Dawn probe to orbit asteroid Vesta

namloc1980

Latest high resolution image of the Bright spots.

Maximus Alexander

And still... no idea what it is.

josip

It doesn't look to me that the white stuff has been exposed by an impact, or at least a recent impact.
Wouldn't there be a ray system of ejecta in that case?
So is it being exposed by subterranean activity/process on Vesta?
Or was it hit by a snowball?

shedweller

I can't help but think it is exposed snow/ice after something impacted the surface. The smaller bits to the top right are probably ejecta? There is a little mound in the centre of the main white area too and this ties in with crater formation and you get a central mound/mountain after the dislodged material comes back together when the impactor has gone deeper.
I did also notice another white bit on the rim of the crater at the 7 or 8 o'clock position. It's right on the edge so it may be where some surface material slipped off to reveal the lovely white snowiness underneath. Maybe unrelated but it does sway my thinking further.

2 stroke

I think everyone is looking at this wrong. The question that we should be asking is what is all that black stuff?
My theory is that the black stuff is extremophile life. The white bits are areas that are toxic or inhospitable to such lifeforms.
If we view the land areas of earth from a distance, we would view large areas of green and desert.
At that distance from the sun, any life could be black to absorb the maximum energy from available sunlight.

namloc1980

2 stroke wrote: »

I think everyone is looking at this wrong. The question that we should be asking is what is all that black stuff?
My theory is that the black stuff is extremophile life. The white bits are areas that are toxic or inhospitable to such lifeforms.
If we view the land areas of earth from a distance, we would view large areas of green and desert.
At that distance from the sun, any life could be black to absorb the maximum energy from available sunlight.

What's the chemical make up of this life? You better call NASA anyway and tell them you just discovered life on Ceres.

2 stroke

namloc1980 wrote: »

What's the chemical make up of this life? You better call NASA anyway and tell them you just discovered life on Ceres.

Call them? Had a knock on the door five minutes after posting that. Luckily I had my tinfoil underpants on.

ps200306

What intrigues me is how similar the black surface and white spots look to what Rosetta found on Comet 67P/C-G. I presume Vesta and Ceres are rocky dwarf planets (olivine was detected by spectroscopy on Vesta). But could they be sooty and icy too? The bodies in the asteroid belt were thought to be all stony or metallic, based on meteorite finds. But some have since been seen outgassing like comets. Could the books be about to be rewritten?

Capt'n Midnight

2 stroke wrote: »

At that distance from the sun, any life could be black to absorb the maximum energy from available sunlight.

It doesn't work that way. Photons of different wavelengths have different energies but the biochemical pathways have specific energy levels. The difference is primarily released as heat.


Why is grass green ?

On earth we have
Blue green algae (like bacteria)
Purple Sulphur Bacteria.

Look at the colours of Lichen

Look at seaweeds
Red algae
Brown Algae


However, instead of the above land plants are descended only from Green Algae


Also
Since there is no atmosphere a lot of the solar radiation is UV which damages organic bonds. Four Billion years ago bacteria on earth created stromatolites by exuding sun cream. They still do in Shark Bay in Oz. There is also the slight problem that water (and CO2) in the asteroid belt can sublime and biology as we know it isn't very active when freeze dried. Other possible liquids like ammonia aren't much better.

MeteoritesEire

Dawn has the VIR, hyperspectral imaging spectrometer to help with these things

so, looks like it's probably hydrated salt deposits according to a talk given on sept 9 by Matthew Izawa (U. of Winnipeg) as told by Dolores Hill who was at the talk and is a senior research specialist at the lunar and planetary lab at the University of Arizona and is a member of a meteorite list I subscribe to.


Composition of Ceres’ Bright Spots

Wednesday, September 9, 2015
Matthew
Izawa

Abstract: The dwarf planet Ceres, located at a mean solar distance of ~2.8 Astronomical Units, is the largest (diameter ~950 km) object in the main asteroid belt between Mars and Jupiter. Several evolution models suggest a differentiated body with potential geologic activity. One of the objectives of the Dawn mission during the Ceres encounter is to search for signs of past or present geological activity, including processes that might be linked to observations of transient water vapour events. One of the most striking features of Ceres’ surface are localized bright areas, which are commonly associated with impact craters. Of particular interest is a bright pit on the floor of a 90.5 km diameter crater named Occator that shows signs of activity in the form of water ice sublimation. I will present evidence that the Ceres bright spots are hydrated salt deposits, using a combination of Dawn Framing Camera (FC) multispectral observations, laboratory spectroscopy, and geochemical data from carbonaceous chondrite leaching experiments. Based on previous spectroscopic mineral identifications, a range of candidate high albedo materials were investigated including ice, Mg-carbonates, brucite, saponite and ammonium saponite, (Mg,Na) sulphate salts, and (Mg,Na) halide salts. Of these, the best matches are to mixtures of hydrated Mg sulfates along with dark ‘average Ceres material’, which may be broadly analogous to aqueously altered carbonaceous chondrite. The bright spots may be forming as a result of sublimation of water from brines exposed near the surface, leaving behind a chemical lag deposit of former solutes, which are predicted on experimental and theoretical grounds to be dominated by MgSO_4 hydrates.



----
http://www.hou.usra.edu/meetings/lpsc2015/pdf/1365.pdf

by the way 'carbonaceous chondrites are a type of meteorite

_Tombstone_

MeteoritesEire wrote: »

Dawn has the VIR, hyperspectral imaging spectrometer to help with these things

so, looks like it's probably hydrated salt deposits according to a talk given on sept 9 by Matthew Izawa (U. of Winnipeg) as told by Dolores Hill who was at the talk and is a senior research specialist at the lunar and planetary lab at the University of Arizona and is a member of a meteorite list I subscribe to.

Yup, European best and brightest reckon it's salt aswell.

_Tombstone_

https://www.youtube.com/watch?v=8er_0yY1S1o

_Tombstone_

New Animation Takes a Colorful Flight Over Ceres

The movie shows Ceres in enhanced color, which helps to highlight subtle differences in the appearance of surface materials. Scientists believe areas with shades of blue contain younger, fresher material, including flows, pits and cracks.

The animated flight over Ceres emphasizes the most prominent craters, such as Occator, and the tall, conical mountain Ahuna Mons. Features on Ceres are named for earthly agricultural spirits, deities and festivals.

https://www.youtube.com/watch?v=nJiw2NxqoBU

_Tombstone_

Astronomers discover unexpected changes of bright spots on Ceres

New and very precise observations using the HARPS spectrograph at the ESO 3.6-metre telescope at La Silla, Chile, have now not only detected the motion of the spots due to the rotation of Ceres about its axis, but also found unexpected additional variations suggesting that the material of the spots is volatile and evaporates in sunlight.

......


The team concluded that the observed changes could be due to the presence of volatile substances that evaporate under the action of solar radiation. When the spots inside the Occator crater are on the side illuminated by the Sun they form plumes that reflect sunlight very effectively. These plumes then evaporate quickly, lose reflectivity and produce the observed changes. This effect, however, changes from night to night, giving rise to additional random patterns, on both short and longer timescales.

If this interpretation is confirmed Ceres would seem to be very different from Vesta and the other main belt asteroids. Despite being relatively isolated, it seems to be internally active. Ceres is known to be rich in water, but it is unclear whether this is related to the bright spots. The energy source that drives this continual leakage of material from the surface is also unknown.