Dawn at Ceres Thread

[Camacha]

Remember this is a very small body, with surface older than the Moon's. It's ancient. There is no tectonics, it's probably barely diferentiated inside. It is alone, nothing is squeezing it. There can not be much activity.

Was it not the point going there to find out whether this is true? Let us not jump to conclusions we do not yet have.

[smjjames]

Liquid water can not exist in vacuum. It will partially turn to gas by boiling and one part will solidify. At temperatures encountered on Ceres, water ice will sublimate away in a matter of weeks. Phase equilibrium is totally shifted towards gas.

That does look like a cryovolcano. Remember this is a very small body, with surface older than the Moon's. It's ancient. There is no tectonics, it's probably barely diferentiated inside. It is alone, nothing is squeezing it. There can not be much activity.

Those flows are not lava, but ejecta sliding down. Nothing we haven't seen before.

http://lroc.sese.asu.edu/news/uploads/LROCiotw/M154813223RE_thumb1.png

Similar thing in Tycho crater.

http://www.nasa.gov/sites/default/files/images/565812main_tycho_full_full.jpg

So you're saying that it may be a pile of ejecta?

It does sort of look like that peak in the middle of craters (you can see some in the smaller craters near the bottom of that Ceres image), but this isn't inside an obvious crater.

Also, not THAT much older than the moon, but point taken.

[grawl]

Well, here goes my explanation about the white spots (I had water going out of volcanos and then freezing in mind).

Anyway, it's a fascinating singleton, it looks huge compared to Ceres size. I can't wait to have a better resolution image of this feature.

[Spock1108]

I disagree with you, that cone may not have been generated by a meteor impact, not craters are large enough to generate around a central peak like that ... I agree, on pndici there are white material runny .. . maybe it isn't just water but a miscela of water, ammonia, salts and so on ... have been found traces of liquid water on Vesta (in short periods after a meteor impact grits).

[78stonewobble]

Couldn't it possibly have been the worlds slooooowest impact of an object (nigh just lying down on the ground), which then slowly melted / collapsed under gravity into the coneshape?

[Frida Space]

Couldn't it possibly have been the worlds slooooowest impact of an object (nigh just lying down on the ground), which then slowly melted / collapsed under gravity into the coneshape?

so close to the sun, no impact can be that slow. even in the Kuiper belt, where impacts are very, very slow compared to impacts in the inner solar system, collisions occur at at least 1 km/s.

[smjjames]

so close to the sun, no impact can be that slow. even in the Kuiper belt, where impacts are very, very slow compared to impacts in the inner solar system, collisions occur at at least 1 km/s.

Maybe slow relative to Ceres and the impactor?

[peadar1987]

Maybe slow relative to Ceres and the impactor?

Ceres' escape velocity is 510 m/s. Nothing on an unpowered trajectory can hit it at less than that speed, regardless of its initial speed, position or direction.

[lajoswinkler]

Was it not the point going there to find out whether this is true? Let us not jump to conclusions we do not yet have.

It's a reasonable explanation. I see none to support an icy wonderland.

So you're saying that it may be a pile of ejecta?

It does sort of look like that peak in the middle of craters (you can see some in the smaller craters near the bottom of that Ceres image), but this isn't inside an obvious crater.

Also, not THAT much older than the moon, but point taken.

I'm not sure what it is. It does look like a cryovolcano, but that doesn't mean it's active. The bright features on it can be created by regolith sliding down as volatiles from the rocks are lost during unimaginable long periods of time.

Well, here goes my explanation about the white spots (I had water going out of volcanos and then freezing in mind).

Anyway, it's a fascinating singleton, it looks huge compared to Ceres size. I can't wait to have a better resolution image of this feature.

Even if it could be water coming out, where would all that water come from? There can be no water cycle on Ceres. We're talking about at least 4 billions of years (several thousands millions!) old surface evident by its extreme errosion. Even with relatively weak activity, that's an awfully long amount of time for such a small body.

I disagree with you, that cone may not have been generated by a meteor impact, not craters are large enough to generate around a central peak like that ... I agree, on pndici there are white material runny .. . maybe it isn't just water but a miscela of water, ammonia, salts and so on ... have been found traces of liquid water on Vesta (in short periods after a meteor impact grits).

There is no liquid water on Vesta's surface. It's one study that suggests possible brief flow of mud made by ices (ice = volatiles) right after one meteoroid impact.

If these things happen on Ceres, they need a power source. Where is it? It seems lots of people see this body as very active. There is no evidence to support that idea and also no probable mechanism for it.

This is not Triton which has the privilege to be far from Sun, squeezed by Neptune, with most of its volatiles intact. This is a much smaller body, perfectly alone, close enough to Sun that any surface volatiles (even water) will be gone in a short time. It's so incredibly old that it would be pretty bold to say it's doing something right now just to entertain us, a measly species that existed an unsignificant fraction of its lifetime. A real monkey behaviour, IMO.

It is possible, but it's highly unlikely.

[smjjames]

Well yeah, it's possible that it's an ancient cryovolcano, one that is inactive for the last 3 billion years. Dawn has instruments to look at the mineral makeup of the feature, which will tell us more about what it is.

[grawl]

Looking at the "cone", the extreme surface erosion is not that evident to me. If the erosion was that extreme and nothing has been happening there, we would'nt see any feature on the surface, apart from the meteor craters, and that cone wouldn't be, well, that cone-y.

Please explain, why could'nt there be water on Ceres ? I understand there are no clouds and else, so a proper earth-like water cycle is out of the possibilities. But what if Ceres has a very slow "metabolism" (don't know the proper term for a planet) ? And what if it's not water but a mix of denser fluids ? Probably not possible, but if only probable things were happening, we wouldn't be there

[rumble]

Let me dream of an icy underground geode-like world . Don't break my vibe man. Science is already a slow, not so fun and abstract thing, so at least let people dream about it. Or share your knowledge while not looking down at non-documented comments, that would be even better In the end we are all educated monkeys after all.

[/rumble]

Well, that being said, let's continue

I must admit, after seeing pictures of the moon Tycho crater, features look quite similar, as with the white spots (that's it for the diamond sea lol). But, on Ceres, where is the crater rim around the cone ?

It is baffling me. Has it been named yet ?

Edited June 18, 2015 by grawl
removed some personal stuff not having its place here

[KerikBalm]

Please explain, why could'nt there be water on Ceres ? I understand there are no clouds and else, so a proper earth-like water cycle is out of the possibilities. But what if Ceres has a very slow "metabolism" (don't know the proper term for a planet) ?

Do you mean H2O, or liquid water?

Liquid water can only exist if the ambient pressure is over a certain threshold:

https://en.wikipedia.org/?title=Triple_point

Now, Cere's has no significant atmosphere, the pressure is too low for liquid water to exist.

Ice will directly sublimate to gas (like dry ice on Earth - CO2)

And when sunlight strikes it... it will sublimate...

Surface ice -> gone

Subsurface ice could still be there, but it shouldn't last very long when exposed.

[grawl]

I see.

What kind of thing can be in a fluid (or kinda) state in these conditions ?

Do we know what types of rocks Ceres' surface is made of ?

[lajoswinkler]

Surface brines are something even Mars probably doesn't have (or has sometimes for a brief time), and it has a relatively significant atmospheric pressure compared to Ceres. Ceres really has nothing except for lonesome gas particles jumping around.

Normal liquids are actually a rare sight in the universe (unless we ignore hidden stuff under planetary crusts). They represent a tiny gap between solid and gas states and can exist only if there is sufficient pressure above them.

There are certain liquids that would literally never evaporate (ionic liquids) but they aren't encountered in nature. Synthetic stuff.

[LordFerret]

Mercury has an atmosphere, granted - thin as it is, yet water ice exists in craters at its north pole. Why couldn't Ceres have water ice?

[Kryten]

The water ice at Mercury is only stable because it is in craters that are permanently shaded.

[grawl]

I found this animation showing the "cone".

Definitely looks like a volcano. For comparison, an earth volcano :

No sign of activity though, with the lack of erosion on Ceres, it could have appeared during Ceres early life, and been standing there extinct the rest of the time.

Edited June 19, 2015 by grawl

[peadar1987]

That's a beautiful volcano! Any idea where it is?

[Darnok]

I found this animation showing the "cone".

http://i.imgur.com/q1SMqJH.gif

Definitely looks like a volcano. For comparison, an earth volcano :

http://static1.squarespace.com/static/51bbeba5e4b0510af19f26f7/t/51e6c9fbe4b0f331b977dd14/1374079484978/cinder%20cone.jpg

No sign of activity though, with the lack of erosion on Ceres, it could have appeared during Ceres early life, and been standing there extinct the rest of the time.

Look at the sharp edges

[rkman]

Remember this is a very small body, with surface older than the Moon's. It's ancient. There is no tectonics, it's probably barely diferentiated inside. It is alone, nothing is squeezing it. There can not be much activity.

Dawn's observations at Vesta revealed its interior is differentiated. With Ceres being larger than Vesta, it only very likely that its interior to is differentiated.

"Ceres appears to be differentiated into a rocky core and icy mantle, and may harbor a remnant internal ocean of liquid water under the layer of ice"

https://en.wikipedia.org/wiki/Ceres_%28dwarf_planet%29

[peadar1987]

Dawn's observations at Vesta revealed its interior is differentiated. With Ceres being larger than Vesta, it only very likely that its interior to is differentiated.

"Ceres appears to be differentiated into a rocky core and icy mantle, and may harbor a remnant internal ocean of liquid water under the layer of ice"

https://en.wikipedia.org/wiki/Ceres_%28dwarf_planet%29

It will depend on the exact composition though. Mars is differentiated, but much rockier than Vesta, so may not be liquid inside any more. Even if Ceres is differentiated, it doesn't mean it's still seismically active.

[lajoswinkler]

Mercury has an atmosphere, granted - thin as it is, yet water ice exists in craters at its north pole. Why couldn't Ceres have water ice?

Mercury does not have an atmosphere. It has atoms of gas (mainly sodium) leaking into space like tiny canon balls, all because of the scorching heat of the Sun. Particle collision is extremely rare. Pressure is only theoretically determined.

Atmosphere is a layer of gas in equilibrium. If you were on Mercury's surface and opened a hole in the can with nothing inside, it would not be filled with those atoms unless its opening is in a proper direction. It could remain perfectly void of matter.

I've mentioned it once on this forum - Mercury is worse than a leather suitcase in space. The suitcase leaks way more particles per unit of surface.

Dawn's observations at Vesta revealed its interior is differentiated. With Ceres being larger than Vesta, it only very likely that its interior to is differentiated.

"Ceres appears to be differentiated into a rocky core and icy mantle, and may harbor a remnant internal ocean of liquid water under the layer of ice"

https://en.wikipedia.org/wiki/Ceres_%28dwarf_planet%29

I said "probably barely diferentiated inside". It's certainly nothing like terrestrial planets. This is a body that barely managed to establish hydrostatic equilibrium.

[grawl]

Look at the sharp edges

http://www.philipcoppens.com/chinesepyr1.jpg

Could it be ....... PYRAMIDS ???

**Aliens**

That's a beautiful volcano! Any idea where it is?

It's the Mayon volcano, located in the Philippines.

More about Mayon volcano

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:

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

Edited June 19, 2015 by grawl

[LordFerret]

Mercury does not have an atmosphere. ...

"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.

- - - Updated - - -

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.

[Kryten]

There are two definitions of the word 'atmosphere'; the first is just some particles gravitationally bound to a body, in which case every planet and most moons has an atmosphere; and the second is an envelope with enough particles for them to significantly collide with each other, which is necessary for them to actually act as a gas. Mercury's exosphere only fits the first definition, and makes no meaningful difference to the surface conditions.