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JRehling
Press Release Source: NASA


NASA's Hubble Reveals Possible New Moons Around Pluto
Monday October 31, 12:30 pm ET


WASHINGTON, Oct. 31 /PRNewswire/ -- Using NASA's Hubble Space Telescope to view the ninth planet in our solar system, astronomers discovered Pluto may have not one, but three moons.
If confirmed, the discovery of the two new moons could offer insights into the nature and evolution of the Pluto system; Kuiper Belt Objects with satellite systems; and the early Kuiper Belt. The Kuiper Belt is a vast region of icy, rocky bodies beyond Neptune's orbit.

"If, as our new Hubble images indicate, Pluto has not one, but two or three moons, it will become the first body in the Kuiper Belt known to have more than one satellite," said Hal Weaver of the Johns Hopkins Applied Physics Laboratory, Laurel, Md. He is co-leader of the team that made the discovery.

Pluto was discovered in 1930. Charon, Pluto's only confirmed moon, was discovered by ground-based observers in 1978. The planet resides about 3 billion miles from the sun in the heart of the Kuiper Belt.

"Our result suggests other bodies in the Kuiper Belt may have more than one moon. It also means planetary scientists will have to take these new moons into account when modeling the formation of the Pluto system," said Alan Stern of the Southwest Research Institute, Boulder, Colo. Stern was co-leader of the research team.

The candidate moons, provisionally designated S/2005 P1 and S/2005 P2, were observed approximately 27,000 miles away from Pluto. The objects are roughly two to three times as far from Pluto as Charon.

The team plans to make follow-up Hubble observations in February to confirm the newly discovered objects are truly Pluto's moons. Only after confirmation will the International Astronomical Union consider names for S/2005 P1 and S/2005 P2.

The Hubble's Advanced Camera for Surveys observed the two new candidate moons on May 15, 2005. The candidates are roughly 5,000 times fainter than Pluto. Three days later, Hubble looked at Pluto again. The two objects were still there and appeared to be moving in orbit around Pluto.

The team looked long and hard for other potential moons around Pluto. "These Hubble images represent the most sensitive search yet for objects around Pluto," said team member Andrew Steffl of the Southwest Research Institute. "It is unlikely that there are any other moons larger than about 10 miles across in the Pluto system," he said.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. The Space Telescope Science Institute in Baltimore conducts Hubble science operations. The Institute is operated for NASA by the Association of Universities for Research in Astronomy, Inc., Washington.


For detailed information and images about this research on the Web, visit:

http://hubblesite.org/news/2005/19

For information about NASA and agency programs on the Web, visit:

http://www.nasa.gov/home




--------------------------------------------------------------------------------
Source: NASA
ElkGroveDan
Click to view attachment
imran
Another reason to get excited about New Horizons!
JRehling
QUOTE (imran @ Oct 31 2005, 11:57 AM)
Another reason to get excited about New Horizons!
*


If this holds up, and I guess it will, what kind of complications does this raise for the Closest Approach instrument pointing? I assume that the nominal plan is completely packed with observations, and you can't add an image without subtracting another one from the plan. Is it possible to add C/A images of the new satellites without losing some of Pluto/Charon?
Proactively, would it be possible to alter the time of arrival by some integer number (eg, 1) of Pluto revolutions to acquire alternative geometries WRT the new satellites while keeping Pluto/Charon geometry the same? It would seem that a very small change in velocity enacted in 2007 could tweak arrival by 6.4 days, if desired.

That's assuming that the new satellites aren't orbiting in synchrony with Charon...

New, larger, light-bucket telescopes on the ground should be able to outperform HST in gathering more data on these bodies long before NH arrives...
remcook
very interesting!

http://www.spaceflightnow.com/news/n0510/31plutomoons/
Mariner9
I doubt this will cause any problems on the encounter planning, because they haven't even launched the vehicle yet. The exact launch date plays a part in which potential arrival dates are possible... so since we don't know exactly when in the launch window the actual launch will take place, I would be willing to bet that there is no firm approach plan in existance yet. I'm sure they have outlines, but minute by minute planning simply is not in existance yet.

And besides, even if it were, they would have ten years to tweak it a bit. That hardly seems like a major problem. I suspect the bigger problem will be in coming up with an approach timing and trajectory that gives them at least a moderate distance approach to one of the new sattelites, and still gets them their desired Pluto and Charon encounters.
RNeuhaus
QUOTE (Mariner9 @ Oct 31 2005, 04:38 PM)
I doubt this will cause any problems on the encounter planning, because they haven't even launched the vehicle yet.  The exact launch date plays a part in which potential arrival dates are possible... so since we don't know exactly when in the launch window the actual launch will take place,  I would be willing to bet that there is no firm approach plan in existance yet.    I'm sure they have outlines, but minute by minute planning simply is not in existance yet.

And besides, even if it were, they would have ten years to tweak it a bit.  That hardly seems like a  major problem.    I suspect the bigger problem will be in coming up with an approach timing and trajectory  that gives them at least a moderate distance approach to one of the new sattelites, and still gets them their desired Pluto and Charon encounters.
*

I thought the same as to you. Perhaps, I am afraid it would be another surprise, with any more moons or any invisible asteroide from Kiuper belt spining around Pluto. It would be a good advise that the NH would have more propellents for main and mini-thrusters than planned to manouver any obstacle since our best telescope still does not look clearly any drifts roaming around Pluto.

Rodolfo
Myran
Once again Hubble proves it value.
Its been speculated there might be more moons at Pluto. Sometimes I wonder if some astronomers got a shrewd intuition. tongue.gif

http://www.boulder.swri.edu/plutonews/
JRehling
QUOTE (RNeuhaus @ Oct 31 2005, 02:46 PM)
I thought the same as to you. Perhaps, I am afraid it would be another surprise, with any more moons or any invisible asteroide from Kiuper belt spining around Pluto.  It would be a good advise that the NH would have more propellents for main and mini-thrusters than planned to manouver any obstacle since our best telescope still does not look clearly any drifts roaming around Pluto.

Rodolfo
*


I respectfully suggest that you really ought to familiarize yourself with some of the basics here -- there are at least four reasons why this scenario is science fiction.

One, there is no way to change the spacecraft at this point -- add mini-thrusters?! The time to make major design alterations came and went a long time ago.

Two, and equally important, you are VASTLY overestimating the hazard, in particular from large objects (observable and steer-around-able). There is a power law that relates the number of impactors WRT size -- if there was a nonnegligible threat of impact with a large object, then there would be a virtual guarantee that the craft would be destroyed by a "rain" of small, but still deadly, particles. Given that we have no reason to fear that (see below), there is virtually zero concern WRT large objects.

Third, while any spacecraft could be destroyed at almost anytime, by a pellet of tiny size, the probability of this is low anyplace in interplanetary space with very rare exceptions. The density of near-Pluto space is lower than that of the asteroid belt, and seven spacecraft have flown through there without incident. Two Pioneers and two Voyagers have flown through the Kuiper Belt, also without incident. Indeed, the various Mars orbiters face a greater threat from debris, and go on year after year -- without incident. In fact, Earth-orbiting spacecraft stand a pretty good example of the low degree of impact menace. And this is already orders of magnitude greater than the threat in near-Pluto space.

Fourth, with the enormous round-trip time for radio signals, any steer-around plan would only make sense for hazards detected well in advance -- and hazards detected well in advance would be, in many cases, detectible from Earth; and in many more cases -- realistically speaking, in almost ALL cases (see above) invisible to the craft until the moment they hit.

The new satellites are estimated to be about 140 km in diameter with orbits 100,000 km across. That is, if a football field were the size of these orbits, the moons themselves would be about the size of a fist. And any undiscovered moons would be more the size of a fingernail. It's really not a great threat that any craft would strike them.

I know that the spirit of this board is in a lot of good fun, but it wouldn't hurt to do a *LITTLE* fact checking before dispensing "good advise".
alan
QUOTE
Unique orbits cannot be calculated from the available
data, but the measured positions are consistent with nearly circular orbits
in the orbital plane of Pluto I (Charon). On this assumption, preliminary
orbital solutions yield a = 64700 +/- 850 km and P = 38.2 +/- 0.8 days for
S/2005 P 1, and a = 49400 +/- and P = 25.5 +/- 0.5 days for S/2005

New moons in resonance with Plutos rotation?
Charon's period is 6.387 days: 6.387 * 4 = 25.6 days ; 6.387 * 6 = 38.3 days
Rob Pinnegar
Just a couple of points concerning this exciting new discovery:

(1) The orbital periods given for the satellites, 38.2 days and 25.5 days, are really close to the Charon 6:1 and 4:1 resonances. (Of course, those periods have some error associated with them; when more precise values are available, we'll have a better idea of this.)

Here's a question for the classical dynamicists in the audience: since Pluto and Charon are both significantly displaced from their mutual barycentre, would an object orbiting that barycentre in the Charon 4:1 or 6:1 resonances have a stable non-elliptical orbit due to three-body effects? What I mean is, could its distance from the system's barycentre reach several maxima and minima per orbit, instead of just one, if the overall ellipticity of the orbit were low enough to start with?

(2) Just running through some quick Matlab calculations: Seen from Pluto's surface, the two new moons should both have total magnitudes in the neighbourhood of -1 or so. So they should be quite visible. If they're in the neighbourhood of 100 to 150 km across, then, as seen from Pluto, they'd both show disks maybe a fifth to a third the size of the Moon as seen from Earth.

If one of them is 150 kilometres across, it could appear as large as the Moon in the Earth's sky as seen from the other, during mutual closest approach (~15000 km).

[Edit: Corrected an ambiguity.]
Alan Stern
See www.boulder.swri.edu/plutonews for a great deal more info.

-Alan
Rob Pinnegar
I'm confused here: On the website cited above, the estimates for the diameter of S/2005 P1 are 160 km if its albedo is 0.04, and 110 km if its albedo is 0.35.

But shouldn't the estimated diameters of the new moons vary roughly as 1/sqrt(albedo)? I would've thought that a ninefold increase in reflectively would decrease the estimated diameter by a factor of about three, since the total brightness has to stay the same.

Using 16.8 as apparent M_v for Charon, and 23.0 as apparent M_v for S/2005 P1 as given on the website, and assuming both bodies have the same albedo, I get a diameter about one-seventeenth of Charon's, or ~70 km, for 2005 P1. Have I got something wrong?
jamescanvin
QUOTE (Alan Stern @ Nov 1 2005, 11:16 AM)
See www.boulder.swri.edu/plutonews for a great deal more info.

-Alan
*


Thanks for the update Alan and congratulations on your teams discovery.


Just to make an obvious point,

Recently on this board we have discussed how NH would have to be very lucky to fly by two Kuiper Belt objects after Pluto-Charon. Now we get two for free! Should get a sample of five now, NH just became even better value!

James
djellison
QUOTE (Alan Stern @ Nov 1 2005, 01:16 AM)
See www.boulder.swri.edu/plutonews for a great deal more info.

-Alan
*


Many thanks, and above all, Congratulations!
Doug
DEChengst
QUOTE (jamescanvin @ Nov 1 2005, 06:45 AM)
Recently on this board we have discussed how NH would have to be very lucky to fly by two Kuiper Belt objects after Pluto-Charon. Now we get two for free! Should get a sample of five now, NH just became even better value!
*


I'm not sure the two moons are as interesting for learning more about differences between Kuiper belt objects as two seperate objects would be. The two moons may have been formed together with Pluto itself so may be very much like Pluto composition wise. The other options ofcourse is that it are captured objects which would be just as interesting as flying by two seperate objects smile.gif
odave
Add my congrats to the pile as well. This is fantastic news!

I also greatly appreciate Alan and John's participation here in UMSF. As we all well know, the Internet is full of kooks, trolls, and all sorts of other miscreants. The fact that members of NH and other mission teams (Jason Perry, Mike Caplinger, et. al.) actively post here is a testament to the quality of the members, moderators, and discussion found in this forum!
Ames
QUOTE (DEChengst @ Nov 1 2005, 01:03 PM)
I'm not sure the two moons are as interesting for learning more about differences between Kuiper belt objects as two seperate objects would be. The two moons may have been formed together with Pluto itself so may be very much like Pluto composition wise. The other options ofcourse is that it are captured objects which would be just as interesting as flying by two seperate objects smile.gif
*


Now let's see - Hmmmm. Name just one object in the solar system that when we looked a little closer at it, nobody said "Woa!" "Wow!" "What The?"
Everything we look at is amazing, and the closer we look the better it gets.
The sheer multitude of landforms, colours, shapes, alignments, hotspots... seem endlessly beautiful and strange.

I can guarantee Pluto et al will not disappoint.

Nick
john_s
QUOTE (Rob Pinnegar @ Nov 1 2005, 02:54 AM)
I'm confused here: On the website cited above, the estimates for the diameter of S/2005 P1 are 160 km if its albedo is 0.04, and 110 km if its albedo is 0.35.

But shouldn't the estimated diameters of the new moons vary roughly as 1/sqrt(albedo)? I would've thought that a ninefold increase in reflectively would decrease the estimated diameter by a factor of about three, since the total brightness has to stay the same.

Using 16.8 as apparent M_v for Charon, and 23.0 as apparent M_v for S/2005 P1 as given on the website, and assuming both bodies have the same albedo, I get a diameter about one-seventeenth of Charon's, or ~70 km, for 2005 P1. Have I got something wrong?
*


No, you don't have anything wrong- we goofed on the web site, though we got the diameter right for the lowest albedo. Thanks for catching the error- we'll fix it! The correct numbers should be something like 160 km for an albedo of 0.04 and 52 km for an albedo 0.35.
Rob Pinnegar
QUOTE (john_s @ Nov 1 2005, 10:47 AM)
No, you don't have anything wrong- we goofed on the web site, though we got the diameter right for the lowest albedo.  Thanks for catching the error- we'll fix it!

Glad I could help. And by the way -- congratulations to your team.
Rakhir
QUOTE (JRehling @ Oct 31 2005, 09:51 PM)
  New, larger, light-bucket telescopes on the ground should be able to outperform HST in gathering more data on these bodies long before NH arrives...
*


If NH is launched during the secondary launch window and if the OWL project is accepted and meet the current schedule, a 60-m class telescope would be available as soon as 2016-2017. It could then be used for the arrival of NH in 2019-2020.
The full 100-m OWL capability would be available too late for NH, in 2020.

Rakhir
RNeuhaus
QUOTE (JRehling @ Oct 31 2005, 05:16 PM)
I respectfully suggest that you really ought to familiarize yourself with some of the basics here -- there are at least four reasons why this scenario is science fiction.

One, there is no way to change the spacecraft at this point -- add mini-thrusters?! The time to make major design alterations came and went a long time ago.
...
...
...

I know that the spirit of this board is in a lot of good fun, but it wouldn't hurt to do a *LITTLE* fact checking before dispensing "good advise".
*

Many thanks to JRehling with your very good explanation. Now, I can feel it more realistic after knowing your details. Sorry of my first reaction since I am a novel of astronomy science. Little by little I will be better off on that.

Taking the advantage of this post, congratulations to Alan and his team for this great news.

Rodolfo
Rob Pinnegar
I just ran through some simple calculations concerning the orbit of the inner new satellite (the one for which a~49000 km).

If this moon were traversing a perfectly circular path around the system's barycentre, with the orbit in the same plane as Charon's, then the total acceleration due to gravity it would experience at closest approach to Charon should be about 5% stronger than the acceleration it experiences when it is farthest away from Charon. So one could conclude from this that the orbit can't really be a perfect circle.

I'm no expert at classical dynamics, but from an intuitive standpoint it's difficult to see how the orbit could be stable under these circumstances unless the moon were in the 4:1 resonance.

My semi-educated guess is that, to first approximation, the moon's distance from Pluto probably varies with an angular frequency that is exactly three times the angular frequency of its revolution about the system's barycentre. For the outer moon it would be five times the revolution frequency.

The only other satellite in the solar system that is in a similar position is Hyperion, but somehow I doubt that the effects are anywhere near as large in Hyperion's case since Saturn's mass is so much greater than Titan's. It will be an interesting problem to solve.

[Edit: ... If it hasn't been solved already, which I'm guessing it has.]
JRehling
QUOTE (Rob Pinnegar @ Nov 2 2005, 09:04 AM)
I just ran through some simple calculations concerning the orbit of the inner new satellite (the one for which a~49000 km).

If this moon were traversing a perfectly circular path around the system's barycentre, with the orbit in the same plane as Charon's, then the total acceleration due to gravity it would experience at closest approach to Charon should be about 5% stronger than the acceleration it experiences when it is farthest away from Charon. So one could conclude from this that the orbit can't really be a perfect circle.
*


A fun additional consideration: The other "moon" that the new ones can synchronize against is Pluto! You calculated a 5% "surge" when the moons are opposite Charon, but 180-deg opposite, there will be another "surge" as Pluto passes, somewhat closer than otherwise.

The Pluto "surge" felt by each outer satellite should be less than the Charon surge by precisely the ratio of their masses. Since that ratio is about 7:1, the Charon surge will be the dominant perturbation, with the Pluto surge lesser but non-negligible.
Rob Pinnegar
QUOTE (JRehling @ Nov 2 2005, 11:22 AM)
A fun additional consideration: The other "moon" that the new ones can synchronize against is Pluto! You calculated a 5% "surge" when the moons are opposite Charon, but 180-deg opposite, there will be another "surge" as Pluto passes, somewhat closer than otherwise.

This is correct and I actually did take it into account -- the calculation referred to above assumed that the moon was circling the Pluto-Charon barycentre, not Pluto itself. Without the Pluto "surge" the difference would be greater than 5%; when the inner new moon reaches closest approach to Charon, the gravitational influence of Charon is about a third of Pluto's!
Rob Pinnegar
The other neat thing is that the total acceleration vector experienced by the new moons due to the combined effects of Pluto and Charon, usually doesn't point straight at the barycentre. When the line connecting Pluto and Charon is perpendicular to the line connecting S2005 P2 to the barycentre, for example, the acceleration vector leans slightly toward Pluto.

My _suspicion_ is that the two new moons reach their greatest distances from the barycentre simultaneously with closest approach to Charon. After that, they start to fall inwards and also start to lead a bit in their orbit. Closest approach to the barycentre coincides with their closest approach to Pluto, after which they trail in their orbits and move farther away. This is however conjecture and I've not got it supported by mathematics. I could have the leading/trailing bit backwards, for example.

Of course, the two new moons will interact with each other a bit, but that ought to be a higher-order effect. [Edit: Actually it wouldn't be higher-order, just smaller in magnitude.]

[Edit: A quick back of the envelope calculation indicates that these effects could cause the inner new moon's distance from the system's barycentre to change by up to 250 kilometres, three times per orbit. Hope I haven't made any major blunders here -- I've assumed a simple harmonic oscillator, in the radial direction only, and have neglected the skew in the acceleration vector.]
tasp
QUOTE (alan @ Nov 1 2005, 12:28 AM)
New moons in resonance with Plutos rotation?
Charon's period is 6.387 days: 6.387 * 4 = 25.6 days ; 6.387 * 6 = 38.3 days
*



If correct, all the satellites of Pluto will essentially repeat their relative positions every 77 days or so. This will limit the number of satellite configurations for the mission designers to evaluate. There won't be any point in moving the arrival date beyond a couple of orbits of the outer satellite. The NH craft will have the same views of all the objects.
JRehling
QUOTE (tasp @ Nov 2 2005, 09:29 PM)
If correct, all the satellites of Pluto will essentially repeat their relative positions every 77 days or so.  This will limit the number of satellite configurations for the mission designers to evaluate.  There won't be any point in moving the arrival date beyond a couple of orbits of the outer satellite.  The NH craft will have the same views of all the objects.
*


Well, it would allow for 24 distinct configurations of the outer satellites, or whatever fraction of those 24 the "arrival window" allows for -- that seems like a considerable variety of options.
Rob Pinnegar
QUOTE (tasp @ Nov 2 2005, 10:29 PM)
If correct, all the satellites of Pluto will essentially repeat their relative positions every 77 days or so.

If we're lucky, the (hypothesized) resonances will turn out to be similar to the Jupiter-Io-Europa-Ganymede system, where periodically all three moons and the central planet arrange themselves in a straight line.

If we're _really_ lucky, this configuration will occur when the moons are all close to the plane of Pluto's orbit around the Sun. If this were the case, New Horizons could make close flybys of all four bodies, concentrating exclusively on one body at a time, during its flyby in '15.

We'll have to see. I guess one approach would be to take two snapshots of the system, 77 days apart. If they turn out to look the same, well, there you have it.
tasp
QUOTE (JRehling @ Nov 3 2005, 12:29 PM)
Well, it would allow for 24 distinct configurations of the outer satellites, or whatever fraction of those 24 the "arrival window" allows for -- that seems like a considerable variety of options.
*



Like in the Jupiter system, due to the resonance of Io, Europa, and Ganymede, certain configurations of the satellites never occur. Like all three in a straight line on the same side of Jupiter. I was annoyed a little when the mission designers of Voyager II's Uranus flyby stated a particularly appealing configuration of the Uranian moons occured just a few days prior to the earliest possible flyby date that preserved the Neptune option. Hence the fuzzy picture of Umbriel.

Should be easier for the analysts to examine ~77 days of moon configurations than potentially years worth.
tedstryk
QUOTE (tasp @ Nov 3 2005, 04:11 PM)
Like in the Jupiter system, due to the resonance of Io, Europa, and Ganymede, certain configurations of the satellites never occur.  Like all three in a straight line on the same side of Jupiter. I was annoyed a little when the mission designers of Voyager II's Uranus flyby stated a particularly appealing configuration of the Uranian moons occured just a few days prior to the earliest possible flyby date that preserved the Neptune option.  Hence the fuzzy picture of Umbriel.

Should be easier for the analysts to examine ~77 days of moon configurations than potentially years worth.
*


Umbriel is an interesting world. But it wasn't worth the loss of Triton and Neptune. Also, no configuration of Uranus's moons in 1986 would be that good. Voyager was approaching like a dart headed straight at a dartboard, so rather than having closest approaches one by one, they were all at once. Also, had they been free of Neptune's constraints, Titania, not Miranda, would have received the close flyby - so they really lucked out!
Here are the best views we got of Umbriel.
Color:


Black and White:



Composite of Wunda (The bright feature at the top):

Phil Stooke
Ted's pics of Umbriel are, as ever, excellent. I processed the same images as well, using different methods for mainly cartographic purposes. These are the results:

Click to view attachment

Click to view attachment

Phil
Phil Stooke
...and here's a mosaic of the entire visible hemisphere in azimuthal equidistant projection.

Phil

Click to view attachment

Blast! I was just replying to Ted, I didn't notice what thread I was in. This should really be in the historic images thread... oops.
JRehling
QUOTE (tasp @ Nov 3 2005, 09:11 AM)
Like in the Jupiter system, due to the resonance of Io, Europa, and Ganymede, certain configurations of the satellites never occur.  Like all three in a straight line on the same side of Jupiter.

Should be easier for the analysts to examine ~77 days of moon configurations than potentially years worth.
*


Good point. A 1:4:6 resonance actually allows 12 configurations (not 4 * 6 = 24) if we assume that the Charon position were fixed (which I suppose it is, barring an exceptional reason for change). When the outermost moon has made 2 laps around Pluto (or the barycenter), the middle moon will have made 3 -- that defines a cycle in twelve Charon revolutions, equaling, yes, 77 days).
tasp
I very much appreciate the Umbriel pictures. Maybe we get the NH2 to update the Voyager portfolio. And maybe we don't. Sigh.

Rectified Wunda picture is new to me, interesting feature. Still not evident what happened there, though.
tedstryk
QUOTE (tasp @ Nov 3 2005, 10:34 PM)
I very much appreciate the Umbriel pictures.  Maybe we get the NH2 to update the Voyager portfolio.  And maybe we don't.  Sigh.

Rectified Wunda picture is new to me, interesting feature.  Still not evident what happened there, though.
*



It is almost certainly a bright crater rim...the question is WHY it is bright. There is also a bright central peak visible in another crater. I made the image by reprojecting the dataset used to make both images I posted to be from the same angle and at the same scale, and then stacked them. I used a color overlay from the posted image.

Here is a sequence of the best views of Umbriel. I am not at home right now, so I don't have a larger version. However, other than the images I already posted, the images aren't shrunken, so it will serve our purposes!



Phil: I also experimented with processing along the lines you did to bring out topography. The posted view focuses on a natural look. When I am home, I may try processing the same images in a similar way, and then merging the datasets to make a sharper image that brings out topography more.
Phil Stooke
Ted, my interests are really in the area of making the most easily interpreted map images, not so much the natural view we would see if we were there. So my stuff can look a bit odd! I'm starting to think about doing more of this stuff...

Phil
mchan
QUOTE (tasp @ Nov 3 2005, 03:34 PM)
I very much appreciate the Umbriel pictures.  Maybe we get the NH2 to update the Voyager portfolio.  And maybe we don't.  Sigh.

Rectified Wunda picture is new to me, interesting feature.  Still not evident what happened there, though.
*


NH2 did not get funding.
tedstryk
QUOTE (Phil Stooke @ Nov 3 2005, 11:15 PM)
Ted, my interests are really in the area of making the most easily interpreted map images, not so much the natural view we would see if we were there.  So my stuff can look a bit odd!  I'm starting to think about doing more of this stuff...

Phil
*



Here is the result of my attempt to merge the two types of processing.

tasp
More good pictures of mysterious Umbriel.

Does anyone have any idea where the pole is?

Or the equator?

When I look at the upper limb, from about 11 o'clock to Wunda, I see a 'ridgy' looking feature. Artifact of processing near the limb, or something more....interesting?

(enlarge picture to see it)

blink.gif
dvandorn
The "ridgy" feature becomes clear when you look at Phil's cartographic-purposed image. There is a large, very degraded crater (or, rather, a basin) located right in that area. The ridge-like structure (visible more as an albedo difference farther into Umbriel's disk) is a basin ring.

-the other Doug
tasp
QUOTE (dvandorn @ Nov 4 2005, 08:26 AM)
The "ridgy" feature becomes clear when you look at Phil's cartographic-purposed image.  There is a large, very degraded crater (or, rather, a basin) located right in that area.  The ridge-like structure (visible more as an albedo difference farther into Umbriel's disk) is a basin ring.

-the other Doug
*



Thanx, I do see that now. I thought it odd something like that would be unnoticed in this time frame.
Phil Stooke
I'm posting more images in the historic images thread...

Phil
Rob Pinnegar
QUOTE (Phil Stooke @ Nov 4 2005, 09:04 AM)
I'm posting more imagfes in the historic images thread...

Good idea Phil. We have got a bit off the Pluto topic here.
tty
QUOTE (tasp @ Nov 3 2005, 06:11 PM)
Like in the Jupiter system, due to the resonance of Io, Europa, and Ganymede, certain configurations of the satellites never occur.  Like all three in a straight line on the same side of Jupiter.


Hmm... I didn't know that and so apparently didn't Robert Heinlein. The big quake in "Farmer in the sky" happened when all 4 galileans lined up.

tty
Rob Pinnegar
QUOTE (tty @ Nov 4 2005, 12:59 PM)
Hmm... I didn't know that and so apparently didn't Robert Heinlein. The big quake in "Farmer in the sky" happened when all 4 galileans lined up.

Callisto can line up with two of the other three, but the last one will always be out of place.
JRehling
QUOTE (Rob Pinnegar @ Nov 4 2005, 12:33 PM)
Callisto can line up with two of the other three, but the last one will always be out of place.
*


I don't know the details of the Heinlein story, but of course the Galileans can also all line up... but with one of them on the other side of Jupiter. We can also presume that the Galileans were capable of aligning on the same side of Jupiter in the past, before the synchrony was established. Finally, it is possible for all four Galileans to be within 180 degrees of each other, and have it be that from Earth they would appear to be on the same side of Jupiter.
dvandorn
Interesting. I always knew, at some level, that the image from "2001" showing all of Jupiter's moons aligned in a string with the planet itself wasn't possible...

-the other Doug
mike
Yeah, but aligned spheres in space are part of what made 2001 such a great movie. smile.gif Movies like that are very rarely made, sadly..
tasp
QUOTE (mike @ Nov 4 2005, 08:23 PM)
Yeah, but aligned spheres in space are part of what made 2001 such a great movie.  smile.gif  Movies like that are very rarely made, sadly..
*



Would a hpothetical observer on Pluto become bored with a too clock like moon parade? Funny to look at it that way, but 'forbidden' configurations of resonant satellites kinda takes some of the pizzaz out of it.

Even if it simplifies NH mission design.
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