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PostPosted: Tue Jun 07, 2016 10:18 am 
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The New Horizons' flyby was a marvelous event for sure, but I get greater satisfaction from looking at the speck of (134340) Pluto with my own eyes, difficult as it might be. In that regard, Pluto will be at opposition in a month (July 7, 2016, at 6:27 pm EDT), so it's currently easy to locate about 25 arc minutes east of magnitude 2.9 Albadah (Pi Sgr), the easternmost and brightest star of the bowl in the "Teaspoon" asterism of Sagittarius.

However, with a nominal declination of -21°, it culminates only about 29° altitude now. As a result, this magnitude 14.1 object has a mean extincted magnitude of 15.0 at its current approximate 3 am transit. One needs a good finder chart to pick it out of the abundance of field stars in the Milky Way location, but those abundant stars also make for plenty of reference points, especially if one checks on multiple nights to observe Pluto's movement.

For me, Pluto is difficult to see with my 12.5-inch Newtonian, and it just looks like a dim star, so "asteroid" is not an inappropriate visual description (especially compared to the seven non-earth regular planets, which all show a disc in my modest telescope). If conditions are not ideal, averted vision may be needed to see it. Pluto is currently in retrograde (westward) motion, and will pass less than 3 arc minutes from Albadah on June 26th. The "glare" from the nearby bright star will likely increase the difficulty of seeing Pluto at that time.

I suppose the difficulty of seeing Pluto is a great part of the allure of tracking it down. I try to do it every year or two at the most. Sky & Telescope and Astronomy magazines have finder charts, but I prefer to make my own with SkyTools. The latter have proven to be accurate as Pluto and the field stars on the charts have matched the objects in the sky at the times for which they were prepared, and indeed, the night-to-night motion of Pluto was also observed to be accurate. Making your own finder chart allows more control, such as field size, magnitude depth, eyepiece field-of-view indicators, etc.

Go-to or setting circles (mechanical or electronic) can certainly put you in the right neighborhood, but I'm lazy and impatient, so I just point at the appropriate area, which is easy now with Albadah as a guide. In any case, a good finder chart is still necessary to determine which pinprick of light is Pluto.

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PostPosted: Sat Jun 11, 2016 9:32 am 
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The Jagged Shores of Pluto's Highlands

https://www.nasa.gov/feature/the-jagged ... -highlands

The red stuff might be tholins.

From the relevant Wikipedia article.

Quote:
Tholins (after the ancient Greek word θολός (tholós) meaning "sepia ink") are a class of heteropolymer molecules formed by solar ultraviolet irradiation of simple organic compounds such as methane or ethane. Tholins do not form naturally on modern-day Earth, but they are found in great abundance on the surface of icy bodies in the outer Solar System. They usually have a reddish-brown appearance.


What's the significance?

Quote:
Tholins can act as an effective screen for protecting planetary surfaces from ultraviolet radiation. A wide variety of soil bacteria are able to use tholins as their sole source of carbon. Tholins could have been the first microbial food for heterotrophic microorganisms before autotrophy evolved.


Cool? It gets even cooler. Pun intended for the outer solar system. Check out this paper from AAAS:

Membrane alternatives in worlds without oxygen: Creation of an azotosome

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4644080/

Quote:
The lipid bilayer membrane, which is the foundation of life on Earth, is not viable outside of biology based on liquid water. This fact has caused astronomers who seek conditions suitable for life to search for exoplanets within the “habitable zone,” the narrow band in which liquid water can exist. However, can cell membranes be created and function at temperatures far below those at which water is a liquid? We take a step toward answering this question by proposing a new type of membrane, composed of small organic nitrogen compounds, that is capable of forming and functioning in liquid methane at cryogenic temperatures. Using molecular simulations, we demonstrate that these membranes in cryogenic solvent have an elasticity equal to that of lipid bilayers in water at room temperature. As a proof of concept, we also demonstrate that stable cryogenic membranes could arise from compounds observed in the atmosphere of Saturn’s moon, Titan, known for the existence of seas of liquid methane on its surface.


Follow Stevenson, Lunine, and Clancy down the rabbit hole:

Quote:
As a proof of concept for vesicle formation in a methane-rich environment, we began our search for polar materials using those that form naturally when ultraviolet light interacts with a methane- and nitrogen-containing atmosphere. From spectroscopic observations by the Cassini orbiter, we know the most common polar compounds in the upper portion of Titan’s methane-nitrogen atmosphere, as shown in Table 1 (visit the link). Lower in the atmosphere, all of these species condense into aerosols, preventing further observation by Cassini. Laboratory experiments to reproduce the methane-nitrogen atmosphere have generally produced a tar-like residue of molecules, called tholins. These tholins have been found to consist of hydrocarbons, nitriles, and amines. Therefore, we have also included primary nitriles and amines of lengths propyl-hexyl in our study, although the abundance of the tholins relative to the Cassini-observed species is uncertain.


Could this be evidence of life on Pluto? Maybe Titan? Being so far from the sun, red wavelengths would peter out while blue wavelengths soldier on to reach these distant worlds. To best absorb blue light, plant-analogues on Pluto and Titan would have to be red since they're reflecting red light.

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PostPosted: Sat Jun 11, 2016 9:56 am 
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For the curious, I riff on the theme of alien plants and colors in this new thread:

viewtopic.php?f=3&t=937&p=2480

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PostPosted: Wed Jun 22, 2016 8:11 pm 
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It Looks Like Pluto Has a Liquid Water Ocean

http://gizmodo.com/it-looks-like-pluto- ... 1782418191

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PostPosted: Thu Jun 23, 2016 7:20 pm 
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A ‘Super Grand Canyon’ on Pluto’s Moon Charon

https://www.nasa.gov/feature/a-super-gr ... oon-charon

Quote:
At this fortuitous viewing angle the canyon is seen edge-on, and at the northern end of the canyon its depth can be easily gauged. Based on this and other images taken around the same time, New Horizons scientists estimate Argo Chasma to be as deep as 5.5 miles (9 kilometers), which is more than five times the depth of the Grand Canyon. There appear to be locations along the canyon’s length where sheer cliffs reaching several miles high occur, and which could potentially rival Verona Rupes on Uranus’ moon Miranda (which is at least 3 miles, or 5 kilometers, high) for the title of tallest known cliff face in the solar system.

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PostPosted: Sun Jul 24, 2016 2:06 pm 
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Transit of Earth, from Pluto.

https://blogs.nasa.gov/pluto/2016/07/22 ... d=26879683

Quote:
Every year, planets orbiting the sun beyond Earth’s orbit reach what astronomers call “opposition,” when they appear in the sky at the position opposite that of the sun. At opposition, the planet, or satellite or asteroid, and the sun line up with Earth between them. Pluto and its moons were at opposition this year on July 8, at 03:30 universal time. Sometimes these alignments are so precise that if you were standing on the surface of one of these bodies and looking back at Earth, you would see our planet transit (or move across) the solar disk.


And the opposition effect:

Quote:
Saturn and its rings and moons had their node crossing in January 2005, and several of the world’s telescopes were watching. The 2.2-meter telescope at Calar Alto Observatory in Spain obtained the three images below at different phase angles. When Saturn was at opposition on the night of Jan. 13, 2005, the phase angle decreased to 0.02 degrees and the rings became stunningly bright, far brighter than they were at a larger phase angle in February and even brighter than they were just one night after opposition. Why did the rings get so bright? And why did Saturn not get bright?

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PostPosted: Wed Sep 14, 2016 8:44 am 
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Pluto close-up pictures reveal 11,000 foot high ice mountains

http://www.telegraph.co.uk/news/science ... tains.html

Quote:
At a press conference last night the team revealed that Pluto, and its moon Charon, have been active and had experienced mountain building in the recent past. They found that Pluto had virtually no impact craters.

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PostPosted: Wed Sep 14, 2016 8:32 pm 
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Scientists Explain Pluto’s Red-Headed Moon

http://www.scientificamerican.com/artic ... aded-moon/

Quote:
During Charon's long winters, radiation from the sun and galactic cosmic rays convertedthe atmosphere to heavier material that does not evaporate rapidly when temperatures rise. When the winter pole tilted back toward the sun, ushering in spring, the remaining methane and nitrogen evaporated, leaving behind material that gradually changed to the reddish organics spotted at the surface. Grundy and his team estimate that about 30 centimeters (12 inches) of tholins would be produced at the poles over Charon's billion-year lifetime. The process should continue in the winter poles today, with material slowly building up its red spot.

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PostPosted: Thu Sep 15, 2016 4:51 pm 
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Pluto: X-ray Detection Sheds New Light on Pluto

http://chandra.harvard.edu/photo/2016/pluto/

Quote:
Detecting X-rays from Pluto is a somewhat surprising result given that Pluto - a cold, rocky world without a magnetic field - has no natural mechanism for emitting X-rays. However, scientists knew from previous observations of comets that the interaction between the gases surrounding such planetary bodies and the solar wind - the constant streams of charged particles from the Sun that speed throughout the solar system -- can create X-rays.

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PostPosted: Tue Sep 20, 2016 7:25 am 
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The Origins of Sputnik Planum, Pluto's Heart

http://www.sciencealert.com/scientists- ... -its-heart

Quote:
The smooth-looking left half of Tombaugh Regio is a 1,000-km-wide plain called Sputnik Planum, and underneath all that ice, this huge expanse is actually a deep basin that extends 4 km downwards.

According to the researchers, that chasm acts as a kind of cold trap, collecting ice into its reaches, and in particular nitrogen and carbon monoxide.

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PostPosted: Sat Sep 24, 2016 11:50 am 
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Pluto's 'Heart' Hints at Deep, Underground Ocean

http://www.space.com/34179-plutos-heart ... ocean.html

Quote:
In a new study, scientists have determined that Pluto's subsurface ocean probably does exist, and that liquid water beneath the dwarf planet's icy shell is at least 60 miles (100 kilometers) deep and about as salty as the Dead Sea on Earth. For perspective, the deepest part of Earth's ocean is about 7 miles (11 km) deep, and Earth is about 150 times the size of Pluto.

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PostPosted: Sat Oct 01, 2016 11:50 am 
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More Evidence for an Ocean inside Pluto

http://blogs.scientificamerican.com/lif ... ide-pluto/

Quote:
The best bet is an internal ocean layer about 100 kilometers thick, and with a roughly 30 percent salinity - that's about the saltiness of Earth's Dead Sea. To be that salty the internal water must have interacted with Pluto's rock core - a similar scenario to those invoked for the salty water inside Enceladus and Europa.

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PostPosted: Wed Oct 19, 2016 9:43 am 
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NASA findings hint of clouds on Pluto during New Horizons mission

https://www.theguardian.com/science/201 ... s-on-pluto

Quote:
Nasa had found seven candidates for clouds, Stern said, each “quite suggestive of possible but rare condensation clouds on Pluto”. He cautioned, however, that “none of them can be confirmed as clouds because all of them are very low lying, close to the surface” – and outside the reach of New Horizons’ instruments.


Imagine, neon or nitrogen snow falling from the sky.

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PostPosted: Thu Oct 20, 2016 10:45 am 
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Landslides on Charon!

http://www.universetoday.com/131492/lat ... es-charon/

Quote:
Beyer said earthquakes or an impact could have jump started the landslide on regions that were ready to slide. “The boulders may have melted and the edges and got slippery enough to begin to slide down the slope,” he said.

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PostPosted: Mon Nov 14, 2016 7:18 pm 
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A Bit of Pluto

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Original tweet from @bitsofpluto:

https://twitter.com/bitsofpluto/status/ ... 5567863808

"Full" size, at least 'til I find the original at NASA.

https://pbs.twimg.com/media/CxPBL_DXcAAOOtx.jpg

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PostPosted: Wed Nov 16, 2016 3:10 pm 
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Pluto's icy surface may conceal a vast ocean, say researchers

https://www.theguardian.com/science/201 ... k-planitia

Quote:
But scientists have been puzzled as to why Sputnik Planitia lies near Pluto’s equator and faces almost directly away from Pluto’s largest moon, Charon, pointing out there is only a 5% likelihood that it could have ended up in such a position by chance.


And the Gray Lady weighs in:

A Heavy Heart May Have Rolled Pluto Over

http://www.nytimes.com/2016/11/17/scien ... heart.html

Quote:
As Pluto reoriented, its spin axis largely remained pointing in the same direction. From the perspective of someone on the surface, it would have seemed that the location of the north pole was changing, in what astronomers call “true polar wander.”


What other planet has polar wander? Mars. If I recall correctly, I posted something in the Mars thread about how its Tharsis region contributes to martian polar wander. I will just quote the Wikipedia article for True Polar Wander on Mars wholesale.

Quote:
For some time, scientists have thought that the location of the poles of Mars have shifted due to the great mass of volcanic material in the Tharsis dome which includes Olympus Mons, the highest volcano in the solar system. A study published in Nature supports this idea. For a period early in the history of Mars, the poles were about 20 degrees away from their present positions. At that time ice was deposited in a region called Dorsa Argentea Formation. Also, the Martian dichotomy was aligned along the equator. A band of rivers formed at around 25 degrees south carried water from the southern highlands to the northern lowlands. After the polar shift, the location of the dichotomy boundary and the band of river valleys shifted. Dorsa Argentea was no longer at the pole. To produce the change in the pole location, the tilt of the planet remained unchanged, rather the crust and mantle moved. They rotated around the core. This new study suggests that the volcanoes and the movement of the poles occurred at about the same time. Volcanoes were erupting when the rivers were flowing with water. Perhaps the volcanoes supplied much water to the atmosphere, as well as carbon dioxide to warm the atmosphere; these effects would provide water for the rivers.

Tharsis is found in the Amazonis quadrangle and the Tharsis quadrangle.


I wonder what this might mean for Venus, if its rotation was affected by a monstrous impact, and if a few aeons will correct the matter turning it into a tropical paradise?

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PostPosted: Fri Dec 30, 2016 4:30 pm 
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Image

Original image is from the Hubble Space Telescope ~2002-2003.

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PostPosted: Wed Jan 11, 2017 1:22 pm 
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How a moon slows the decay of Pluto’s atmosphere

http://sciencebulletin.org/archives/9044.html

In short, Charon serves as an effective barrier against the solar wind.

What astronomers may want to consider for the prospects of life on the planet 'round Proxima Centauri is if it's a binary planet or just has a large moon. Coupled with a robust magnetic field, these circumstances may protect Proxima Centauri b from its parent's flares.

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PostPosted: Sat Jan 21, 2017 9:03 am 
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Pluto 'Landing' in Color

http://www.space.com/35396-pluto-descen ... video.html

Assembled from New Horizons imagery. Pardon if this is a repost (it gave me déjà vu) but it's pretty nifty.

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PostPosted: Tue Jan 31, 2017 11:04 am 
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Did Pluto's Weird Red Spots Result from Crash That Spawned Charon?

http://www.space.com/35501-pluto-red-sp ... ision.html

Quote:
Now, researchers in Japan suggest this dark reddish material was created by the giant collision that may have given birth to Charon. Just as Earth's moon likely arose from the debris of a Mars-size body's crash into the newborn Earth, so has previous work proposed that Charon was the result of a cosmic impact.

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PostPosted: Wed Feb 01, 2017 1:17 pm 
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Pluto: Still a Planet in New Mexico Listen Queue

http://www.npr.org/templates/story/stor ... Id=8922998

Old news, but considering the lingering issue of the IAU not elaborating"What constitutes clearing a path" and the number of people who voted on the redefinition, it's a heartening thought.

My conspiracy theory is Pluto was demoted at the height of the Iraq War, Pluto is the only planet discovered by a citizen of the U.S.A., and this was the IAU's 'sending a message' to America regarding foreign policy by 'demoting' a planet with a dodgy definition.

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PostPosted: Sat Feb 25, 2017 10:47 am 
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Official naming of surface features on Pluto and its satellites: First step approved

https://www.sciencedaily.com/releases/2 ... 114747.htm

Quote:
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.

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PostPosted: Mon Apr 24, 2017 10:34 am 
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When Pluto Changed from a Fuzzy Dot into a Full-Fledged World

https://blogs.scientificamerican.com/gu ... ged-world/

Quote:
Three days out from Pluto the fog suddenly lifted, a shock of suddenly recognizing what’s really in that fuzzy photograph you’ve been turning over and over in your hands. The disk was now a globe. Those smudges of a week ago were now clearly craters, or maybe basins. Those funny streaks turned into mountain ranges. Over here, look! Are those canyons, channels, grabens, maybe? Those on the team trained to read the landscapes of geology, were now bursting with insights, ideas, hypotheses, guesses. What do you do exactly when you’re on the landing party tasked to explore an unknown planet?

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PostPosted: Fri Jun 16, 2017 8:23 am 
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When New Horizons' next target passed in front of a star, this scientist was watching from Argentina

http://www.planetary.org/blogs/guest-bl ... paign.html

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PostPosted: Thu Jun 29, 2017 9:17 pm 
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‘X’ Marks a Curious Corner on Pluto’s Icy Plains

https://www.nasa.gov/feature/x-marks-a- ... icy-plains

Do you see it? The space snail?

NASA's explanation? A block of dirty water ice.

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