APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

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Expand view Topic review: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by Znon » Tue May 26, 2015 1:37 am

Given that they think that the density is around that of water it is also possible that the small body is made of Lithium or Sodium (not very likely or probable). When hit by a small impactor it would uncover Lithium or Sodium that has a shiny surface that has not been exposed to the solar wind.

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by BMAONE23 » Fri May 01, 2015 7:11 pm

How about the tip of a Diamond Core :mrgreen:
(there is more than one kind of ICE)

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by ta152h0 » Fri May 01, 2015 6:53 pm

LED lighting occurring naturally ? Free ice cold one if I am right

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by sallyseaver » Fri May 01, 2015 4:45 am

I would like to propose a different conjecture about the surface of Ceres from what I proposed earlier.

It occurred to me that any ice that would have been present from the primordial surface of Ceres (from releasing steam that froze in cold space) would most likely have been blasted away from galactic cosmic-ray particles and solar energetic particles (from the solar winds). I initially thought that the rocky material on the surface of Ceres would have protected ice underneath. However, without a protective magnetosphere, a thin layer of rocky material would probably not be enough to protect ice underneath.

Consider this. Planets, asteroids and meteorites are bombarded with
Solar energetic particles [SEPs] – 10^3 eV to 10^9 eV
protons, electrons, helium ions, and high-Z [HZE] ions
Intergalactic cosmic rays – 10^5 to 10^21 eV*
“All of the natural elements in the periodic table are present in cosmic rays, in roughly the same proportion as they occur in the solar system.” They are going so fast that the electrons and nuclei travel separately. The mix of nuclei is about 90% hydrogen nuclei (protons), 9% are helium nuclei (alpha particles) and 1% nuclei
of other heavier elements [HZE ions]
These energies are the same or greater than particle accelerators. If you took a rock, coated it with ice in proportion to an ice layer that might exist on Ceres with a subsequent coating of a thick layer of mud; then were able to introduced this model of Ceres into the particle stream of a working particle accelerator, and let it sit there for 2 to 4 billion years, would you expect the ice to still be present?

It's not a perfect analogy, but you get the idea.


On the other hand, magnesium is the 9th most abundant element in the universe. According to information curated and published by Mathematica and Wolfram Research, Inc, magnesium is 12% of meteorites for example. (http://periodictable.com/Elements/012/data.html)

According to my favorite theoretical model, there is a strong likelihood that magnesium would be present on Ceres in abundance. Evidently, magnesium only occurs naturally in combination with other elements. Given the general abundance of hydrogen and oxygen in our solar system, we could expect magnesium hydroxide and magnesium oxide (which are white substances), but we could also expect magnesium sulfate (due to an abundance of sulfur in the parent nebula for our solar system) and similarly, we can expect magnesium carbonate. All of these are white or colorless.

A magnesium sulfate mineral found on neighboring planet Mars is meridianiite. It is clear to colorless and would reflect light nicely.

Also, diffusive losses from the bombardment of meridianiite (and other magnesium sulfates) would include water vapor.

I learned from the Russell interview that Ron-Astro posted, that this idea of the bright spots being due to certain salts is one of the contenders that Dawn Team is considering (meridianiite and other magnesium substances qualify as salts).

Chris Russel wrote: from
http://www.space.com/28776-nasa-dawn-ce ... rview.html
But there are people who are holding out for salt — not necessarily table salt, but salts of various minerals that may be white in appearance. So we have sort of a dichotomy of opinion in the team as to whether this has a dry or wet explanation. But we'll get to the bottom of this when we can resolve the bottom of the feature.


I have missed participating in this discussion with you all. [I did not stop discussing due to lack of interest, but was detained by work.]



† Cosmic Rays http://imagine.gsfc.nasa.gov/science/ob ... rays2.html
* Energies: http://www.gizmag.com/cosmic-rays/28997/;

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by Ron-Astro Pharmacist » Thu Mar 12, 2015 5:18 pm

http://phys.org/news/2015-03-revolution ... tml#ajTabs

Maybe for these types of engines they'll have to come up with a new measure of power for those of us who need a mental clue.
Horsefly.jpg
Horsefly.jpg (5.82 KiB) Viewed 12594 times
Horsefly power?

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by Ron-Astro Pharmacist » Tue Mar 10, 2015 4:32 pm

Update on Dawn - It arrived. :wink: Wonder if Ceres is on DST?

http://www.space.com/28776-nasa-dawn-ce ... rview.html

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by Ann » Mon Mar 02, 2015 4:54 pm

Image
Hi, Art, welcome back! :D

Ann

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by Ron-Astro Pharmacist » Mon Mar 02, 2015 4:46 pm

neufer wrote:The TITY-BOLE LAW: Many Volcanoes Erupt Marshmallows, Certainly!
Welcome back "Billy". Hope you enjoyed your vacation!! Hope all's well with Montana. :wink: Oh – I forget this is a Ceres discussion. Anyone know how hot it gets in the center of an asteroid of that size?

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by Chris Peterson » Mon Mar 02, 2015 2:59 pm

geckzilla wrote:It is not the mere presence of ice that is unexpected to me but its existence in an isolated but apparently fresh state on the surface of a world not obviously undergoing any other sort of activity. Look at those craters. It looks pretty old.
I don't think there's anything surprising or unexpected at all. Asteroids have low albedos because they have space weathered surfaces. Ceres may have an underlying surface layer with a high ice content, but even if it doesn't, any unweathered rock will be higher albedo. So a meteorite impact will almost certainly create a spot that is more reflective.

Large impacts are rare; small ones are not. It is probably harder to explain a large area that is just a few percent brighter than it is a small spot that is a few hundred percent brighter.

In any case, I don't think the mission scientists are surprised by the spot (or spots) at all. It would be very strange indeed if Ceres didn't have a varied surface (like every other body in the Solar System). Everyone is curious about the nature of the variation, not surprised it is present.

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by neufer » Mon Mar 02, 2015 12:56 pm

Nitpicker wrote:
“We estimate that approximately 6 kg of water vapour is being produced per second, requiring only a tiny fraction of Ceres to be covered by water ice, which links nicely to the two localised surface features we have observed,” says Laurence O’Rourke, Principal Investigator for the Herschel asteroid and comet observation programme
It doesn't sound quite violent enough to be like any kind of volcano I've ever heard of.
My toilet flush probably has a flow rate of 6 litres per second!
The TITY-BOLE LAW: Many Volcanoes Erupt Marshmallows, Certainly!

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by Nitpicker » Mon Mar 02, 2015 12:35 pm

geckzilla wrote:
Nitpicker wrote:It doesn't sound quite violent enough to be like any kind of volcano I've ever heard of. My toilet flush probably has a flow rate of 6 litres per second!
Yes, exactly. Either I need to accept this new form of "volcano" as an adequate word for describing such a phenomenon which may also bear analogous similarities to typical volcanoes or a different word would be more appropriate. Why not geyser? It seems to work for Enceladus. Cryovolcano is catchy, I suppose, but if you could safely walk around in it and not even notice the water movement, it's totally overrated.
Comet-like sublimation seems more likely at this stage. But "geysers" seem to be used fairly regularly to describe cryo-volcanic eruptions.

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by geckzilla » Mon Mar 02, 2015 10:34 am

Nitpicker wrote:It doesn't sound quite violent enough to be like any kind of volcano I've ever heard of. My toilet flush probably has a flow rate of 6 litres per second!
Yes, exactly. Either I need to accept this new form of "volcano" as an adequate word for describing such a phenomenon which may also bear analogous similarities to typical volcanoes or a different word would be more appropriate. Why not geyser? It seems to work for Enceladus. Cryovolcano is catchy, I suppose, but if you could safely walk around in it and not even notice the water movement, it's totally overrated.

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by Nitpicker » Mon Mar 02, 2015 10:22 am

geckzilla wrote:Maybe so. I'm definitely dubious of the whole cryovolcano thing. Or perhaps it's the volcano part which bothers me because when I think of volcanoes I think of a very active surface that sees a lot of remodeling. Ceres holds its secrets for another day.
“We estimate that approximately 6 kg of water vapour is being produced per second, requiring only a tiny fraction of Ceres to be covered by water ice, which links nicely to the two localised surface features we have observed,” says Laurence O’Rourke, Principal Investigator for the Herschel asteroid and comet observation programme
It doesn't sound quite violent enough to be like any kind of volcano I've ever heard of. My toilet flush probably has a flow rate of 6 litres per second!

But the notion of a cross-over in the classification of asteroids and comets (and also, independently, of terrestrial planets forming with a significant supply of water-bearing, hydrated minerals) is quite compelling to me.

Dawn is going to take quite a while to spiral in really close to Ceres. I understand it won't achieve its maximum planned image resolution (<100 m per pixel) until the end of the year. And it might be a few months yet before these bright spots are close enough to be resolved convincingly.

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by geckzilla » Mon Mar 02, 2015 9:50 am

Maybe so. I'm definitely dubious of the whole cryovolcano thing. Or perhaps it's the volcano part which bothers me because when I think of volcanoes I think of a very active surface that sees a lot of remodeling. Ceres holds its secrets for another day.

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by Nitpicker » Mon Mar 02, 2015 8:37 am

geckzilla wrote:It is not the mere presence of ice that is unexpected to me but its existence in an isolated but apparently fresh state on the surface of a world not obviously undergoing any other sort of activity. Look at those craters. It looks pretty old.
But it possibly matches with this:
http://www.esa.int/Our_Activities/Space ... anet_Ceres

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by geckzilla » Mon Mar 02, 2015 7:54 am

It is not the mere presence of ice that is unexpected to me but its existence in an isolated but apparently fresh state on the surface of a world not obviously undergoing any other sort of activity. Look at those craters. It looks pretty old.

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by Nitpicker » Mon Mar 02, 2015 7:35 am

I don't understand why small localised ice patches would be so unexpected on Ceres (especially if they are supplied from the mantle via some mechanism). Its semi-major axis lies just beyond the water frost line of the Solar system (which just happens to divide the main asteroid belt). Ceres has a density only twice that of water, indicating that it is likely to contain a lot of it. It has a noticeable oblateness, which could indicate a rocky core and an icy mantle. And its spectra tell of a crust rich in hydrated minerals, indicating water below.

And Sally, as for my confidence in the 9% number, I think it was more a case of my lack of confidence in your method of disputing it (which was totally bogus). And as for the formation of the Solar System, I'm not so familiar with the literature, but I am less familiar with the notions that you appear to attribute to the "standard model". You will need to argue your case in much smaller steps if you want me to take your theories seriously. There is a helluva lot of H2O in the Solar System and resonances with migrating gas giants, would appear to be the most likely cause of its wide distribution.

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by geckzilla » Mon Mar 02, 2015 6:33 am

I don't know if I'm defending (or attacking for that matter) anyone's ideas so much as I am beating myself up for being a know-it-all earlier even though I didn't post my thoughts on the matter to reveal as much. And Nitpicker points out that the facts were all right there in writing but it's something I still failed to understand. I still won't say it's any kind of ice right now but especially water ice would be a very strange and unusual thing indeed. I just think it's much brighter than originally suspected.

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by sallyseaver » Mon Mar 02, 2015 6:17 am

Thank you, Geckzilla , for representing my concern regarding a steadfast sticking to the 9% number at a time when the reports are that scientists are surprised by the light spots and light areas on Ceres. And thank you so much for passing on the information from Chris Russell regarding a possible 0.4 albedo for the bright white spot on Ceres. I receive your caution that it is a casual report, not a formally published - and there fore reliable - report.

Nitpicker, thank you for explaining why you had the confidence about the 9% number. I am properly chastened for trying to report results from a dataset that I did not understand as I should have. :oops: I hope that someday I can convince you that my lack of understanding about albedo measurements and datasets does not translate to a lack of understanding about mass, space, time, physics and planet formation.

I think this comment of yours is particularly relevant to our conversation:
Nitpicker wrote: It should also be noted that there are quite a few different kinds of albedo measurements and they are all frequently mixed up and bandied about by amateur enthusiasts, making the numbers somewhat rubbery. Not to mention that variable albedo measurements are all dependent on resolution in one way or another. I am sure the figures I've quoted for variation of albedo on the Moon, are not based on the best photographic resolution currently possible. I'd bet there are small patches/pebbles/grains on the surface of the Moon, that reflect light with a much higher albedo than the quoted maximum of 0.183.
This comment, on the other hand, seems a little out of place:
Nitpicker wrote:Yes, but we were right to stick with that conclusion, rather than speculate over a handful of new, higher resolution images from Dawn, with hardly any published technical details. Once technical details of the newest images become available publicly, the situation will be different.
C'mon, Nitpicker, you wouldn't publish a paper on results from a new constrast-enhanced image, but isn't the purpose of this thread to conjecture on the new, higher-resolution images from Dawn, given the new unexpected results? (And if there was not an interest in finding a new explanation for unexpected results, I would not have jumped in with my explanation from Mass Vortex Theory.)

Given your commitment to Standard Theory (the current status quo consensus), please explain why you say the following:
Nitpicker wrote:It would not be a great surprise to find ice of some form and in some proportion, weathered to some degree, on the surface of Ceres. It is entirely expected.
I thought that planets and asteroids were supposedly formed from rocky material in orbit around the newly formed sun colliding, generating heat, separating into layers, and then gradually cooling down. An ice layer has never been part of the Standard-Theory explanation for planet, or dwarf-planet formation that I have seen (I freely admit that I am not as acquainted with the literature as you are). We have some observations about ice layers on some moons, but I have not seen a Standard-Theory explanation for this observed feature.

With Ceres, you have the problem of an ice layer plus another layer of rocky debris on top. You say that the ice could be "weathered to some degree," but space weather does not account for rocky material distributed over the whole surface. As far as I know, space weather has to do with high speed ions and electrons discharged by the sun; space weather is monitored by ground-based magnetometers and magnetic observatories. So, space weather involves electromagnetic forces and charged particles, not rocky stuff.

Please explain why an ice layer with a dusting of rocky material fits within the explanation of Standard Theory. [I think other readers may be interested in this also.]

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by Nitpicker » Mon Mar 02, 2015 6:12 am

geckzilla wrote:I'm saying we should have talked about what Hubble's albedo measurements meant. I'm annoyed that I didn't interpret it very well, myself.
I don't think anyone realised, initially, that the "mystery" link from the APOD caption, was quoting the Hubble results -- "barely a 9% higher albedo than the surrounding surface" -- whilst discussing the Dawn images. Having said that, the "mystery" link is dated only a week or so after Dawn's image resolution began to exceed Hubble's, and only a day or so after Dawn doubled that resolution. The "mystery" link also stated: "The resolution of the photographs are currently at 14 kilometers (8.5 miles) per pixel, so we don't yet have enough detail to resolve if these are pinprick spots, or brighter regions that are blurring into points through our fuzzy vision."

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by geckzilla » Mon Mar 02, 2015 3:55 am

Now you're talking. :)

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by Nitpicker » Mon Mar 02, 2015 3:51 am

geckzilla wrote:Yes, the results in that paper are no doubt accurate for an average albedo measurement over the surface of Ceres. But it says little or nothing about the characteristics of small, isolated features such as the bright patch. To state that the patch can't be bright because of these measurements is erroneous. Now that we have a closer look at just how small it is, it is remarkable that it shows up at all in Hubble's images. I'm leaning towards the conclusion that the patch is very bright indeed.
But given that we know the Hubble pixels have an area of about 900 km2, if the albedo of the bright patches is 1.0, they must have an area of about 10 km2. If the albedo of the patches is 0.4, they must have an area of about 30 km2. (In nice round figures.)

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by geckzilla » Mon Mar 02, 2015 3:19 am

Yes, the results in that paper are no doubt accurate for an average albedo measurement over the surface of Ceres. But it says little or nothing about the characteristics of small, isolated features such as the bright patch. To state that the patch can't be bright because of these measurements is erroneous. Now that we have a closer look at just how small it is, it is remarkable that it shows up at all in Hubble's images. I'm leaning towards the conclusion that the patch is very bright indeed.

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by Nitpicker » Mon Mar 02, 2015 3:03 am

Well, yes, it appears I have largely misinterpreted you today. :roll:

Here is a brief conference paper discussing the Hubble results. Note "Fig. 2." showing maximum albedo 8% higher than global average:
http://www.lpi.usra.edu/meetings/abscic ... f/5455.pdf

Re: APOD: Dark Craters and Bright Spots on... (2015 Feb 18)

by geckzilla » Mon Mar 02, 2015 2:49 am

You seem to be taking it personally. I'm saying we should have talked about what Hubble's albedo measurements meant. I'm annoyed that I didn't interpret it very well, myself.

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