Subtract one hour for Central, 2 hours for Mountain and 3 hours for Pacific). Keep in mind the probe will be busy shooting photos and gathering data during the flyby, so we’ll have to wait until Wednesday July 15 to see the the detailed close ups of Pluto and its moons. Even then, New Horizons’ recorders will be so jammed with data and images, it’ll take months to beam it all back to Earth.

Chasms, craters, and a dark north polar region are revealed in this image of Pluto’s largest moon Charon taken by New Horizons on July 11, 2015. The annotated version includes a diagram showing Charon’s north pole, equator, and central meridian, with the features highlighted. Credits: NASA/JHUAPL/SWRI
A new photo of Charon, too! Chasms, craters, and a dark north polar region are revealed in this image of Pluto’s largest moon taken by New Horizons on July 11, 2015. The annotated version includes a diagram showing Charon’s north pole, equator, and central meridian, with the features highlighted. The prominent crater is about 60 miles (96 km) across; the chasms appear to be geological faults. 
Credits: NASA/JHUAPL/SWRI

Fasten your seat belts — we’re in for an exciting ride.

We’ll be reporting on results and sharing photos from the flyby here at Universe Today, but you’ll also want to check out NASA’s live coverage on NASA TV, its website and social media.

Monday, July 13
10:30 a.m. to noon – Media briefing on mission status and what to expect broadcast live on NASA TV

Tuesday, July 14
7:30 to 8 a.m. – Arrival at Pluto! Countdown program on NASA TV

At approximately 7:49 a.m., New Horizons is scheduled to be as close as the spacecraft will get to Pluto, approximately 7,800 miles (12,500 km) above the surface, after a journey of more than 9 years and 3 billion miles. For much of the day, New Horizons will be out of communication with mission control as it gathers data about Pluto and its moons.

The moment of closest approach will be marked during a live NASA TV broadcast that includes a countdown and discussion of what’s expected next as New Horizons makes its way past Pluto and potentially dangerous debris.

8 to 9 a.m. – Media briefing, image release on NASA TV

Wednesday, July 15

3 to 4 p.m. – Media Briefing: Seeing Pluto in a New Light; live on NASA TV and release of close-up images of Pluto’s surface and moons, along with initial science team reactions.

We’ll have the latest Pluto photos for you, but you can also check these excellent sites:

* Long Range Reconnaissance Imager (LORRI) archive
Pluto Photojournal
* New Horizons science photo gallery

Need more Pluto? Spend a few minutes watching this excellent New York Times mission documentary.

Red-faced Pluto Full of Surprises

Hey, Mars, you’ve got company. Looks like there’s a second “red planet” in the Solar System — Pluto. Color images returned from NASA’s New Horizons spacecraft, now just 10 days from its encounter with the dwarf planet, show a distinctly ruddy surface with patchy markings that strongly resemble Mars’ appearance in a small telescope.

Animation of Pluto rotating from photos taken by New Horizons two weeks before the flyby. Credit:
Animation of Pluto’s rotation from photos taken by New Horizons two weeks before the flyby. What are those four nearly parallel dark streaks? Credit: NASA/JHUAPL/SWRI

On Mars, iron oxide or rust colors the planet’s soil, while Pluto’s coloration is likely caused by hydrocarbon molecules called tholins that are formed when cosmic rays and solar ultraviolet light interact with methane in Pluto’s atmosphere and on its surface. Airborne tholins fall out of the atmosphere and coat the surface with a reddish gunk.

Scientists at Johns Hopkins University’s Hörst Laboratory have produced complex chemical compounds called tholins, which may give Pluto its reddish hue. Credits: Chao He, Xinting Yu, Sydney Riemer, and Sarah Hörst, Johns Hopkins University
Scientists at Johns Hopkins University’s Hörst Laboratory have produced complex chemical compounds called tholins, which may give Pluto its reddish hue.
Credits: Chao He, Xinting Yu, Sydney Riemer, and Sarah Hörst, Johns Hopkins University

A particular color or wavelength of UV light called Lyman-alpha is most effective at stimulating the chemical reactions that build hydrocarbons at Pluto. Recent measurements with New Horizons’ Alice instrument reveal the diffuse glow of Lyman-alpha light all around the dwarf planet coming from all directions of space, not just the Sun.

Since one of the main sources of Lyman-alpha light besides the Sun are regions of vigorous star formation in young galaxies, Pluto’s cosmetic rouge may originate in events happening millions of light years away.

Triton's pink too! Montage of Neptune's largest moon, Triton (1,683 miles in diameter) and the planet Neptune showing the moon's sublimating south polar cap (bottom) and enigmatic "cantaloupe terrain". Credit: NASA
Triton’s pink too! Montage of Neptune’s largest moon, Triton (1,683 miles in diameter) and the planet Neptune showing the moon’s sublimating south polar cap (bottom) and enigmatic “cantaloupe terrain”. Photo taken by Voyager 2 in 1989. Credit: NASA

“Pluto’s reddish color has been known for decades, but New Horizons is now allowing us to correlate the color of different places on the surface with their geology and soon, with their compositions,” said New Horizons principal investigator Alan Stern of the Southwest Research Institute, Boulder, Colorado.

Tholins have been found on other bodies in the outer Solar System, including Titan and Triton, the largest moons of Saturn and Neptune, respectively, and made in laboratory experiments that simulate the atmospheres of those bodies.

True color photos showing the two hemispheres of Pluto. At right, you can clearly see the four streaks in a row. New Horizons will approach fly by the hemisphere on the left side.
True color photos showing the two hemispheres of Pluto photographed on June 27, 2015. At left, a large, dark red patch is visible. The four streaks in a row are seen at right. New Horizons will fly by the hemisphere in the left image. Credit:  NASA/JHUAPL/SWRI

As you study the photos and animation, you’ll notice that Pluto’s largest dark spot is redder than the most of the surface; you also can’ help but wonder what’s going on with those four evenly-spaced dark streaks in the equatorial zone. When I first saw them, my reaction was “no way!” They look so neatly lined up I assumed it was an image artifact, but after seeing the rotating movie, maybe not. It’s more likely that low resolution enhances the appearance of alignment.

Dark streaks on Triton formed by deposits from ice or cryovolcanos. Credit: NASA
Dark streaks on Triton deposited downwind from ice or cryovolcanos. Credit: NASA

But what are they? Located as they are on the Charon-facing side of Pluto, they may be related to long-ago tidal stresses induced by each body on the other as they slowly settled into their current tidally-locked embrace or something as current as seasonal change.

Voyager 2 photographed cyrovolcanos at Triton during its 1989 flyby of the Neptune system. Nitrogen geysers and plumes of gas and ice as high as 5 miles (8 km) were seen erupting from active volcanoes, leaving dark streaks on its icy surface.

Images showing the increase in detail from late June through July 1 as New Horizons homes in on Pluto. Credit:
Images showing the increase in detail from late June through July 1 as New Horizons homes in on Pluto. That possible big crater (seen in bottom middle photo) now looks more like a large, dark patch, BUT we still don’t know for sure what it is. Credit: NASA / JHUAPL / SwRI / Björn Jónsson
It's instructive to compare these images based on observations with the Hubble Space Telescope made well before New Horizons's arrival. They appear to record the large dark spot and possible the multiple streaks. Credit: NASA/ESA
It’s instructive to compare these images, based on observations with the Hubble Space Telescope made well before New Horizons’s arrival, with current photos. They appear to record the large dark spot and possibly the multiple streaks. Credit: NASA/ESA

Seasonal heating from the Sun is the most likely cause for Triton’s eruptions; Pluto’s dark streaks may have a similar origin.

Animation of Pluto and Charon from images taken between June 23 and June 29. Credit:
Animation of Pluto and Charon from images taken between June 23 and June 29. Credit: NASA/JHUAPL/SWR
To give you a better picture in your head how big these small bodies are, Pluto and Charon would both fit within the United States with room to spare. Credit: Laboratory for Atmospheric and Space Physics (LASP)
To better picture in your head how big these small bodies really are, Pluto and Charon would both fit within the United States with room to spare. Credit: Laboratory for Atmospheric and Space Physics (LASP)

Today, New Horizons lies just 7.4 million miles (11.9 million km) from its target. Sharpness and detail visible will rapidly improve in just a few days.

“Even at this resolution, Pluto looks like no other world in our Solar System,” said mission scientist Marc Buie of the Southwest Research Institute, Boulder in a recent press release.

Indeed!

The Dwarf Planet Eris

Eris is the largest dwarf planet in the Solar System, and the ninth largest body orbiting our Sun. Sometimes referred to as the “tenth planet”, it’s discovery is responsible for upsetting the traditional count of nine planets in our Solar System, as well as leading the way to the creation of a whole new astronomical category.

Located beyond the orbit of Pluto, this “dwarf planet” is both a trans-Neptunian object (TNO), which refers to any planetary object that orbits the Sun at a greater distance than Neptune – or 30 astronomical units (AU). Because of this distance, and the eccentricity of its orbit, it is also a member of a the population of objects (mostly comets) known as the “scattered disk”.

The discovery of Eris was so important because it was a celestial body larger than Pluto, which forced astronomers to consider, for the first time in history, what the definition of a planet truly is.

Discovery:

Eris, which has the full title of 136199 Eris, was first observed in 2003 during a Palomar Observatory survey of the outer solar system by a team led by Mike Brown, a professor of planetary astronomy at the California Institute of Technology. The discovery was confirmed in January 2005 after the team examined the pictures obtained from the survey in detail.

Classification:

At the time of it’s discovery, Brown and his colleagues believed that they had located the 10th planet of our solar system, since it was the first object in the Kuiper Belt found to be bigger than Pluto. Some astronomers agreed and liked the designation, but others objected since they claimed that Eris was not a true planet. At the time, the definition of “planet” was not a clear-cut since there had never been an official definition issued by the International Astronomical Union (IAU).

The matter was settled by the IAU in the summer of 2006. They defined a planet as an object that orbits the Sun, which is large enough to make itself roughly spherical. Additionally, it would have to be able to clear its neighborhood – meaning it has enough gravity to force any objects of similar size or that are not under its gravitational control out of its orbit.

In addition to finally defining what a planet is, the IAU also created a new category of “dwarf planets“. The only difference between a planet and a dwarf planet is that a dwarf planet has not cleared its neighborhood. Eris was assigned to this new category, and Pluto lost its status as a planet. Other celestial bodies, including Haumea, Ceres, and Makemake, have been classified as dwarf planets.

artist's impression shows the distant dwarf planet Eris. New observations have shown that Eris is smaller than previously thought and almost exactly the same size as Pluto. Eris is extremely reflective and its surface is probably covered in frost formed from the frozen remains of its atmosphere. Credit: ESO
Artist’s impression shows the distant dwarf planet Eris, highlighting its bright surface. Credit: ESO

Naming:

Eris is named after the Greek goddess of strife and discord. The name was assigned on September 13th, 2006, following an unusually long consideration period that arose over the issue of classification. During this time, the object became known to the wider public as Xena, which was the name given to it by the discovery team.

The team had been saving this name, which was inspired by the title character of the television series Xena: Warrior Princess, for the first body they discovered that was larger than Pluto. They also chose it because it started with the letter X, a reference to Percival Lowell’s hunt for a planet he believed to exist the edge of the Solar System (which he referred to as “Planet X“).

According to fellow astronomer and science writer Govert Schilling, Brown initially wanted to call the object “Lila”. This name was inspired by a concept in Hindu mythology that described the cosmos as the outcome of a game played by Brahma, and also because it was similar to “Lilah” – the name of Brown’s newborn daughter.

Size and Orbit:

The actual size and mass of Eris has been the subject of debate, as official estimates have changed with time and subsequent viewing. In 2005, using images from the Hubble Space Telescope. the diameter of Eris was measured to be 2397 ± 100 km (1,489 miles). In 2007, a series of observations of the largest trans-Neptunian objects with the Spitzer Space Telescope estimated Eris’s diameter at 2600 (+400/-200) km (1616 miles).

A diagram showing solar system orbits. The highly tilted orbit of Eris is in red. Credit: NASA
A diagram showing solar system orbits. The highly tilted orbit of Eris is in red. Credit: NASA

The most recent observation took place in November of 2010, when Eris was the subject of one of the most distant stellar occultations yet achieved from Earth. The teams findings were announced on October 2011, and contradicted previous findings with an estimated diameter of 2326 ± 12 km (1445 miles).

Because of these differences, astronomers have been hard-pressed to maintain that Eris is more massive than Pluto. According to the latest estimates, the Solar System’s “ninth planet” has a diameter of 2368 km (1471 miles), placing it on par with Eris. Part of the difficulty in accurately assessing the planet’s size comes from interference from Pluto’s atmosphere. Astronomers expect a more accurate appraisal when the New Horizons space probe arrives at Pluto in July 2015.

Eris has an orbital period of 558 years. Its maximum possible distance from the Sun (aphelion) is 97.65 AU, and its closest (perihelion) is 37.91 AU. This means that Eris and its moon are currently the most distant known objects in the Solar System, apart from long-period comets and space probes.

Eris’s orbit is highly eccentric, and brings Eris to within 37.9 AU of the Sun, a typical perihelion for scattered objects. This is within the orbit of Pluto, but still safe from direct interaction with Neptune (29.8-30.4 AU). Unlike the eight planets, whose orbits all lie roughly in the same plane as the Earth’s, Eris’s orbit is highly inclined – the planet is tilted at an angle of about 44° to the ecliptic.

Moons:

Eris has one moon called Dysnomia, which is named after the daughter of Eris in Greek mythology, which was first observed on September 10th, 2005 – a few months after the discovery of Eris. The moon was spotted by a team using the Keck telescopes in Hawaii, who were busy carrying out observations of the four brightest TNOs (Pluto, Makemake, Haumea, and Eris) at the time.

Eris (center) and its moon of Dysnomia (left of center), taken by the Hubble Space Telescope. Credit: NASA/ESA/Mike Brown
Eris (center) and its moon of Dysnomia (left of center), taken by the Hubble Space Telescope. Credit: NASA/ESA/Mike Brown

Interesting Facts:

The dwarf planet is rather bright and can be detected using something as simple as a small telescope. Models of internal heating via radioactive decay suggest that Eris may be capable of sustaining an internal ocean of liquid water at the mantle-core boundary. These studies were conducted by Hauke Hussmann and colleagues from the Institute of Astronomy, Geophysics and Atmospheric Sciences (IAG) at the University of São Paulo.

Brown and the discovery team followed up their initial identification of Eris with spectroscopic observations of the planet, which were made on January 25th, 2005. Infrared light from the object revealed the presence of methane ice, indicating that the surface may be similar to that of Pluto and of Neptune’s moon Triton.

Due to Eris’s distant eccentric orbit, its surface temperature is estimated to vary between about 30 and 56 K (?243.2 and ?217.2 °C). This places it on par with Pluto’s surface temperature, which ranges from 33 to 55 K (-240.15 and -218.15 °C).

We have many interesting articles on planets here at Universe Today, including this article on What is the newest planet and the 10th planet.

If you are looking for more information, try Eris and NASA’s Solar System Exploration entry.

Astronomy Cast has an episode on Pluto’s planetary identity crisis.

Source:

It Looks Like These Are All the Bright Kuiper Belt Objects We’ll Ever Find

The self-professed “Pluto Killer” is at it again. Dr. Michael Brown is now reminiscing about the good old days when one could scour through sky survey data and discover big bright objects in the Kuiper Belt. In his latest research paper, Brown and his team have concluded that those days are over.

Ten years ago, Brown discovered what is now known as the biggest Kuiper Belt object – Eris. Brown’s team found others that rivaled Pluto in size and altogether, these discoveries led to the demotion of Pluto to dwarf planet. Now, using yet another sky survey data set but with new computer software, Brown says that its time to move on.

Instigators of the big heist - David Rabinowitz, Brown and Chad Trujillo, left to right. The researchers discovered dozens of Kuiper Belt objects (KBO) including six of the eight largest KBOs including the largest, Eris.
Instigators of the big heist – Rabinowitz, Brown and Trujillo, left to right. The researchers co-discovered dozens of Kuiper Belt objects (KBO) including nine of the ten largest KBOs including the largest, Eris.

Like the famous Bugs Bunny cartoon, its no longer Rabbit Season or Duck Season and as Bugs exclaims to Elmer Fudd, there is no more bullets. Analyzing seven years worth of data, Brown and his team has concluded we are fresh out of Pluto or Charon-sized objects to be discovered in the Kuiper Belt. But for Dr. Brown, perhaps it now might be Oort Cloud season.

His latest paper, A Serendipitous All Sky Survey For Bright Objects In The Outer Solar System, in pre-print, describes the completion of analysis of two past sky surveys covering the northern and southern hemisphere down to 20 degrees in Galactic latitude. Using revised computer software, his team scoured through the data sets from the Catalina Sky Survey (CSS) and the Siding Spring Survey (SSS). The surveys are called “fast cadence surveys” and they primarily search for asteroids near Earth and out to the asteroid belt. Instead Brown’s team used the data to look at image frames spaced days and months apart.

Update: In a Twitter communique, Dr. Brown stated, “I would say we’re out of BRIGHT ones, not big ones. Could be big ones lurking far away!” His latest work involved a southern sky survey (SSS) to about magnitude 19 and the northern survey (CSS) to 21. Low albedo (dark) and more distant KBOs might be lurking beyond the detectability of these surveys that are in the range of Charon to Pluto in size.

Animation showing the movement of Eris on the images used to discover it. Eris is indicated by the arrow. The three frames were taken over a period of three hours. (Credit: Brown, et al.)
Animation showing the movement of Eris on the images used to discover it. Eris is indicated by the arrow. The three frames were taken over a period of three hours. More images over several weeks were necessary to determine its orbit.(Credit: Brown, et al.)

Objects at Kuiper Belt distances move very slowly. For example, Pluto orbits the Sun at about 17,000 km/hr (11,000 mph), taking 250 years to complete one orbit. These are speeds that are insufficient to maintain ven a low-Earth orbit. Comparing two image frames spaced just hours apart will find nearby asteroids moving relative to the star fields but not Kuiper belt objects. So using image frames spaced days, weeks or even months apart, they searched again. Their conclusion is that all the big Kuiper belt objects have been found.

The only possibility of finding another large KBO lies in a search of the galactic plane which is difficult due to the density of Milky Way’s stars in the field of view. The vast number of small bodies in the Kuiper belt and Oort Cloud lends itself readily to statistical analysis. Brown states that there is a 32% chance of finding another Pluto-sized object hiding among the stars of the Milky Way.

Artists concept of the view from Eris with Dysnomia  in the background, looking back towards the distant sun. Credit: Robert Hurt (IPAC)
Artists concept of the view from Eris with Dysnomia in the background, looking back towards the distant sun. Credit: Robert Hurt (IPAC)

Dr. Brown also released a blog story in celebration of the discovery of the largest of the Kuiper Belt objects, Eris, ten years ago last week. Ten years of Eris, reminisces about the great slew of small body discoveries by Dr. Brown, Dr. Chad Trujillo of Gemini Observatory and Dr. David Rabinowitz of Yale Observatory.

Brown encourages others to take up this final search right in the galactic plane but apparently his own intentions are to move on. What remains to be seen — that is, to be discovered — are hundreds of large “small” bodies residing in the much larger region of the Oort Cloud. These objects are distributed more uniformly throughout the whole spherical region that the Cloud defines around the Sun.

Furthermore, Dr. Brown maintains that there is a good likelihood that a Mars or Earth-sized object exists in the Oort Cloud.

Small bodies within our Solar System along with exo-planets are perhaps the hottest topics and focuses of study in Planetary Science at the moment. Many graduate students and seasoned researchers alike are gravitating to their study. There are certainly many smaller Kuiper belt objects remaining to be found but more importantly, a better understanding of their makeup and origin are yet to be revealed.

Artist's concept of the Dawn spacecraft at the protoplanet Ceres Illustration of Dawn's approach phase and RC3 orbit This artist’s concept of NASA’s Dawn  spacecraft shows the craft orbiting high above Ceres, where the craft will arrive in early 2015 to begin science investigations. (Image credit: NASA/JPL-Caltech)
Artist’s concept of the Dawn spacecraft at the protoplanet Ceres Illustration of Dawn’s approach phase and RC3 orbit This artist’s concept of NASA’s Dawn spacecraft shows the craft orbiting high above Ceres, where the craft will arrive in early 2015 to begin science investigations. (Image credit: NASA/JPL-Caltech)

Presently, the Dawn spacecraft is making final approach to the dwarf planet Ceres in the Asteroid belt. The first close up images of Ceres are only a few days away as Dawn is now just a couple of 100 thousand miles away approaching at a modest speed. And much farther from our home planet, scientists led by Dr. Alan Stern of SWRI are on final approach to the dwarf planet Pluto with their space probe, New Horizons. The Pluto system is now touted as a binary dwarf planet. Pluto and its moon Charon orbit a common point (barycenter) in space that lies between Pluto and Charon.

So Dr. Brown and team exits stage left. No more dwarf planets – at least not soon and not in the Kuiper belt. Will that upstage what is being called the year of the Dwarf Planet?

But next up for close inspection for the first time are Ceres, Pluto and Charon. It should be a great year.

The relative sizes of the inner Solar System, Kuiper Belt and the Oort Cloud. (Credit: NASA, William Crochot)
The relative sizes of the inner Solar System, Kuiper Belt and the Oort Cloud. (Credit: NASA, William Crochot)

References:

A Serendipitous All Sky Survey For Bright Objects In The Outer Solar System

Ten Years of Eris

2015, NASA’s Year of the Dwarf Planet, Universe Today

What is the Kuiper Belt?, Universe Today

2015: NASA’s Year of the Dwarf Planet

Together, the space probes Dawn and New Horizons have been in flight for a collective 17 years. One remained close to home and the other departed to parts of the Solar System of which little is known. They now share a common destination in the same year: dwarf planets.

At the time of these NASA probes’ departures, Ceres had just lost its designation as the largest asteroid in our Solar System. Pluto was the ninth planet. Both probes now stand to deliver measures of new data and insight that could spearhead yet another revision of the definition of planet.

A comparison of the trajectories of New Horizon (left) and the Dawn missions (right). (Credit: NASA/JPL, SWRI, Composite- T.Reyes)
A comparison of the trajectories of New Horizons (left) and the Dawn missions (right). (Credit: NASA/JPL, SWRI, Composite- T.Reyes)

Certainly, NASA’s Year of the Dwarf Planet is an unofficial designation and NASA representatives would be quick to emphasize another dozen or more missions that are of importance during the year 2015. However, these two missions could determine the fate of billions or more small bodies just within our galaxy, the Milky Way.

If Ceres and Pluto are studied up close – mission success is never a sure thing – then what is observed could lead to a new, more certain and accepted definition of planet, dwarf planet, and possibly other new definitions.

The New Horizons mission became the first mission of NASA’s New Frontiers program, beginning development in 2001. The probe was launched on January 19, 2006, atop an Atlas V 551 (5 solid rocket boosters plus a third stage). Utilizing more compact and lightweight electronics than its predecessors to the outer planets – Pioneer 10 & 11, and Voyager 1 & 2 – the combination of reduced weight, a powerful launch vehicle, plus a gravity assist from Jupiter has lead to a nine year journey. On December 6, 2014, New Horizons was taken out of hibernation for the last time and now remains powered on until the Pluto encounter.

This "movie" of Pluto and its largest moon, Charon b yNASA's New Horizons spacecraft taken in July 2014 clearly shows that the barycenter -center of mass of the two bodies - resides outside (between) both bodies. The 12 images that make up the movie were taken by the spacecraft’s best telescopic camera – the Long Range Reconnaissance Imager (LORRI) – at distances ranging from about 267 million to 262 million miles (429 million to 422 million kilometers). Charon is orbiting approximately 11,200 miles (about 18,000 kilometers) above Pluto's surface. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)
This “movie” of Pluto and its largest moon, Charon, by NASA’s New Horizons spacecraft taken in July 2014 clearly shows that the barycenter – the center of mass of the two bodies – resides outside (between) both bodies. The 12 images that make up the movie were taken by the spacecraft’s best telescopic camera – the Long Range Reconnaissance Imager (LORRI) – at distances ranging from about 267 million to 262 million miles (429 million to 422 million kilometers). Charon is orbiting approximately 11,200 miles (about 18,000 kilometers) above Pluto’s surface. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)

The arrival date of New Horizon is July 14, 2015. A telescope called the Long Range Reconnaissance Imager (LORRI) has permitted the commencement of observations while still over 240 million kilometers (150 million miles) from Pluto. The first stellar-like images were taken while still in the Asteroid belt in 2006.

Pluto was once the ninth planet of the Solar System. From its discovery in 1930 by Clyde Tombaugh until 2006, it maintained this status. In that latter year, the International Astronomical Union undertook a debate and then a membership vote that redefined what a planet is. The change occurred 8 months after New Horizons’ launch. There were some upset mission scientists, foremost of which was the principal investigator, Dr. Alan Stern, from the Southwest Research Institute in San Antonio, Texas. In a sense, the rug had been pulled from under them.

A gentleman’s battle ensued between opposing protagonists Dr. Stern and Dr. Michael Brown from Caltech. In 2001, Dr. Brown’s research team began to discover Kuiper belt objects (Trans-Neptunian objects) that rivaled the size of Pluto. Pluto suddenly appeared to be one of many small bodies that could likely number in the trillions within just one galaxy – ours. According to Dr. Brown, there could be as many as 200 objects in our Solar System similar to Pluto that, under the old definition, could be defined as planets. Dr. Brown’s work was the straw that broke the camel’s back – that is, it led to the redefinition of planet, and the native of Huntsville, Alabama, went on to write a popular book, How I Killed Pluto and Why It Had It Coming.

Dr. Stern’s story involving Pluto and planetary research is a longer and more circuitous one. Stern was the Executive Director of the Southwest Research Institute’s Space Science and Engineering Division and then accepted the position of Associate Administrator of NASA’s Science Mission Directorate in 2007. Clearly, after a nine year journey, Stern is now fully committed to New Horizons’ close encounter. More descriptions of the two protagonists of the Pluto debate will be included in a follow on story.

Artist’s concept depicting the Dawn spacecraft thrusting with its ion propulsion system as it travels from Vesta (lower right) to Ceres (upper left). The galaxies in the background are part of the Virgo supercluster. Dawn, Vesta and Ceres are currently in the constellation Virgo from the perspective of viewers on Earth. (Image credit: NASA/JPL)
Artist’s concept depicting the Dawn spacecraft thrusting with its ion propulsion system as it travels from Vesta (lower right) to Ceres (upper left). The galaxies in the background are part of the Virgo supercluster. Dawn, Vesta, and Ceres are currently in the constellation Virgo from the perspective of viewers on Earth. (Image credit: NASA/JPL)

The JPL and Orbital Science Corporation developed Dawn space probe began its journey to the main asteroid belt on September 27, 2007. It has used gravity assists and flew by the planet Mars. Dawn spent 14 months surveying Vesta, the 4th largest asteroid of the main belt (assuming Ceres is still considered the largest). While New Horizons has traveled over 30 Astronomical Units (A.U.) – 30 times the distance from the Earth to the Sun – Dawn has remained closer and required reaching a little over 2 A.U. to reach Vesta and now 3 A.U. to reach Ceres.

The Dawn mission had the clear objective of rendezvous and achieving orbit with two asteroids in the main belt between Mars and Jupiter. Dawn was also sent packing the next generation of Ion Propulsion. It has proven its effectiveness very well, having used ion propulsion for the first time to achieve an orbit. Pretty simple, right? Not so fast.

As Dawn was passing critical design reviews during development, the redefinition of planet lofted its second objective – the asteroid 1 Ceres – to a new status. While Pluto was demoted, Ceres was promoted from its scrappy status of biggest of the asteroids – the debris, the leftovers of our solar system’s development – to dwarf planet. Even 4 Vesta is now designated a proto-planet.

Artist rendition of Dawn spacecraft orbiting Vesta(Credit: NASA/JPL-Caltech)
Artist rendition of Dawn spacecraft orbiting Vesta. (Credit: NASA/JPL-Caltech)

So now the stage is set. Dawn will arrive first at a dwarf planet – Ceres – in April. With a small, low gravity body and ion propulsion, the arrival is slow and cautious. If the two missions fair well and achieve their goals, 2015 is likely to become a pivotal year in the debate over the classification of non-stellar objects throughout the universe.

Just days ago, at the American Geophysical Union Conference in San Francisco, Dr. Stern and team described the status and more details of the goals of New Horizons. Since arriving, more moons of Pluto have been discovered. There is the potential that faint rings exist and Pluto may even harbor an interior ocean due to the tidal forces from its largest moon, Charon. And Dawn mission scientists have seen the prospects for Ceres’ change. Not just the status, the latest Hubble images of Ceres is showing bright spots which could be water ice deposits and could also harbor an internal ocean.

The Solar System is becoming a more crowded place. This picture shows the sizes of dwarf planets Pluto, Ceres, Eris, and Makemake as compared to Earth and Earth's Moon, here called "Luna." None of the distances between objects are to scale. (Credit: NASA)
The Solar System is becoming a more crowded place. This picture shows the sizes of dwarf planets Pluto, Ceres, Eris, and Makemake as compared to Earth and Earth’s Moon, here called “Luna.” None of the distances between objects are to scale. (Credit: NASA)

So other NASA missions notwithstanding, this is the year of the dwarf planet. NASA will provide Humanity with its first close encounters with the most numerous of small round – by their self-gravity – bodies in the Universe. They are now called dwarf planets but ask Dr. Stern and company, the public, and many other planetary scientists and you will discover that the jury is still out.

References:

JHU/APL New Horizons Mission Home Page

NASA Dawn Mission Home Page

Related Universe Today articles:

NASA’s New Horizons

NASA’s Dawn Mission