Tag: New Horizons

Active volcanoes on Pluto?

9:16 am

Elevation map of Wright Mons on Pluto
Elevation map of Wright Mons on Pluto

The uncertainty of science: According to new research published yesterday, scientists now posit that there might be recent volcanic activity on Pluto, based on data and images sent back by New Horizons during its fly-by of the planet in 2015.

You can read the paper here. From its abstract:

The New Horizons spacecraft returned images and compositional data showing that terrains on Pluto span a variety of ages, ranging from relatively ancient, heavily cratered areas to very young surfaces with few-to-no impact craters. One of the regions with very few impact craters is dominated by enormous rises with hummocky flanks. Similar features do not exist anywhere else in the imaged solar system. Here we analyze the geomorphology and composition of the features and conclude this region was resurfaced by cryovolcanic processes, of a type and scale so far unique to Pluto. Creation of this terrain requires multiple eruption sites and a large volume of material (>104 km3) to form what we propose are multiple, several-km-high domes, some of which merge to form more complex planforms. The existence of these massive features suggests Pluto’s interior structure and evolution allows for either enhanced retention of heat or more heat overall than was anticipated before New Horizons, which permitted mobilization of water-ice-rich materials late in Pluto’s history. [emphasis mine]

The image to above is Figure 10 in the paper’s supplementary material [pdf]. It shows the volcano-like appearance of Wright Mons on Pluto, a mound approximately 3,000 feet high with a central depression equally deep, with a volume “similar in magnitude to that of the Hawaiian volcano Mauna Loa.”

These conclusions are quite tantalizing, but the amount of data is sparse, and thus it is wise not to take them too seriously. For example, the scientists have no idea how Pluto could presently have any form of liquid or active volcanism. Another mission to Pluto — studying it over a long time from orbit — will be required to determine how active the planet really is, or if it is active at all.

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New Horizons discovers two binary asteroids in Kuiper Belt

10:32 am

Overview map
Click for full map.

As New Horizons traveled from Pluto to the asteroid Arrokoth in 2018, scientists used it to take images of the relatively nearby asteroids that it was passing, and found that two of those asteroids appeared elongated.

[T]he team fit the shapes with a two-body model: two asteroids in a tight orbit. Even though the individual rocks weren’t resolved, the modeling showed that two bodies were better able to explain the elongation, as well as the brightness seen. The model for 2011 JY31 had two 50-km-wide objects nearly 200 km apart, while for 2014 OS393, the model had slightly smaller bodies (30 km across) that orbited each other 150 km apart.

The map, cropped and further annotated by me, shows New Horizons’ path during this time period, with the two binary asteroids indicated in blue.

This data, combined with the double lobe shape of Arrokoth (formerly named Ultima Thule), strongly suggests that it was not unusual for these primitives asteroids in the early solar system to coalesce from comparably sized partners.

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Pluto’s mountains are white-capped but with methane not ice

6:23 pm

Pluto's white-capped mountains
Pluto’s mountains, capped with methane snow.
Click for full figure.

Scientists now theorize that the white-capped mountains first photographed by New Horizons during its 2015 fly-by of Pluto are capped not with ice but with methane snow, as part of that planet’s methane gas-ice cycle.

The image to the right, from their paper, shows these white-capped mountains on Pluto.

The exact composition of this frost on Pluto was unclear. While researchers identified methane, it was unknown whether it is pure frozen methane, frozen methane diluted with frozen nitrogen or a mix of both. The uncertainty about the frost’s composition made it unclear how it might have formed.

To help solve these mysteries, scientists in this new study examined high-resolution data from New Horizons, focusing on the composition of the frost at high altitudes. This new analysis revealed that the snowcap frost “is almost pure methane ice, with traces of nitrogen ice,” Bertrand said.

The researchers also developed high-resolution computer simulations of Pluto’s climate. They focused on how methane circulates around the dwarf planet. [emphasis mine]

Though their simulations of the methane cycle that produces the caps are reasonable, I purposely highlight the fact that this is what they are, and as such must be treated with great skepticism. We might now know the composition of these snowcaps, but our overall knowledge of Pluto remains to limited to trust blindly any computer model.

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New Horizons sees stellar parallax

3:04 pm

New Horizons is now far enough away from Earth that its perspective of the universe shifts at least two nearby stars into slightly different positions than seen on Earth.

On April 22-23, the spacecraft turned its long-range telescopic camera to a pair of the closest stars, Proxima Centauri and Wolf 359, showing just how they appear in different places than we see from Earth. Scientists have long used this “parallax effect” – how a star appears to shift against its background when seen from different locations — to measure distances to stars.

An easy way to see parallax is to place one finger at arm’s length and watch it jump back and forth when you view it successively with each eye. Similarly, as Earth makes it way around the Sun, the stars shift their positions. But because even the nearest stars are hundreds of thousands of times farther away than the diameter of Earth’s orbit, the parallax shifts are tiny, and can only be measured with precise instrumentation. “No human eye can detect these shifts,” Stern said.

But when New Horizons images are paired with pictures of the same stars taken on the same dates by telescopes on Earth, the parallax shift is instantly visible. The combination yields a 3D view of the stars “floating” in front of their background star fields.

The resulting 3D image, available at the link, is very cool. Both stars clearly appear closer than the surrounding background stars, which of course is true as they are among the closest stars to the Sun.

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New simulations of Pluto’s atmosphere

9:42 am

New simulations of Pluto’s atmosphere, created using data obtained during the 2015 fly-by by New Horizons of Pluto, suggest that the planet’s thin atmosphere, mostly made up of nitrogen, generally blows in a retrograde direction when compared with the planet’s rotation.

Bertrand and his colleagues set out to determine how circulating air – which is 100,000 times thinner than that of Earth’s – might shape features on the surface. The team pulled data from New Horizons’ 2015 flyby to depict Pluto’s topography and its blankets of nitrogen ice. They then simulated the nitrogen cycle with a weather forecast model and assessed how winds blew across the surface.

The group discovered Pluto’s winds above 4 kilometers (2.5 miles) blow to the west — the opposite direction from the dwarf planet’s eastern spin — in a retro-rotation during most of its year. As nitrogen within Tombaugh Regio vaporizes in the north and becomes ice in the south, its movement triggers westward winds, according to the new study.

The press release is very badly written. It tries to make it sound as this work discovered the atmosphere of Pluto, and that this process is more unique in the solar system than it is. It also neglects to mention that we only have good information about one hemisphere of Pluto. The fly-by did not see the planet’s other half, and so any computer model based on New Horizons’ data is by definition guaranteed to be half incomplete, with gigantic uncertainties.

Still, it gives us another example of the unexpected complexity of the geological processes on Pluto, something no one expected for a place so far from the Sun where there is so little energy to drive such processes.

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New Horizons confirms solar wind slows at greater solar distances

9:57 am

The New Horizons science team today released data that confirms that, as theorized, the speed of the solar wind decreases as it travels farther from the Sun.

As the solar wind moves farther from the Sun, it encounters an increasing amount of material from interstellar space. When interstellar material is ionized, the solar wind picks up the material and, researchers theorized, slows and heats in response. SWAP [an instrument on New Horizons] has now detected and confirmed this predicted effect.

The SWAP team compared the New Horizons solar wind speed measurements from 21 to 42 astronomical units to the speeds at 1 AU from both the Advanced Composition Explorer (ACE) and Solar TErrestrial RElations Observatory (STEREO) spacecraft. (One AU is equal to the distance between the Sun and Earth.) By 21 AU, it appeared that SWAP could be detecting the slowing of the solar wind in response to picking up interstellar material. However, when New Horizons traveled beyond Pluto, between 33 and 42 AU, the solar wind measured 6-7% slower than at the 1 AU distance, confirming the effect.

The data also suggests that New Horizons could exit the heliosphere and enter interstellar space as early as sometime in the 2020s.

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New Horizons team renames “Ultima Thule” to “Arrokoth”

12:57 pm

The New Horizons team has renamed the Kuiper Belt object that the spacecraft flew past on January 1, 2019 from its informal nickname of “Ultima Thule” to “Arrokoth,” which means “sky” in Powhatan/Algonquian language.

This official, and very politically correct, name has apparently gotten the stamp of approval from the IAU.

In accordance with IAU naming conventions, the discovery team earned the privilege of selecting a permanent name for the celestial body. The team used this convention to associate the culture of the native peoples who lived in the region where the object was discovered; in this case, both the Hubble Space Telescope (at the Space Telescope Science Institute) and the New Horizons mission (at the Johns Hopkins Applied Physics Laboratory) are operated out of Maryland — a tie to the significance of the Chesapeake Bay region to the Powhatan people.

“We graciously accept this gift from the Powhatan people,” said Lori Glaze, director of NASA’s Planetary Science Division. “Bestowing the name Arrokoth signifies the strength and endurance of the indigenous Algonquian people of the Chesapeake region. Their heritage continues to be a guiding light for all who search for meaning and understanding of the origins of the universe and the celestial connection of humanity.” [emphasis mine]

It is a good name, especially because its pronunciation is straight-forward, unlike the nickname.

The blather from Glaze above, however, is quite disingenuous. The Algonquian people have had literally nothing to do with the modern scientific quest for “meaning and understanding of the origins of the unverse.” They were a stone-age culture, with no written language. It was western civilization that has made their present lives far better. And it was the heritage of western civilization, not “the indigenous Algonquian people” that made the New Horizons’ journey possible. Without the demand for knowledge and truth, as demanded by western civilization, we would still not know that Arrokoth even existed.

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New Horizons data suggests the Kuiper Belt is emptier that previously believed

12:33 pm

The uncertainty of science: An analysis of data from New Horizons now suggests a paucity of small objects in the Kuiper Belt.

Using New Horizons data from the Pluto-Charon flyby in 2015, a Southwest Research Institute-led team of scientists have indirectly discovered a distinct and surprising lack of very small objects in the Kuiper Belt. The evidence for the paucity of small Kuiper Belt objects (KBOs) comes from New Horizons imaging that revealed a dearth of small craters on Pluto’s largest satellite, Charon, indicating that impactors from 300 feet to 1 mile (91 meters to 1.6 km) in diameter must also be rare.

I therefore wonder how the objects we do find there formed. The volume of space in the Kuiper Belt is gigantic, and if the larger bodies found so far are the bulk of the objects there, what did they coalesce from? Moreover, it seems unlikely that the few large objects we have found there would have been able to clear the region out of small objects.

Overall, this is a fundamental mystery tied directly to how the solar system formed, and illustrates how little we know about that process.

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New high resolution images of Ultima Thule

5:59 pm

Highest resolution image of Ultima Thule
Click for full resolution image.

The New Horizons team has released new high resolution images of Ultima Thule, taken during its fly-by on January 1, 2019.

These new images of Ultima Thule – obtained by the telephoto Long-Range Reconnaissance Imager (LORRI) just 6½ minutes before New Horizons’ closest approach to the object (officially named 2014 MU69) at 12:33 a.m. EST on Jan. 1 – offer a resolution of about 110 feet (33 meters) per pixel.

…The higher resolution brings out a many surface features that weren’t readily apparent in earlier images. Among them are several bright, enigmatic, roughly circular patches of terrain. In addition, many small, dark pits near the terminator (the boundary between the sunlit and dark sides of the body) are better resolved. “Whether these features are craters produced by impactors, sublimation pits, collapse pits, or something entirely different, is being debated in our science team,” said John Spencer, deputy project scientist from SwRI.

Available at the link above is a three-second long movie they created from these images, showing Ultima Thule as it zips across the camera’s view.

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IAU approves China’s proposed names for Chang’e-4 landing site

10:07 am

That was fast! The International Astronomical Union (IAU) has approved all of the proposed names that China submitted for the features at or near Chang’e-4 landing site.

The IAU Working Group for Planetary System Nomenclature has approved the name Statio Tianhe for the landing site where the Chinese spacecraft Chang’e-4 touched down on 3 January this year, in the first-ever landing on the far side of the Moon. The name Tianhe originates from the ancient Chinese name for the Milky Way, which was the sky river that separated Niulang and Zhinyu in the folk tale “The Cowherd and the Weaver Girl”.

Four other names for features near the landing site have also been approved. In keeping with the theme of the above-mentioned folk tale, three small craters that form a triangle around the landing site have been named Zhinyu, Hegu, and Tianjin, which correspond to characters in the tale. They are also names of ancient Chinese constellations from the time of the Han dynasty. The fifth approved name is Mons Tai, assigned to the central peak of the crater Von Kármán, in which the landing occurred. Mons Tai is named for Mount Tai, a mountain in Shandong, China, and is about 46 km to the northwest of the Chang’e-4 landing site.

Compare this fast action with the IAU’s approval process for the names the New Horizons team picked for both Pluto and Ultima Thule. It took the IAU more than two years to approve the Pluto names, and almost three years to approve the Charon names. It is now almost two months after New Horizons’ fly-by of Ultima Thule, and the IAU has not yet approved the team’s picks for that body.

Yet it is able to get China’s picks approved in less than a month? Though it is obviously possible that there is a simple and innocent explanation for the differences here, I think this illustrates well the biases of the IAU. Its membership does not like the United States, and works to stymie our achievements if it can. This factor played a part in the Pluto/planet fiasco. It played a part in its decision to rename Hubble’s Law. And according to my sources, it was part of the background negotiations in the naming of some lunar craters last year to honor the Apollo 8 astronauts.

The bottom line remains: The IAU has continually tried to expand its naming authority, when all it was originally asked to do was to coordinate the naming of distant astronomical objects. Now it claims it has the right to approve the naming of every boulder and rock anywhere in the universe. At some point the actual explorers are going to have to tell this organization to go jump in a lake.

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New Horizons’ farewell image of Ultima Thule

4:34 pm

Ultima Thule's shape

The New Horizons science team has released the last sequence of images taken by the spacecraft as flew away after its flyby.

The link has a nice video of that sequence. However, it is the information gleaned from this sequence that is most interesting.

The newly released images also contain important scientific information about the shape of Ultima Thule, which is turning out to be one of the major discoveries from the flyby.

The first close-up images of Ultima Thule – with its two distinct and, apparently, spherical segments – had observers calling it a “snowman.” However, more analysis of approach images and these new departure images have changed that view, in part by revealing an outline of the portion of the KBO that was not illuminated by the Sun, but could be “traced out” as it blocked the view to background stars.

Stringing 14 of these images into a short departure movie, New Horizons scientists can confirm that the two sections (or “lobes”) of Ultima Thule are not spherical. The larger lobe, nicknamed “Ultima,” more closely resembles a giant pancake and the smaller lobe, nicknamed “Thule,” is shaped like a dented walnut.

The image on the right shows their preliminary guess at Ultima Thule’s overall shape, as suggested by these new images.

The spacecraft has still not sent back the images it took during its closest approach, so there are likely more surprises coming.

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New image of Ultima Thule

6:10 pm

Ultima Thule

The New Horizons science team today released the newest and highest quality image yet of the Kuiper Belt object Ultima Thule. The image can be seen by clicking on the slightly reduced and cropped to the right.

Obtained with the wide-angle Multicolor Visible Imaging Camera (MVIC) component of New Horizons’ Ralph instrument, this image was taken when the KBO was 4,200 miles (6,700 kilometers) from the spacecraft, at 05:26 UT (12:26 a.m. EST) on Jan. 1 – just seven minutes before closest approach. With an original resolution of 440 feet (135 meters) per pixel, the image was stored in the spacecraft’s data memory and transmitted to Earth on Jan. 18-19. Scientists then sharpened the image to enhance fine detail. (This process – known as deconvolution – also amplifies the graininess of the image when viewed at high contrast.)

The oblique lighting of this image reveals new topographic details along the day/night boundary, or terminator, near the top. These details include numerous small pits up to about 0.4 miles (0.7 kilometers) in diameter. The large circular feature, about 4 miles (7 kilometers) across, on the smaller of the two lobes, also appears to be a deep depression. Not clear is whether these pits are impact craters or features resulting from other processes, such as “collapse pits” or the ancient venting of volatile materials.

They have only begun downloading the best data and images, so expect better images in the future.

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More results from New Horizons

1:42 pm

Today’s press conference did not release any significantly new images. In fact, they did not provide much new information at all. They noted that based on the data obtained so far, they have confirmed that Ultima Thule has no moons closer than 100 miles, or further than 500 miles, but they have not yet gotten the data that looks in that gap.

They created a stereoscopic image using two images produced thirty minutes apart. This helps tell us where the bumps and depressions are on the surface, something that cannot be clearly determined from the first image because the sun was shining directly on it, producing no shadows. From this it appears that the smaller lobe has a very significant bump. More data from New Horizons will have to be downloaded to confirm this.

The reddish color of Ultima Thule places it in the center of a class of Kuiper Belt objects dubbed cold classical objects. This will help them better determine its make-up as more data arrives.

Overall, this press conference was mostly hype. They don’t yet have enough data from the spacecraft, and won’t have it for weeks. I’m therefore puzzled why they bothered today, unless they did it simply to keep the hype up about the mission so as to encourage funding to look for another object to fly past.

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“We have a snow-man!”

12:30 pm

Ultima Thule, the snowman

The quote in the headline comes from Alan Stern, the principle scientist for New Horizons, during today’s press conference revealing the first high resolution images of Ultima Thule. The press release for this conference is now online. The image on the right is a reduced cropped version of the main release image today. If you click on it you can see the full resolution version.

The images reveal that Ultima Thule actually is two objects in contact with each other. In addition, the snowman description is apt, as it has a mottled appearance as if it was shaped roughly and somewhat gently over time. Tiny pebbles and rocks softly came together to form two snowballs that then eventually came to touch and join.

They describe this as the most primitive object ever observed. It is also dark, and red in color, like dark reddish dirt.

More images and data is still coming in, to be released in another press conference tomorrow.

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Another image of Ultima Thule

9:47 am

Ultima Thule again

The image on the right was released during this morning’s first briefing outlining the successful confirmation of New Horizons’ fly-by of Ultima Thule (still on-going as I post this). It, along with other data, has provided an explanation for why the scientists have not detected a significant variation in brightness: Our view is looking down at the object’s poles

Images taken during the spacecraft’s approach — which brought New Horizons to within just 2,200 miles (3,500 kilometers) of Ultima at 12:33 a.m. EST — revealed that the Kuiper Belt object may have a shape similar to a bowling pin, spinning end over end, with dimensions of approximately 20 by 10 miles (32 by 16 kilometers). Another possibility is Ultima could be two objects orbiting each other. Flyby data have already solved one of Ultima’s mysteries, showing that the Kuiper Belt object is spinning like a propeller with the axis pointing approximately toward New Horizons. This explains why, in earlier images taken before Ultima was resolved, its brightness didn’t appear to vary as it rotated. The team has still not determined the rotation period.

They note that the highest resolution images will not arrive until February, though they do expect some good images by tomorrow.

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“We have a healthy spacecraft.”

8:44 am

The words above were just announced in the control room for New Horizons. They have confirmation that the spacecraft survived the fly-by of Ultima Thule, and is now ready to begin downloading the data it obtained.

It will take literally a year to get all of that data. They will be holding a first press conference within an hour to outline in greater detail the spacecraft’s status, followed by another briefing at 2 pm Eastern where they will likely release the first images.

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First faint image of Ultima Thule

8:09 am

Ultima Thule, first image

In anticipation of receiving data from the fly-by just past midnight last night, the New Horizons team has released the image above, taken 24 hours earlier.

Just over 24 hours before its closest approach to Kuiper Belt object Ultima Thule, the New Horizons spacecraft has sent back the first images that begin to reveal Ultima’s shape. The original images have a pixel size of 6 miles (10 kilometers), not much smaller than Ultima’s estimated size of 20 miles (30 kilometers), so Ultima is only about 3 pixels across (left panel). However, image-sharpening techniques combining multiple images show that it is elongated, perhaps twice as long as it is wide (right panel). This shape roughly matches the outline of Ultima’s shadow that was seen in observations of the object passing in front of a star made from Argentina in 2017 and Senegal in 2018.

This object is definitely strangely shaped.

New Horizons is traveling fast, which is why we won’t get good images until practically the instant the fly-by happens. And the first downloads from that fly-by are due to arrive within the next two hours. Keep your fingers crossed that the spacecraft operated as programmed and captured Ultima Thule in all its weird glory.

One point about the sad state of journalism these days. Numerous media publications posted stories last night celebrating that fly-by, as if they knew it was a success. This is bunk. We won’t know what happened until this morning. To imply we do is the hallmark of fake news.

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Watching New Horizons’ flyby of Ultima Thule

9:07 am

NASA has announced that the partial government shutdown will no longer prevent full coverage by the agency of the New Horizons’ fly-by of Kuiper Belt object Ultima Thule just past midnight on January 1, 2019.

This entire shutdown is pure theater, and a joke. If the government was truly out of money, it would be impossible for NASA to suddenly obtain funds to finance a New Horizons’ fly-by broadcast. The problem is that legally the government should be out of money, as Congress has the power of the purse and has not approved funding. Unfortunately, we no longer obey the law, and so our government can now do whatever it wants, free from all legal constraints.

Meanwhile the article at the link provides some good information on watching the fly-by:

Though people can now continue to enjoy the coverage through NASA’s New Horizons twitter account and NASA TV, APL will continue providing coverage in their own YouTube channel, as well as with Stern’s personal twitter account and New Horizon’s account.

The twitter feeds will mostly be junk. I would focus on the streaming links.

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No rotational light curve from Ultima Thule?

8:55 pm

Data from New Horizons as it is quickly approaching Ultima Thule has found that even though the object is expected to be oblong or even two objects it has shown absolutely no variation in light as it rotates.

Even though scientists determined in 2017 that the Kuiper Belt object isn’t shaped like a sphere – that it is probably elongated or maybe even two objects – they haven’t seen the repeated pulsations in brightness that they’d expect from a rotating object of that shape. The periodic variation in brightness during every rotation produces what scientists refer to as a light curve.

“It’s really a puzzle,” said New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute. “I call this Ultima’s first puzzle – why does it have such a tiny light curve that we can’t even detect it? I expect the detailed flyby images coming soon to give us many more mysteries, but I did not expect this, and so soon.”

They have several theories, all implausible, to explain this. It could be they are looking at the object’s pole. Or maybe a dust cloud or numerous tumbling moons surround the object and hide the light variation.

Fortunately, we shall have an answer to this mystery in less than two weeks, when New Horizons zips past.

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New Horizons sees no hazards, will do closest fly-by of Ultima Thule

9:04 am

After three weeks of intense observations and seeing no significant objects orbiting close to the Kuiper Belt object Ultima Thule, the New Horizons team has decided to go for the closest fly-by on January 1, 2019.

After almost three weeks of sensitive searches for rings, small moons and other potential hazards around the object, New Horizons Principal Investigator Alan Stern gave the “all clear” for the spacecraft to remain on a path that takes it about 2,200 miles (3,500 kilometers) from Ultima, instead of a hazard-avoiding detour that would have pushed it three times farther out. With New Horizons blazing though space at some 31,500 miles (50,700 kilometers) per hour, a particle as small as a grain of rice could be lethal to the piano-sized probe.

We should begin to see more detailed images soon. Because of the speed in which New Horizons is traveling, it will not get very close until it is almost on top of Ultima Thule, so the best images will all occur over a very short span of time.

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New Horizons completes another course correction before flyby

11:53 pm

On December 2 New Horizons successfully completed another engine burn to refine its course for its January 1, 2019 flyby of the Kuiper Belt object Ultima Thule.

The maneuver was designed to keep New Horizons on track toward its ideal arrival time and closest distance to Ultima, just 2,200 miles (3,500 kilometers) at 12:33 a.m. EST on Jan. 1. At the time of the burn New Horizons was 4.03 billon miles (6.48 billion kilometers) from Earth and just 40 million miles (64 million kilometers) from Ultima – less than half the distance between Earth and the Sun. From that far away, the radio signals carrying data from the spacecraft needed six hours, at light speed, to reach home.

The team is analyzing whether to conduct up to three other course-correction maneuvers to home in on Ultima Thule.

The distance to Ultima Thule is still too much to produce detailed images. New Horizons however is going very fast, so in the coming three weeks this will change drastically, and for the better.

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Evidence of nitrogen ice glaciers on Pluto

2:49 pm

Using data sent back by New Horizons during its fly-by of Pluto scientists now think they have identified land forms created by past nitrogen ice glaciers.

The washboard and fluted terrain … occur at the location on Sputnik Planitia’s perimeter where elevations and slopes leading into the surrounding uplands are lowest, and also where a major tectonic system coincides with the edge of Sputnik Planitia. The low elevation of the area makes it a natural setting for past coverage by nitrogen ice glaciers, as indicated by modeling of volatile behavior on Pluto performed by Dr. Bertrand at Ames.

Through comparison of the washboard and fluted texture with parallel chains of elongated sublimation pits (depressions in the surface formed where ice turns directly into a gas) seen in southern Sputnik Planitia, the ridges are interpreted to represent water ice debris liberated by tectonism of underlying crust. This water ice debris was buoyant in the denser, pitted glacial nitrogen ice that is interpreted to have formerly covered this area, and collected on the floors of the elongated pits. After the nitrogen ice receded via sublimation, the debris was left as the aligned ridges, mimicking the sublimation texture – washboard ridges where deposited on flat terrain, and fluted ridges where deposited on steeper slopes.

This is strange stuff. The solid bedrock here, water ice, will float on the nitrogen ice sitting on top of it. Thus, the material that wants to sublimate away, nitrogen, sometimes has to fight its way past the water ice that has risen to the top of the pile.

To put it mildly, we hardly understand these alien processes. This research is merely a first stab, the first hand-waving.

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New Horizons makes final big course correction

7:26 pm

New Horizons this week successfully made its final major course correction in preparation for its January 1st fly-by of the Kuiper Belt object the science team has dubbed Ultima Thule.

NASA’s New Horizons spacecraft carried out a short engine burn on Oct. 3 to home in on the location and timing of its New Year’s flyby of the Kuiper Belt object nicknamed Ultima Thule.

Word from the spacecraft that it had successfully performed the 3½-minute maneuver reached mission operations at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, at around 10:20 p.m. EDT. The maneuver slightly tweaked the spacecraft’s trajectory and bumped its speed by 2.1 meters per second – just about 4.6 miles per hour – keeping it on track to fly past Ultima (officially named 2014 MU69) at 12:33 am EST on Jan. 1, 2019.

As the spacecraft gets closer they will do more refinements, but right now they are a very precise course. The January 1st fly-by will end a spectacular fall season of planetary mission rendezvous, landings, fly-bys and sample gatherings.

Posted from Chicago.

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New Horizons snaps first picture of Ultima

8:48 am

It isn’t much more than a tiny moving dot across a sea of stars, but on August 16, 2018 New Horizons was able to capture its first series of images of its January 1st fly-by target, the Kuiper belt object they have nicknamed Ultima Thule.

This first detection is important because the observations New Horizons makes of Ultima over the next four months will help the mission team refine the spacecraft’s course toward a closest approach to Ultima, at 12:33 a.m. EST on Jan. 1, 2019. That Ultima was where mission scientists expected it to be – in precisely the spot they predicted, using data gathered by the Hubble Space Telescope – indicates the team already has a good idea of Ultima’s orbit.

Ultima was 100 million miles away at the time.

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True color images of Pluto and Charon

9:24 am

The New Horizons science team has released mosaic global images of Pluto and Charon, calibrated to capture their true colors as closely as possible.

These natural-color images result from refined calibrations of data gathered by New Horizons’ Multispectral Visible Imaging Camera (MVIC).”That processing creates images that would approximate the colors that the human eye would perceive – bringing them closer to ‘true color’ than the images released near the encounter,” said Alex Parker, a New Horizons science team co-investigator from Southwest Research Institute, Boulder, Colorado.

Because MVIC’s color filters don’t closely match the wavelengths sensed by human vision, mission scientists applied special processing to translate the raw MVIC data into an estimate of the colors that the eye would see. The colors are more subdued than those constructed from the raw MVIC color data, because of the narrower wavelength range sensed by the human eye.

Both images were taken as New Horizons zipped toward closest approach to Pluto and its moons on July 14, 2015; Charon was taken from a range of 46,091 miles (74,176 kilometers) and Pluto from 22,025 miles (35,445 kilometers). Each is a single color MVIC scan, with no data from other New Horizons imagers or instruments added. The striking features on each are clearly visible, from Charon’s reddish north-polar region known as Mordor Macula, to the bright expanse of Pluto’s, nitrogen-and-methane-ice rich “heart,” named Sputnik Planitia.

I must add that these images show only one hemisphere, since the New Horizons flyby did not get a good look at the opposite hemisphere. We won’t know what the other half of both planets look like for many decades.

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Global topographic maps of Pluto and Charon

9:14 am

Using data and images from New Horizons scientists have now produced the first global topographic maps of Pluto and Charon.

Obviously, the resolution for the maps of both planets is very uneven, since the spacecraft only saw part of each planet at high resolution during its fly-by. Nonetheless, they note some of the more interesting details revealed:

These maps reveal a rich variety of landforms on both Pluto and Charon. The topographic maps confirm that the highest known mountains on Pluto are the Tenzing Montes range, which formed along the southwestern margins of the frozen nitrogen ice sheet of Sputnik Planitia. These steep-sided icy peaks have slopes of 40° or more and rise several kilometers above the floor of Sputnik Planitia. The highest peak rises approximately 6 kilometers (3.7 miles) above the base of the range, comparable to base-to-crest heights of Denali in Alaska, and Kilimanjaro in Kenya. Pluto’s mountains must be composed of stiff water ice in order to maintain their heights, as the more volatile ices observed on Pluto, including methane and nitrogen ice, would be too weak and the mountains would collapse.

The topographic maps also reveal large-scale features that are not obvious in the global mosaic map. The ice sheet within the 1000-kilometer (625-mile) wide Sputnik Planitia is on average 2.5 kilometers (1.5 miles) deep while the outer edges of the ice sheet lie an even deeper 3.5 km (or 2.2. miles) below Pluto’s mean elevation, or ‘sea level’ surface. While most of the ice sheet is relatively flat, these outer edges of Sputnik Planitia are the lowest known areas on Pluto, all features that are evident only in the stereo images and elevation maps. The topographic maps also reveal the existence of a global-scale deeply eroded ridge-and-trough system more than 3000 kilometers (or 1864 miles) long, trending from north-to-south near the western edge of Sputnik Planitia. This feature is the longest known on Pluto and indicates that extensive fracturing occurred in the distant past. Why such fracturing occurred only along this linear band is not well understood.

On Charon the topographic maps also reveal deep depressions near the north pole that are ~14 kilometers (8.7 miles) deep, deeper than the Marianas Trench on Earth. The equatorial troughs that form the boundary between the northern and southern plains on Charon also feature high relief of ~8 kilometers. The mapping of fractured northern terrains and tilted crustal blocks along this boundary could be due to cryovolcanic resurfacing, perhaps triggered by the foundering of large crustal blocks into the deep interior of Charon. The rugged relief also indicates that Charon retains much of its original topography caused by its history of fracturing and surface disruption.

These maps are obviously only our first stab at mapping both planets. We will need orbiters around both to truly detail their surface features.

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New Horizons awakened to begin preparations for January 1 2019 flyby

9:07 am

The New Horizons engineering team has brought the spacecraft out of hibernation to begin preparations for its January 1 2019 flyby of Kuiper Belt object 2014 MU69, which they have dubbed Ultima Thule.

New Horizons will begin its approach phase of the MU69 flyby on August 16, 2018, when it will begin imaging MU69 and the area around it to begin acquiring data about the KBO and its surroundings. Also, New Horizons will look for potential debris that could pose a hazard to itself, such as moons or rings.

Should any potential dangers be found, New Horizons has four planned opportunities to make trajectory changes from early October to early December 2018. The backup trajectory has a distance from MU69 of 10,000 kilometers (around 6,200 miles). Using the backup trajectory would lead to less and/or lower-quality science data gathered due to the probe flying by MU69 further away than planned.

The approach phase will last from August 16 to December 24, 2018, after which the core phase will begin.

The core phase begins just one week before the flyby and continues until two days afterward. It contains the flyby and the majority of the data gathering.

Based on this schedule, we should begin to get some interesting pictures of Ultima Thule by the fall.

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Dunes on Pluto?

9:14 am

Dunes on Pluto

Cool image time! Scientists reviewing images taken by New Horizons when it flew past Pluto in 2015 have discovered what appear to be dunes of methane on the icepack of nitrogen of Sputnik Planitia. The image on the right, cropped to post here, shows these dunes. You can see the full image if you click on it.

Following spatial analysis of the dunes and nearby wind streaks on the planet’s surface, as well as spectral and numerical modelling, scientists believe that sublimation (which converts solid nitrogen directly into a gas) results in sand-sized grains of methane being released into the environment.

These are then transported by Pluto’s moderate winds (which can reach between 30 and 40 kmh), with the border of the ice plain and mountain range providing the perfect location for such regular surface formations to appear.

The scientists also believe the undisturbed morphology of the dunes and their relationship with the underlying glacial ice suggests the features are likely to have been formed within the last 500,000 years, and possibly much more recently.

There remains a lot of uncertainty here. The features do look like dunes in the image, but it is also possible that other phenomenon not yet understood could have caused this pattern on the icepack surface. Also, the resolution of the image is not sufficient to really see detail at this level. A different process on the surface could be fooling our eyes.

Nonetheless, the scientists hypothesis makes sense, and fits the data known. It also demonstrates again that, even billions of miles from the Sun, in as alien an environment we can imagine, the planet Pluto is an active and complex place.

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New Horizons team picks Ultima Thule as nickname for 2014 MU69

5:27 pm

In their continuing effort to give interesting names to their targets, the New Horizons team has chosen the name Ultima Thule for 2014 MU69, the Kuiper Belt object it will fly past on January 1, 2019.

With substantial public input, the team has chosen “Ultima Thule” (pronounced ultima thoo-lee”) for the Kuiper Belt object the New Horizons spacecraft will explore on Jan. 1, 2019. Officially known as 2014 MU69, the object, which orbits a billion miles beyond Pluto, will be the most primitive world ever observed by spacecraft – in the farthest planetary encounter in history.

Thule was a mythical, far-northern island in medieval literature and cartography. Ultima Thule means “beyond Thule”– beyond the borders of the known world—symbolizing the exploration of the distant Kuiper Belt and Kuiper Belt objects that New Horizons is performing, something never before done.

“MU69 is humanity’s next Ultima Thule,” said Alan Stern, New Horizons principal investigator from Southwest Research Institute in Boulder, Colorado. “Our spacecraft is heading beyond the limits of the known worlds, to what will be this mission’s next achievement. Since this will be the farthest exploration of any object in space in history, I like to call our flyby target Ultima, for short, symbolizing this ultimate exploration by NASA and our team.”

Their spacecraft will be the first to see this object up close. It is their right to name it. And if the International Astronomical Union objects, they can go to hell. I guarantee that future generations of space-farers will know this tiny world by this name, and this name alone.

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New Horizons takes the most distant pictures from Earth ever taken

8:43 am

Kuiper Belt Object 2012 HE85

The New Horizons science team has released three images taken by the spacecraft from almost 3.8 billion miles from Earth, the most distant images ever taken.

The routine calibration frame of the “Wishing Well” galactic open star cluster, made by the Long Range Reconnaissance Imager (LORRI) on Dec. 5, was taken when New Horizons was 3.79 billion miles (6.12 billion kilometers, or 40.9 astronomical units) from Earth – making it, for a time, the farthest image ever made from Earth.

…LORRI broke its own record just two hours later with images of Kuiper Belt objects 2012 HZ84 and 2012 HE85 – further demonstrating how nothing stands still when you’re covering more than 700,000 miles (1.1 million kilometers) of space each day.

The images themselves are not spectacular to look at, though the two images of two different Kuiper Belt objects are the best ever taken of such objects, and certainly contain data that scientists will be able to use. The image on the right is one of these objects, 2012 HE85. For example, note how it does not appear to be round.

This exercise is in preparation for the January 1, 2019 fly-by of 2014 MU69, where the images will be sharp and detailed, and provide us a good look at such a distant object.

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