APOD: Sharpest Ultima Thule (2019 Feb 28)

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APOD: Sharpest Ultima Thule (2019 Feb 28)

Post by APOD Robot » Thu Feb 28, 2019 5:06 am

Image Sharpest Ultima Thule

Explanation: On January 1, New Horizons swooped to within 3,500 kilometers of the Kuiper Belt world known as Ultima Thule. That's about 3 times closer than its July 2015 closest approach to Pluto. The spacecraft's unprecedented feat of navigational precision, supported by data from ground and space-based observing campaigns, was accomplished 6.6 billion kilometers (over 6 light-hours) from planet Earth. Six and a half minutes before closest approach to Ultima Thule it captured the nine frames used in this composite image. The most detailed picture possible of the farthest object ever explored, the image has a resolution of about 33 meters per pixel, revealing intriguing bright surface features and dark shadows near the terminator. A primitive Solar System object, Ultima Thule's two lobes combine to span just 30 kilometers. The larger lobe, referred to as Ultima, is recently understood to be flattened like a fluffy pancake, while the smaller, Thule, has a shape that resembles a dented walnut.

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Re: APOD: Sharpest Ultima Thule (2019 Feb 28)

Post by Boomer12k » Thu Feb 28, 2019 8:54 am

As you look at the larger part, it appears to be a combination of about 7 other rocks, smashed into an 8th...the center portion...

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Re: APOD: Sharpest Ultima Thule (2019 Feb 28)

Post by orin stepanek » Thu Feb 28, 2019 11:58 am

Almost looks like it has human characteristics! :D :wink:
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Re: APOD: Sharpest Ultima Thule (2019 Feb 28)

Post by martinw89 » Thu Feb 28, 2019 1:03 pm

The description implies this is the best image we'll get from the flyby, but it's also still 6.5 minutes from closest approach. Why is that? Was the phase angle unfavorable during the flyby? Or was New Horizons too close at closest approach to image all of Ultima Thule in a single composite image? Or was it simply moving too fast at closest approach to make a composite?

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Re: APOD: Sharpest Ultima Thule (2019 Feb 28)

Post by MarkBour » Thu Feb 28, 2019 5:06 pm

martinw89 wrote:
Thu Feb 28, 2019 1:03 pm
The description implies this is the best image we'll get from the flyby, but it's also still 6.5 minutes from closest approach. Why is that? Was the phase angle unfavorable during the flyby? Or was New Horizons too close at closest approach to image all of Ultima Thule in a single composite image? Or was it simply moving too fast at closest approach to make a composite?
The first link in the APOD description (Kuiper Belt world known as Ultima Thule) gives a nice article that explains this.

I have sometimes tried to capture a photograph of scenery looking out the window of a car or bus (generally as a passenger!). While moving at 60 km/h or so, it can be difficult to get a shot without blurring, etc. This set of images was taken while passing this tiny world at 51,500 km/h. It seems that it was only possible using extreme effort from occultation data taken all over the world, and even then was kind of risky, but they nailed it. Amazingly, these are higher resolution (33m per pixel) than any photo they got from the Pluto flyby! They were only about 3,500 km from Ultima Thule when they snapped them.

I am just realizing how hard it might be to get an image like one of the images in this composite. Going back to riding in a car, I just constantly readjust my hold on the camera to keep the desired objective in view. On a probe such as New Horizons, though, what ability do they have to aim the LORRI camera? It may only be possible by aiming the New Horizons spacecraft itself.
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Re: APOD: Sharpest Ultima Thule (2019 Feb 28)

Post by neufer » Thu Feb 28, 2019 5:23 pm

MarkBour wrote:
Thu Feb 28, 2019 5:06 pm

I am just realizing how hard it might be to get an image like one of the images in this composite. Going back to riding in a car, I just constantly readjust my hold on the camera to keep the desired objective in view. On a probe such as New Horizons, though, what ability do they have to aim the LORRI camera? It may only be possible by aiming the New Horizons spacecraft itself.
https://en.wikipedia.org/wiki/Long_Range_Reconnaissance_Imager wrote:
<<LORRI is pointed by moving the entire spacecraft, which limits the exposure time. The spacecraft does not have reaction wheels and is stabilized by thrusters.>>
https://en.wikipedia.org/wiki/New_Horizons#Propulsion_and_attitude_control wrote:
<<There are 16 thrusters on New Horizons: four 4.4 N and twelve 0.9 N plumbed into redundant branches. The larger thrusters are used primarily for trajectory corrections, and the small ones (previously used on Cassini and the Voyager spacecraft) are used primarily for attitude control and spinup/spindown maneuvers. Two star cameras are used to measure the spacecraft attitude. They are mounted on the face of the spacecraft and provide attitude information while in spin-stabilized or 3-axis mode. In between the time of star camera readings, spacecraft orientation is provided by dual redundant miniature inertial measurement units. Each unit contains three solid-state gyroscopes and three accelerometers. Two Adcole Sun sensors provide attitude determination. One detects the angle to the Sun, whereas the other measures spin rate and clocking.>>
Next time you plan to take photos from a moving vehicle I hope you are better prepared, Mark.
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Re: APOD: Sharpest Ultima Thule (2019 Feb 28)

Post by MarkBour » Thu Feb 28, 2019 5:56 pm

neufer wrote:
Thu Feb 28, 2019 5:23 pm
Next time you plan to take photos from a moving vehicle I hope you are better prepared, Mark.
I just really have to stop doing it while driving.
Also, New Horizon's LORRI only has about a 0.29 degree field of view!
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Re: APOD: Sharpest Ultima Thule (2019 Feb 28)

Post by orin stepanek » Thu Feb 28, 2019 11:29 pm

Ultima Thule: so very far, and yet New Horizons brings it to my computer room! Fantastic accomplishment! Somethings in this day and age are rewarding! :D 8-)
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Re: APOD: Sharpest Ultima Thule (2019 Feb 28)

Post by Me Too » Fri Mar 01, 2019 12:10 am

martinw89 wrote:
Thu Feb 28, 2019 1:03 pm
The description implies this is the best image we'll get from the flyby, but it's also still 6.5 minutes from closest approach. Why is that? Was the phase angle unfavorable during the flyby? Or was New Horizons too close at closest approach to image all of Ultima Thule in a single composite image? Or was it simply moving too fast at closest approach to make a composite?
What is your beef? We fired a bullet at tremendous velocity past a moving object over may billions of miles, without 'instant communications', and missed closest approach by only 6 minutes??? And you are complaining??? The Star Trek mentality is truly amazing.

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Re: APOD: Sharpest Ultima Thule (2019 Feb 28)

Post by MarkBour » Fri Mar 01, 2019 6:03 pm

Boomer12k wrote:
Thu Feb 28, 2019 8:54 am
As you look at the larger part, it appears to be a combination of about 7 other rocks, smashed into an 8th...the center portion...

:---[===] *
Interesting, I see what you mean. Actually, it feels like about twice that many visible clumps as I stare at it a while. This could have been caused by compositing of the different images, but I think it is real, visible in any one of the images.
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What do you notice about the pancakes made from the lumpy batter?

Post by neufer » Fri Mar 01, 2019 6:57 pm

MarkBour wrote:
Fri Mar 01, 2019 6:03 pm
Boomer12k wrote:
Thu Feb 28, 2019 8:54 am

As you look at the larger part, it appears to be a combination of about 7 other rocks, smashed into an 8th...the center portion...
Interesting, I see what you mean. Actually, it feels like about twice that many visible clumps as I stare at it a while. This could have been caused by compositing of the different images, but I think it is real, visible in any one of the images.
https://www.scientificamerican.com/article/bring-science-home-gluten-pancakes/ wrote:
The Scientific Secret of Fluffy Pancakes
Scientific American, Esme Trontz: September 12, 2013

Flour contains a protein called glutenin (or gluten), which is crucial for the formation and structure of pancakes and baked goods.

• Whisk together flour, sugar, baking powder, baking soda and salt in the medium bowl labeled "Mixed until combined-lumpy."

• Whisk egg and melted butter into milk until combined. Make a well in the center of the dry ingredients in the "Mixed until combined-lumpy" bowl. Pour in milk mixture and whisk very gently until just combined. Some lumps of flour should remain in the batter; you may see streaks of flour , too. (Do not mix until smooth.)

• Have an adult help you to safely turn on the stove - top burner when you are ready to cook the pancakes.

• From the "Mixed until combined-lumpy" bowl, place one-quarter cup of batter onto two to four spots on the skillet. Cook the pancakes until large bubbles begin to appear. Using a thin, wide spatula, flip pancakes and cook until golden brown on second side. Put the two pancakes on a plate. What do you notice about the pancakes made from the lumpy batter?

• Make observations of the fluffiness and height of the pancakes. How much did they rise? How much did the pancakes spread out on the pan as they cooked? Taste the pancakes and note their flavors and textures. Are the pancakes soft and fluffy?

• Cook the "Mixed until smooth" batter in the same manner as the first batch. How are these pancakes different from the pancakes from the lumpy batter? Are they taller or shorter than the first batch of pancakes? How much did they spread out compared with the first batch?
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Re: APOD: Sharpest Ultima Thule (2019 Feb 28)

Post by Astronymus » Fri Mar 08, 2019 11:39 pm

I can imagine it to be a normal process that an object of that size forming in a proto-planetary disc gathers more material along its plane of orbit or equator. Rotating and gathering layer after layer on the same area. Once the mass is too great the structure collabses under its own gravitation and forms a sphere.

Those two collided after they stopped growing and stuck together. Which also resulted in a shared rotation axis.
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Red MU69 <=> Green 69TM

Post by neufer » Sat Mar 09, 2019 5:21 pm

https://en.wikipedia.org/wiki/Thulium wrote: <<Thulium is the element with symbol 69Tm. [Ultima Thule :arrow: ]

69Tm is the 13th and third-last element in the lanthanide series. Thulium is the second-least abundant of the lanthanides, after radioactively unstable promethium which is only found in trace quantities on Earth. It is an easily workable metal with a bright silvery-gray luster. It is fairly soft and slowly tarnishes in air. Despite its high price and rarity, thulium is used as the radiation source in portable X-ray devices, and in some solid-state lasers. It has no significant biological role and is not particularly toxic.

Thulium was discovered by Swedish chemist Per Teodor Cleve in 1879 by looking for impurities in the oxides of other rare earth elements. Cleve started by removing all of the known contaminants of erbia (Er2O3). Upon additional processing, he obtained two new substances; one brown and one green. The brown substance was the oxide of the element holmium and was named holmia by Cleve, and the green substance was the oxide of an unknown element. Cleve named the oxide thulia and its element thulium after Thule, an Ancient Greek place name associated with Scandinavia or Iceland. Thulium's atomic symbol was once Tu, but this was changed to Tm.

Thulium was so rare that none of the early workers had enough of it to purify sufficiently to actually see the green color; they had to be content with spectroscopically observing the strengthening of the two characteristic absorption bands, as erbium was progressively removed. The first researcher to obtain nearly pure thulium was Charles James, a British expatriate working on a large scale at New Hampshire College in Durham. In 1911 he reported his results, having used his discovered method of bromate fractional crystallization to do the purification. He famously needed 15,000 purification operations to establish that the material was homogeneous.

Holmium-chromium-thulium triple-doped yttrium aluminum garnet (Ho:Cr:Tm:YAG, or Ho,Cr,Tm:YAG) is an active laser medium material with high efficiency. It lases at 2080 nm and is widely used in military applications, medicine, and meteorology. Single-element thulium-doped YAG (Tm:YAG) lasers operate at 2,01 μm. The wavelength of thulium-based lasers is very efficient for superficial ablation of tissue, with minimal coagulation depth in air or in water. This makes thulium lasers attractive for laser-based surgery.

Despite its high cost, portable X-ray devices use thulium that has been bombarded in a nuclear reactor as a radiation source. These sources have a useful life of about one year, as tools in medical and dental diagnosis, as well as to detect defects in inaccessible mechanical and electronic components. Such sources do not need extensive radiation protection – only a small cup of lead.

Thulium-170 is gaining popularity as an X-ray source for cancer treatment via brachytherapy. This isotope has a half-life of 128.6 days and five major emission lines of comparable intensity (at 7.4, 51.354, 52.389, 59.4 and 84.253 keV). Thulium-170 is one of the four most popular radioisotopes for use in industrial radiography.

Thulium has been used in high-temperature superconductors similarly to yttrium. Thulium potentially has use in ferrites, ceramic magnetic materials that are used in microwave equipment. Thulium is also similar to scandium in that it is used in arc lighting for its unusual spectrum, in this case, its green emission lines, which are not covered by other elements. Because thulium fluoresces with a blue color when exposed to ultraviolet light, thulium is put into euro banknotes as a measure against counterfeiting. The blue fluorescence of Tm-doped calcium sulfate has been used in personal dosimeters for visual monitoring of radiation. Tm-doped halides in which Tm is in its 2+ valence state, are promising luminescent materials that can make efficient electricity generating windows based on the principle of a luminescent solar concentrator, possible.>>
Art Neuendorffer