Starship Asterisk*

Fly Over Dwarf Planet Ceres

Explanation: What would it look like to fly over dwarf planet Ceres? Animators from the German Aerospace Center recently took actual images and height data from NASA's robotic Dawn mission -- currently visiting Ceres -- to generate several fascinating virtual sequences. The featured video begins with a mock orbit around the 950-km wide space rock, with the crater featuring two of the enigmatic white spots soon rotating into view. The next sequences take the viewer around the Ceres' north and south poles, and then over a limb of the dark world highlighting its heavily cratered surface. Here, terrain height on the asteroid belt's largest object has been digitally doubled, while an artificial star field has been added in the background. The Dawn spacecraft will likely remain an unusual artificial moon of Ceres long after its mission concludes.

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In other words this is a lie.

Guest wrote:In other words this is a lie.

Terrain mapping actual imagery is the best, most accurate way of visualizing these things. It's routinely used for all planetary data sets, including those for Earth (like the Blue Marble data).

I think if one realizes so easily that this is not an actual video of an actual fly over and that what it is is in fact explained quite clearly, then no, it's not a lie. It might not have been what one wanted or expected, though.

The first sequence makes it look like Ceres's axis of rotation is closely aligned with the Milky Way's axis. But it is not. This is otherwise a great video. I am unhappy with myself for getting distracted by the backdrop.

Are there any other large bodies in the solar system with such irregularly-shaped craters? Some are very close to hexagonal. Something is very different there.

Guest wrote:In other words this is a lie.

The sequence of data-based imagery presented is an admirable effort to answer the speculative question posed in the lead sentence "What would it look like to fly over dwarf planet Ceres?"

Sorry if this is confusing.

From the depth, and tone, of your comment, one is lead to speculate that you have mistaken this for a political discussion site. Please do not linger on your journey to those indecorous shores to which you are drawn. Godspeed.

As the caption explains what it is...it is not a lie...it is what it is...a computer animation, simulation, of what it would be like to fly over it... I am sure no deception is intended.

Ceres...I don't know if I agree with "dwarf planet"..."protoplanet", "planetesimal", maybe...but it has differences from Asteroids, and I suppose "dwarf planet" is deserved under those considerations....but it shares something in common with Enceladus... Water...maybe an Ocean of it under the surface, as ice...but more than all the Fresh Water on Earth...this makes it an OASIS in space and ripe for a pit-stop in the future. Water could be mined...shipped back to Mars, or forward to Jupiter. On Mars...craters could be covered, and filled, becoming Reservoirs.
So... it was collecting water objects...comets...and other things.

Ummmm...and so that makes it collectible...OK...MINE!!!!...I call dibs on it....heh, heh, heh...I am going to have the water concession....Awm gonna be RICH!!!!

OK, so very interesting place, and desirable in the future for a base...

:---[===] *

I love the images and it would be great to see a version with an average human/house/monument stood there for scale reference.
It gives me vertigo looking at it as it looks so small but I suspect a scaled refernce would put it more into context.

If this is intended to show what a flyover would look like, then why the vertical exaggeration, and why the contrived star field? In fact, this is not what a flyover would look like.

Guest wrote:In other words this is a lie.

How is it a lie if it uses actual data and images?

Cousin Ricky wrote:If this is intended to show what a flyover would look like, then why the vertical exaggeration, and why the contrived star field? In fact, this is not what a flyover would look like.

Other than artistic purposes and awe factor, which work, the star field is likely there because it is expected to be visible in the darkness of space. It has been an issue here numerous times that space images don't show stars "nice image of the ISS but where are the stars".
As far as the galactic plane issue goes, nothing is stated in the write up regarding this being an equatorial orbit. Orbits can be around any axis even one that coincides with the galactic plane.

Why 2x the vertical? Please show same with 1x.

Guest wrote:In other words this is a lie.

guest2 wrote:Why 2x the vertical? Please show same with 1x.

Troll much?

This is a non-issue.
Virtually everything APOD presents is in some way manipulated. Images are cropped, combined, enhanced, in false color, sharpened or whatever is needed to either make it aesthetically pleasing, or usable for scientific or educational porpoises.
In this particular case it is an animation. A simulation based on real data. It is as close as you are going to get without actually being there yourself (in which case it would probably be too dark to see much with the naked eye anyway).
It is what it is because it is the best way to represent the data in a meaningful way for the chosen goal.

If you don't understand this, go watch C-SPAN.

guest2 wrote:Why 2x the vertical? Please show same with 1x.

Just what I was thinking. Exaggerated relief helps bring out terrain features, but it would be nice to see what an actual fly-by might look like. And with a surface gravity of 0.29m/s^2, Ceres has plenty of relief already.

I'll agree with the posters complaining about the vertical exaggeration.
It makes it more dramatic... but this is not a "fly over of the Dwarf Planet Ceres". It's a fly over of a imaginary dwarf planet that's a caricature based on Ceres.
--for years there used to be a parody organization called the "Flat Venus Society" that lobbied against the JPL reconstructions of Venus topography with the 10x exaggerated scale that is in all the public relations image releases. Admittedly, this is only 2x exaggeration, so it's not quite so egregious as the Venus images. Still.

What makes an asteroid like Ceres round?

From an aesthetic point-of-view, the field-of-view chosen for the rendering camera is quite large. This setting causes the resulting imagery to look as if Ceres is a small paper-mache model, much like the old 'Mystery Science Theatre 3000' opening sequence.
This sequence would benefit greatly from changing the rendering camera from what is probably a 30 to 40 degree field-of-view to a much more dramatic 10-15 degree field-of-view, or smaller. Yes, this would necessitate changes to the camera animation (camera-Ceres distance) in order to see all of Ceres in one frame, but the results would be worth it.

Also, depending on the resolution of the elevation data, this video might be improved by using the collected heightfield data to generate all shadows instead of simply texture-mapping imagery with static shadows. Scientifically sound color could still be rendered if this heightfield were textured with imagery taken with a DAWN-Ceres-Sun phase angle of near zero. This would solve the issue most visible during the sequence when we are looking down upon the (north?) pole as Ceres rotates: the circumpolar craters are not lit properly.

Overall, though, I enjoyed this APOD.

beefcalf wrote:Also, depending on the resolution of the elevation data, this video might be improved by using the collected heightfield data to generate all shadows instead of simply texture-mapping imagery with static shadows.

They are still working with a very limited set of imagery. This is probably the best that is currently feasible. Once the dataset becomes richer, and the elevation data better resolved, a wider range of possibilities will open up (as with the models that have been created for Mercury, Earth, the Moon, Mars, and numerous outer moons). And the data will probably find its way into Google [Earth], Stellarium, and other apps capable of 3D rendering, allowing us to choose our own view right from our computers.

I see this as a work in progress.

WilardChicago wrote:What makes an asteroid like Ceres round?

gravity (See dwarf planet and hydrostatic equilibrium)

Craine wrote:

Guest wrote:In other words this is a lie.

guest2 wrote:Why 2x the vertical? Please show same with 1x.

Troll much?

This is a non-issue.
Virtually everything APOD presents is in some way manipulated. Images are cropped, combined, enhanced, in false color, sharpened or whatever is needed to either make it aesthetically pleasing, or usable for scientific or educational porpoises.
In this particular case it is an animation. A simulation based on real data. It is as close as you are going to get without actually being there yourself (in which case it would probably be too dark to see much with the naked eye anyway).
It is what it is because it is the best way to represent the data in a meaningful way for the chosen goal.

If you don't understand this, go watch C-SPAN.

I don't think the two guests are the same person and they aren't saying anything against the rules. Rough way to start the thread and not the nicest way to put it, but some people do not like this video and it's ok if they express this feeling it as long as they're not insulting.

Agreed that this was a bad way to start the blog stream...

But I was wondering about the surface itself. In some areas, there are craters inside craters with smaller craters in them. And in other areas, the surface appears to be much less cratered, smoother perhaps, with what appears to be that white surface feature/gradient in abundance. Is this an artifact of image processing or are we looking at surface areas of different ages? Could this be evidence of some sort of internal activity in recent geological time frames?

I have a visceral response to photographs like this...it is almost a kind of panic, and I think it is related to understanding, grokking, that "there but for the grace of What goes Earth, and life." Isn't life strange?

hope the end of the mission is an Eros style landing with cameras rolling

Frankly, I'm more curious about the rotational exaggeration vs the relief exaggeration.

How fast does Ceres actually rotate?

Scott