NASA Have Seen Some Astonishing Things on the Moon | LRO 4K

Let me ask you a question: “If you could visit any place on the Moon, where would you go?” Observe the cratered and dust-covered landscape. Here are mountains and craters, scientific wonders and mysteries shrouded in pitch-black shadows. But without the right map, it would be easy to miss

some

of the wonderful features of our closest celestial neighbor. Fortunately for us, for a decade and a half, the LRO (or Lunar Reconnaissance Orbiter) has been compiling that map. In ways never

seen

before, it has imaged lunar terrain features, helping scientists learn more about the Moon's ever-evolving surface and the processes that govern it.

With more than 8 billion different measurements taken, its complex analysis has made the Moon the most exhaustively measured of any non-terrestrial object in the solar system, and has given us the tools we need to perhaps one day lay foundations. permanent there. What did you find? And since the Moon is an object you've probably

seen

thousands of times in the night sky throughout your life, it's time to find out: how well do you really know it? I'm Alex McColgan and you're watching Astrum. And in this LRO superslice, we'll explore

some

of the most fascinating discoveries and landmarks photographed by the LRO throughout its mission to the Moon to date.] The LRO has been scanning the surface of the Moon since 2009.

It is equipped with a powerful camera, capable of taking high-definition photographs, which it sends to NASA's Planetary Data System. The LRO can send up to 155 gigabytes of data per day, or 55 terabytes per year. By comparison, it took New Horizons two full years to transmit data from its only Pluto flyby. Although the LRO was launched more than a decade ago, it is still operational and we are constantly learning new

things

about the lunar surface thanks to its high-powered camera and topographic mapping capabilities. [Let's see that camera in action. We'll start with a place rich in incredible contrast: Jackson Crater.] Unfortunately, this oblique angle is not visible to us on Earth, since it is located on the far side of the Moon.

A bit like the Tycho crater on the near side of the Moon, when it formed it created a lightning system that stretched across 1000 km. Lightning systems form when particularly fine material is ejected far beyond the crater rim, although their formation is still under study. Jackson Crater itself is about 70 km in diameter and, due to its size, is a complex crater, as can be seen from its terraced walls and elevation in the central region. This crater is actually tilted, the east side of the crater is 6000 m high and the west side is only 3000 m high. The base of the crater has an elevation of 1000 m, and the peak is made up of material that was pushed up from another 1000 m below.

Some of the dark spots seen along the walls are shadows due to the angle of the Sun in the sky, but there are also sections of darker materials, compared to the predominantly lighter colored floor. Although it's not as light as this image would

have

you think. Your viewing angle and the angle of the Sun play an important role in how contrasts appear on the lunar surface. Focus here on the central peak of this image. We will now switch to a top-down perspective of this same peak, taken at a different time of the lunar day. Suddenly, the crater basin and the tip of the mountain peak appear much darker than before.

But a side-by-side comparison shows how the differences can be seen in both images. And that's not the only optical illusion the Moon can fool you with. Look closely at this image. As you think? Are these bubble regions inverted, or do these sections actually rise higher than the wavy-textured material surrounding them? Well, for a long time I could only see that it was inverted. But maybe if you look around the image, it will suddenly change perspective. What type of image did you see first? Are you like me and need proof that it's not actually backwards? Well, let's take a look at the same region but from a different angle.

Seeing it like this makes me wonder how I could

have

seen anything else! This is a small region of the Moon called Ina. It's only 2 or 3 kilometers wide and 64 meters deep, and no one really knows how something like this formed. It is one of several similar regions on the Moon, although this is the most prominent. To some extent, a similar optical illusion can occur with small craters. Do you see domes here or craters? Sometimes rotating the image can help get the right perspective. In my opinion, that's why LRO is so useful: we don't just get top-down views, but oblique perspectives too!

Moving on to another unusual lunar region, let's take a look at the Komarov crater. This crater would be quite normal by lunar standards if it weren't for the fact that it has huge fracture lines running through the base. Komarov Crater itself is even larger than Jackson Crater, at 95 km in diameter. Which means they are up to 500m deep and 2.5km wide! It is believed that 2.6 billion years ago, magma accumulated beneath the crater, causing large amounts of pressure to fracture the crust; although it seems that the magma never reached the surface, that is, the fractures were never filled and have remained that way since then.

But although it didn't happen in this case, there are examples on the Moon of magma breaking through and accumulating on the surface. An example of this can be found west of the Plato crater, a large 100 kilometer wide crater seen towards the north of the Moon, visible with a telescope or binoculars from Earth. This image has some pretty spectacular points of interest to see, the most obvious being this channel running through the ground. This section here is a lava vent, when the Moon was much more geologically active. Coming out of the vent, heading southwest, is something known as a rima or rille.

These are channels cut by lava that melts and erodes as it passes through the hillside, something like a river on Earth. Towards the east in this image we see the rim of Plato's crater. Plato itself was probably filled with lava at some point, as the base is darker and softer than the northern regions. However, in this image we can see that a huge section of crust has collapsed from the crater wall, creating a 24 km wide sinking block. In other words, this section was once connected to the upper plain, but has since collapsed under its own weight, separated, and fallen a bit into the crater.

Let's take a look at one more crater. This impressive view is from the Apollo 15 mission, overlooking the Aristarchus crater. Aristarchus is seen to the northwest of the Moon, and although Aristarchus is only 40 kilometers in diameter, it is bright enough to see with the naked eye. From Apollo's point of view, we can see a really wide perspective of the crater. Around it are more streams and lava chimneys, and a small lightning system can be seen extending from the center. From this angle, with the shadow protruding from the rim, you can get an idea of ​​the depth of the crater.

This complex crater has prominent walls; however, the uplift found in the center appears quite small. From the LRO perspective, we again have a much higher resolution view of Aristarchus and can perform a close examination of the crater walls and base. The walls are similar in appearance to Jackson Crater; However, looking at the peak toward the center of the crater reveals some important differences. Not only is the peak much smaller, but it also has a banding pattern, revealing layers of crust that would otherwise have been hidden hundreds of meters deep. It is also likely that the base of the crater formed from molten lava, rock melted by the impactor.

Fracture lines due to rapid cooling are evident everywhere, and by looking at where the walls meet the base of the crater, you can easily imagine how this base was once liquid. This area is known as Montes Carpatus, and what is immediately evident here are the variations in contrast. Generally speaking, looking at the darker regions of the Moon indicates older material, but it also indicates what it is made of. The darker regions in this image are believed to have formed from explosive volcanic activity more than three billion years ago. The lava would also have descended through valleys like these.

White dots also dot the surface; These are small impact craters and appear white because they are much cooler than the surrounding regions and space erosion has not yet had a chance to darken them. The Lunar Reconnaissance Orbiter, unlike the Mars Reconnaissance Orbiter, has the special ability to be able to take photographs from both an angle and a top-down perspective. This means we can see the

moon

's mountains as if from the cockpit of an airplane, giving us a better sense of height and scale. However, our sense of scale is already seriously altered, since on Earth we have visual cues that help us judge how high or far away something is.

For example, we can say that the background must be tens of kilometers away, because the atmosphere makes the mountains quite hazy. We can also see the town, some trees, all of which helps us know approximately the size of the object we are looking at. But on the Moon we have none of that: no trees, no atmosphere, no cities. Just by looking at this image, how big would you say this mountain is? How wide is the foreground in this image? It would be fun to see your guesses in the comments. But, perhaps surprisingly, the foreground of this image is about 15 kilometers wide, and the mountain in the foreground is almost 7 kilometers high!

These two peaks in the back are a whopping 200 km apart and approximately 4,500 m high. Surprisingly, these peaks are not named as they would be if they were on Earth at that size. The best way to get an idea of ​​the scale of these images is to use this amazing tool that NASA has released called Quickmap, where you can view the

moon

under various filters, including a topographic map. Here is the mountain in the foreground of the image and here are the peaks in the background. You'll also notice that these peaks are located around the rim of a crater.

Almost all of the mountains we will see today can be found on the edges or in the centers of craters. Including these found in the famous Copernicus crater. When craters form, we all tend to think of the circle they create, but large craters usually have a rise in the center. Surprisingly, this is not predominantly due to an effect like a drop of water hitting a puddle of water, or elastic rebound, in which the center shoots back after impact. This only happens with materials with elastic force that try to return to their original shape. Rather, craters have elevation in the center because the surface material tries to return to a gravitational equilibrium.

The Copernicus Crater can be easily seen on the moon's surface with an amateur telescope and, as a result, is one of the most viewed features of the moon from Earth. These mountains in the center look impressive, but they only rise about 1000 m above the crater floor. Zooming out a little, you can see how dwarfed they are by the surrounding crater walls, reaching 4000m above the crater floor. Here is the crater from another angle, and one thing you will notice is that the basin of this crater is irregular, but comparatively flat. This is because after the massive impact that caused this 100 kilometer wide crater, the floor was lava that finally solidified.

Moving on to a new location on the moon, we arrive at the Apennines, an impressive 3-5 km high mountain range that sits on the edge of one of the largest impact craters in the entire solar system; the Imbrium Basin, or Mare Imbrium. These mountains look interesting next to this mare, or plain of solidified lava, and this crevice, something like a gorge found on the moon. But in addition to being a very interesting sight, there is something special about this place. In fact, it's where the Apollo 15 mission landed in 1971, which means there's also a terrestrial perspective of these mountains.

Here is the lunar module with these same mountains in the background. And from here it looks like they are very close, but remember that our perception of

things

is biased! In reality, these rise about 5 km high from the plain on which the chamber is located; higher than the Himalayan front above the plains of Nepal and India on Earth. Astronauts also investigated the rift using their lunar rover. This stream actually drops 380m! The Rille ones are a bit mysterious as it's not clear why they are there. One major theory is that they are magma tunnels exposed or collapsed beneath the moon's surface when it was most geologically active.

From the perspective of the LunarReconnaissance Orbiter, the footprints left by the rover can still be seen today, as there is no wind on the Moon to cover the footprints with dust. So although the Apollo mission occurred about 40 years before this photo was taken, the remains can still be seen in impeccable detail. It wouldn't be right to talk about some of the highest points on the moon without talking about the highest point! Unfortunately, it doesn't look too impressive as it has a very shallow slope: only 3 degrees. [It is near one of the largest impact craters in the entire solar system, and certainly the largest on the Moon,] the Aitken Basin, which probably formed 4 billion years ago. [This is where the Chinese Chang'e 4 mission landed in 2018, which LRO was able to impressively capture!] As you can see, this crater is huge and would have created a lot of ejecta.

These ejecta accumulated around the crater, including what is now known as the highest point on the moon. The basin was probably caused by a low-speed impact with an object 200 kilometers in diameter, and would have been at an acute angle as the ejecta was mainly thrown in one direction. Interestingly, the lowest point of the moon is not that far from the highest point! The lowest point, which is located at the bottom of a crater within the basin, is -9106 m, and the highest point is higher than Everest, at 10,786 m! Just a side note for anyone curious, these heights come from comparing the average radius of the moon to the elevation of that point.

As you can see, the surface of the moon is full of craters. No matter where you are on the moon, there will be craters of various sizes. This implies that the surface is old and has not been renewed by recent mantle lava eruptions; The most recent eruption is believed to have occurred 1.2 billion years ago. There are an estimated 300,000 impact craters larger than 1 km in diameter on the Moon's surface in front of us, and millions more smaller than that, like the ones you're currently observing. The Moon can have such small craters because it has no atmosphere, which means that every meteorite headed toward the Moon will crash into its surface.

On Earth, most meteors burn up in the atmosphere. Imagine how many shooting stars there are every night. If it were not for the Earth's atmosphere, all of them would also impact our surface. The interesting thing about each crater you see here is that you can roughly estimate the age of a crater based on its degree of erosion. Craters that appear very smooth are much older than craters surrounded by lighter substances, with sharp, defined edges. The bright spots have not had as much time to suffer the effects of weathering. But weathering on the moon? How can it be?

Well, this erosion is not caused by water or air, but by small micrometeorite impacts and by the intense radiation from the Sun that obscures the thin outer layer of the Moon. If we speed up to the end of this image, we can see a relatively new crater only a few hundred meters in diameter. Using the LRO's narrow-angle camera, we can see up close the effects of such an impact on the lunar surface. These linear patterns are the effects of the impact ejecta. Finer dust would have been blown across the surface with some force, and larger rocks would not have gone as far, although they would have left a trail from where they moved away from the impact.

The crater itself is not very clear in this image due to the time of lunar day it was taken; the Sun near the horizon casts long shadows on the surface, although fresh material can still be seen exposed along the crater wall. crater. Comparing this to an ancient crater, here you can see a much smoother and darker looking crater, although still brighter than the heavily eroded surface in the surrounding area. However, what I like about this image is that when you zoom in, you can see some ejecta that fell from another impact outside the image. Here is a rock that landed on the crater wall and then rolled halfway down.

The only problem with these top-down perspectives is that you don't get much of a concept of depth in the image. How shallow or deep can craters get? Fortunately, the LRO not only scans the surface, but can also take more oblique photographs of the moon, which can definitely help us appreciate the depth. Look at this fantastic image. This crater is about 21 km in diameter and has some fascinating details around it. Once again we can see the traces left by huge rocks rolling down the slopes, and very bright walls that imply that it is a young crater, although with darker material at the base.

The contrasts are actually quite vivid and it almost seems like some parts could have been liquid at some point. The impact would have initially melted the rock into lava, which flowed to the bottom, accumulating in pools that have since solidified. The impactor was probably 2 kilometers in diameter and hit the Moon ten times faster than the speed of a bullet. That would have really been a collision! Another great image I have to show you is this one, a 10 km diameter crater. What's special about it is its interesting raised edge. This is another example of rock melting on impact, but this time it tilts past the edge and flows downward, before solidifying again.

If we look closely around the crater, we can also see ejecta scattered across the surface, disturbing the ground and leaving brighter areas exposed. See? Once you know what you're looking at, even the Moon becomes very interesting. But these have been very pristine craters. What happens if a meteor falls somewhere a little less conventional? Here is a crater within a crater. The impactor hit the largest crater wall, meaning it has a rather unusual shape, although from a top-down perspective, it still appears quite circular. As a side note, this image is a true color image of the moon.

Most other images of the Moon are taken in black and white to save bandwidth; Astronomers prefer resolution over color, although the LRO's lower resolution camera is capable of capturing color, and this is an example of that. But certain craters can also be unconventional in other ways. There's a little-understood phenomenon on the Moon that scientists have so far struggled to explain: the cold spots found on the Moon after the Sun sets. So far, we've only focused on the cameras equipped on the LRO, but it has a number of other instruments on board, including the Diviner Lunar Radiometer Experiment, which has mapped the Moon's surface temperatures.

There are two thousand spots on the Moon that get colder than surrounding areas when the Sun sets. When the sun rises again over the spots, they normalize their temperature and quickly blend into the background. The only thing these places seem to have in common? They are always found around young craters of no less than 50 m and no more than 2.3 km. But the spots themselves are much larger than the craters. Here's a heat map of the crater I just showed you. White is the hottest parts of the image, blue is the coldest. As you can see, a large cold region surrounds the young crater.

There is an investigation underway to discover the cause. What do you think it could be? [Speaking of cold areas, let's now jump to one of the coldest places in the solar system. It is an image that I personally find impressive. This crater, located near the Moon's south pole, is almost always in shadow. Here the Sun never rises far above the horizon, meaning that only the peaks of the crater jut out far enough to be enveloped in light. What remains is a striking contrast, almost like the symbol of yin and yang. This is without a doubt my new desktop background image.

But this region is not only a hauntingly beautiful place, it is actually one of the candidates for the future Artemis mission to the moon. The lunar South Pole is of particular importance for future human missions, since it is believed that millions of tons of water ice can be found in this region, at the bottom of craters like this one, always protected from the sun's rays. If there is to be a future colony on the Moon, this is approximately where it would be located. [While the massive craters, pristine mountains, and shadow-dotted landscapes are hauntingly beautiful to look at, a big part of why the images taken by LRO are so important is how well they advance our scientific understanding of the formation of the Moon.] Let's take a look Look at one of these images.

At first glance, it may seem unremarkable, but a deeper look tells a different story. See those two big round depressions? These are impact craters, very similar to many others that cover the lunar surface. But if we zoom out, we see that these craters are located in an unusual dome-shaped structure. This is Bishop Gruithuisen Gamma. Notice how the western side of the dome appears lighter where the sunlight reflects off its steep slope. In contrast, the western sides of the craters are immersed in shadow due to their low elevation. Shadows on the Moon are very dark compared to those on Earth due to the absence of Rayleigh scattering in the atmosphere.

The Moon has no atmosphere, so the only light that reaches the dark regions is reflections from the lunar surface itself, which is actually not that reflective. It is generally very dark, with an average albedo of 0.12, about as dark as moist soil. Directly east of the dome is a dark shadow cast by the dome itself, and it gives you an idea of ​​its height. The dome is imposing, with a slope of up to 20 degrees and rises 1,500 meters above the lunar surface. With a diameter of 20 kilometers, it is equivalent to the metropolitan area of ​​a medium-sized city. That's pretty big!

As we zoom out further, we see that the dome is surrounded by darker, much flatter terrain. This plain, or mare, is the result of basaltic lava flows that flooded topographic lows about 4 billion years ago, resulting in the uniform surface we see now. Think of it as ice cream dripping into the cracks of a wafer cone. Zooming out even further, we see a second dome located southeast of Mons Gruithuisen Gamma. This is the Mons Gruithuisen delta, and it is even larger than its cousin: it rises 1,800 meters above the surrounding surface and spans 27 kilometers in diameter. The dark basalt plain that surrounds both domes is part of a vast sea: Oceanus Procellarum, or "Ocean of Storms", which covers 10.5% of the lunar surface.

I don't know about you, but I think "ocean" is an appropriate word. The domes look like islands! The Gruithuisen Domes, like the Oceanus Procellarum, are believed to have formed from ancient lava flows. But why did they abandon these unusual structures? Believe it or not, there may be clues here on Earth. This is Mount Saint Helens, an active stratovolcano located in the Pacific Northwest of the United States. Maybe you can see where I'm going with this. As you can see, it is dome-shaped. Stratovolcanoes like this one result from pyroclastic flows of silica-rich materials such as rhyolite, dacite, and andesite.

Once ejected from the Earth's crust, these high-viscosity lavas move slowly as they cool, hardening into conical or dome-shaped formations over time. We suspect that the Gruithuisen Domes, like terrestrial stratovolcanoes, are made of highly silicic material, and recent thermal measurements by the LRO's Diviner instrument support this theory, suggesting that the domes have a different composition from the surrounding plain. . So unlike the basalt lavas of the Moon, which settled on smooth, low surfaces, these more viscous, silica-rich lavas extruded slowly, like thick molasses, and eventually cooled and left the enormous domes seen now. . But this is where it gets strange.

On Earth, stratovolcanoes like Mount St. Helens are a unique product of water and plate tectonics. At the convergence of two tectonic plates, a subduction zone can occur where cooler, denser material from an oceanic plate is pushed beneath the less dense plate and back into Earth's fiery mantle. The remelted material gives rise to silica-rich magmas, such as rhyolite or dacite, which then rise. But unlike here on Earth, there is no liquid water or tectonic plates on the Moon. So how did these silica-rich magmas form? We are not sure! One explanation suggests that when lunar magma nearly cooled and crystallized, it left a residual liquid that could have been extremely rich in silica.

The problem, however, is that this process, known as fractional crystallization, would produce only small amounts of silicic material, which would not be enough to explain a huge 27-kilometer goliath like the Mons Gruithuisen delta. A second model suggests that the silicic materials formed when basaltic magma rose upward, causing rocks on the lunar surface to melt.partially and will form rhyolites and dacites. If this were indeed the case, then the Gruithuisen Domes should be almost the same age as the surrounding basalt plain. We don't yet know if this is true, but future research could shed light on the chronology and composition of these mysterious structures.

For me, the most exciting part is that we may be just a year away from getting an answer. NASA plans to send a Commercial Lunar Cargo Services rover to this region in 2025. This mission will explore the surface of the Moon and collect rock samples that should shed light, not only on the mysterious Gruithuisen Domes, but on lunar volcanism in general. And the high-definition images taken by the LRO, like the ones we've been studying today, will provide NASA with crucial information for selecting a safe, navigable landing site. It's exciting to imagine how this mission will contribute to our current understanding of the Moon with ground-based images and rock samples, and I honestly can't wait.

Which of the two theories to explain the formation of the Gruithuisen Domes do you think sounds more plausible? I'd love to hear your ideas in the comments! [As you can see now, not everything that happens on the Moon is fully understood. For example, let's move on to this harmless, nameless crater. As you can see, there are many tiny craters inside. And this crater is again inside another crater. Maybe you can see where I'm going with this. Zooming out, these craters are not only in another crater, but are apparently contained within two very well-aligned craters. Or is that really what it is?

Well, we're not sure. Both craters are named after one: 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 that aligned very well, but further investigation suggests otherwise. If they were the result of chance collisions, then there should be a random distribution of concentric craters on the Moon's surface. However, this is not the case. Take a look at this. The population of concentric craters actually accumulates around certain areas, especially around the edge of this region of the Moon, called Oceanus Procellarum.

Another factor to consider is that most of these craters are similar in age. Searching for clues in the crater itself also reveals something interesting. This outer crater should be about twice as deep as it currently is compared to other craters of similar size around the Moon. Now, while some concentric craters on the Moon will surely be the result of double impacts, the location, age and depth of most of the craters means that something else must be at play. One theory is that some of these impacts occurred during a time when the Moon's surface in this region was in a state between solid and liquid, with a consistency similar to cold lava or honey.

When the impact occurred, it caused waves to propagate outward, but then stopped and never smoothed out until it cooled completely and froze in place. Although this is seen as an external possibility. The most likely theory is that when the Moon was most geologically active, the craters in the region were pushed up from below by magma trying to escape to the surface. This would explain the shallow depth 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 don't know for sure.

What do you think it could be? Now, apart from the occasional meteor, you probably think the Moon's surface hardly changes. And while you're right about that, we have found evidence that material occasionally moves around on the Moon. See if you can see what I'm talking about in this image as I scroll through it. This is the rim 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, and dark material has apparently fallen out. down slope. Let's take a closer look at what's happening as we approach the most prominent landslide in this crater.

The material appears to originate in box-shaped canyons toward the top of the crater rim. The material falling here is clearly very fine, probably less than a meter in diameter, as individual rocks cannot be distinguished within the slide. However, the largest rocks that fell away appear to have reached the bottom of the crater. What's interesting is that the main mass of the slide appears to actually be made up of many smaller masses. Check out these individual trails here. So it probably didn't happen all at once, but is happening over time. The slides were probably caused by small meteorites that collided with the crater wall.

These small impacts and subsequent landslides round out the edges of the crater, which is why the oldest types of craters on the Moon appear so smooth compared to newer craters. Here's another puzzle to try to solve. Here we have the notable Messier crater. Normally, craters are round, but not Messier Crater. It is elongated with a groove like a crater floor. What's going on here? The mystery continues if you zoom out a little. Directly next to the Messier crater are two more craters. The one on the left appears much older than the other, as it appears to have been eroded compared to the recent impact crater on the right.

It turns out that the newer crater covered an older one? But let's zoom out again. What other clues can we see? Actually, a big clue are these lines coming out of the crater. These are called lightning bolts and reveal the direction in which the debris fell after impact. In rounded craters, debris can go in all directions, such as that originating in Tycho Crater. However, here the debris goes in three different directions: north and south from this crater and only west from this one. So what would cause that? Well, the answer is that an impactor hits the surface at a very low angle, less than 15 degrees.

And in this particular case, it appears that the impactor had already broken into three pieces before even touching the surface of the Moon. Yes, these three craters are likely to hit the Moon almost at the same time, even the "oldest" crater. What really happened here is that the ejecta from this second crater probably fell directly onto the other crater due to the low angle of impact, meaning it has been artificially aged. However, there are some other really interesting aspects of this image, like the solidified pool of impact melt found at the bottom of the crater, or this region here that appears to have sunk a bit.

The impact melt in the first image also appears to have flowed to the left of the image. It really is a fascinating set of craters. Let's take a look at another asymmetric crater and try to figure out why it has the shape it does. While it could be that this crater is also the result of two impacts, or an impactor breaking in two just before colliding with the Moon, scientists believe this is probably not the case here. Notice the shadows in this image, above and below the crater. It is evident that this crater is right at the top of a peak.

Zooming out and looking at a topographic map of the region reveals this to be the case. In fact, this may well have been the highest peak in the local area, until, by chance, this impactor obliterated it completely. Imagine that Everest is suddenly felled by a meteorite! The shape of this crater was probably caused not only by the angle at which the impactor approached, but also because it hit this steep slope. It may not look that steep from the oblique angle, however, in just about 20 km, there is an 8 km elevation difference from the peak to the bottom of this nearby crater.

In the next image, there is not much to see. The only thing visible in this wide expanse is this peak, basking in the sunlight. Why is this significant? Well, this peak is on the rim of the Aepinus crater, a crater located near the north pole of the Moon. As I mentioned, future colonies on the Moon will be located somewhat close to the north and south poles, because hidden at the bottom of the craters, here where the Sun never shines, there are large pockets of water ice, essential for any colony to survive. . . Water can be used for drinking, washing, cooking and farming;

Additionally, breaking down water 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 on the Sun, unlike other parts of the Moon where the day and night cycle lasts 28 days. 14-Earth days in constant darkness are not good for a solar energy system. However, a peak like this, poking out into the sun as the surrounding area experiences nighttime, would be an ideal location to install solar panels and power a colony there. It's not a perfect solution, as peaks like this will eventually also become covered in darkness depending on the time of year, but 89% of the time it is definitely better than other regions of the Moon where you would receive sunlight for about 50%. weather.

A couple more islands in the dark, this time from the far side of the Moon, found in Bhabha Crater. These are the central peaks that lie in the middle of this 80 km wide crater complex. [Islands in the Dark are a fitting way to end our exploration of the Moon through the eyes of LRO. When it comes to space, that's all the Moon is, that's all any astronomical body is. An island floating in a sea of ​​darkness, dotted with stars. And yet, incredible beauty and wonder can be found on these islands. The LRO remains operational and will continue to operate until 2024 and 2025.

As it carefully circles the Moon through time and the seasons, perhaps it will encounter new wonders: new craters and asteroid impacts, or new rockfalls caused by by lunar earthquakes. The Moon's surface is slowly evolving even now. And finally, once it has run its course and taken its last image, LRO will fall gracefully from its orbit and contribute to the Moon's history by creating one last crater. This small crater won't be as large as Aitken Basin, but given the Moon's lack of wind or climate, it will likely remain there for millennia: a frozen testament in the regolith of the orbiter that did so much to map the Moon's landscape. for us.

After all, by giving us this knowledge, you may have paved the way for the first humans to set foot on the Moon and call its eerie, beautiful, cratered landscape home.]