It looks like you're using an Ad Blocker.
Please white-list or disable AboveTopSecret.com in your ad-blocking tool.
Some features of ATS will be disabled while you continue to use an ad-blocker.
The images were taken with the Lunar Reconnaissance Orbiter’s Wide Ange Camera, which can snap between roughly 50-100 km (30 – 60 miles) of lunar landscape in one image. As LRO circles the Moon, the camera builds up a map of the entire surface, but only one narrow strip at a time. Astronomers can then use those images to create a mosaic of the Moon as seen from any angle… but it’s not easy.
To get the mosaic to look right, you can’t just take an image from one spot of the Moon and stitch it onto an image from another. The lighting angle will be different, for one thing, making shadows go all wonky. Also, the LRO camera points straight down, so whatever is directly beneath it will be close by, while something off to the side will be farther away. Stuff farther away will look smaller, and you have to correct for that as well.
It’s taken a while, but LRO scientists have figured out how to correct for all that, and are now able to make these cool maps. The big remaining issue are those missing strips, spots the camera missed because another camera was being used at the time. But still, it’s pretty amazing they can make this map at all.
And why is it different from what we see on Earth? The Moon spins almost exactly once for every time it orbits the Earth — that’s a natural consequence of the effect of the Earth’s gravity on the Moon over time. That means we only see one half of the Moon, and the other half is always pointing away from us.
This LRO image shows the east side of the Moon which is the hemisphere of the Moon facing away from its direction of orbital motion (it may help to read a description I wrote of this for a moon of Saturn). As seen from this perspective, the Earth is off the image to the left. So everything on the left half of this picture we can see from Earth, and everything on the right we can’t*.