APOD: New Horizons at Ultima Thule (2018 Dec 29)

[APOD Robot]

New Horizons at Ultima Thule

Explanation: When we celebrate the start of 2019, on January 1 the New Horizons spacecraft will flyby Ultima Thule. A world of the Kuiper belt 6.5 billion kilometers from the Sun, the nickname Ultima Thule (catalog designation 2014 MU69) fittingly means "beyond the known world". Following its 2015 flyby of Pluto, New Horizons was targeted for this journey, attempting the most distant flyby for a spacecraft from Earth by approaching Ultima Thule to within about 3500 kilometers. The tiny world itself is about 30 kilometers in size. This year, an observing campaign with Earth-based telescopes determined the shape of the object to be a contact binary or a close binary sytem as in this artist's illustration. New Horizons will image close up its unexplored surface in the dim light of the distant Sun.

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[Boomer12k]

I hope all goes well....

:---[===] *

[Fred the Cat]

I think I've noted before the ultimate thule would be to hop on to an existing ride and see where it leads you.

[Ann]

I was reminded of this, the ultimate(?) soother of sore throats.

"Th" is pronounced the same was as "t" in Swedish, so there can't be much difference between Thule and Tulo, can there?

Ann

[Ann]

Click to view full size image

The background in this APOD seems unnaturally bright, almost as if it showed something weird going on in the sky of the Earth.

Ann

[neufer]

.

• "If you've done six impossible things this morning, why not round it off with breakfast at Milliways, the Restaurant at the End of the Universe." Milliways is built on the fragmented remains of an eventually ruined planet which is enclosed in a vast time bubble and projected forward in time to the precise moment of the End of the Universe. The restaurant building resembles a giant glittering starfish. In the arms of the star are the bars, the kitchens, the force-field generators and the Time Turbines.

[Chris Peterson]

New Horizons will image close up its unexplored surface in the dim light of the distant Sun.

How dim? Well, about 180 times brighter than the full Moon from Earth. If you were sitting on Ultima Thule you could read comfortably, with the illumination level similar to office or living room lighting, or a highly overcast day on Earth.

[BDanielMayfield]

I was reminded of this, the ultimate(?) soother of sore throats.

"Th" is pronounced the same was as "t" in Swedish, so there can't be much difference between Thule and Tulo, can there?

Ann

Right. I was glad to come across something showing the pronunciation as "TooLee".

I note that the artist has imagined UT as being particularly fractal in shape and coloration, with the two parts being practically twins in all but size. This was a reasonable idea I suppose, but "the universe is stranger than we can imagine", so expect something different. We also now know that it has shown an unexpectedly uniform light curve as NH has approached it, something the artist would not have factored in when coming up with this work.

Bruce

[Chris Peterson]

I was reminded of this, the ultimate(?) soother of sore throats.

"Th" is pronounced the same was as "t" in Swedish, so there can't be much difference between Thule and Tulo, can there?

Ann

Right. I was glad to come across something showing the pronunciation as "TooLee".

Interesting. I've always pronounced it that way, but I come to it through Norse folklore. But that's the wrong pronunciation in English, where it has always been said with a soft "th" sound... as it should be, coming from Latin through Greek, both with that same sound.

[Tszabeau]

It/they look like backlit gila monsters.

[BDanielMayfield]

The background in this APOD seems unnaturally bright, almost as if it showed something weird going on in the sky of the Earth.

Ann

Yes, notably unrealistic backlighting. The artist has shown us the backside of beyond.

But, what does the P in today's APOD stand for, since it isn't a photo?

[BDanielMayfield]

I was reminded of this, the ultimate(?) soother of sore throats.

"Th" is pronounced the same was as "t" in Swedish, so there can't be much difference between Thule and Tulo, can there?

Ann

Right. I was glad to come across something showing the pronunciation as "TooLee".

Interesting. I've always pronounced it that way, but I come to it through Norse folklore. But that's the wrong pronunciation in English, where it has always been said with a soft "th" sound... as it should be, coming from Latin through Greek, both with that same sound.

I can't state my source for "Toolee" Chris, as there have been numerous pop press articles of late, which makes that pronunciation far from definitive. How would the locals who live and work in Thule Greenland pronounce it?

[BDanielMayfield]

Here's something more correct on the pronunciation of Thule from wikipedia:

Thule (/ˈθjuːliː/ THEW-lee[1] Greek: Θούλη Thoúlē, Latin: Thūlē) was the place located furthest north, which was mentioned in ancient Greek and Roman literature and cartography.

[Chris Peterson]

Right. I was glad to come across something showing the pronunciation as "TooLee".

Interesting. I've always pronounced it that way, but I come to it through Norse folklore. But that's the wrong pronunciation in English, where it has always been said with a soft "th" sound... as it should be, coming from Latin through Greek, both with that same sound.

I can't state my source for "Toolee" Chris, as there have been numerous pop press articles of late, which makes that pronunciation far from definitive. How would the locals who live and work in Thule Greenland pronounce it?

They would pronounce it the Danish way, a hard "T". Because that's the proper Germanized pronunciation. And correct... if you're speaking a Germanic language. But the original source is Greek, Θούλη, and that's how it entered into English, with the same soft "th" sound as the Greek theta. So really, if we're using the word while speaking English, to an English audience, we should probably use the conventional English pronunciation, the one given in all English language dictionaries, right?

[sillyworm 2]

Well..I'm as beyond excited as I've ever been before!

[msadesign]

I'm happy to see that image, at least in part, because it reminds me of a question that has been bothering me for sometime. The question is this: what is the ambient light level at Ultima Thule? What sort of compensatory adjustments must be made by the various instruments to get useful data? Or, to get a representative data suitable for public consumption?

Will light levels approach those implied by the artist's vision?

I'm certain that the team knows the levels to be expected, and knows them quite accurately. But what are they?

I've been thinking more generally about the limited time the spacecraft will have on station. The huge relative velocities imply that even more light is required for useful images.

I suppose there is, somewhere, a discussion of these and other issues. But where?

[And I can't wait to see what that thing looks like!].

Thanks, everyone!

[Chris Peterson]

I'm happy to see that image, at least in part, because it reminds me of a question that has been bothering me for sometime. The question is this: what is the ambient light level at Ultima Thule? What sort of compensatory adjustments must be made by the various instruments to get useful data? Or, to get a representative data suitable for public consumption?

Will light levels approach those implied by the artist's vision?

I'm certain that the team knows the levels to be expected, and knows them quite accurately. But what are they?

I've been thinking more generally about the limited time the spacecraft will have on station. The huge relative velocities imply that even more light is required for useful images.

I suppose there is, somewhere, a discussion of these and other issues. But where?

[And I can't wait to see what that thing looks like!].

Thanks, everyone!

See my comment above.

[Ann]

New Horizons will image close up its unexplored surface in the dim light of the distant Sun.

How dim? Well, about 180 times brighter than the full Moon from Earth. If you were sitting on Ultima Thule you could read comfortably, with the illumination level similar to office or living room lighting, or a highly overcast day on Earth.

Thanks for that info, Chris.

Still, the background light in the APOD appears to be "too scattered" and "ambient", as if the sunlight had been scattered all over the place by a nice Earth-like atmosphere. That obviously can't be the case though, can it, Chris?

Ann

[Chris Peterson]

New Horizons will image close up its unexplored surface in the dim light of the distant Sun.

How dim? Well, about 180 times brighter than the full Moon from Earth. If you were sitting on Ultima Thule you could read comfortably, with the illumination level similar to office or living room lighting, or a highly overcast day on Earth.

Thanks for that info, Chris.

Still, the background light in the APOD appears to be "too scattered" and "ambient", as if the sunlight had been scattered all over the place by a nice Earth-like atmosphere. That obviously can't be the case though, can it, Chris?

Of course, there can be no atmosphere around this body (bodies). It lacks the mass to hold an atmosphere, and it's too far from the Sun to be outgassing. I can't tell what we're supposed to see in this image. Is all that glow the Milky Way? Is the Sun blocked by the probe? If so, why do we see anything at all on the sides of the bodies facing the viewer?

Really, I can live without these artist interpretations. I don't think they ever come very close to reality.

[heehaw]

Could not agree more with Chris; artists have no place when we have, or hope to soon have, facts!

[geckzilla]

Here's a great thread from Alex Parker (with some pictures featuring real data!) for those who don't favor the illustration:
https://twitter.com/Alex_Parker/status/ ... 0128668674

It's a fun trip.

[neufer]

Thule as Tile on the Carta Marina of 1539 by Olaus Magnus, where it is shown located to the north west of the Orkney islands.

---

Edgar Allan Poe's poem "Dream-Land" (1844):

• By a route obscure and lonely,
  Haunted by ill angels only,
  Where an Eidolon, named Night,
  On a black throne reigns upright.
  I have reached these lands but newly
  From an ultimate dim Thule –
  From a wild weird clime, that lieth, sublime,
  Out of Space – out of Time.

[Ann]

Here's a great thread from Alex Parker (with some pictures featuring real data!) for those who don't favor the illustration:
https://twitter.com/Alex_Parker/status/ ... 0128668674

It's a fun trip.

Thanks, Geck, that's so interesting!

Ann

[neufer]

... the background light in the APOD appears to be "too scattered" and "ambient", as if the sunlight had been scattered all over the place by a nice Earth-like atmosphere. That obviously can't be the case though, can it, Chris?

Of course, there can be no atmosphere around this body (bodies). It lacks the mass to hold an atmosphere, and it's too far from the Sun to be outgassing. I can't tell what we're supposed to see in this image. Is all that glow the Milky Way? Is the Sun blocked by the probe? If so, why do we see anything at all on the sides of the bodies facing the viewer?

Really, I can live without these artist interpretations. I don't think they ever come very close to reality.

New Horizons scientists puzzled by lack of a 'light curve' from their Kuiper Belt flyby target
Credits: NASA/JHUAPL/SwRI

<<NASA's New Horizons spacecraft is bearing down on Ultima Thule, its New Year's flyby target in the far away Kuiper Belt. 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.

"It's possible that Ultima's rotation pole is aimed right at or close to the spacecraft," said Marc Buie, also of the Southwest Research Institute. That explanation is a natural, he said, but it requires the special circumstance of a particular orientation of Ultima.

"Another explanation," said the SETI Institute's Mark Showalter, "is that Ultima may be surrounded by a cloud of dust that obscures its light curve, much the way a comet's coma often overwhelms the light reflected by its central nucleus." That explanation is plausible, Showalter added, but such a coma would require some source of heat to generate, and Ultima is too far away for the Sun's feeble light to do the trick.>>

10199 Chariklo, a [238 km wide] centaur, was the first minor planet discovered to have rings. It has two rings, perhaps due to a collision that caused a chain of debris to orbit it. The rings were discovered when astronomers observed Chariklo passing in front of the star UCAC4 248-108672 on June 3, 2013 from seven locations in South America. While watching, they saw two dips in the star's apparent brightness just before and after the occultation. The observations revealed what is likely a 19-kilometer -wide ring system. In addition, astronomers suspect there could be a moon orbiting amidst the ring debris. If these rings are the leftovers of a collision as astronomers suspect, this would give fodder to the idea that moons (such as the Moon) form through collisions of smaller bits of material. Chariklo's rings have not been officially named, but the discoverers have nicknamed them Oiapoque and Chuí, after two rivers near the northern and southern ends of Brazil.

A second [~238 km wide] centaur, 2060 Chiron, is also suspected to have a pair of rings. Based on stellar-occultation data that were initially interpreted as resulting from jets associated with Chiron's comet-like activity, the rings are proposed to be 324 km in radius. Their changing appearance at different viewing angles can explain the long-term variation in Chiron's brightness over time.

A ring around Haumea, a [1630 km wide] dwarf planet and resonant Kuiper belt member, was revealed by a stellar occultation observed on 21 January 2017. This makes it the first trans-Neptunian object found to have a ring system. The ring has a radius of about 2,287 km, a width of ≈70 km and an opacity of 0.5. The ring plane coincides with Haumea's equator and the orbit of its larger, outer moon Hi’iaka (which has a semimajor axis of ≈25,657 km). The ring is close to the 3:1 resonance with Haumea's rotation, which is located at a radius of 2,285 ± 8 km. It is well within Haumea's Roche limit, which would lie at a radius of about 4,400 km if Haumea were spherical (being nonspherical pushes the limit out farther).

[BDanielMayfield]

Here's a great thread from Alex Parker (with some pictures featuring real data!) for those who don't favor the illustration:
https://twitter.com/Alex_Parker/status/ ... 0128668674

It's a fun trip.

That really is a great thread geck, thanks for sharing it. Real nice learning that Ultima Thule is a member of the Classical Cold Kuiper belt, which is in the plain of the solar system, and likely to be the oldest object we've ever observed. Sweet!