Here are the bright Martian spots in full resolution, via HiView (I've since learned that those JPEG downloads are typically not full resolution):




For viewing convenience, here is the central (brightest) portion:



Bright spots on Ceres:



I can't say they are a perfect match of one another (the Cerean feature is more compact?); but not very bad, either. On Mars, an impactor might have come from top-right, while on Ceres an impactor could have come from the left.

mmm,Yes, very similar Habukaz..

I had missed this. Safe mode June 30th. The last full Marc Rayman update was June 29th.

AWST has some recent quotes from Dr. Rayman here:
Dawn Prolongs 2nd Reconnaissance Orbit at Ceres After Orientation Issue

Dwarf planet spacecraft safe mode party over Independence Day weekend. Sheesh.

Thanks for that link. But doesn't

contradict the earlier statement?:

Since when are the cameras and spectrometer part of the navigation system?

The 6/29 Dawn Journal discusses the instrument anomaly... the real safe mode happened 6/30.

You've made a very good case for the impact hypothesis Habukaz, you've almost convinced me I've been barking up the wrong tree about this feature. =)
We'll see when Dawn gets sorted out and get to take images at HAMO distance in a few weeks.

I see Calderas, sinkholes and impact craters in many places and I think all three processes have played a part in the surface topology we see today. Don't give up on Cryovolcanism just yet Ant.

OWW:

Thanks for that link. But doesn't

"Just prior to entering safe mode, Dawn's telemetry revealed resets of the computers that manage cameras and an infrared mapping spectrometer on the probe."

contradict the earlier statement?:

"NASA's Dawn spacecraft is healthy and stable, after experiencing an anomaly in the system that controls its orientation."

Since when are the cameras and spectrometer part of the navigation system?

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Not necessarily a contradiction. An anomaly in one system can cause a problem which results in a reset elsewhere. I don't know the chain of events, but it's not necessarily a contradiction.

Phil

You're comparing apples with oranges. There's no atmosphere on Ceres to disrupt rubble piles. Its gravitational field is too feeble and the Roche limit too close, to result in anything other than single impact craters.

Quite apart from that, there's no evidence on steep slopes of the existence of a bright layer of material anywhere near the surface.

There's no evidence for bright material on the steep slopes of Husband Hill near Spirit either, John, yet the rover inadvertently exposed such by dragging its stalled wheel. Absence of evidence is not evidence of absence.

Additionally, I see no reason why 'rubble pile' loose associations of meteoroids might not exist, esp. in the main asteroid belt. Small objects formed in effectively zero gravity may well break apart over time from thermal stresses yet remain in close proximity to each other for an extended period of time.

I find an impact origin for these bright spots by far the most compelling hypothesis to date. Hopefully higher-resolution imagery will soon resolve this debate.

Not only could the asteroid have been in "flying formation" already, but the other spots east of the "primary" could just be secondary craters - either excavated by fragments of the impactor itself or surface material it sent flying in a "direct fire" way (i.e. with a non-parabolic path).

As I recall, that material is actually regarded as having originated in solution deep underground, prior to deposition on the surface via a spring or geyser - exactly what I've been arguing for to explain the spots on Ceres.

The time any recently-separated components of a rubble-pile asteroid spend in close proximity with one another, would be an extremely small fraction of their total lifespan, and the odds of colliding with another asteroid during that interval would be equally astronomical!

The central spot looks nothing like an impact crater. The debate should be resolved once and for all when their chemical composition is announced. I'm expecting ice and salt at spots inside Occator crater and salt at all the others. Also looking forward to colour images to see if any spots display a brown hue indicative of radiation-darkened salt.

Oh I am not. I said "almost", and in doing so giving credit for Habukaz presenting his interpretation very well. =)
I still think the most likely outcome will be that most of the lighter areas to have salts, with Occator being the exception.

There's a few siblings in craters that lack central peaks that have a pit that look similar even though not being bright. And we mentioned that earlier, that the remaining salt in those cases might simply have been dusted over.
And as John Broughton pointed out right before me, the central pit does not look like an impact crater in Occator neither do the pits in the other craters that have a similar formation.

According to the Dawn website's graphics, the Dawn spacecraft is thrusting again. It is now at 2,680 miles above Ceres and descending.

Andy

It has been since before the 6/30 safing event that we've had any image releases. Now they're changing orbits, but either 1) haven't gotten the cameras working again, or 2) haven't seen fit to release any images taken since the safing event?

Something seems wrong, there. The Dawn team has not been very reticent about releasing images, and I'd think if they had begun taking pictures again, we'd have seen at least one of them.

I wonder if there is something more seriously wrong with Dawn than we've been told?

-the other Doug