Where New Horizons is

[bystander]

New Horizons Returns Last Bits of 2015 Flyby Data to Earth
NASA | JHU-APL | SwRI | New Horizons | 2016 Oct 27

[bystander]

Pluto's Icy, Slushy Heart
Massachusetts Institute of Technology | 2016 Nov 16

Data from New Horizons mission suggest a water-ice ocean lies beneath Pluto’s heart-shaped basin.

[img3="New Horizons team has found evidence of any icy, slushy ocean beneath Pluto’s "heart" Image: NASA/JHUAPL"]http://news.mit.edu/sites/mit.edu.newso ... eart_0.jpg[/img3][hr][/hr]

Beneath Pluto’s “heart” lies a cold, slushy ocean of water ice, according to data from NASA’s New Horizons mission. In a paper published today in the journal Nature, the New Horizons team, including researchers from MIT, reports that the dwarf planet’s most prominent surface feature — a heart-shaped region named Tombaugh Regio — may harbor a bulging, viscous, liquid ocean just below its surface.

The existence of a subsurface ocean may solve a longstanding puzzle: For decades, astronomers have observed that Tombaugh Regio, which is Pluto’s brightest region, aligns almost exactly opposite from the dwarf planet’s moon, Charon, in a locked orientation that has lacked a convincing explanation.

A thick, heavy ocean, the new data suggest, may have served as a “gravitational anomaly,” or weight, which would factor heavily in Pluto and Charon’s gravitational tug-of-war. Over millions of years, the planet would have spun around, aligning its subsurface ocean and the heart-shaped region above it, almost exactly opposite along the line connecting Pluto and Charon. ...

New analysis adds support for a subsurface ocean on Pluto
University of California, Santa Cruz | 2016 Nov 16

Findings suggest other large objects in the Kuiper belt may also have liquid oceans beneath frozen shells ...

Reorientation of Sputnik Planitia implies a subsurface ocean on Pluto - F. Nimmo et al

• Nature 540(7631):94 (01 Dec 2016) DOI: 10.1038/nature20148

Cracked, Frozen and Tipped Over: New Clues From Pluto's Past
University of Arizona | 2016 Nov 16

Research by two UA planetary scientists reveals fascinating clues about Pluto, suggesting the small world at the fringes of our solar system is much more active than anyone ever imagined. ...

Reorientation and faulting of Pluto due to volatile loading within Sputnik Planitia - James T. Keane et al

• Nature 540(7631):90 (01 Dec 2016) DOI: 10.1038/nature20120

[neufer]

[b][color=#0000FF]Doikk Na'ts & his Doremian Beshniquel[/color][/b]

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http://www.cbs.com/shows/the-late-show- ... ffair-too/

[bystander]

Modeling Offers New Perspective on How Pluto’s “Icy Heart” Came to Be
University of Maryland | College of Computer, Mathematical, and Natural Sciences | 2016 Nov 30

[c][attachment=0]Pluto and Charon.jpg[/attachment][/c][hr][/hr]

New UMD-led study suggests heart's location and Charon's existence led to heart's formation

Pluto’s “icy heart” is a bright, two-lobed feature on its surface that has attracted researchers ever since its discovery by the NASA New Horizons team in 2015. Of particular interest is the heart’s western lobe, informally named Sputnik Planitia, a deep basin containing three kinds of ices—frozen nitrogen, methane and carbon monoxide—and appearing opposite Charon, Pluto’s tidally locked moon. Sputnik Planitia’s unique attributes have spurred a number of scenarios for its formation, all of which identify the feature as an impact basin, a depression created by a smaller body striking Pluto at extremely high speed.

A new study led by Douglas Hamilton, professor of astronomy at the University of Maryland, instead suggests that Sputnik Planitia formed early in Pluto’s history and that its attributes are inevitable consequences of evolutionary processes. ...

“The main difference between my model and others is that I suggest that the ice cap formed early, when Pluto was still spinning quickly, and that the basin formed later and not from an impact,” said Hamilton, who is lead author of the paper. “The ice cap provides a slight asymmetry that either locks toward or away from Charon when Pluto’s spin slows to match the orbital motion of the moon.” ...

Scientists Probe Mystery of Pluto’s Icy Heart
NASA | JHU-APL | SwRI | New Horizons | 2016 Dec 01

The rapid formation of Sputnik Planitia early in Pluto’s history - Douglas P. Hamilton et al

• Nature 540(7631):97 (01 Dec 2016) DOI: 10.1038/nature20586

[bystander]

Could There Be Life in Pluto's Ocean?
Washington University, St. Louis | 2016 Dec 01

[img3="View of Pluto with color-coded topography as measured by NASA's New Horizons spacecraft. Purple and blue are low and yellow and red are high, and the informally named Sputnik Planitia stands out at top as a broad, 1300 km- (800 mile-) wide, 2.5 km- (1.5 mile-) deep elliptical basin, most likely the site of an ancient impact on Pluto. New Horizons data imply that deep beneath this nitrogen-ice filled basin is an ocean of dense, salty, ammonia-rich water. (Photo: P.M. Schenk LPI/JHUAPL/SwRI/NASA)"]https://source.wustl.edu/wp-content/upl ... 60x657.jpg[/img3][hr][/hr]

Pluto is thought to possess a subsurface ocean, which is not so much a sign of water as it is a tremendous clue that other dwarf planets in deep space also may contain similarly exotic oceans, naturally leading to the question of life, said one co-investigator with NASA’s New Horizon mission to Pluto and the Kuiper Belt.

William McKinnon ... argues that beneath the heart-shaped region on Pluto known as Sputnik Planitia there lies an ocean laden with ammonia.

The presence of the pungent, colorless liquid helps to explain not only Pluto’s orientation in space but also the persistence of the massive, ice-capped ocean that other researchers call “slushy” — but McKinnon prefers to depict as syrupy. ...

http://asterisk.apod.com/viewtopic.php?p=258192#p258192
http://asterisk.apod.com/viewtopic.php?p=264246#p264246

[neufer]

It seems there was a post by Alohascope predating NASA on the discovery of the ocean. I remember his observation as not being well received. Seems odd that they were not applauded at the time.

The concept of "subsurface oceans of medium-sized outer planet satellites and large trans-neptunian objects" preceded the 2015 the New Horizons flyby of Pluto by at least a decade:

Hussmann, Hauke; Sohl, Frank; Spohn, Tilman (November 2006). "Subsurface oceans and deep interiors of medium-sized outer planet satellites and large trans-neptunian objects" (PDF). Icarus. 185 (1): 258–273. Bibcode:2006Icar..185..258H. doi:10.1016/j.icarus.2006.06.005.

Alohascope was making a number of additional (and probably unwarranted) assumptions:

http://asterisk.apod.com/viewtopic.php? ... 71#p251571

[geckzilla]

Alohascope was a dick about everything. You wanna ram stuff down our throats too? You can join him. I've got no patience for guest accounts. For all I know you are Alohascope.

[Seaquest]

Alohascope was a dick about everything. You wanna ram stuff down our throats too? You can join him. I've got no patience for guest accounts. For all I know you are Alohascope.

I speak merely as Seaquest, but surely if you approached the site owners they would eliminate Guest Accounts? While I did not see any cause for anyone to dislike ALohascope I do understand your angst, as even if you agreed with Alohascope the vehement opposition from some of the other posters would force you to take whatever measures necessary to appease them.

[geckzilla]

Alohascope was a dick about everything. You wanna ram stuff down our throats too? You can join him. I've got no patience for guest accounts. For all I know you are Alohascope.

I speak merely as Seaquest, but surely if you approached the site owners they would eliminate Guest Accounts? While I did not see any cause for anyone to dislike ALohascope I do understand your angst, as even if you agreed with Alohascope the vehement opposition from some of the other posters would force you to take whatever measures necessary to appease them.

Guest accounts are for people who temporarily visit the forum. People who engage in long, drawn out battles tend to get banned. I can't PM guest accounts as a moderator or do anything, really, so they just get banned quickly. Most guests make good use of the system. A few like to engage in combat. Those ones usually go bye bye because they're not there for any purpose other than apparently to ruffle our feathers. For whatever reason, they just like to do that. And so I respond by stopping it. There's nothing more to it. Now please leave me alone.

[bystander]

Official Naming of Surface Features on Pluto and its Satellites: First Step Approved
International Astronomical Union | 2017 Feb 23

The New Horizons flyby of Pluto and its satellites returned a scientific treasure trove of information about these distant and surprisingly complex worlds, showing a vast nitrogen glacier as well as ice mountains, canyons, cliffs, craters and more. Now the categories for official names have been approved and the name proposals can be submitted by the New Horizons team.

In 2015, in partnership with NASA’s New Horizons mission and the SETI Institute, the International Astronomical Union (IAU) endorsed the Our Pluto naming campaign, which allowed the public to participate in the exploration of Pluto by proposing names for surface features on Pluto and its satellites that were still awaiting discovery. Each of the system's six worlds was designated a set of naming themes set out by the IAU's Working Group for Planetary System Nomenclature (WGPSN). The public responded with overwhelming enthusiasm, suggesting and voting on thousands of names within these categories, as well as proposing names not fitting the approved set of themes.

Working with the New Horizons team, the IAU has agreed to revised naming themes (listed below) for Pluto, and its largest moon, Charon. For its four smaller moons — Styx, Nix, Kerberos, and Hydra — the themes remain unchanged. Some of these themes build on the connection between the Roman god Pluto and the mythology of the underworld. Other themes celebrate the human spirit of exploration.

• Pluto:
  • Gods, goddesses, and other beings associated with the Underworld from mythology, folklore and literature.
    Names for the Underworld and for Underworld locales from mythology, folklore and literature.
    Heroes and other explorers of the Underworld.
    Scientists and engineers associated with Pluto and the Kuiper Belt.
    Pioneering space missions and spacecraft.
    Historic pioneers who crossed new horizons in the exploration of the Earth, sea and sky.
  Charon:
  • Destinations and milestones of fictional space and other exploration.
    Fictional and mythological vessels of space and other exploration.
    Fictional and mythological voyagers, travellers and explorers.
    Authors and artists associated with space exploration, especially Pluto and the Kuiper Belt.
  Styx:
  • River gods.
  Nix:
  • Deities of the night.
  Kerberos:
  • Dogs from literature, mythology and history.
  Hydra:
  • Legendary serpents and dragons.

Using the revised themes, the New Horizons team will now propose names for the surface features to the IAU, as the body responsible for the official naming of celestial bodies and their surface features. The IAU’s Working Group for Planetary System Nomenclature will then decide on the formal names. ...

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<<The Secret of the Ninth Planet is a science-fiction novel written by Donald A. Wollheim and first published in the United States in 1959 by the John C. Winston Co. Wollheim takes his heroes on a grand tour of the solar system as that team struggles to prevent an alien force from blowing up the sun.

Partway to Saturn they encounter a Plutonian ship, a dumbbell shaped, globe-and-rod craft that launches what looks like a lightning bolt at Magellan. The bolt is absorbed by the bazooka rocket that the men had already launched at the alien ship. A tactical atomic bomb on a rocket obliterates half of the Plutonian ship, which flees.

At Saturn they find the Sun-tap station on Iapetus and, wary of booby traps, drop an H-bomb on it. At Uranus the Sun-tap station sits on Oberon and again they wipe it out with a bomb. Then they head toward Pluto, figuring that they will hit the Sun-tap station at Neptune on their way home. They soon overtake the half-ruined Plutonian ship, which hits Magellan with an energy bolt that nearly cripples the ship, but then Burl obliterates the alien completely with an atomic blast.

Arriving at Pluto, an Earth-sized world, the Earthmen discover the last Plutonian city at the north pole with two dumbbell ships hovering over it. They put Magellan into a low equatorial orbit to avoid being spotted while they finish repairing the ship.

Burl and two companions go down to the surface to explore, working their way north and landing their small rocketship several times to examine a dead Plutonian city. Finally they come to within a mile of the planet’s last stronghold. They infiltrate the place, set out a small atomic bomb with its timer set for four hours, and try to leave. Discovered and chased by Plutonians, Burl is trapped and knocked out.

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He regains consciousness in a transparent enclosure on the surface of Triton, just outside the main temple of the Plutonians’ lunar religion. He finds the controls and frees himself, then he joins a ragtag band of Neptunians while Magellan lures the two dumbbell ships out into space where the crew destroys them both. Inside the temple Burl finds the inner sanctum lined with glass cases containing aliens, including one of his companions, in suspended animation, waiting to be sacrificed. Burl battles the priests and smashes the cases in a desperate fight. As each alien regains consciousness it joins the fight and soon there are no more Plutonians.

With all of the Plutonians dead, the danger to the solar system is past. Burl sees then the people of other planets and of other stars coming together in peace and mutual understanding.>>

[bystander]

New Horizons Halfway from Pluto to Next Flyby Target
NASA | JHU-APL | SwRI | New Horizons | 2017 Apr 03

[img3="A KBO among the Stars: In preparation for the New Horizons flyby of 2014 MU69 on Jan. 1, 2019, the spacecraft’s Long Range Reconnaissance Imager (LORRI) took a series of 10-second exposures of the background star field near the location of its target Kuiper Belt object (KBO). This composite image is made from 45 of these 10-second exposures taken on Jan. 28, 2017. The yellow diamond marks the predicted location of MU69 on approach, but the KBO itself was too far from the spacecraft (544 million miles, or 877 million kilometers) even for LORRI’s telescopic “eye” to detect. New Horizons expects to start seeing MU69 with LORRI in September of 2018 – and the team will use these newly acquired images of the background field to help prepare for that search on approach. Credits: NASA/JHUAPL/SwRI"]http://pluto.jhuapl.edu/Multimedia/Scie ... ow-USE.png[/img3][hr][/hr]

How time and our spacecraft fly – especially when you’re making history at 32,000 miles (51,500 kilometers) per hour.

Continuing on its path through the outer regions of the solar system, NASA's New Horizons spacecraft has now traveled half the distance from Pluto – its storied first target – to 2014 MU69, the Kuiper Belt object (KBO) it will fly past on Jan. 1, 2019. The spacecraft reached that milestone at midnight (UTC) on April 3 – or 8 p.m. ET on April 2 – when it was 486.19 million miles (782.45 million kilometers) beyond Pluto and the same distance from MU69.

"It's fantastic to have completed half the journey to our next flyby; that flyby will set the record for the most distant world ever explored in the history of civilization,” said Alan Stern, New Horizons principal investigator from the Southwest Research Institute in Boulder, Colorado.

Later this week – at 21:24 UTC (or 5:24 p.m. ET) on April 7 – New Horizons will also reach the halfway point in time between closest approaches to Pluto, which occurred at 7:48 a.m. ET on July 14, 2015, and MU69, predicted for 2 a.m. ET on New Year's Day 2019. The nearly five-day difference between the halfway markers of distance and time is due to the gravitational tug of the sun. The spacecraft is actually getting slightly slower as it pulls away from the sun's gravity, so the spacecraft crosses the midpoint in distance a bit before it passes the midpoint in time. ...


Where is New Horizons?

[BDanielMayfield]

51,500 km per hr is 14.3 km per second. Fast, but slowing a little since it's coasting up-hill, out of the Sun's gravity well.

[bystander]

Nap Time for New Horizons: NASA Spacecraft Enters Hibernation
NASA | JHU-APL | SwRI | New Horizons | 2017 Apr 10

NASA’s New Horizons spacecraft has eased into a long summer’s nap, entering a hibernation phase on April 7 that will last until early September. ...

Before today, New Horizons had been “awake” for almost two and a half years, since Dec. 6, 2014, when the team began final preparations for Pluto approach and encounter operations. The 852 days since the end of its last hibernation period is the longest -- by far -- New Horizons has remained in active operations since it was launched in January 2006.

But that’s because New Horizons was in the throes of its prime mission: conducting a six-month flyby of the Pluto system that culminated with close approach on July 14, 2015; that was followed by 16 months transmitting the data from that flight back to Earth. The spacecraft then began an extended mission in the Kuiper Belt, making distant observations of several Kuiper Belt objects -- setting up for a close flyby on Jan. 1, 2019, of one particular object known as 2014 MU69 -- and sampling the space environment in the outer reaches of the solar system. ...

This hibernation period will last 157 days -- ending on Sept. 11 -- but mission activity won’t necessarily stop. The science and mission operations teams will be developing detailed command loads for the MU69 encounter, shaping the science observations for much of nine-day flyby. Their plans currently accommodate two potential flyby altitudes; the team will narrow its choice to the final altitude as it learns more about the properties and orbit of MU69, which was discovered less than three years ago. ...

New Horizons pioneered routine cruise-flight hibernation for NASA. Not only has hibernation reduced wear and tear on the spacecraft’s electronics, it also lowered operations costs and freed up NASA Deep Space Network tracking and communication resources for other missions.

[bystander]

Scientist Measures Brightness of Universe with New Horizons
Rochester Institute of Technology | 2017 Apr 11

Planetary mission offers up-close view of Cosmic Optical Background

[img3="The New Horizons spacecraft flew by Pluto and is headed for the Kuiper Belt in the outer solar system. The space camera, LORRI, aboard New Horizons could be used to re-measure the brightness of the cosmic optical background, said RIT scientist Michael Zemcov. (Credit: NASA/JHUAPL/SwRI)"]http://www.rit.edu/news/lib/filelib/201 ... yi1yRr.jpg[/img3][hr][/hr]

Images taken by NASA’s New Horizons mission on its way to Pluto, and now the Kuiper Belt, have given scientists an unexpected tool for measuring the brightness of all the galaxies in the universe ...

In the study ... Michael Zemcov used archival data from the instrument onboard New Horizons—the Long Range Reconnaissance Imager, or LORRI—to measure visible light from other galaxies. The light shining beyond the Milky Way is known as the cosmic optical background. Zemcov’s findings give an upper limit to the amount of light in the cosmic optical background. ...

Light from the cosmic optical background can reveal the number and location of stars, how galaxies work and give insights into the peculiar nature of exotic physical processes, such as light that may be produced when dark matter decays. ...

Measurement of the Cosmic Optical Background using the
Long Range Reconnaissance Imager on New Horizons - Michael Zemcov et al

• Nature Communications 8:15003 (11 Apr 2017) DOI: 10.1038/ncomms15003
  arXiv.org > astro-ph > arXiv:1704.02989 > 10 Apr 2017

[bystander]

New Horizons Deploys Global Team for Rare Look at Next Flyby Target
NASA | JHU-APL | SwRI | New Horizons | 2017 May 25

[img3="Projected path of the 2014 MU69 occultation on June 03
Credits: Lowell Observatory/Larry Wasserman"]https://www.nasa.gov/sites/default/file ... ne_3_0.png[/img3][hr][/hr]

On New Year’s Day 2019, more than 4 billion miles from home, NASA’s New Horizons spacecraft will race past a small Kuiper Belt object known as 2014 MU69 – making this rocky remnant of planetary formation the farthest object ever encountered by any spacecraft.

But over the next six weeks, the New Horizons mission team gets an “MU69” preview of sorts – and a chance to gather some critical encounter-planning information – with a rare look at their target object from Earth.

On June 3, and then again on July 10 and July 17, MU69 will occult – or block the light from – three different stars, one on each date. To observe the June 3 “stellar occultation,” more than 50 team members and collaborators are deploying along projected viewing paths in Argentina and South Africa. They’ll fix camera-equipped portable telescopes on the occultation star and watch for changes in its light that can tell them much about MU69 itself.

“Our primary objective is to determine if there are hazards near MU69 – rings, dust or even satellites – that could affect our flight planning,” said New Horizons Principal Investigator Alan Stern, of Southwest Research Institute (SwRI) in Boulder, Colorado. “But we also expect to learn more about its orbit and possibly determine its size and shape. All of that will help feed our flyby planning effort.” ...

[bystander]

New Mysteries Surround New Horizons' Next Flyby Target
NASA | JHU APL | SwRI | New Horizons | 2017 Jul 06

[img3="Four members of the New Horizons’ South African observation team scan the sky while waiting for the start of the 2014 MU69 occultation, early on the morning of June 3, 2017. Credits: NASA/JHUAPL/SwRI/Henry Throop"]https://www.nasa.gov/sites/default/file ... gazers.jpg[/img3][hr][/hr]

NASA’s New Horizons spacecraft doesn’t zoom past its next science target until New Year’s Day 2019, but the Kuiper Belt object, known as 2014 MU69, is already revealing surprises.

Scientists have been sifting through data gathered from observing the object’s quick pass in front of a star – an astronomical event known as an occultation – on June 3. More than 50 mission team members and collaborators set up telescopes across South Africa and Argentina, along a predicted track of the narrow shadow of MU69 that the occultation would create on Earth’s surface, aiming to catch a two-second glimpse of the object’s shadow as it raced across the Earth. Accomplishing the observations of that occultation was made possible with the help of NASA’s Hubble Space Telescope and Gaia, a space observatory of the European Space Agency (ESA).

Combined, the pre-positioned mobile telescopes captured more than 100,000 images of the occultation star that can be used to assess the environment around this Kuiper Belt object (KBO). While MU69 itself eluded direct detection, the June 3 data provided valuable and unexpected insights that have already helped New Horizons. ...

[neufer]

New Mysteries Surround New Horizons' Next Flyby Target
NASA | JHU APL | SwRI | New Horizons | 2017 Jul 06

• 
  Last night I saw upon a star,
  A KBO who wasn't thar,
  He wasn't thar again today
  Oh, how I wish he'd go away..

.

July 6, 2017 New Mysteries Surround New Horizons' Next Flyby Target

<<Combined, the pre-positioned mobile telescopes captured more than 100,000 images of the occultation star that can be used to assess the environment around this Kuiper Belt object (KBO). While MU69 itself eluded direct detection, the June 3 data provided valuable and unexpected insights that have already helped New Horizons. "These data show that MU69 might not be as dark or as large as some expected," said occultation team leader Marc Buie, a New Horizons science team member from Southwest Research Institute (SwRI) in Boulder, Colorado.

Initial estimates of MU69's diameter, based primarily on data taken by the Hubble Space Telescope since the KBO's discovery in 2014, fall in the 20-40-kilometer range – though data from this summer's ground-based occultation observations might imply it's at or even below the smallest sizes expected before the June 3 occultation.

Besides MU69's size, the readings offer details on other aspects of the Kuiper Belt object. "These results are telling us something really interesting," said New Horizons Principal Investigator Alan Stern, of SwRI. "The fact that we accomplished the occultation observations from every planned observing site but didn't detect the object itself likely means that either MU69 is highly reflective and smaller than some expected, or it may be a binary or even a swarm of smaller bodies left from the time when the planets in our solar system formed.">>

[Ann]

Scientist Measures Brightness of Universe with New Horizons
Rochester Institute of Technology | 2017 Apr 11

Planetary mission offers up-close view of Cosmic Optical Background

[img3="The New Horizons spacecraft flew by Pluto and is headed for the Kuiper Belt in the outer solar system. The space camera, LORRI, aboard New Horizons could be used to re-measure the brightness of the cosmic optical background, said RIT scientist Michael Zemcov. (Credit: NASA/JHUAPL/SwRI)"]http://www.rit.edu/news/lib/filelib/201 ... yi1yRr.jpg[/img3][hr][/hr]

Images taken by NASA’s New Horizons mission on its way to Pluto, and now the Kuiper Belt, have given scientists an unexpected tool for measuring the brightness of all the galaxies in the universe ...

In the study ... Michael Zemcov used archival data from the instrument onboard New Horizons—the Long Range Reconnaissance Imager, or LORRI—to measure visible light from other galaxies. The light shining beyond the Milky Way is known as the cosmic optical background. Zemcov’s findings give an upper limit to the amount of light in the cosmic optical background. ...

Light from the cosmic optical background can reveal the number and location of stars, how galaxies work and give insights into the peculiar nature of exotic physical processes, such as light that may be produced when dark matter decays. ...

Measurement of the Cosmic Optical Background using the
Long Range Reconnaissance Imager on New Horizons - Michael Zemcov et al

• Nature Communications 8:15003 (11 Apr 2017) DOI: 10.1038/ncomms15003
  arXiv.org > astro-ph > arXiv:1704.02989 > 10 Apr 2017

Wow, this is old news - from April this year! For some reason I didn't notice it before, but it is indeed interesting. Imagine using the camera on New Horizons (on its way to Pluto) to measure the brightness of the universe! And it could be done, too, because it's dark in the outer solar system, not light-polluted by cosmic dust like the inner solar system!

Ann

[neufer]

Imagine using the camera on New Horizons (on its way to Pluto) to measure the brightness of the universe! And it could be done, too, because it's dark in the outer solar system, not light-polluted by cosmic dust like the inner solar system!

• Out past all those dust bunnies

<<Zodiacal light is a faint, diffuse, and roughly triangular white glow visible in the night sky that appears to extend from the vicinity of the Sun along the ecliptic or zodiac. It is caused by sunlight scattered by space dust in the zodiacal cloud. The dust particles are between 10 and 300 micrometres in diameter, most with a mass around 150 micrograms. The zodiacal light decreases in intensity with distance from the Sun, but in naturally dark skies, it is visible as a band completely around the ecliptic. In fact, the zodiacal light covers the entire sky and is largely responsible for the total natural skylight on a moonless, clear night. Another phenomenon—a faint, but slightly brighter, oval glow—directly opposite of the Sun is the gegenschein.

The source of the dust has been long debated. Until recently, it was thought that the dust originated from the tails of active comets and from collisions between asteroids in the asteroid belt. Many of our meteor showers have no known active comet parent bodies. Over 85 percent of the dust is attributed to occasional fragmentations of Jupiter-family comets that are nearly dormant. Jupiter-family comets have orbital periods of less than 20 years and are considered dormant when not actively outgassing, but may do so in the future. The first fully dynamical model of the zodiacal cloud demonstrated that only if the dust was released in orbits that approach Jupiter, is it stirred up enough to explain the thickness of the zodiacal dust cloud. The dust in meteoroid streams is much larger, 300 to 10,000 micrometres in diameter, and falls apart into smaller zodiacal dust grains over time.

Particles can be reduced in size by collisions or by space weathering. When ground down to sizes less than 10 micrometres, the grains are removed from the inner Solar System by solar radiation pressure. The dust is then replenished by the infall from comets.

2015 results from the secondary ion dust spectrometer COSIMA on board the ESA/Rosetta orbiter confirmed that the parent bodies of interplanetary dust are most probably Jupiter-family comets such as comet 67P/Churyumov-Gerasimenko.>>

[neufer]

[b]New Horizons exploration target 2014 MU69 occults a star NASA / JHUAPL / SwRI / Emily Lakdawalla[/b]

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Click to play embedded YouTube video.

In total eclipse of a star,
New Horizons' future flyby target makes its presence known
Emily Lakdawalla • July 19, 2017

<<On July 17, 2017 at 03:50 UTC, members of the New Horizons science team successfully observed Kuiper belt object 2014 MU69 passing in front of a background star in the constellation Sagittarius. The 24 frames in this animation were separated by 0.2 seconds apiece. In each 0.2 seconds, the shadow of 2014 MU69 passed 4 kilometers across Earth's surface. Observations like these will allow the team to constrain the size and position of the New Horizons mission's flyby target, improving the precision of their encounter planning. This animation has been processed from the originally published version to reduce noise and align the star field.

The animation above has 24 frames, and the star is only blocked by one of them. Amanda Zangari, who participated in the observations, told me that this is not the only successful observation, and that it's the shortest chord. In other words, the team got multiple tracks of the star behind MU69, some of which blotted out the star for longer than this observation did. The resulting data that will be superior for constraining the size and shape of MU69 than a single observation would have been.

This video by the New Horizons team gives a little taste of what was involved in deploying an array of 16-inch telescopes across the occultation's probable path in order to catch this brief but important event.>>

[bystander]

Pluto Features Given First Official Names
International Astronomical Union | 2017 Sep 07

[img3="Names of Surface Features on Pluto -- Credit: NASA/JHUAPL/SwRI/Ross Beyer"]https://www.iau.org/static/archives/ima ... u1704a.jpg[/img3][hr][/hr]

The Working Group for Planetary System Nomenclature (WGPSN) of the International Astronomical Union (IAU) has officially approved the naming of fourteen features on the surface of Pluto. These are the first geological features on the planet to be named following the close flyby by the New Horizons spacecraft in July 2015.

The IAU has assigned names to fourteen geological features on the surface of Pluto. The names pay homage to the underworld mythology, pioneering space missions, historic pioneers who crossed new horizons in exploration, and scientists and engineers associated with Pluto and the Kuiper Belt. This is the first set of official names of surface features on Pluto to be approved by the IAU, the internationally recognised authority for naming celestial bodies and their surface features.

NASA’s New Horizons team proposed the names to the IAU following the first reconnaissance of Pluto and its moons by the New Horizons spacecraft. Some of the names were suggested by members of the public during the Our Pluto campaign, which was launched as a partnership between the IAU, the New Horizons project and the SETI Institute. Other names had been used informally by the New Horizons science team to describe the many regions, mountain ranges, plains, valleys and craters discovered during the first close-up look at the surfaces of Pluto and its largest moon, Charon. ...

Pluto Features Given First Official Names
NASA | JHU-APL | SwRI | New Horizons | 2017 Sep 07

[bystander]

New Horizons Files Flight Plan for 2019 Flyby
NASA | JHU-APL | SwRI | New Horizons | 2017 Sep 06

[img3="Artist's concept of NASA’s New Horizons spacecraft flying by a possible binary 2014 MU69 on Jan. 1, 2019. Early observations of MU69 hint at the Kuiper Belt object being either a binary orbiting pair or a contact (stuck together) pair of nearly like-sized bodies with diameters near 20 and 18 kilometers (12 and 11 miles). Credits: Carlos Hernandez"]https://www.nasa.gov/sites/default/file ... flyby2.jpg[/img3][hr][/hr]

NASA’s New Horizons mission has set the distance for its New Year’s Day 2019 flyby of Kuiper Belt object 2014 MU69, aiming to come three times closer to MU69 than it famously flew past Pluto in 2015.

That milestone will mark the farthest planetary encounter in history – some one billion miles (1.5 billion kilometers) beyond Pluto and more than four billion miles (6.5 billion kilometers) from Earth. If all goes as planned, New Horizons will come to within just 2,175 miles (3,500 kilometers) of MU69 at closest approach, peering down on it from celestial north. The alternate plan, to be employed in certain contingency situations such as the discovery of debris near MU69, would take New Horizons within 6,000 miles (10,000 kilometers)— still closer than the 7,800-mile (12,500-kilometer) flyby distance to Pluto. ...

If the closer approach is executed, the highest-resolution camera on New Horizons, the telescopic Long Range Reconnaissance Imager (LORRI) should be able to spot details as small as 230 feet (70 meters) across, for example, compared to nearly 600 feet (183 meters) on Pluto. ...

[neufer]

New Horizons Files Flight Plan for 2019 Flyby
NASA | JHU-APL | SwRI | New Horizons | 2017 Sep 06

If all goes as planned, New Horizons will come to within just 2,175 miles (3,500 kilometers) of MU69 at closest approach, peering down on it from celestial north. The alternate plan, to be employed in certain contingency situations such as the discovery of debris near MU69, would take New Horizons within 6,000 miles (10,000 kilometers)— still closer than the 7,800-mile (12,500-kilometer) flyby distance to Pluto. ...

If the closer approach is executed, the highest-resolution camera on New Horizons, the telescopic Long Range Reconnaissance Imager (LORRI) should be able to spot details as small as 230 feet (70 meters) across, for example, compared to nearly 600 feet (183 meters) on Pluto. ...

How the heck will New Horizons know when & where to point its cameras

[bystander]

Hibernation Over, New Horizons Continues Kuiper Belt Cruise
NASA | JHU-APL | SwRI | New Horizons | 2017 Sep 12

A long summer break ended for NASA’s New Horizons on Sept. 11, as the spacecraft “woke” itself on schedule from a five-month hibernation period.

Long Distance Numbers

[youtube]https://www.youtube.com/watch?v=tKkfzAHNxNE[/youtube]
On Sept. 11, 2017, New Horizons was 3.62 billion miles (5.82 billion kilometers) from Earth.
At that distance, a radio signal sent from the spacecraft reached Earth 5 hr and 24 min later.

The 157-day hibernation period that ended Sept. 11 was the spacecraft's first "rest" since
before the Pluto flyby in July 2015, and one of two hibernation periods before the MU69 flyby.

New Horizons is 369 million miles (593 million kilometers) – about four times the distance
between Earth and the Sun – from 2014 MU69, which it will fly by in 476 days.

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Signals confirming that New Horizons had executed on-board computer commands to exit hibernation reached mission operations at the Johns Hopkins Applied Physics Lab in Laurel, Maryland, via NASA's Deep Space Network station in Madrid, Spain, at 12:55 p.m. EDT. Mission Operations Manager Alice Bowman of APL confirmed that the spacecraft was in good health and operating normally, with all systems coming back online as expected.

Over the next three days, the mission ops team will bring the spacecraft into "active" mode, preparing it for a series of science-instrument checkouts and data-collection activities that will last until mid-December. "It's another working science cruise through the Kuiper Belt for New Horizons," Bowman added.

Plenty of activity awaits New Horizons over the next several weeks, both the team on Earth and the spacecraft – which is more than 3.6 billion miles (5.8 billion kilometers) from home, speeding toward a close flyby of Kuiper Belt object (KBO) 2014 MU69 on Jan. 1, 2019.

The spacecraft will train its instruments on numerous distant KBOs, making long-distance observations with the telescopic Long Range Reconnaissance Imager (LORRI), while also continuously measuring the Kuiper Belt's radiation, dust, and gas environment. The team also will test the spacecraft’s instruments in preparation for next year’s approach to MU69, and transmit a new suite of fault-protection software – also known as autonomy software – to New Horizons’ computer in early October.

Meanwhile, the science, mission design and operations teams continue to shape the details of MU69 observation plan. On Dec. 9, New Horizons will carry out a course-correction maneuver to set its arrival time at MU69. (NASA recently announced the nominal and backup flyby distances to MU69.

On Dec. 22 New Horizons goes back into hibernation, where it will remain until next June 4 – when the team wakes the spacecraft for the last time to begin preparations for the MU69 approach.