Starship Asterisk*

Lunar Time Lapse Panorama including Yutu Rover

Explanation: Where has the Yutu rover been on the Moon? Arriving in 2013 mid-December, the Chinese Yutu robotic rover has spent some of the past month and a half exploring Mare Imbrium on Earth's Moon. Because it uses solar power, the mechanical Jade Rabbit goes into sleep mode to endure the two-week long lunar night. Pictured above is a digitally created time-lapse composite panorama showing the region surrounding the Chang'e 3 lander, capturing the desk-sized rover in three positions. On the far right, Yutu is seen heading south to investigate greener pastures, likely never to return to its lander again.

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Cool, that is by far the biggest and most detailed picture that I've seen so far of Yutu on the Moon.

Why in this photo does the moon soil seem greenish (or brownish) while in Apollo photos it is mostly gray?

I presume that the fading of Yutu's wheel tracks as it moves away from the lander, seen in the right-most part of the image, is an artefact of editing many pics into one? They will be there for thousands of years, and not fade like footprints in damp sand.

Conversely, the apparently black, star-less sky exactly reproduces the Apollo pics. But I don't suppose that will reassure the conspiracists - the Chinese will have copied that in making their studio pictures, won't they?
John

Sinan İpek wrote:Why in this photo does the moon soil seem greenish (or brownish) while in Apollo photos it is mostly gray?

The colour photos from the Apollo landings show lots of colour in the soil. Here's a section of an Apollo 14 panorama near the Mauro Highlands, compared to the soil around Yutu.
You can likely see some colour variation in the Yutu image -- two vertical purple streaks in particular. This is repeated over and over again across the panorama, suggesting to me some sort of refraction issue in the lens. For this and other reasons I wouldn't attach too much weight to the exact soil colours as shown in these released images.

Rob

rstevenson wrote:

Sinan İpek wrote:Why in this photo does the moon soil seem greenish (or brownish) while in Apollo photos it is mostly gray?

The colour photos from the Apollo landings show lots of colour in the soil. Here's a section of an Apollo 14 panorama near the Mauro Highlands, compared to the soil around Yutu.

Apollo 14 - soil.jpg

Yutu - soil.jpg

You can likely see some colour variation in the Yutu image -- two vertical purple streaks in particular. This is repeated over and over again across the panorama, suggesting to me some sort of refraction issue in the lens. For this and other reasons I wouldn't attach too much weight to the exact soil colours as shown in these released images.

Rob

This may seem a stupid question but it’s never stopped me before – How many of the rocks in the picture are moon rocks vs. debris left over from the meteor that hit the moon?

Could we get a good sampling from the material brought back by our Apollo astronauts to know how much of the soil/rock were lunar in origin in the vicinity of an impact crater like this?

I might think that most of the rocks are lunar but most of the soil from micro-meteoroid origin.

It's well studied, Ron. In fact there are piles of the stuff you can go look at yourself in museums. There was a large collection I saw at the Smithsonian Natural History Museum.

http://en.wikipedia.org/wiki/Lunar_soil

Wikipedia wrote:Over time, material is mixed both vertically and horizontally (a process known as "gardening") by impact processes. However, the contribution of material from great distances is relatively minor, such that the soil composition at any given location largely reflects the local bedrock composition.

I don't suppose the policy of "pack it in, pack it out" applies to lunar travel, but that looks like too many campsites I've seen. Luckily it lacks diapers and McDonalds wrappers.
I also wondered about the disappearing tire tracks.

Ron-Astro Pharmacist wrote:This may seem a stupid question but it’s never stopped me before – How many of the rocks in the picture are moon rocks vs. debris left over from the meteor that hit the moon?

While it's technically possible for a body to strike the Moon as slow as about 2 km/s, that would be incredibly rare. The typical range of speeds is much higher, with an average of around 40 km/s. What that means is there are virtually no meteorites on the Moon. Without an atmosphere to slow meteoroids down, they vaporize on impact. So if you look at the lunar regolith, you'll find microscopic dust of extralunar origin. But by far most of the dust is lunar in origin, as are all the rocks large enough to see.

Sinan İpek wrote:Why in this photo does the moon soil seem greenish (or brownish) while in Apollo photos it is mostly gray?

I wouldn't describe the color as greenish, but it's always dangerous to look too closely at the color in images- and not just astronomical images. Just pick any well photographed object on Earth and Google some images. The color will be all over the place. Accurate color (to the extent such a thing even exists) depends on very complex calibration, and even then, two different instruments will never produce identical results. It's hardly surprising that the we see some difference between a modern electronic sensor and 1960s era film emulsion.

As if that wasn't enough, the Moon does show subtle variations in color, so images made in one place are likely to look different from images made elsewhere, even with identical equipment.

You can see a repeating pattern of color across this image, a gradient that varies from slightly green to slightly magenta. I'd say it's a stitching artifact, and that this image was made up of between 22 and 24 horizontal slices. It doesn't appear to be stitched vertically.

Rob[/quote]

This may seem a stupid question but it’s never stopped me before – How many of the rocks in the picture are moon rocks vs. debris left over from the meteor that hit the moon?

Could we get a good sampling from the material brought back by our Apollo astronauts to know how much of the soil/rock were lunar in origin in the vicinity of an impact crater like this?

I might think that most of the rocks are lunar but most of the soil from micro-meteoroid origin.[/quote]

Ron, Thank you for asking a most interesting question. My mind had not gone in that direction and I found the answers given to be really informative.

Bill

Chris Peterson wrote:

Ron-Astro Pharmacist wrote:This may seem a stupid question but it’s never stopped me before – How many of the rocks in the picture are moon rocks vs. debris left over from the meteor that hit the moon?

While it's technically possible for a body to strike the Moon as slow as about 2 km/s, that would be incredibly rare. The typical range of speeds is much higher, with an average of around 40 km/s. What that means is there are virtually no meteorites on the Moon. Without an atmosphere to slow meteoroids down, they vaporize on impact. So if you look at the lunar regolith, you'll find microscopic dust of extralunar origin. But by far most of the dust is lunar in origin, as are all the rocks large enough to see.

I found the answers given to be really informative.

Me too Bill! Thanks Geck and Chris. I’m always amazed how much of what I think I know - isn’t true.

Chris Peterson wrote:

Sinan İpek wrote:Why in this photo does the moon soil seem greenish (or brownish) while in Apollo photos it is mostly gray?

I wouldn't describe the color as greenish, but it's always dangerous to look too closely at the color in images- and not just astronomical images. Just pick any well photographed object on Earth and Google some images. The color will be all over the place. Accurate color (to the extent such a thing even exists) depends on very complex calibration, and even then, two different instruments will never produce identical results. It's hardly surprising that the we see some difference between a modern electronic sensor and 1960s era film emulsion.

That was exactly what I thought. I think those cameras used by Apollo were calibrated finely, i.e. their white balance. And also, the film emulsion used by NASA is kind of superior to those brand new electronic CCD's used by Chineese in maintaining colors.
And I know that even our eye/brain system errs in recognizing the tint of objects; since, basicly, there's no such thing as 'exact color'. A simple experiment with red/cyan 3D glasses can show this. Put the glasses on for five minutes and then put them off and look around. You'll see that your left and right eyes recognize colors differently.

Sinan İpek wrote:I think those cameras used by Apollo were calibrated finely, i.e. their white balance. And also, the film emulsion used by NASA is kind of superior to those brand new electronic CCD's used by Chineese in maintaining colors.

Actually, I'm not sure that the film was calibrated all that accurately in terms of color. And CCD color is vastly superior to that of any film emulsion that ever existed. The combination of linearity, wide dynamic range, and well controlled color channel filters makes it much easier to extract useful color information from electronic sensors than from film.

Great pic. Even so I know conspiracy theorists (not a real science ) are going to declare its fake because of the disconnected tracks. I told one of them China used the same stage set as the Apollo missions. I regretted it because he took me as serious.

I'm catching up on a few previous apod's after being off the net, off the grid, and out of this world for a few lovely days.

This is the cutest little rover I've ever seen!

Reportedly Yutu may have failed to fold itself up and turn on its heater before nightfall, so it might freeze to death overnight -- and remember that a night on the Moon lasts a fortnight here on Earth, and overnight lows are around -150 degrees C. Brrr. Poor little rover.

Ron-Astro Pharmacist wrote: This may seem a stupid question but it’s never stopped me before – How many of the rocks in the picture are moon rocks vs. debris left over from the meteor that hit the moon?

Could we get a good sampling from the material brought back by our Apollo astronauts to know how much of the soil/rock were lunar in origin in the vicinity of an impact crater like this?

I might think that most of the rocks are lunar but most of the soil from micro-meteoroid origin.

Wonderful question, and you have had many good answers to which I will add.

When a meteor or micrometeor hits a planetary surface the vast majority of the debris will be from the planet itself. It's an energy thing. A meteor crater is far larger then the meteor and a micrometeor impact would have a similar effect. So while the dust and rocks that you see are undoubtedly mostly of moon origin, meteor and micrometeor impacts may have some nexus to its current location and physical and chemical composition. The meteor impacts can local fracture and transport rocks as well as vaporizing rocks and dust which then condenses back into glassy dust.

Yutu moon rover not dead yet!
http://www.universetoday.com/109326/chi ... lfunction/