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New Horizons

r4pt0r

By r4pt0r
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  • 2 weeks later...
Aethon

Aethon

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nh-1-pluto-haze_0.jpg

 

Haze layers over Pluto.

A bunch of new Pluto papers have been published.

 

  1. The age-dating of Pluto’s surface through crater counts has revealed that Pluto has been geologically active throughout the past 4 billion years. Further, the surface of Pluto’s informally-named Sputnik Planum, a massive ice plain larger than Texas, is devoid of any detectable craters and estimated to be geologically young – no more than 10 million years old.
  2. Pluto’s moon Charon has been discovered to have an ancient surface. As an example, the great equatorial expanse of smooth plains on Charon informally named Vulcan Planum (home of the “moated mountains” informally named Kubrick and Clarke Mons) is likely a vast cryovolcanic flow or flows that erupted onto Charon’s surface about 4 billion years ago. These flows are likely related to the freezing of an internal ocean that globally ruptured Charon's crust.
  3. The distribution of compositional units on Pluto’s surface – from nitrogen-rich, to methane-rich, to water-rich – has been found to be surprisingly complex, creating puzzles for understanding Pluto’s climate and geologic history. The variations in surface composition on Pluto are unprecedented elsewhere in the outer solar system.
  4. Pluto’s upper atmospheric temperature has been found to be much colder (by about 70 degrees Fahrenheit) than had been thought from Earth-based studies, with important implications for its atmospheric escape rate. Why the atmosphere is colder is a mystery.
  5. Composition profiles for numerous important species in Pluto’s atmosphere (including molecular nitrogen, methane, acetylene, ethylene and ethane) have been measured as a function of altitude for the first time. 
  6. Also for the first time, a plausible mechanism for forming Pluto’s atmospheric haze layers has been found. This mechanism involves the concentration of haze particles by atmospheric buoyancy waves (called “gravity waves” by atmospheric scientists), created by winds blowing over Pluto’s mountainous topography.
  7. Before the flyby, the presence of Pluto’s four small moons raised concerns about debris hazards in the system. But the Venetia Burney Student Dust Counter only counted a single dust particle within five days of the flyby. This is similar to the density of dust particles in free space in the outer solar system — about 6 particles per cubic mile — showing that the region around Pluto is, in fact, not filled with debris.
  8. New Horizons’ charged-particle instruments revealed that the interaction region between the solar wind and Pluto’s atmosphere is confined on the dayside of Pluto to within 6 Pluto radii, about 4,500 miles (7,000 kilometers). This is much smaller than expected before the flyby, and is likely due to the reduced atmospheric escape rate found from modeling of ultraviolet atmospheric occultation data. 
  9. The high albedos (reflectiveness) of Pluto’s small satellites – about 50 to 80 percent – are entirely different from the much lower albedos of the small bodies in the general Kuiper Belt population, which range from about 5 to 20 percent. This difference lends further support to the idea that these satellites were not captured from the general Kuiper Belt population, but instead formed by agglomeration in a disk of material produced in the aftermath of the giant collision that created the entire  Pluto satellite system.

http://www.nasa.gov/feature/science-papers-reveal-new-aspects-of-pluto-and-its-moons

 

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Frida Space

Frida Space

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Had a quick read through the five papers. These are my personal highlights, not by any means complete. I still suggest to anyone who's really interested to read the actual papers, they're quite fascinating!

Atmosphere

  • Near-symmetry between ingress and egress structure
  • Pressure profile consistent with Earth-based observations
  • Strong temperature inversion within the first 20 km from the ground with horizontal variations (stronger at ingress, where it goes all the way down to the surface, than egress)
  • Surface pressure of 9-12 microbar: no big atmospheric mass change in recent years
  • Air temperature adjacent to surface is 42-48 K, close to saturation temperature of N2
  • First 1800 km of height are dominated by N2, with abundant minor species (methane, acetylene, ethylene, ethane)
  • Over 20 haze layers, the most visible of which are at 10, 30, 90 and 190 km from the ground. Haze density near surface is 0.8 particles per centimetre cube
  • 10^23 and 5 x 10^25 molecules of nitrogen and methane are lost due to Jeans escape every second, respectively (146 and 42000 tons a year, if my calculations are correct). If these rates have been constant throughout Pluto's history (which doesn't seem to be the case), Pluto has lost 6 cm of nitrogen and 28 m of methane
  • Hazes could be due to gravity waves produced via orographic forcing (winds at speeds of <10 m/s blowing across the mountains and being lifted up in the atmosphere)

Interaction with solar wind

  • Solar wind speed is 403 km/s. Very high density and pressures are likely due to a strong interplanetary shock that was felt by New Horizons 5 days prior to flyby
  • Measurements at 20 RP (Plutonian radii) inbound show the solar wind is not slowing down (<1%), suggesting no pickup of heavy ions and therefore that few atmospheric molecules are escaping upstream and becoming ionized
  • At 9.6 RP behind Pluto (tailward), solar wind is slowed by 20% according to SWAP, and PEPSSI detects an enhancement of keV ions
  • This suggests the region of Pluto-Sun interaction extends >400 RP tailward but only 6 RP upstream. However, considering probable compressed state of this region at the moment of flyby, it is likely that it usually extends up to 25 RP upstream
  • Dust counter (SDC) detected 102 events between 5 days prior to flyby and 5 days after flyby, however only one is very likely (95%) to be a dust impact
  • Considering SDC carved 0.83 km^3 during this period, the resulting density of dust is one particle every 1.2 km^3, slightly more than what was observed in the previous months leading to flyby
  • SDC detects grains bigger than 1.4 micrometers

Geology

  • Sputnik Planum covers 870,000 km^2 and is 3-4 km below surrounding uplands. It is fragmented in a cellular pattern in its central and northern parts, with each cell separated by 100 m-deep troughs and with the centres of the cells being on average 50 m above the edges
  • The other half of Tombaugh Regio (i.e. the eastern part) is 2-4 km above Sputnik Planum and is populated by many pits (sublimation?), with depths of 1 km and diameters of up to 25 km. 1.5-6 km wide troughs contain glacial flows towards Sputnik Planum
  • Crater sizes range from 0.5 to 250 km
  • Globally, the surface dates back to epoch of gas giant migration (4 bln years ago), except for Tartarus Dorsa, mountain ranges and Sputnik Planum
  • Sputnik Planum has no crater > 2 km, suggesting it's <10 million years old. However, its basin (perhaps an impact crater) is likely very ancient and modified
  • Two quasi-circular mounds (Wright and Piccard Monts) to the south of Sputnik Planum are likely cryovolcanoes. They are 4-6 km high and 150-225 km wide
  • Charon's northern terrains are networks of polygonal troughs 3-6 km deep; the southern terrains are smoother plains, possibly hinting to tectonic resurfacing, with fields of small hills and less crater which hint at cryovolcanic resurfacing
  • Overall, Charon is very different from Pluto, not showing signs of volatile transport (except possibly for Mordor Macula). Maybe the volatiles were lost to space due to the lower gravity?
  • Pluto's activity can be explained by atmosphere-surface interaction, volatile mobility, radiogenic heat. However, youngness of mountain chains and possible cryovolcanoes is mysterious

Composition

  • Main ices are: N2, CO (very volatile) and CH4 (less volatile), which act like Earth snow even at Pluto's frigid 35-50 K. Other ices include water (which, being very rigid at such low temperatures, is the bedrock on which the other ices flow, sublimate and condense, and also makes up most of the mountains), C2H6 and NH3, plus obviously non-volatile tholins.
  • Sputnik Planum features all three of the main ices, but no water ice. The three ices are all soluble in each other to an extent, so they are likely mixed at a molecular level
  • CH4 is found in Sputnik Planum, crater rims and pathces in northern mid-latitudes
  • N2 is found in Sputnik Planum, crater floors and none in the high northern latitudes (which have been in constant sunlight since the '80s, so any N2 there is likely to have sublimated long ago
  • Sputnik Planum is continuously refreshed by glacial flows, possibly powered by convective overturning
  • Four major global albedo units are evident: low equatorial regions (Cthulhu Regio, Krun Macula), northern summer polar region (Lowell Regio), sliver of southern winter hemisphere, and high-albedo Tombaugh Regio. Darkest equatorial regions have albedos similar to some outer solar system moons rich in carbonaceous or organic materials (Hyperion, Phoebe, Umbriel)
  • Albedo interacts with composition: high-albedo regions absorb more sunlight, driving sublimation
  • Charon is made predominantly of water ice, partially in crystalline phase

Minor Moons

  • All four are highly elongated objects
  • Their very high albedos (56-83%, approx. 6-8x brighter than a typical KBO) mean they are unlikely to be captured KBO objects. Also, their albedos suggest they are rich in water ice
  • Their highly asymmetrical shapes (see double-lobed Kerberos) suggest a growth process by agglomeration of small objects into single, loosely bound, macroporous bodies, which in turn is consistent with formation within the remnant disk of the Pluto-Charon-forming collision
  • The abundance of water ice suggests the two parents of Pluto and Charon were at least partially differentiated on the inside, with icy surfaces
  • Crater counts (11 on Nix, 3 on Hydra) lead to densities equal or great than the ones of Pluto's oldest surfaces (i.e. they are >4 bln years old)
  • Regolith sharing between moons is less extensive than thought
  • Surfaces are mostly greish (neutral in color), except for a reddish crater on Nix, implying different composition either in the impacting body or in the moon's subsurface layers, excavated by the impact

Sorry for the long post -- hope it helps! :)

Edited by Frida Space
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  • 2 weeks later...
fredinno

fredinno

Posted
Posted
5 hours ago, insert_name said:

is that curve in the upper right corner the edge of pluto, or just the photo

Looks like the photo- Pluto should have a slight haze due to its thin atmosphere at the edge.

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  • 2 weeks later...
Frida Space

Frida Space

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An update on the status of the New Horizons mission.

  • New Horizons is 5.23 bln km from Earth and 330 mln km from Pluto. All systems are healthy. So far, just over 50% of the Pluto data has been donwloaded. Data transmission from the flyby will end in October-November 2016. If the extended mission proposal won't be approved, the mission will end in December due to lack of funding.
  • The extended mission proposal was submitted to NASA last week. A response should arrive by June or July 2016. The extended mission features a 3,000 km flyby of 2014 MU69 on January 1st, 2019; performing remote observations of 20+ KBOs between 2016 and 2020 to determine their shapes, albedos, and search for any moons or rings; continuing to sample the plasma, gas and dust environment until 2021, when NH will be at 50 AU from the Sun.
  • New estimates put the diameter of 2014 MU69 between 21 and 40 km. It's located about 1.5 bln km past Pluto. Its low orbital eccentricity (0.036) makes it a classical KBO, or cubewano. Its low orbital inclination (1.9°) makes it a cold cubewano.
  • By flying so close to it, New Horizons will reach much better spatial resolutions than during the Pluto flyby (102 m/pixel with Ralph/MVIC; 25 m/pixel with LORRI!)
  • As you probably know already, New Horizons already completed 4 burns in October-November 2015 which provided some 57 m/s of Delta-V required to turn towards MU69. MU69 was selected last August from five potential targets (PTs). The other finalist was 2014 PN70, a slightly larger world which required a bit more fuel to be reached.
  • MU69 is 1,000x more massive than comet 67P, but 500,000x less massive than Pluto, making it an intermediate-mass object which would be very useful to study if we want to better understand the formation of the solar system.
  • The scientific goals of MU69's flyby are: mapping the global surface in high res and color, mapping the composition of the surface, determining the surface's properties, looking for moons and studying its atmosphere or exosphere, if there is one. If approved, the flyby operations will start 100 days prior to the encounter, in September 2018. The data transmission will require at least 20 months, ending at the end of 2020.

A few images:

The spatial resolution during MU69's flyby simulated using Mars' moon Phobos.

Simulated-KBO.jpg

The plan for remote observations of 20+ KBOs between 2016 and 2020.

KBO-Observations.jpg

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fredinno

fredinno

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On 4/15/2016 at 2:44 PM, Frida Space said:

New Horizons is 5.23 bln km from Earth and 330 mln km from Pluto. All systems are healthy. So far, just over 50% of the Pluto data has been donwloaded. Data transmission from the flyby will end in October-November 2016. If the extended mission proposal won't be approved, the mission will end in December due to lack of funding.

Wut? The data hasn't all been downlinked?

The extended mission has STILL not been approved despite all the burns being long finished?

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Frida Space

Frida Space

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1 hour ago, fredinno said:

Wut? The data hasn't all been downlinked?

Due to the incredible distance of New Horizons, power limitations, transmission limitations etc., only 55% of the Pluto flyby data has been downloaded so far! All of the images however have already arrived, but we should still be getting some pretty good data.

1 hour ago, fredinno said:

The extended mission has STILL not been approved despite all the burns being long finished?

The proposal was submitted to NASA just a week ago. For me it's pretty much a no-brainer decision but obviously due to all the economics involved, it will take them until June or July to decide. The burns were executed within the primary mission, with NASA's permission, because if they had waited until NASA's approval for the extended mission, the burns would have become too expensive delta-V-wise.

Edited by Frida Space
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ProtoJeb21

ProtoJeb21

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I can't believe this...

New Horizons has found evidence of liquid Nitrogen that once covered parts of Pluto's surface within the last 80,000 years. Why is Pluto imitating Mars so much? First the orange-red coloring, then the giant impact basin, next the "polar caps" (if you would CALL them polar caps), and now evidence of past liquids! It would be pretty cool if Pluto was once a lot like Titan and is the Kuiper Belt's equivalent to Mars.

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  • 3 weeks later...
HoloYolo

HoloYolo

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On 4/19/2016 at 3:36 PM, ProtoJeb21 said:

I can't believe this...

New Horizons has found evidence of liquid Nitrogen that once covered parts of Pluto's surface within the last 80,000 years. Why is Pluto imitating Mars so much? First the orange-red coloring, then the giant impact basin, next the "polar caps" (if you would CALL them polar caps), and now evidence of past liquids! It would be pretty cool if Pluto was once a lot like Titan and is the Kuiper Belt's equivalent to Mars.

Mars-Pluto connection confirmed? Aliens like Orange-Brown/Red so much they had to make two planets with the same color?

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ProtoJeb21

ProtoJeb21

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2 minutes ago, HoloYolo said:

Mars-Pluto connection confirmed? Aliens like Orange-Brown/Red so much they had to make two planets with the same color?

It also looks like aliens gave Pluto a redesign to make it look interesting to us puny humans. If you look at Pluto's surface, there are so many unknown phemonenon that it may as well be artificial terrain. UFO-like things have been spotted around Pluto in many images. In fact, I found one myself in an image taken a few days before New Horizons closest approach. And do you know about the "snail-rock" on Pluto? It looks artificial and is found in one of the many shallow "ravines" in Sputnik Planum. It looks like the aliens were designing that area to look scientifically interesting, but forgot to take one of their plow-like thingies.

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HoloYolo

HoloYolo

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1 minute ago, ProtoJeb21 said:

It also looks like aliens gave Pluto a redesign to make it look interesting to us puny humans. If you look at Pluto's surface, there are so many unknown phemonenon that it may as well be artificial terrain. UFO-like things have been spotted around Pluto in many images. In fact, I found one myself in an image taken a few days before New Horizons closest approach. And do you know about the "snail-rock" on Pluto? It looks artificial and is found in one of the many shallow "ravines" in Sputnik Planum. It looks like the aliens were designing that area to look scientifically interesting, but forgot to take one of their plow-like thingies.

GET THE TINFOIL! CONSPIRACY! What does NASA not want us to know next?

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ProtoJeb21

ProtoJeb21

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Just now, HoloYolo said:

GET THE TINFOIL! CONSPIRACY! What does NASA not want us to know next?

That there are aliens around KIC 8462852? Also maybe NASA is secretly part of a society that worships ogres like Shrek?

Okay, I was joking about the last part, but this year there's been a lot of signs that NASA is covering up the fact that there are aliens on the far side of the moon.

To get back to this thread's topic, if Pluto's terrain isn't artificial, I think the band of tholins across its equator was caused by a ring system. After Charon formed, the remaining methane ices were being pulled apart from one another by Charon's gravity. After being up there for so long, the methane was transformed into Tholins by solar radiation. But Charon eventually pushed the ring into Pluto. Tidal interactions caused he ring system to stretch up for over 100 miles. Eventually, the entire ring system has snowed down onto Pluto's equatorial region. This would explain why impact craters have revealed lighter areas under the dark tholins.

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HoloYolo

HoloYolo

Posted
Posted
11 minutes ago, ProtoJeb21 said:

That there are aliens around KIC 8462852? Also maybe NASA is secretly part of a society that worships ogres like Shrek?

Okay, I was joking about the last part, but this year there's been a lot of signs that NASA is covering up the fact that there are aliens on the far side of the moon.

To get back to this thread's topic, if Pluto's terrain isn't artificial, I think the band of tholins across its equator was caused by a ring system. After Charon formed, the remaining methane ices were being pulled apart from one another by Charon's gravity. After being up there for so long, the methane was transformed into Tholins by solar radiation. But Charon eventually pushed the ring into Pluto. Tidal interactions caused he ring system to stretch up for over 100 miles. Eventually, the entire ring system has snowed down onto Pluto's equatorial region. This would explain why impact craters have revealed lighter areas under the dark tholins.

If there was a ring system would there have been an impact that created Charon like how we got our Moon? The ring concealed to into Charon and the remaining bits and pieces rained down on Pluto?

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