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Rick Woods
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Mysteries of the Planets
      #6092182 - 09/20/13 05:36 PM

This seemed like the most appropriate place to post this.

I'm wondering about unexplained phenomena for the planets. I know about some, and I'm hoping others will know more. Any good ones are welcome; if it's a new one on me, I'd like to pick the brain of whoever knows about it. Here are the ones I can think of now:

Venus:
- Ashen Light
- Cause of atmospheric superrotation
- Nature of the atmospheric ultraviolet absorber

Mars:
- Blue Clearing (no, this has never been resolved)
- 3.45 micron Sinton band
- Observation of Olympus Mons as an albedo (non-cloud) feature
- Transient dark features
- Detection of Methane
- Searchlight terrain

Moon:
- TLPs

I don't know of any on Mercury.
I'm on shaky ground with the outer planets; what sorts of long-standing mysteries do they have?


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CPellier
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Re: Mysteries of the Planets new [Re: Rick Woods]
      #6092822 - 09/21/13 03:03 AM

Interesting list ! For Mars I have some answers....
- Blue Clearing (no, this has never been resolved)
We are now considering that this is a mere opposition effect. Blue clearing is strongly correlated with the weeks around opposition and so the disappearance of ground features far from opposition in blue light must be due to any kind of albedo variation with the angle of viewing from Earth.
- 3.45 micron Sinton band
I don't know that one, can you explain ?
- Observation of Olympus Mons as an albedo (non-cloud) feature
Why is it a mistery ? Since we see the ground we see the shape of the caldera as well...
- Transient dark features
Dark underground revealed by strong convective winds accompanying dust clouds. Maybe sometimes kind of shadows...
- Searchlight terrain
Again I don't know this one ?


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CPellier
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Re: Mysteries of the Planets new [Re: CPellier]
      #6092841 - 09/21/13 03:23 AM

For Jupiter:
- Nature of the chemical component that makes the class of the red spots: GRS, BA, NNTZ LRS


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Special Ed
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Re: Mysteries of the Planets new [Re: CPellier]
      #6092953 - 09/21/13 08:20 AM Attachment (9 downloads)

Hello,

Here is something on Blue Clearing from CMO that reinforces what Christophe said.

I made this observation of Mars that includes a possible sighting of the shadow of giant Olympus Mons. There was some discussion in the CMO newsletter about being able to visually detect the presence of the volcano when the geometry was right (which it was for this observation). There is also a dark albedo feature just to one side of the volcano--that might be what I saw--not the shadow.

BTW, Communications in Mars Observations (CMO) is an outstanding resource on the Web for Mars observers--I highly recommend it.


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stanislas-jean
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Re: Mysteries of the Planets new [Re: Special Ed]
      #6093009 - 09/21/13 09:01 AM

Regarding the blue clearing over a steady season on Mars, they are many counterexamples showing holes in atmosphere or through a "layer".
The problem of such phenomena as for many other subjects regular numerous observationnal data for a valuable coverage are necessary with correlation tentatives with other phenoména.
The law regarding the ground reflectivity that increase with wavelength doesnot imply obligatory the problem solved.
The atmosphere also scatter the light, on venus too, and this is interfering with for the blue clearing.
CMO is not the only reference for data, you may have also the BAA, the Alpo, the japanese Alpo and some others.
Stanislas-Jean


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Rick Woods
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Re: Mysteries of the Planets new [Re: CPellier]
      #6093180 - 09/21/13 10:58 AM

Hi Christophe, good to see you here!

Quote:

Interesting list ! For Mars I have some answers....
- Blue Clearing (no, this has never been resolved)
We are now considering that this is a mere opposition effect. Blue clearing is strongly correlated with the weeks around opposition and so the disappearance of ground features far from opposition in blue light must be due to any kind of albedo variation with the angle of viewing from Earth.




Not necessarily.
"Blue clearings have been recorded 60 to 70 days from opposition by Slipher (1962); and more recently, 166 to 72 days from the 1965 opposition (Capen, 1966) and 175 to 349 days from the 1967 opposition by the author."
"Martian Blue-Clearing During 1967 Apparition", C. Capen, Icarus 12, 118-127, 1970

There is little to no work being done on the issue currently. (I have a huge file on this.)

Quote:

- 3.45 micron Sinton band
I don't know that one, can you explain ?




In 1956, Wm. Sinton at Lowell Obs. recorded IR bands at 3.45, 3.58, and 3.69 microns in the dark areas of Mars, but not the light, matching the signature of chlorophyll. The 3.58 and 3.69 bands were subsequently shown to originate in Earth's atmosphere, but the 3.45 band remains unexplained. The most recent work on this I could find was by Jim Bell in 2000, and it was inconclusive. In a private communication, he said that had never been followed up on due to his work load, and as far as he knew it was still an open question.
(Much smaller file on this.)

Quote:

- Observation of Olympus Mons as an albedo (non-cloud) feature
Why is it a mistery ? Since we see the ground we see the shape of the caldera as well...




It may not be. All I have is a copy of a handwritten note by C. Capen that says:
"Olympus Mons feature does not show on green, blue, UV - It may not be moving - probably a surface albedo feature - Nix Olympica re-discovered. Not resolved on other images on other nights. This is a 10-night span. - May be first photographic observation of Nix Oly."
That, and a list of reference numbers for photographic plates that are boxed up and stored in some attic at Lowell. I'm hoping they get exhumed and digitized someday soon. If I'm interpreting the plate ID numbers correctly, they were from 1986.

Quote:

- Transient dark features
Dark underground revealed by strong convective winds accompanying dust clouds. Maybe sometimes kind of shadows...




Maybe. I don't have much on this, and most of it is from Slipher's book "Mars, the Photographic Story". There are photos.

Quote:

- Searchlight terrain
Again I don't know this one ?




Almost nothing on this. Mainly, an entry on pg.202 of "The Moon and The Planets - A Catalog of Astronomical Anomalies" by Wm. R. Corliss. They were imaged by the Viking orbiter - a picture is in the book - and appear to be limited to the polar regions. "Bright elongated patterns... bounded by abrupt margins that sustain a linear trend for 100km or more, maintaining a parallel or slightly diverging aspect... transect major topographical features without changing direction".

I'm still running down references on all of these. (Apologies if I oversimplified or over-generalized some of the descriptions for the sake of brevity.)


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Rick Woods
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Re: Mysteries of the Planets new [Re: CPellier]
      #6093185 - 09/21/13 11:00 AM

Quote:

For Jupiter:
- Nature of the chemical component that makes the class of the red spots: GRS, BA, NNTZ LRS




Thank you! I'll start researching this one too. (I love a mystery! )


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Rick Woods
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Re: Mysteries of the Planets new [Re: Special Ed]
      #6093219 - 09/21/13 11:18 AM

Quote:

Hello,

Here is something on Blue Clearing from CMO that reinforces what Christophe said.




I have that article in my file. It's unconvincing, particularly in light of the second sentence; the author is predisposed to disbelief in the whole thing. I don't believe they did their homework. I also have the article referenced in the Sheehan quote, and as far as I can tell, it draws no such conclusion.

Quote:

I made this observation of Mars that includes a possible sighting of the shadow of giant Olympus Mons. There was some discussion in the CMO newsletter about being able to visually detect the presence of the volcano when the geometry was right (which it was for this observation). There is also a dark albedo feature just to one side of the volcano--that might be what I saw--not the shadow.




What a great observation! What a rush that must have been. I hope I can see it myself sometime.

I'm not sure how the two fit together (I still haven't seen the Lowell photo plates); but either Capen was talking about the first photographic detection, or was thinking about some sort of frost or something on the mountain
(note the emphasis on its not being a cloud - it must have looked like a cloud). I hope to see those plates eventually; maybe that'll set the whole thing to rest.

Edit: Re. your observation; This also relates to the issue of being able to detect craters on Mars in the telescope. Rodger W. Gordon deals with this extensively in his book "Observing the Craters of Mars, Part 1". Also see Astronomy Magazine, Sept. 1986, "Hunting Martian 'Astroblemes'" by C. Capen.

Edited by Rick Woods (09/21/13 11:44 AM)


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Rick Woods
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Re: Mysteries of the Planets new [Re: stanislas-jean]
      #6093220 - 09/21/13 11:20 AM

Quote:

Regarding the blue clearing over a steady season on Mars, they are many counterexamples showing holes in atmosphere or through a "layer".
The problem of such phenomena as for many other subjects regular numerous observationnal data for a valuable coverage are necessary with correlation tentatives with other phenoména.
The law regarding the ground reflectivity that increase with wavelength doesnot imply obligatory the problem solved.
The atmosphere also scatter the light, on venus too, and this is interfering with for the blue clearing.
CMO is not the only reference for data, you may have also the BAA, the Alpo, the japanese Alpo and some others.
Stanislas-Jean




Hi Stan,

I think I agree with everything you just said.


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David Knisely
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Re: Mysteries of the Planets new [Re: Rick Woods]
      #6093513 - 09/21/13 02:09 PM

Hi there Rick. Regarding the "shadows" on the down-sun side of Olympus Mons, during the fine 2005 apparition, Damian Peach took a sequence of images that clearly shows not only faint darkening on the terminator side of that volcano but shadowing effects from at least one (if not two) of the other large Tharsis shields. He once linked the images together into a rotating animated sequence, and the darkening of the shadowing effects do get noticeably darker as each volcano approaches the terminator. It looks pretty clear that the shadowing effects may be visible given the right conditions. Clear skies to you.

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Rick Woods
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Re: Mysteries of the Planets new [Re: David Knisely]
      #6093719 - 09/21/13 04:01 PM

I completely agree, David. I'm mystified by assertions that relief is impossible to see on Mars by telescope.

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CPellier
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Reged: 08/07/10

Re: Mysteries of the Planets new [Re: Rick Woods]
      #6093754 - 09/21/13 04:30 PM

Hi Rick and all,
I support on my side the CMO theory for blue clearing for at least one reason: it is the only one that brings an explanation of what we see, maybe not perfect, but excellent. The planet Mars is deeply observed by mankind and it is the planet we most know after ours... and I just find very curious that no atmospheric explanation can yet be brought for the "blue clearing".
The smoking gun here is the very good correlation of the evolution of angle of view from Earth and the phenomenon, even Earl Slipher did noticed that in his book (Rik you do have it don't you ?). Yes there are some occurrences far from opposition but they might be explained by other reasons (presence and evolution of water ice clouds).
Proportionnaly, it just like when we shifted from geocentrism to heliocentrism: geocentrism was unable to explain some movements of the planets - because it was false. Well here the atmospheric point of view looks not able to explain the blue clearing; and at ISMO we argue that this is then a ground phenomena and the explanation is more fruitful.
I believe that the ground of Mars has curious properties of albedo in blue light. Three years ago I have written an article in the CMO review that describes another strange phenomenon observed: dark features more visible in violet light than in blue light.
The phenomenon is rather close to the blue clearing and yet no clouds is involved here; and, there is also a variation with the angle of view: it was not visible at opposition ! How strange isn't it ?
(I will share some more point of view later for the other interesting things we are reading here)


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Rick Woods
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Re: Mysteries of the Planets new [Re: CPellier]
      #6094066 - 09/21/13 08:26 PM

Christophe,
Well, you might be right. I don't know. But I'm leery of an explanation that discards a large number of the observations just to make the remaining ones fit.
I sure wish an in situ station would take measurements and observations at the same time and location a blue clearing was observed from Earth. That might be informative. And remember, the greatest number of observations are made at opposition time; that would have to skew the numbers.
Well, that's why they call it a mystery, I guess. I hope we know for sure some day.
(Yes, I have Slipher's book.)

I tried to download your article, but got an error on the web site. Probably Win8 again. I'll try later. I have Thomas and Veverka's 1986 article on contrast reversal on Mars, but I read it quite a while ago, and haven't thought much about it since then.


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Rick Woods
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Re: Mysteries of the Planets new [Re: Rick Woods]
      #6094408 - 09/22/13 01:35 AM

Had to go download it from XP; the copy kept crashing in Win8. Grr!

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Rick Woods
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Re: Mysteries of the Planets new [Re: Rick Woods]
      #6095003 - 09/22/13 12:35 PM

Excellent article, Christophe! Thanks for that link. It looks like Thomas and Veverka were talking about something different than you were.
Fascinating that Valhalla corresponds with the dichotomy boundary; another example of relief features on Mars being visible telescopically.


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Special Ed
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Re: Mysteries of the Planets new [Re: Rick Woods]
      #6095883 - 09/22/13 10:11 PM

Quote:

Quote:

Hello,

Here is something on Blue Clearing from CMO that reinforces what Christophe said.




I have that article in my file. It's unconvincing, particularly in light of the second sentence; the author is predisposed to disbelief in the whole thing. I don't believe they did their homework. I also have the article referenced in the Sheehan quote, and as far as I can tell, it draws no such conclusion.

Quote:

I made this observation of Mars that includes a possible sighting of the shadow of giant Olympus Mons. There was some discussion in the CMO newsletter about being able to visually detect the presence of the volcano when the geometry was right (which it was for this observation). There is also a dark albedo feature just to one side of the volcano--that might be what I saw--not the shadow.




What a great observation! What a rush that must have been. I hope I can see it myself sometime.

I'm not sure how the two fit together (I still haven't seen the Lowell photo plates); but either Capen was talking about the first photographic detection, or was thinking about some sort of frost or something on the mountain
(note the emphasis on its not being a cloud - it must have looked like a cloud). I hope to see those plates eventually; maybe that'll set the whole thing to rest.

Edit: Re. your observation; This also relates to the issue of being able to detect craters on Mars in the telescope. Rodger W. Gordon deals with this extensively in his book "Observing the Craters of Mars, Part 1". Also see Astronomy Magazine, Sept. 1986, "Hunting Martian 'Astroblemes'" by C. Capen.




Rick,

Re: the blue clearing--I think there is something lost in translation here. I know these people thought very carefully about what they were saying.

Re: my observation of the shadow of Olympus Mons--thanks! It was a peak observational experience for me (no pun intended).

As far as visually detecting relief on Mars--that's not a controversy I want to get involved in. I think it might be possible given the right optics, seeing conditions, geometry, and visual acuity of the observer, but I don't think I ever would fulfil all those prerequisites. Imagers might be able to do it.

Visually, I might be able to indirectly detect craters by observing the dark albedo feature in the floor of a crater but detecting the walls, terracing, etc.--I doubt it. I have indirectly seen Vallis Marineris by watching a dust storrm flow down the giant canyon. http://www.asod.info/?p=205
I'm happy indirectly seeing the giant impact basins like Hellas and Argyre by seeing the indirect effects--ground fog, frost, etc.

Edited by Special Ed (09/22/13 10:31 PM)


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Rick Woods
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Re: Mysteries of the Planets new [Re: Special Ed]
      #6096600 - 09/23/13 10:51 AM

Special,

Good link and observation! You prompted me to go back to my sketch book for that time. I guess I didn't know about the dust storm at the time; but I have one sketch from 10/20/2005 of the Solis Lacus area that has almost no detail, and my notes say "disk almost featureless even though seeing good - global dust storm?".

Quote:

As far as visually detecting relief on Mars--that's not a controversy I want to get involved in. I think it might be possible given the right optics, seeing conditions, geometry, and visual acuity of the observer, but I don't think I ever would fulfil all those prerequisites. Imagers might be able to do it.




Yeah, you'd need a bigger telescope and better eyes than mine, that's for sure.


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Rick Woods
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Re: Mysteries of the Planets new [Re: CPellier]
      #6097396 - 09/23/13 08:47 PM

Quote:

For Jupiter:
- Nature of the chemical component that makes the class of the red spots: GRS, BA, NNTZ LRS




What is the mystery? Are they unable to measure or deduce the chemicals required? Can you point me to where this is discussed somewhere?
Thanks!


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Special Ed
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Re: Mysteries of the Planets new [Re: Rick Woods]
      #6097585 - 09/23/13 10:37 PM

Quote:

Special,

Good link and observation! You prompted me to go back to my sketch book for that time. I guess I didn't know about the dust storm at the time; but I have one sketch from 10/20/2005 of the Solis Lacus area that has almost no detail, and my notes say "disk almost featureless even though seeing good - global dust storm?".

Quote:

As far as visually detecting relief on Mars--that's not a controversy I want to get involved in. I think it might be possible given the right optics, seeing conditions, geometry, and visual acuity of the observer, but I don't think I ever would fulfil all those prerequisites. Imagers might be able to do it.




Yeah, you'd need a bigger telescope and better eyes than mine, that's for sure.




Thanks, Rick. That's pretty cool that you caught that dust storm too. Just goes to show that once you get familiar with the classical albedo features you notice when something is not there. A mystery that can be solved.

Just wanted to mention that the best imagers have imaged Olympus Mons in the last apparition--pretty amazing what they can do now.


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CPellier
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Reged: 08/07/10

Re: Mysteries of the Planets new [Re: Rick Woods]
      #6099765 - 09/25/13 04:39 AM

Quote:

Quote:

For Jupiter:
- Nature of the chemical component that makes the class of the red spots: GRS, BA, NNTZ LRS




What is the mystery? Are they unable to measure or deduce the chemicals required? Can you point me to where this is discussed somewhere?
Thanks!




I have no web reference in mind right now, but I have read many times that the component that gives the color to the red spots is not identified. We just know that it must be brought from deeper inside by the strong vortices that they are, and it reacts with sunlight UV by reddening.

Regarding the question of the visibility of martian relief - the question is when you can affirm that you have seen the relief itself just like on Earth we see in 3D a mountain for example.
Olympus Mons is very easy to image even with small telescopes but what we are seeing at opposition is "only" the albedo differences of the region. Yet, those differences are enough to catch the caldera of the Mons with the losange shape of its extended flank. But is this relief ? Not really !
On the other hand we manage to detect easily effects of the relief, like shadows (very easy to image at quadrature before opposition, Tharsis volcanoes and Valhalla), or when the Tharsis summits pop up through morning haze (second part of aphelical apparitions), we can add brightening at opposition due to reflexion of sunlight (Olympus Mons at early november 2005, spectacular even visually), and frost in fall/winter (one crater imaged in 2005).
The dust trapped in Valles Marineris Michael is also a nice manifestation of relief !
But none of this is really seeing the relief.


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