Dawn at Ceres Thread

[theend3r]

I found this animation showing the "cone".

That's not a realistic represenation though, the heightmap is exaggerated to better show the structure of the surface.

I think it's at least 2x smaller irl.

[smjjames]

Ceres' cone looks cropped at the top. This and the darker flows/trails/collapse on the side makes me think it had erupted violently before going silent.

I had that in mind:

http://i.telegraph.co.uk/multimedia/archive/01747/volcano_1747497i.jpg

It's an Indonesian volcano, located on the island of Java, the Merapi.

Would it theoretically be possible for an impactor to have clipped off the top of that? I know the chances are astronomically low because it would have to have so many things be exactly right.

[Findthepin1]

Hubble captured the bright spots in a series of photos of Ceres years ago. For them to still be there means, if they're ice, that the ice is being actively replenished. As LordFerret mentioned, Ceres is too warm for ice, and any on the ground would sublime away fairly quickly. I don't suspect a cryovolcano to be responsible, at least not in the traditional sense of the term.

My theory is that a large impact event (the one that caused the crater containing the primary group of spots) created a lot of upwelling in the mantle (which is expected to be mostly ice) and made a "lake" of liquid water extending down to the rocky part of Ceres, and up to a few miles beneath the surface. Much more recently, a small asteroid impacted Ceres above the lake and broke a hole in the crust. Water was released from the hole and froze. This would account for the very reflective surface of the spots, and their position on the globe.

[smjjames]

What about light colored minerals, could that maybe explain some of the bright spots? Dawn does have sensors that determine the minerals (or at least give clues to) present on the surface.

[LordFerret]

Hubble captured the bright spots in a series of photos of Ceres years ago. For them to still be there means, if they're ice, that the ice is being actively replenished. As LordFerret mentioned, Ceres is too warm for ice, and any on the ground would sublime away fairly quickly. I don't suspect a cryovolcano to be responsible, at least not in the traditional sense of the term.

My theory is that a large impact event (the one that caused the crater containing the primary group of spots) created a lot of upwelling in the mantle (which is expected to be mostly ice) and made a "lake" of liquid water extending down to the rocky part of Ceres, and up to a few miles beneath the surface. Much more recently, a small asteroid impacted Ceres above the lake and broke a hole in the crust. Water was released from the hole and froze. This would account for the very reflective surface of the spots, and their position on the globe.

I didn't state that, lajoswinkler did.

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Would it theoretically be possible for an impactor to have clipped off the top of that? I know the chances are astronomically low because it would have to have so many things be exactly right.

I proposed the same scenario a while back (this thread?).

[smjjames]

I didn't state that, lajoswinkler did.

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I proposed the same scenario a while back (this thread?).

If you did, I didn't see the post, sorry. Anyways, theres a crater RIGHT next to it and it seems to have the right direction to it. No expert on that though.

[lajoswinkler]

"Mercury has very little atmosphere" - https://solarsystem.nasa.gov/planets/profile.cfm?Object=Mercury

"Mercury has a very tenuous and highly variable atmosphere (surface-bound exosphere)" - https://en.wikipedia.org/?title=Atmosphere_of_Mercury

Mercury has an atmosphere.

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As for water ice on Ceres (or better yet, within Ceres)...

"We see no real evidence for ice at the surface of Ceres," Rivkin said, noting that the dwarf planet is too warm. "However, conditions beneath Ceres’ surface should allow buried ice to remain there." - http://www.astrobio.net/news-exclusive/ice-on-ceres-an-interesting-paradox/

"One of several mysterious bright spots on dwarf planet Ceres could be venting a plume of water vapor into space, ..." - http://news.nationalgeographic.com/2015/03/150317-ceres-nasa-dwarf-planet-plume-space-science/

And (a year old already)...

"Astronomers have discovered direct evidence of water on the dwarf planet Ceres in the form of vapor plumes erupting into space, possibly from volcano-like ice geysers on its surface.

Using European Space Agency's Herschel Space Observatory, scientists detected water vapor escaping from two regions on Ceres, a dwarf planet that is also the largest asteroid in the solar system. The water is likely erupting from icy volcanoes or sublimation of ice into clouds of vapor." - http://www.space.com/24366-dwarf-planet-ceres-water-ice-volcanoes.html

I would not close the book on there being water ice on or in Ceres. I'll just sit here and wait for the real authorities at ESA and NASA to explain it.

You're using popular science sources and Wikipedia, which is notorious for someone's opinions becoming the media-infecting "truth".

If we're gonna use your definition of atmosphere, then ALL planetary bodies and everything has an atmosphere because everything in this universe gives off gas, no matter how tiny amounts. Even few hundred metres asteroids. Toolbag one astronaut lost during EVA on ISS had an atmosphere. Hell, even ISS has atmosphere, then.

So where's the limit? Definitions are used to give meaning to the stuff that makes up this world. Your definition is meaningless because it does not offer distinguishable differences, therefore no informations.

Mercury has no atmosphere. It has traces of outgassing that does not behave like a real gas (infinitesimally small probability of particle interactions), it is not stratified, and constantly seeps away, just like suitcases, teapots, tiny asteroids and space probes have.

[Red Iron Crown]

Locking for cleanup. Please stand by, service will be returned shortly.

And we're back.

Please try to keep the thread on topic, which in this case is Ceres and the Dawn probe's approach to it. Even more so, please refrain from discussing the personalities of other posters, if you feel they are out of line then hit the report button or add them to your ignore list.

Edited June 20, 2015 by Red Iron Crown

[KerikBalm]

You're using popular science sources and Wikipedia, which is notorious for someone's opinions becoming the media-infecting "truth".

To be fair, the wikipedia article is quite good, the only problem is the title.

Throughout the article, "exosphere" is used 12 times, the word "atmosphere" is used 4 times in reference to Mercury - two of which are basically saying it doesn't have one.

In order of appearance:

* "Mercury has a very tenuous and highly variable atmosphere (surface-bound exosphere)"

* "The existence of a Mercurian atmosphere had been contentious before 1974"

* "consensus had formed that Mercury, like the Moon, lacked any substantial atmosphere."

* "observations by Messenger reported in 2014 note the atmosphere is supplemented by materials vaporized off the surface by meteors both sporadic and in a meteor shower"

All the other times, the article calls it an exosphere.

The article as a whole supports the view: Mercury has no proper atmosphere. For all intents and purposes, it has no atmosphere. There are some very sparse particles flying around.

This is more of a case of using a reference that doesn't actually support what they cite it to support.

[Requia]

You're using popular science sources and Wikipedia, which is notorious for someone's opinions becoming the media-infecting "truth".

For many of those sources sure, but one of them is NASA.

[lajoswinkler]

Finally, a less exposed image of the spots. Ceres is still much brighter here than it really is.

"A cluster of mysterious bright spots on dwarf planet Ceres can be seen in this image, taken by NASA's Dawn spacecraft from an altitude of 2,700 miles (4,400 kilometers). The image, with a resolution of 1,400 feet (410 meters) per pixel, was taken on June 9, 2015."

http://photojournal.jpl.nasa.gov/catalog/PIA19579

Also, compare this,

with this.

Edited June 22, 2015 by lajoswinkler

[Ethanadams]

the white dots remind me of when you spill some flour into dirt

[smjjames]

Finally, a less exposed image of the spots. Ceres is still much brighter here than it really is.

"A cluster of mysterious bright spots on dwarf planet Ceres can be seen in this image, taken by NASA's Dawn spacecraft from an altitude of 2,700 miles (4,400 kilometers). The image, with a resolution of 1,400 feet (410 meters) per pixel, was taken on June 9, 2015."

http://photojournal.jpl.nasa.gov/catalog/PIA19579

http://photojournal.jpl.nasa.gov/jpeg/PIA19579.jpg

Also, compare this,

http://www.nasa.gov/sites/default/files/thumbnails/image/pia19578-1041.jpg

with this.

http://photojournal.jpl.nasa.gov/jpeg/PIA19574.jpg

Still looks like a mountain to me, and a pretty big one at that, for Ceres anyway. That small whiteish spot in the third pic looks like it's a small peak or hill as well.

[Aanker]

Lajos, I used to be a photography purist who would never edit or otherwise tinker with my images because doing so would spoil the 'true appearance' of what they depicted. But then I came upon the realization that the human eye, the visual cortex and the rest of the brain are lying to us in infinitely more insidious and uncompromising ways than a photograph can or ever will.

A popular example. The pages of a book appear to be white in your typical indoor lighting environment. Yet outdoors, compared to a white page illuminated by natural sunlight, the same page would be darker than the black print (also reflecting some sunlight). Our eyes are more sensitive to contrast between light and dark and certain key colours than they are at determining the 'true' brightness of an object. In truth, neither the white page illuminated by indoor lighting nor the one reflecting the sun's light are truly white - they're greyish-brown - and the same analogy can be used for Ceres.

The white spots aren't really perfectly white. I mean, honestly, they can't be unless they emit such light on their own or reflect 100% of all incoming light. But they are clearly much brighter than their surroundings, something the human eye wouldn't just be able to pick up, it would reinforce through a complex system of signals inside the retina. And our interior photo manipulation doesn't end there. We recognize orientations, lines, circles, shadows and terrain - these are characteristics of higher processing inside the brain. If NASA has upped the contrast in these images, it's not so much a scam as it is a way to make an easier time for our brains in processing these images.

The only really objective way of presenting this type of information would be to show each pixel in the image as a value in a table, set your upper and lower bounds, and then use calculations to delineate which areas are true 'points of interest'. But that's the crux of it, isn't it: the purpose of these images isn't to present us with objective data, it is to give us something beautiful to look at as a reward of sorts. Or to inform us in a brief and effective way on what the world roughly looks like. The purpose of what is presented is as important as the presentation itself, and in this case it isn't supposed to be 100% truthful anyway.

[KerikBalm]

Finally, a less exposed image of the spots. Ceres is still much brighter here than it really is.

Well, that sort of depends on your monitor, and the ambient lighting conditions. turn your screen's brightness down to its minimum level, and look at the image at night (wide open retinas) and you will percieve it to be brighter than if you looked at your dime screen while outside in broad daylight.

Its an image, not the actual object. The image our eyes form of actual objects is also distorted and not consistent.

Anyway, here's a dimmer version of it (same data, just everything made dimmer).

The bright spot should be brighter, as it was overexposed... one doesn't know how bright to make those pixels that were overexposed/at their maximum value already.

[grawl]

Finally, a less exposed image of the spots. Ceres is still much brighter here than it really is.

Also, compare this,

http://www.nasa.gov/sites/default/files/thumbnails/image/pia19578-1041.jpg

with this.

http://photojournal.jpl.nasa.gov/jpeg/PIA19574.jpg

All I could see in the second picture was this cute little chicken

What jumps to my eyes is that the cone seems to have changed its shape in the interval between pictures 2 and 3. BUT I wouldn't trust picture 3 on the perfect 3D cone impression it gives at first glance. Looking closely, it might as well be a concave shape.

One wild thought would be to think that is a still-active feature, isn't it ?

The other feature, the one that looks like a drop of flour on the floor, does actually look like it's material thrown by the asteroid impact. Maybe there was a pocket of this lighter-coloured material right there, just under the surface.

By the way, I have no idea how these pictures are generated. Is it a mix of radar heightmaps and photo textures ? Or is it simply the raw picture from the camera with some filters ? Or something else ?

Some of them do have a surreal look.

Edited June 23, 2015 by grawl

[lajoswinkler]

Lajos, I used to be a photography purist who would never edit or otherwise tinker with my images because doing so would spoil the 'true appearance' of what they depicted. But then I came upon the realization that the human eye, the visual cortex and the rest of the brain are lying to us in infinitely more insidious and uncompromising ways than a photograph can or ever will.

A popular example. The pages of a book appear to be white in your typical indoor lighting environment. Yet outdoors, compared to a white page illuminated by natural sunlight, the same page would be darker than the black print (also reflecting some sunlight). Our eyes are more sensitive to contrast between light and dark and certain key colours than they are at determining the 'true' brightness of an object. In truth, neither the white page illuminated by indoor lighting nor the one reflecting the sun's light are truly white - they're greyish-brown - and the same analogy can be used for Ceres.

The white spots aren't really perfectly white. I mean, honestly, they can't be unless they emit such light on their own or reflect 100% of all incoming light. But they are clearly much brighter than their surroundings, something the human eye wouldn't just be able to pick up, it would reinforce through a complex system of signals inside the retina. And our interior photo manipulation doesn't end there. We recognize orientations, lines, circles, shadows and terrain - these are characteristics of higher processing inside the brain. If NASA has upped the contrast in these images, it's not so much a scam as it is a way to make an easier time for our brains in processing these images.

The only really objective way of presenting this type of information would be to show each pixel in the image as a value in a table, set your upper and lower bounds, and then use calculations to delineate which areas are true 'points of interest'. But that's the crux of it, isn't it: the purpose of these images isn't to present us with objective data, it is to give us something beautiful to look at as a reward of sorts. Or to inform us in a brief and effective way on what the world roughly looks like. The purpose of what is presented is as important as the presentation itself, and in this case it isn't supposed to be 100% truthful anyway.

I think you might've misinterpreted the whole "NASA images" discussion here which spiked around the color, not illumination. We're just in search of information on what kind of filters are used. For example, in the latest Cassini's images of Dione, it was said the images (monochrome) were taken through clear filters, meaning it's "full spectrum", as it's called in photography jargon. And that's ok. We know it's grayscale containing wide spectrum and that's it. The problem is when we're fed with images without basic information supplied. Is that too much to ask? It really isn't. Is it grayscale or is it really just gray to us? Is it overexposed? Are the colors false? Basic questions.

I'm well aware of how our eyes+brain work and I'm by no means ignorant in the field of photography or physiology.

The problem of not supplying the public with basic information is that it leads to confusion and confusion leads to mistrust. You know how teh interwebs work. NASA's public relations should know that inadequate information today causes massive confusion and conspiracy theories and whatnot. It ultimatively returns back as lowered public support, yet NASA still behaves inert and slow like it's living in the 60s when all the public got was nice photos in magazines.

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All I could see in the second picture was this cute little chicken

http://s9.postimg.org/ftaq6rtf3/Sans_titre.png

What jumps to my eyes is that the cone seems to have changed its shape in the interval between pictures 2 and 3. BUT I wouldn't trust picture 3 on the perfect 3D cone impression it gives at first glance. Looking closely, it might as well be a concave shape.

One wild thought would be to think that is a still-active feature, isn't it ?

The other feature, the one that looks like a drop of flour on the floor, does actually look like it's material thrown by the asteroid impact. Maybe there was a pocket of this lighter-coloured material right there, just under the surface.

By the way, I have no idea how these pictures are generated. Is it a mix of radar heightmaps and photo textures ? Or is it simply the raw picture from the camera with some filters ? Or something else ?

Some of them do have a surreal look.

Chicken FTW.

The photos are not radar heightmaps with pasted textures. They are taken by a Framing Camera and are grayscale. I have no idea what's the spectral range of the images.

The Framing Camera is designed to acquire detailed optical images for scientific purposes as well as for navigation in the vicinities of Vesta and Ceres. Dawn carries two identical and physically separate cameras for redundancy, each with its own optics, electronics and structure. Each camera is equipped with an f/7.9 refractive optical system with a focal length of 150mm and can use 7 color filters, provided mainly to help study minerals on Vesta's surface. In addition to detecting the visible light humans see, the cameras register near-infrared energy. Each camera includes 8 gigabits of internal data storage. The Max Planck Institute for Solar System Research, Germany, was responsible for the cameras' design and fabrication, in cooperation with the Institute for Planetary Research of the German Aerospace Center and the Institute for Computer and Communication Network Engineering of the Technical University of Braunschweig.

I assume the photos are taken through clear filters, so we're getting something like 400-1100 nm, as you can see here.

http://indico.cern.ch/event/43007/material/6/0?contribId=19

That's basically VIS+NIR combined so it's quite close to VIS only.

The conical thing is just photographed from a different perspective.

[smjjames]

Lajos, I used to be a photography purist who would never edit or otherwise tinker with my images because doing so would spoil the 'true appearance' of what they depicted. But then I came upon the realization that the human eye, the visual cortex and the rest of the brain are lying to us in infinitely more insidious and uncompromising ways than a photograph can or ever will.

Actually, theres an illusion in the second photograph. It may be called something else, but I call it the 'inside out craters' illusion. If you're looking at the bottom area, the illusion isn't really present, but as soon as you look at the upper portion for a few seconds, boom, the craters appear to be 'inside out' or as raised terrain. I mean, you and I know that they aren't actually inside out, but your brain and eyes want to percieve them as inside out.

What jumps to my eyes is that the cone seems to have changed its shape in the interval between pictures 2 and 3. BUT I wouldn't trust picture 3 on the perfect 3D cone impression it gives at first glance. Looking closely, it might as well be a concave shape.

One wild thought would be to think that is a still-active feature, isn't it ?

Not really, we're just looking at it from a different angle and seeing the opposite face that we couldn't see very well before.

Also, does anybody know the scale of that feature? It seems to tower over everything else in that region.

Edited June 23, 2015 by smjjames

[baggers]

Actually, theres an illusion in the second photograph. It may be called something else, but I call it the 'inside out craters' illusion. If you're looking at the bottom area, the illusion isn't really present, but as soon as you look at the upper portion for a few seconds, boom, the craters appear to be 'inside out' or as raised terrain. I mean, you and I know that they aren't actually inside out, but your brain and eyes want to percieve them as inside out.

Not really, we're just looking at it from a different angle and seeing the opposite face that we couldn't see very well before.

Also, does anybody know the scale of that feature? It seems to tower over everything else in that region.

The "illusion" is implied by a classic convention: in almost every classic painting for example, main light source came from the upper rigth corner. Our brain have accepted that convention and use it to render the 2D shadows in depth.

In space, ligth could came from everywhere. This could trick our brain if it don't came "from the top". Especially if the picture (or portion of it) haven't an obvious reference point for the direction of incoming light.

Just rotate the second picture for having a top incoming ligth instead of a bottom one and your brain will properly understand the shadows.

(Note that if you do that, maybe you couldn't return to the "illusion" by rotating back the pic: If your brain "know" that the pic "is upside down" it will correct itself the rendering. And not let you roll back to the previous statement.

That sort of image rendering is not a full conscious process. Like heart beat, "you" (as a more complex and conscious brain process) don't really have much control on it. ^^)

Edited June 24, 2015 by baggers

[grawl]

Also, does anybody know the scale of that feature? It seems to tower over everything else in that region.

It's something around 12km x 6km if I recall correctly

[Candlelight]

Heyhey...

We have a better look at the mysterious dots on the surface:

Thanks Dawn.

You're quite a buddy these days.

But you are still second place, behind New Horizons.

And a question.Who else here, but me, would like to send a Rosetta-like mission and deploy a lander to land in the crater with the spots.

Edited June 24, 2015 by Candlelight

[Ralathon]

And a question.Who else here, but me, would like to send a Rosetta-like mission and deploy a lander to land in the crater with the spots.

I'd love landers everywhere. But it takes about 320m/s to land on Ceres from Dawn's lowest planned orbit. That's a pretty heavy lander for something operating beyond Mars orbit.

[Scotius]

I'd love landers everywhere. But it takes about 320m/s to land on Ceres from Dawn's lowest planned orbit. That's a pretty heavy lander for something operating beyond Mars orbit.

So...anyone got news about Cannae\EmDrive? With such engine at our disposal, we could probe the heck of every asteroid, comet and (smaller) dwarf planets in the system. Given enough time and will of course

[KerikBalm]

"So...anyone got news about Cannae\EmDrive?"

Well, contrary to the popular saying... no news is bad news.

Don't pin your hopes on it... its highly unlikely that it works as claimed.

[lajoswinkler]

Radon86, you haven't paid attention.

Here's a better photo of the dots.

http://photojournal.jpl.nasa.gov/jpeg/PIA19579.jpg

Yes, it would be interesting to land something there.