I'm not sure if we have enough precision in our measurements to say what type of ice it is. However, it is in the range of being reflected light and we have no evidence they are light sources. Also, I read yesterday (but I can't remember where) while researching this topic that the lights at first appear to stay lit while the background fades, and therefore seem to be light sources, but in fact they do fade as they move past the terminus, which would also confirm their reflective nature. (I think this was one of the NASA scientists. I'll have to find the source.)

I haven't seen enough evidence to convince me of the material. Fresh ice from cryovolcanos? Polished mirrors from ETI? It's all speculation for now, and considering we are about to receive much more accurate figures in a few days/weeks, I'm happy to wait.

A while back in this thread, I took up the issue of the bright spots at Ceres' terminator. I pointed out that the terminator is far from a simple, smooth or continuous line on a cratered world. Crater floors fall dark before their rims, even if Sunward of still lighted high ground.
The series of images taken on February 25th shows the bright spot at the the center of a 57 mile-wide crater. It rotates out of the Sun's reach, and is surrounded by darkness. The bright spot still appears bright.
The images give the impression that it only fades away due to geometric foreshortening. It appears to be a flat object that is eventually seen edge-on, and so, becomes invisible.
We will have a wait of over five weeks before mew images of Ceres are made available. Dawn swung wide of Ceres on its way to settling into a circular orbit. The Sun is currently in the same part of the sky as Ceres, from Dawn's point of view, and will remain there as the space probe approaches the planet. They will avoid taking pictures in the direction of the Sun, for fear of damaging the camera with excessive light.

All this speculation is so much fun to read. Hopefully, within a few weeks there will be an answer to the mystery.

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Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.

No need to wait Bob. I have a crystal ball that can see into the future! Let's take a look:



Hmm.. somehow I thought it would be more significant than that.

I'm not sure if we have enough precision in our measurements to say what type of ice it is. However, it is in the range of being reflected light and we have no evidence they are light sources. Also, I read yesterday (but I can't remember where) while researching this topic that the lights at first appear to stay lit while the background fades, and therefore seem to be light sources, but in fact they do fade as they move past the terminus, which would also confirm their reflective nature. (I think this was one of the NASA scientists. I'll have to find the source.)

I haven't seen enough evidence to convince me of the material. Fresh ice from cryovolcanos? Polished mirrors from ETI? It's all speculation for now, and considering we are about to receive much more accurate figures in a few days/weeks, I'm happy to wait.

if they raise above the surface of the crater...of course they stay lit, even when the edges of the crater go into shade...it's just a mineral...

betting in a coffe, with croasaint - that it's only mineral crystal...
betting in lunch, that it's a meteor made mineral crystal...
who wants to bet?
;)

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non-profit org. Play4Life in Zagreb, Croatia, EU

A rise in the terrain inside the crater which contains the bright spots was carefully looked for. They were looking for evidence of a mound of debris built up by an ice volcano. No evidence of such a rise was found. The possibility of a mound inside the crater is now discounted by NASA.

Update.

Ceres' Mystery Bright Spots May be Ice Plumes

Unexpected bright spots discovered on the surface of the dwarf planet Ceres may be plumes of ice blasting out into space.

NASA’s Dawn spacecraft arrived at Ceres, the largest object in the asteroid belt, earlier this month and is in the process of positioning itself for a 14-month study.

http://news.discovery.com/space/ceres-mystery-bright-spots-may-be-ice-plumes-150318.htm

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The ice plumes being discussed, as an explanation for the bright spots on Ceres could have a couple of different sources. Sublimation of surface ice directly to vapor is suggested, but a new thermal model of Ceres seems to indicate that ice wouldn't be present at the low latitude of the bright spot, but only at more poleward locations.
Cryovolcanoes are another possibility, but here, too, there are problems. Pressure on the supposed subterranean ocean from the layers above might squeeze out icy vapor onto the surface of Ceres, but another new study indicates that this pressure is likely to open cracks in the ice, and relieve the pressure before any vapor can be forced to the surface.

It has also been suggested that radioactive elements in Ceres' core could have produced enough heat to drive cryovolcanoes thermally. However, this seems a long shot in so small a world as Ceres. It seems likely than any radiogenic heat would have dissipated long ago.
In any case, NASA has gone on record as thinking a cryovolcano at the site of the bright spot unlikely. They reportedly looked over the site carefully and found neither a mound of debris that a cryovolcano might leave behind, or cracks in the surface, through which it might issue.

The assertion that the crater on Ceres containing the bright spot is, at one point, seen edge-on, or so near to this as to prevent a view of its floor is questionable. I examined photographs of lunar craters seen from similar angles. The floors of these craters were definitely visible.
The hypothesis about elevated icy vapor plumes was presumably sought because of the difficulty of explaining how the bright spot, if surface ice, could be reflecting light from the dark floor of the crater in which it lies. The most efficient reflector imaginable can't reflect light when there is none.
The further problem of how the sort of thin vapor expected to be found on Ceres could have a reflective efficiency of at least 40 percent, the figure now being given for the bright spot, does not appear to have been considered.

According to the published schedule, Dawn will be taking images of Ceres today. Judging by past experience, we may hope to be shown these pictures on about the 15th or 16th. Further images are planned for the 14th. These will probably be released on the 19th or 20th. Because of current uncertainties about Ceres' period of rotation, the bright spots may, or may not be visible in these images. It will be interesting to see which is the case.

Dawn's Ceres Color Map Reveals Surface Diversity

A new color map of dwarf planet Ceres, which NASA's Dawn spacecraft has been orbiting since March, reveals the diversity of the surface of this planetary body. Differences in morphology and color across the surface suggest Ceres was once an active body, Dawn researchers said today at the 2015 General Assembly of the European Geosciences Union in Vienna.

"This dwarf planet was not just an inert rock throughout its history. It was active, with processes that resulted in different materials in different regions. We are beginning to capture that diversity in our color images," said Chris Russell, principal investigator for the Dawn mission, based at the University of California, Los Angeles.



These images, from Dawn's visible and infrared mapping spectrometer (VIR), highlight two regions on Ceres containing bright spots. The top images show a region scientists have labeled "1" and the bottom images show the region labeled "5."

http://www.nasa.gov/jpl/dawns-ceres-color-map-reveals-surface-diversity/index.html

New Images.

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The area now called 'area 5' is the location of the much discussed double bright spot. The brighter of the two is by far the brightest thing on Ceres. Area 1 is a smaller, less brilliant bright spot, elsewhere on the planet.
Area one proved to be cooler than its darker surroundings, just as one would expect of a lighter colored surface. It reflects more solar energy, and so absorbs less heat; basic physics. Oddly, area 5 showed no temperature difference from the darker areas around it. NASA reportedly reacted to this discovery with surprise.
A couple of questions come to mind.
1.) How does a light colored surface not reflect more energy than a dark one?
2.) Where did the bright spot get the extra heat to offset its natural, relative coolness?

New, clearer pictures of the bright spots on Ceres were taken on April 14th and 15th. According to Dr. Chris Russell, principal investigator for the Dawn mission, the bright spots are still not optically resolved, even at the current resolution of 1300 meters per pixel. That's about 8 times better than the previous best resolution.
The estimated reflectivity or albedo of the spots will presumably have to be raised considerably. This was previously given as a minimum of 40 percent, based on an 8 times larger reflective area.
Link to article on new images, including quote from Dr. Russell, below:
http://www.nbcnews.com/science/space/dwarf-planet-ceres-white-spots-return-dawns-new-video-n344981

Weird, the closer they get the less they know about these mysterious white spots. No mention of alien space craft yet.

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Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.

Weird, the closer they get the less they know about these mysterious white spots. No mention of alien space craft yet.

They are just the marker lights .....

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Weird, the closer they get the less they know about these mysterious white spots. No mention of alien space craft yet.

They are just the marker lights .....

for a Space port?
or did a McClaine light them up?
:D LoL

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non-profit org. Play4Life in Zagreb, Croatia, EU

Maybe it's just a used space ship lot, lighted up to attract customers.

Dawn begins Ceres science mission

Nasa’s Dawn spacecraft settled into its first science orbit around the 950km-wide asteroid Ceres on Thursday.

Since arriving at Ceres on 6 March, Dawn has been manoeuvring into the 13,500km-high orbit using its ion engine. This is relatively new technology that a provides small but constant thrust, which allows satellites to be used much more flexibly.

http://www.theguardian.com/science/2015/apr/23/spacewatch-dawn-science-mission-ceres

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Dawn's first image of Ceres with a resolution of 1300 meters per pixel was released today. It was taken on the 24th. This indicates the usual 5 days delay for arranging transmission back to Earth, and image processing. The previous best images had a resolution of 2100 meters per pixel, not 1300 meters, as I erroneously stated before. Link below to large size version of this image:
http://photojournal.jpl.nasa.gov/jpegMod/PIA19319_modest.jpg

More pictures at this same resolution will become available over the next several days. Those of the bright spots should probably be released around May 9th through the 11th.