We may take the Moon for granted, but what
a sight to behold it is in our sky. It’s big enough and close enough to us that
we can easily make out surface details with the naked eye, like the dark Mare and bright
craters. Just looking at it through a telescope is
impressive enough, however what I’m about to show you in this video will make the telescope
view pale in comparison. You see, we are fortunate enough to have not
only have visited the Moon, but also have an orbiter around it right now with a powerful
camera that has been scanning the surface since 2009. So, what has it seen? I’m Alex McColgan, and you’re watching
Astrum. Stick with me in this video, and I will show
you some of the LRO’s most recent impressive and puzzling images of the Moon. Let’s start off with an innocuous little
unnamed crater. As you can see, there are plenty of tiny craters
within it. And this crater is within another crater again. Maybe you can see where I’m going with this. Zooming out, not only are these craters in
another crater, but apparently, they are contained within two very nicely aligned craters. Or is that really what this is? Well, we aren’t sure. Both of these craters are named as one, the
Bell E crater. This peculiar type of crater is known as a
donut, or concentric crater. It is possible that they are the result of
two impactors aligning up nicely, but further investigation suggests otherwise. If they were the result of chance collisions,
then there should be a random distribution of concentric craters across the surface of
the Moon. However, that is not the case. Have a look at this. The population of concentric craters actually
clump up around certain areas, especially around the edge of this region of the Moon
here, called Oceanus Procellarum. Another factor to consider is that most of
these craters are of similar ages. Looking for clues in the crater itself also
reveals something interesting. This outer crater should be around twice as
deep as it currently is when comparing it to other similar sized craters around the
Moon. Now, while a few concentric craters on the
Moon will certainly be the result of double impacts, the location, age and depth of most
craters means that something else must be at play. One theory is that some of these impacts occurred
during a time when the surface of the Moon in this region was in a state in between solid
and liquid, with a consistency similar to cool lava or honey. As the impact happened, it caused ripples,
which propagated outwards, but then stopped and never smoothed off until it was fully
cooled and frozen in place. Although this is seen as an outside possibility. The most likely theory is that when the Moon
was more geologically active, craters in the region were pushed up from beneath by magma
trying to escape onto the surface. This would explain the shallowness of the
crater, and why we see concentric craters mainly around specific points on the Moon. However, while this is the best theory we
have at the moment, we still don’t know for sure. What do you think it could be? Now, apart from the occasional meteor, you
probably think the surface of the Moon barely changes at all. And while you are mostly right with that,
we have found evidence that material does move on the Moon occasionally. See if you can spot what I’m talking about
in this image here as I pan across. This is the edge of a large 32 km wide crater
known as Kepler Crater, and what you may notice along the crater wall is evidence that landslides
have occurred here, with the dark material apparently having fallen down the slope. Let’s have a closer look at what’s going
on by zooming in on the most prominent of landslides in this crater. The material seems to originate from box canyons
towards the top of the crater rim. The material coming down here is clearly very
fine, certainly less than a metre across, as no individual rocks can be resolved within
the slide, however the largest rocks that got dislodged seem to have all made it to
the bottom of the crater floor. What’s interesting is that the main mass
of the slide seems to actually be made up of many smaller slide masses. Look at these individual trails here. So, it probably didn’t all happen at once,
but is happening over time. The slides were likely triggered by tiny meteors
striking the crater wall. These tiny impacts and the subsequent landslides
round off the edges of the crater, which is why the oldest types of craters on the Moon
look so smooth compared to the freshest craters. Here’s another puzzle to try and solve. Here, we have the remarkable Messier Crater. Typically, craters are round, but not Messier
Crater. It is elongated with a slit for a crater floor. What is going on here? The mystery continues if you zoom out a bit. Directly next to Messier Crater are two more
craters. The one on the left seems much older than
the other, as it seems to have been weathered away compared to the fresh impact crater on
the right. Did the newer crater just so happen to cover
an older one? But let’s zoom out again. What other clues can we see? Actually, a big clue are these lines coming
away from the crater. These are called rays, and they reveal the
direction the debris fell after the impact. On rounded craters, debris can go in all directions,
like the ones that originate from Tycho Crater. However here, debris goes in three distinct
directions, north and southward from this crater and only westward from this one. So, what would cause that? Well, the answer is, an impactor striking
the surface at a very low angle, less than 15 degrees. And in this particular case, it seems like
the impactor had already broken apart into three parts before it even hit the Moon’s
surface. Yes, all three of these craters likely hit
the Moon at just about the same time, even the “older” crater. What actually happened here is that ejecta
from this second crater likely fell directly on top of this other crater due to the low
angle of the impact, which means that it has been artificially aged. There are some other really interesting aspects
of this image though, like the solidified pond of impact melt found at the bottom of
the crater, or this region here which appears to have caved in a bit. The impact melt in the first image also appears
to have flowed down towards the left of the image. It really is a fascinating set of craters. Let’s have look at another asymmetrical
crater and try and figure out why it has the shape it does. While it could be that this crater is also
the result of two impacts, or one impactor breaking up into two just before it collided
with the Moon, scientists think this is likely not the case here. Notice the shadows in this image, above and
below the crater. It is apparent that this crater is right on
the cusp of a peak. Zooming out and looking at a topographical
map of the region reveals that this is the case. In fact, this may well have been the tallest
peak in the local area, until by chance, this impactor came along a totally wiped it out. Imagine Everest suddenly being taken out by
a meteor! The shape of this crater was probably not
only caused by the angle the impactor approached from, but also because it hit this steep slope. It might not look that steep from the oblique
angled shot, however over only about 20km, there’s an 8km difference in elevation from
the peak here to the bottom of this nearby crater. In this next image, there’s not too much
to see. The only thing visible in this wide expanse
is this peak, basking in the light of the Sun. Why is this significant? Well, this peak is on the rim of Aepinus crater,
a crater found near the north pole of the Moon. Future colonies on the Moon will be located
somewhat near the north and south poles, because tucked away at the bottom of the craters here
where the Sun never shines are large pockets of water ice, essential for any colony to
subsist off of. Water can be used for drinking, washing, cooking,
and farming, plus breaking the h2o down into oxygen and hydrogen provides breathable air
and rocket fuel. These poles also have the added benefit that
there are peaks here that are almost always in the Sun, unlike other parts of the Moon
where the day and night cycle is 28 days long. 14-Earth-days in constant darkness is not
good for a solar powered power system. A peak like this one however, poking out in
the Sun while the surrounding area experiences night-time, would be an ideal location for
solar panels and powering a colony there. It’s not a perfect solution, as peaks like
this one will eventually also be covered in darkness depending on the time of year, but
89% of the time is definitely better than other regions on the Moon where you’d get
sunlight for roughly 50% of the time. I’ll just leave you with a couple more islands
in the darkness, this time from the far side of the Moon, found in Bhabha crater. These are the central peaks found in the middle
of this 80 km wide complex crater. Want to know more about complex craters? Then check out this other video in the LRO
series I made here. So, there we have it! A look at some of the newest and most interesting
images from the Lunar Reconnaissance Orbiter. What do you like about the Moon? And what would you like to see more of in
future episodes? Let me know in the comments. Thanks for watching! If you enjoyed the video, I hope I earn your
subscription today! Be sure to check out this playlist for more
space videos too. And lastly, if you want to support the channel
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