Scientists Found Mysterious Holes on the Moon — And They Lead Somewhere Deep

[00:00:00]Scientists have just uncovered a lunar crater so large, so fresh, and so unexpectedly dangerous that it's forcing a complete rewrite of what we thought we knew about the moon.

[00:00:12]If something [music] like this can form without warning, then every plan for a permanent base suddenly looks fragile, maybe even naive.

[00:00:21]So now the question isn't how we build on the moon, but whether we ever safely can.

[00:00:28]This isn't about falling into it or toxic leaks. The threat is what this crater proves. [music] The moon is still actively being hit, and when it happens, it's sudden and unforgiving.

[00:00:41]A recent study shows that while the odds of a direct strike on a future base are low, that risk grows with every structure we put on the surface.

[00:00:50]More infrastructure means more exposure.

[00:00:54]And there's no safety net, no atmosphere to slow incoming objects, no warning system. An impact would be immediate and likely catastrophic.

[00:01:03]So why does this crater stand out?

[00:01:06]Because it shouldn't exist, at least not yet. It's about 740 ft wide and 140 ft deep. According to existing models, an impact of this scale should happen roughly once every 139 years.

[00:01:21]But this one is recent, which means either we got extremely lucky or the models are wrong. And if the models are wrong, then the risk has been underestimated all along.

[00:01:34]The structure of the crater adds to the concern. Its steep walls suggest it formed in dense, solid ground, likely ancient lava flows.

[00:01:44]But the real danger isn't only the crater itself, it's also what the impact unleashed.

[00:01:50]A wide ejecta field surrounds it. Dust and rock blasted outward at high speed.

[00:01:56]These fragments can travel hundreds of feet, hitting with enough force to damage or destroy anything in their path.

[00:02:04]Not just at the impact site, >> [music] >> but far beyond it.

[00:02:09]This changes the equation. The danger isn't just rare direct hits, it's the cascading effect. High [music] velocity debris spreading across large areas with no warning. And yet, lunar missions are accelerating.

[00:02:23]NASA's Artemis program is pushing toward long-term human presence on the moon.

[00:02:28]New habitation modules are being designed to support crews, experiments, and surface operations.

[00:02:36]But all of it depends on a single assumption, >> [music] >> that the moon is predictable.

[00:02:41]This crater suggests it isn't. [music] And all this comes right as NASA has launched Artemis 2, sending astronauts around the moon for the first time in 50 years.

[00:02:52]And pushing one step closer to a long-term human presence there.

[00:02:59]>> There's something happening inside the moon, something that nobody expected.

[00:03:04]Not a dramatic shift you'd see on the outside, but deep down, where things seem frozen in time, scientists have uncovered a hidden layer of what you could only call moon goo.

[00:03:16]Remember those school lessons about the crust, mantle, and core? Much like the Earth, the moon is made up of layers, a crust, mantle, and core. However, the moon's core is much smaller compared to ours.

[00:03:29]Earth's core is huge. It makes up about a third of our entire planet's mass. The moon's core makes up only about 1 to 2% of its mass, and its diameter is about 1/5 the diameter of the moon itself.

[00:03:42][music] It's surrounded by a hard rocky mantle.

[00:03:45]But, it turns out that between these two layers, that mysterious goo layer, and it's way more important than you might think.

[00:03:53]The layer is soft and partially molten, ebbing and flowing like the tides in our oceans.

[00:03:59]It rises and falls, stretching and shifting as if it were alive. Its movement isn't chaotic, but subtle and regular.

[00:04:08]We always knew that the moon influences our seas [music] and oceans, causing tides with its gravity. But it turns out that we influence it back. The goo ocean reacts to the gravitational dance between Earth and the Sun.

[00:04:22]Also, the molten layer could be made of ilmenite, a very intriguing material.

[00:04:27]Ilmenite is rich in titanium, a strong and lightweight metal that we really love over here on Earth. Titanium is used in everything from airplane parts and spacecraft to medical devices, even in everyday items like bikes and laptops. All because it's incredibly strong and very resistant to corrosion and heat. So, if the moon might have a molten layer rich in ilmenite, that would be awesome. Astronomers are already planning for lunar bases. And if we had a material to build structures, spacecraft, or even tools for astronauts right there, that would be a game-changer. Otherwise, we'd need to transport materials from Earth, which is extremely costly. This is our first tangible sign that the moon is not just a cold, boring rock. Instead, it's dynamic, living, and breathing with moving forces beneath the surface.

[00:05:20]NASA used new special tools to discover this, the Gravity Recovery and Interior Laboratory and the Lunar Reconnaissance Orbiter.

[00:05:29]These are both space missions [music] designed to study the moon, but they don't just look at the surface like a telescope. Instead, they help measure things we can't see with our eyes, >> [music] >> like the moon's gravity and how it changes over time.

[00:05:43]GRAIL sent two small spacecraft around the moon named Ebb and Flow. Clever.

[00:05:49]The idea was for these spacecraft to fly close to each other and measure tiny differences in the moon's gravity as they go. It's like they were feeling the moon's invisible pull in different places. If the moon's gravity was stronger in one spot, the spacecraft moved closer together. And if it was weaker, they moved farther apart.

[00:06:09]This helps scientists understand what's going on inside the moon, even if they can't actually go there. And the spacecraft intentionally crashed into the moon in December 2012 to end the mission.

[00:06:21]The Lunar Reconnaissance Orbiter is a bit different. It takes super detailed pictures of the moon and collects other important information about its surface.

[00:06:29]By combining the information from both GRAIL and LRO, we were able to find this goo layer.

[00:06:36]But this discovery actually challenges everything we thought we knew about lunar geology. How did this molten layer get there? How long has it existed? And perhaps more fascinating, how it stayed warm for millions of years. That's some million-dollar questions.

[00:06:52]The moon's core generates heat just like ours. But it's not as easy as saying, "Oh, the core's heat probably keeps it warm and molten."

[00:07:01]Well, first, the moon's core is much smaller and less active than Earth's, meaning it produces significantly less heat. Plus, the moon is much cooler than Earth in general, with temperature dropping to minus 200° F on the surface.

[00:07:15]How could this inner layer still stay in this flowing state? That's still a mystery. In any case, this goo could actually explain a lot of stuff about the moon. For example, astronomers were exploring moonquakes and how they happen. Now they think that it might be this semi-molten layer shifting and moving beneath the surface.

[00:07:35]Now, beyond the moon itself, it also tells us more about other celestial bodies. If the moon, something we considered basically a huge static rock, has such a dramatic life, what about other planets, moons, or asteroids?

[00:07:49]Could they also hide similar hidden movements beneath their surfaces?

[00:07:54]We can even understand our own planet better, learn more about how tides and similar stuff works.

[00:08:00]There are so many great discoveries we've been making on the moon. Recently, we found some awesome stuff beneath the surface, massive caves [music] hidden for millions of years.

[00:08:10]For over 50 years, scientists have suspected [music] that the moon's surface is full of underground tunnels and caves. These are known as lava tubes because they were formed by lava, duh.

[00:08:22]Millions of years ago, the moon was pretty unstable.

[00:08:25]>> [music] >> It underwent some volcanic activity, causing eruptions. When a volcano erupts, lava can flow across the surface. As the outer layer of the lava cools and hardens, it forms a solid roof of dark material. It's actually what these famous dark spots on the moon are.

[00:08:42]These are dark, hardened remains of ancient lava.

[00:08:45]But the hot molten lava continues to flow through the center.

[00:08:49]>> [music] >> Once the eruption ends and the lava drains away, what's left behind is an empty hollow tunnel, hence a lava tube.

[00:08:57]On Earth, we have lava tubes in places like Hawaii or Iceland, where volcanic activity has created similar underground tunnels. The same thing happened on the moon billions of years ago. Although they're much crazier compared to ours.

[00:09:11]In fact, lunar lava tubes are now thought to be some of the largest and longest in the entire solar system.

[00:09:18]One such cave was discovered beneath the famous Mare Tranquillitatis, the place where Apollo 11 first landed, and it's [music] at least 340 ft deep. Now, all these lava systems have remained hidden just beneath the surface, untouched for millions of years.

[00:09:33]>> [music] >> Only now they finally managed to prove their existence.

[00:09:38]Scientists from the University of Trento in Italy found them using special radar technology and advanced computer methods. These techniques let you see underground by sending radar waves. The waves bounce back and give clues about what's hidden underneath. By analyzing the way these waves reflected back, the researchers could detect the shape and size of the hidden caves.

[00:10:01]Now, the best thing about this discovery is that we could build all our bases there. These caves protect from radiation, harsh winds, and meteoroids.

[00:10:11]NASA even found evidence that some of these caves stay at a steady 63° Fahrenheit. That's some crazy coziness for the moon. And on top of that, there could even be some water there.

[00:10:23]So, humans could take shelter inside these natural tunnels and build entire colonies on the moon. Then, I know what you're thinking. Could unexpected lunar monsters hide deep in those caves? Well, sure. There's a huge potential for exploring these caves and finding some awesome stuff. But, even if we managed to find a miracle, like small life or microbial organisms, there's a 99% chance that there won't be actual animals or monsters. It would just be impossible for them to develop in such conditions. But, it would make a great horror movie.

[00:10:58]Researchers want to send robots or drones to explore the tunnels first, and then see if they're safe enough for humans. And it's not just the US getting in on the action. China is also investigating the possibility of using these moon caves as a future base, showing that the race to explore and settle the moon is heating up.

[00:11:20]You might think high-tech telescopes let us see every inch of the moon, but that's not true.

[00:11:26]At our satellite's South Pole, lie giant craters untouched by sunlight for eons, stuck in pitch black, colder than Pluto, and almost impossible to explore.

[00:11:38]However, maybe we have to if we want to explore space.

[00:11:42]Because the darkness hides some must-have resources that will make life and long-distance travel in space possible.

[00:11:49]Yes, we're talking about water locked up as tiny crystals in the lunar soil.

[00:11:55]Now, water in space is always good news.

[00:11:58]You've probably heard that scientists are also obsessed with finding it on Mars.

[00:12:03]If the red planet has any type of water below its surface, it raises the exciting possibility that life might have existed there.

[00:12:11]Even microbes would be the biggest discovery in human history. That's why rovers are poking around [music] Martian craters and drilling into the soil like some very dedicated space gardeners.

[00:12:23]But as incredible as [music] water on Mars would be, water on the moon might be even more valuable to us in the short term. The reasons are simple. The distance and the gravity of the moon.

[00:12:35]We can reach our satellite in 3 days.

[00:12:37]That's almost nothing.

[00:12:39]It takes at least 7 days to reach New [music] York from London via a cruise ship.

[00:12:43]But more important than the length of the trip is the possibility of using the moon as a pit stop.

[00:12:49]Stop, refuel, and relaunch so we can resume exploration. [music] The gravity on the moon is only 1/6 as strong as Earth's.

[00:13:00]That's not just useful for endlessly entertaining yourself by jumping around.

[00:13:05]This difference means that launching rockets from our satellite is much easier compared to launching them from Earth, which requires a tremendous amount of fuel just to break free from the atmosphere.

[00:13:16]For example, the Saturn V rocket, which took astronauts to the moon during the Apollo missions, was made up of more than 90% fuel just to get off the ground.

[00:13:26]On the moon, however, it's much easier to launch a rocket. That means that we could carry heavier loads with less fuel.

[00:13:34]It's like being able to take a bigger suitcase on your trip.

[00:13:38]If we can find and use ice on the moon to create rocket fuel, it would turn our satellite into a practical and affordable stop for exploring the solar system.

[00:13:47]Not to mention that by applying [music] some basic chemistry, we could extract oxygen from water and use it for breathing or rocket engines.

[00:13:56]Also, >> [music] >> astronauts would need water to drink and grow crops on the lunar base.

[00:14:01]So, what do we know about the latest discoveries?

[00:14:05]For a long [music] time, scientists thought the moon was completely dry.

[00:14:10]But in 2009, NASA basically crashed a rocket into a crater. It caused an explosion of ice and vapor, [music] like fireworks, and finally confirmed that the moon had some kind of water.

[00:14:23]But how much? [music] Well, enough to matter.

[00:14:26]The data suggests there could be hundreds of millions of tons of water ice [music] locked up in the moon's polar regions. Some estimates roughly say 1.3 trillion pounds. That's about [music] the same weight as 460 million cars. Not exactly lakes, but still a lot.

[00:14:45]And there still [music] could be more.

[00:14:47]This water could also contribute to uncovering cool scientific secrets.

[00:14:52]The ice is ancient, which makes it like [music] a time capsule from the early days of the solar system.

[00:14:58]Studying those frozen molecules might tell us not only how water got to the moon, but also how it appeared on Earth.

[00:15:07]Anyway, what's all that water doing on the moon? How did it get there?

[00:15:12]Scientists assume that some of it probably hitched a ride on comets and asteroids billions of years ago.

[00:15:18]Many of those space rocks carried ice, and some of that water ended up in the polar regions.

[00:15:24]Another source [music] could be the way solar wind interacts with the lunar surface.

[00:15:29]In any case, however this ice appeared on the moon, the real trick is where it ended up, inside its polar craters.

[00:15:36]And while we can find the ice not only in the craters at the South Pole, that's where the largest, most stable reserves are believed to be.

[00:15:44]Some of those craters are enormous. One of the most famous is called the Shackleton crater, and it's over 13 miles wide and more than 2 miles deep.

[00:15:55]That's almost twice as deep as the Grand Canyon.

[00:15:57]>> [music] >> The moon barely tilts on its axis, only about 1°. So, the sun never peaks over the rims of those deep [music] polar pits.

[00:16:07]The temperatures dip to around -400° Fahrenheit there.

[00:16:11]Any water or chemicals trapped in that frozen dirt just stay there, locked away like in a freezer.

[00:16:18]Something really cool is that at the South Pole, you have parts that are stuck in the perpetual darkness.

[00:16:24]But some nearby mountain ridges get almost non-stop sunlight.

[00:16:29]Scientists call [music] them the peaks of eternal light.

[00:16:32]They're perfect for setting up solar panels, while still being close enough to access the icy treasures hidden below.

[00:16:40]The poles of the moon are the only places [music] in our solar system we know of where perpetual day and night exist side by side.

[00:16:49]But the eternal night isn't just fascinating, it's dangerous.

[00:16:53]The terrain out there is absolutely unforgiving. We can't even simulate something like that on Earth. We don't even know what it looks like from the inside.

[00:17:03]It's worse than exploring the northernmost part of Antarctica while wearing a blindfold.

[00:17:08]So, now that we know this, is that potential water even obtainable?

[00:17:13]That question is probably worth several trillions of dollars.

[00:17:17]Yes, there's water over there, but getting to it won't be like scooping ice cream from a bowl.

[00:17:22]What we're really talking about are microscopic ice crystals mixed into lunar dust.

[00:17:28]To make use of it, machines would need to dig and heat up the soil, then capture the vapor before it escapes back into space.

[00:17:36]And then there's freezing.

[00:17:39]Even assuming a human or rover could safely reach the bottom of a crater, it'd be almost impossible to navigate.

[00:17:46]Batteries and equipment probably wouldn't last, and it's impossible to use solar panels or electronics down there. They'd freeze in minutes.

[00:17:54]However, NASA's Lunar Reconnaissance Orbiter uses all kinds of radars and sensors to sniff out what the crater looks like inside.

[00:18:03]And now there's an even sharper tool, ShadowCam. A camera so sensitive it can capture details in light a hundred times dimmer than what our eyes can [music] see.

[00:18:14]Basically, the ultimate night vision device.

[00:18:17]With it, we can [music] finally map those pits without even setting foot there.

[00:18:22]That's why engineers are thinking [music] up all sorts of clever solutions. Some concepts involve nuclear-powered rovers with headlights strong enough to carve through the dark.

[00:18:33]Others want robots [music] that rappel down crater walls or hop across the floor like pogo sticks.

[00:18:39]There are even ideas for drills that could melt frozen soil and trap water vapor like condensation on a cold soda can.

[00:18:47]The silver lining [music] is that this water isn't going anywhere.

[00:18:50]Until we improve our technology, the supply will wait for us.

[00:18:55]That being said, space agencies are already making advancements. [music] In fact, more than half a dozen new missions are lined up over the next few years.

[00:19:05]NASA's [music] Artemis program is getting ready to send astronauts back around the moon and then down to [music] the South Pole.

[00:19:13]China's Chang'e 7 is planning to check out those dark craters.

[00:19:18]And private companies like Firefly and Blue Origin are gearing up to deliver [music] equipment and experiments.

[00:19:25]Now, here's a bonus lesser-known fun [music] fact. The moon smells.

[00:19:31]When Apollo astronauts brought lunar dust into their landers, it [music] mixed with the oxygen inside and ended up smelling pretty strong. They said it was like burnt gunpowder or fireworks.

[00:19:42]Lunar dust has nothing to do with gunpowder, [music] but its particles are highly reactive. After sitting in space for billions of years, they reacted instantly with oxygen [music] in the cabin, creating that smoky odor.

[00:19:55]Future explorers [music] are definitely going to notice that smell, too, since lunar dust tends to stick to everything.

[00:20:02]Let's hope that, aside from everything else, scientists will work out air fresheners for the moon base.

[00:20:10]>> Technological progress does not stand still, and over the past decade, the resolution of images of the lunar surface has improved greatly.

[00:20:18]Many pits have been discovered on the surface, and some of them are really impressive in size.

[00:20:23]The largest are hundreds of feet deep.

[00:20:25]However, technology is not yet advanced enough for us to study the bottom of such pits in detail. That's why a recent discovery is surprising. It turns out that huge pits can extend deep into the rock of the moon. It's a groundbreaking discovery. Let's figure out why.

[00:20:40]So, look at this giant underground cave.

[00:20:43]Leonardo Carrer and Lorenzo Bruzzone from the University of Trento were thrilled to finally confirm the existence of such structures on the moon. They analyzed images taken by the Mini-RF instrument on board the Lunar Reconnaissance Orbiter in 2010.

[00:20:57]The original images didn't have excellent resolution, so the authors had to do a huge amount of work [music] using modern data analysis and modeling techniques.

[00:21:06]But first things first, why does it all matter so much?

[00:21:10]Well, instead [music] of building homes on the surface of the moon, we might be able to live inside these natural caves.

[00:21:17]They could offer protection from dangerous things like harmful space radiation, extreme temperature swings, and even meteorites.

[00:21:24]>> [music] >> According to planetary geologist Wes Patterson from Johns Hopkins, even though we'd still have to bring materials from Earth to make those caves habitable, [music] using them would be a lot easier and cheaper than bases on the surface.

[00:21:38]Based on the collected data, the cave is about 150 [music] ft wide and up to 260 ft long, which is just a bit smaller than a football field.

[00:21:48]>> [music] >> It's located in a deep pit called the Mare Tranquillitatis pit, which [music] likely formed when an ancient lava tube collapsed. Although the moon has no active volcanoes today, billions of years ago, its surface [music] was covered with lava that flowed through valleys, carving out these tubes below the surface.

[00:22:06]Over time, some of the lava tubes became unstable [music] and collapsed, creating pits like the one in question. NASA's Lunar Reconnaissance Orbiter, LRO, has already found more than 200 of such pits on [music] the moon.

[00:22:20]It means there could be hundreds of hidden caves waiting to be explored on our satellite.

[00:22:25]When publishing their findings in Nature Astronomy, the researchers suggested that the caves could offer future astronauts a safe place to live and work, protecting them from the moon's extreme conditions.

[00:22:38]And extreme they are.

[00:22:39]One of the biggest challenges of living on the moon is its temperatures.

[00:22:43]>> [music] >> The lunar surface gets extremely hot during the day, reaching about 250° Fahrenheit, and then the temperature drops below -200° Fahrenheit at night.

[00:22:54]But, inside the caves, the temperature could stay much more consistent.

[00:22:58]A separate study done in 2022 used computer simulations to predict that some of those caves [music] could maintain a comfortable temperature of about 63° F, much easier to manage, right?

[00:23:10]Unfortunately, getting to the caves won't be easy.

[00:23:13]The Mare Tranquillitatis cave is over 400 ft below the surface [music] at the bottom of a steep slope covered in loose debris.

[00:23:21]It would take some clever engineering to get up and down that slope. The options could be using jetpacks, a lunar elevator, or some other kind of technology. We must find a way to transport astronauts safely. There's also a lot more to discover. [music] Radar technology could help scientists find even more caves and lava tubes on the moon. In the future, a [music] spacecraft with higher resolution radar could even map the insides of the pits that LRO has [music] already found.

[00:23:46]According to the researchers, this kind of complete survey could help [music] them figure out the best locations for future lunar bases and other explorations. And there's another potential bonus. Those caves could contain water.

[00:23:58]Scientists have already found frozen water on the moon under the surface and in permanently [music] shadowed craters.

[00:24:04]Tiny amounts are also scattered across the lunar dirt. Water is a critical resource for any moon base, and finding it in the caves could make the idea of living there even more realistic.

[00:24:12][music] All in all, this discovery could be a game-changer for lunar exploration.

[00:24:17]Living in natural caves on the moon might be [music] a more practical and safer option than building something on the surface.

[00:24:24]It could also bring us one step [music] closer to making the moon a place where humans can live and work for the long term.

[00:24:34]>> Soon we might start constructing loads of stuff on the moon.

[00:24:39]All because India's moon mission has recently detected sulfur near the moon's south pole.

[00:24:46]This chemical element can come in extremely handy for creating infrastructure on our satellite.

[00:24:53]It's the first time this chemical element has been discovered on Earth's natural satellite.

[00:24:59]This sought-after element is mostly found near Earth's volcanoes.

[00:25:04]Its appearance on the moon speaks volumes about the satellite's volcanic history and its past atmospheric conditions.

[00:25:13]The mission's rover detected this chemical element less than a week after touching down around 70° from the moon's South Pole on the 23rd of August, 2023.

[00:25:24]This historic landing on the lunar surface made India the fourth country to safely land a mission on the moon.

[00:25:32]>> [applause] >> It's also the first spacecraft to touch down so close to the South Pole of our satellite. It's an area of strategic importance because it's believed to be home to deposits of water ice.

[00:25:45]If it turns out to be true, future missions might be able to harvest it and turn this water ice into drinking water or even rocket fuel.

[00:25:55]For 2 weeks, the lander carried out the data collection mainly focused on the analysis of the moon's soil and its extremely [music] thin atmosphere.

[00:26:05]Meanwhile, the solar-powered Pragyan rover started its quest to find frozen water on the moon.

[00:26:11]As for the lander, it demonstrated another amazing feat on the 3rd of September.

[00:26:16]The spacecraft fired up its engines and lifted itself for about 16 in into the air. Then it made a tiny hop to land 12 to 16 in away from its original position.

[00:26:28]It's kind of a big deal.

[00:26:31]Being able to get a lander back off the surface of the moon is essential for future missions, showing that they can safely return soil samples or even astronauts back home after a lunar mission.

[00:26:45]In September, the Indian spacecraft was put into sleeping mode.

[00:26:49]The 14-day long lunar night was approaching and the spacecraft wasn't designed to collect scientific data during this period of time.

[00:26:58]So far, we've learned about a few major findings of the mission.

[00:27:03]One is related to measuring the temperature of the moon's topsoil at different depths.

[00:27:08]Intriguingly, the surface of the satellite in that region turned out to be hotter than expected.

[00:27:14]It was believed that the temperature could be between 68° and 86° Fahrenheit on the surface.

[00:27:21]But it was around 158° Fahrenheit, way hotter than it should be.

[00:27:28]The other discovery indicates the presence of several chemical elements, including oxygen.

[00:27:34]Besides, the data received from the spacecraft confirms the presence of aluminum, calcium, iron, titanium, silicon, and other chemical elements on the lunar surface close to the South Pole.

[00:27:48]The rover also used special instruments designed [music] to measure quakes and rumbles beneath the lunar surface to detect some seismic activity.

[00:27:58]It brings us back to the sulfur detected thanks to the rover's spectroscope.

[00:28:04]Scientists are currently working on figuring out whether this element formed on the surface in a natural way or whether it's the result of volcanic activity or a meteor strike.

[00:28:16]Another astonishing thing found on the moon is a rock. And it may be the oldest known Earth rock.

[00:28:23]A 0.7-in wide chip included in a large rock collection brought to our planet by Apollo astronauts might actually be a 4-billion-year-old fragment of Earth.

[00:28:36]This finding could help us paint a better [music] picture of the intense pounding early Earth got at the dawn of its life.

[00:28:45]It could go like this.

[00:28:46]Soon after the rock formed, an asteroid impact might have blasted it from Earth.

[00:28:51]At that time, our planet's satellite [music] was three times closer to Earth than it is today.

[00:28:58]The collision was so powerful that this chunk of [music] terrestrial rock found its way to the moon. Later, this fragment got engulfed in a lunar breccia, a motley kind of rock.

[00:29:09]Eventually, the rock was brought back home to Earth by Apollo 14 [music] astronauts.

[00:29:15]Even though scientists had found meteorites coming from Mars and the moon before, it was the first [music] time a rock from the moon turned out to be a terrestrial meteorite.

[00:29:24]They also found out that the rock [music] had formed in a water-rich environment at temperatures and pressures corresponding to those at around 12 miles beneath the surface of our planet.

[00:29:37]In 2019, China's Chang'e-4 mission made history by [music] landing on the far side of the moon.

[00:29:44]The mission's rover helped researchers visualize structures hidden deep below the surface of the satellite, revealing billions of years of lunar history. The Yutu-2 rover made this discovery with the help of its lunar penetrating radar.

[00:30:00]It imaged deep into the moon's surface and listened to echoes of sound bouncing back off structures hidden from view under the surface of the moon.

[00:30:11]It turned out those structures were resting at depths of almost 1,000 ft.

[00:30:16]The research suggests that the first 130 ft under the surface are made up of layers of dust, soil, [music] and rocks.

[00:30:24]The instruments also discovered a concealed crater that must have formed after a large object slammed into the moon's surface.

[00:30:32]Long, long ago, ancient lava was likely to be flowing deep underground.

[00:30:38]Researchers believe that [music] the broken rocks around the formation might be debris produced by the impact. They also found that the volcanic rock layers were thinner [music] the closer they were to the surface.

[00:30:51]Such a thickness variation of lava flows might mean a decrease in the number and magnitude of eruptions over time.

[00:30:59]So, lunar volcanic activity gradually dwindled since the moon's formation around 4 and 1/2 billion years ago.

[00:31:09]On the far side of the moon, there is one of the largest and oldest impact craters in our solar system, the South Pole-Aitken Basin.

[00:31:18]Unfortunately, from Earth, you can only see its outer rim, which looks like a huge chain of mountains.

[00:31:24]It's a ginormous 8-mi [music] deep dent stretching for more than 1,500 mi in diameter and covering 1/4 of the moon's surface.

[00:31:35]Astronomers are sure that this crater [music] appeared when an asteroid collided with the moon around 4 billion years ago.

[00:31:43]And now, look at this gigantic [music] chunk of metal the size of four states of Connecticut. As for its weight in pounds, it's enough to say that the number contains [music] 18 zeros.

[00:31:55]This mysterious mass is hidden about 180 [music] mi under the moon's surface.

[00:32:00]Somewhere in the middle of the South Pole-Aitken [music] Basin.

[00:32:05]It was discovered when GRAIL, which stands for NASA's Gravity Recovery and Interior Laboratory mission, gathered [music] data about our natural satellite.

[00:32:15]When examining this information, scientists noticed that in one place on the moon's surface, >> [music] >> there was a weird change in gravity.

[00:32:23]After researching this phenomenon, they concluded that something mysterious was weighing down the basin floor there.

[00:32:30]So far, researchers haven't figured out the origin of the bizarre lump, but there are several theories.

[00:32:38]One of them claims that the finding is a chunk of dense oxide, which appeared when the moon was just taking its shape.

[00:32:45]At that time, the satellite was still covered with ancient oceans of magma, and the lump could be formed at the final stages of its cooling. However, most scientists support another theory, according to which the puzzling mass is part of the giant asteroid that once created the South Pole-Aitken Basin.

[00:33:03]Since the thing is metallic, it's probably the iron-nickel core of the asteroid.

[00:33:10]There might be a labyrinth of lava tubes on the moon. Not so long ago, astronomers received the results of underground topography and discovered a massive cave under the surface of Earth's satellite.

[00:33:23]It could be the result of the lunar volcanic activity that happened more [music] than 3 billion years ago.

[00:33:30]Streams of lava hardened, creating a thick, hard crust on the outside.

[00:33:36]But inside, it kept flowing, melting the rock and creating tunnels and caves.

[00:33:42]Numerous small pits in the moon's surface discovered [music] by NASA seem to be the openings to such lava tubes.

[00:33:49]If this theory is confirmed, the underground tunnels might serve not only as a convenient location for human-crewed space missions, but also as much-needed water sources for astronauts.

[00:34:03]>> There's a huge hole on Mars, more than 300 ft wide, and it seems that NASA agrees that it could be an opening into an underground world.

[00:34:12]Could a mysterious space civilization be hiding in there?

[00:34:16]Well, experts from NASA think that the hole might lead to a lower layer under the surface of the red planet. You can think of it like a trapdoor that opens into a basement. Scientists care a lot about holes like this because they might connect to big underground caves.

[00:34:31]These caves would be hidden from the surface and could be safer places for life to exist.

[00:34:37]>> [music] >> You see, Mars' surface is a rough place.

[00:34:41]It's freezing cold, extremely dry, and constantly hit by radiation.

[00:34:46]>> [music] >> Meanwhile, underground spaces are different. They're like natural shelters, protecting anything inside.

[00:34:52]>> [music] >> That's what makes them some of the best places to look for signs of life on Mars.

[00:34:59]Interestingly, NASA is usually very when talking about life on other planets.

[00:35:04]Until now, most researchers have been focusing on tiny life forms like microbes, which might be hiding in frozen oceans on nearby planets and moons. But now, scientists really think this hole could lead to huge underground caves.

[00:35:19]If that's true, besides looking for signs of life, this spot could become a target for future astronauts, since the caves could turn into great shelters and even a Martian base.

[00:35:32]The photo with the hole isn't new. It was taken in 2017 by the Mars Reconnaissance Orbiter.

[00:35:38]In the image, we can see many holes scattered across the ground.

[00:35:42]The area basically looks like Swiss cheese. Most of the holes have dark dusty ground under a thin layer of light-colored frozen carbon dioxide, aka dry ice.

[00:35:53]But one hole stands out from the rest.

[00:35:55]It's perfectly round, sits in [music] the upper part of the image, and is about 328 ft wide. That's a massive opening.

[00:36:04]>> [music] >> The hole also has a perfectly round crater around it. It's like something punched through the surface and left a ring behind. Scientists think it may have been caused by a meteor impact.

[00:36:15]Scientists believe Mars was much more like Earth billions of years ago, with better conditions for life. But today, the best chance of finding signs of life is underground.

[00:36:25]Mars no longer has a strong magnetic field or a thick atmosphere. So, So, its surface is constantly blasted by harmful radiation from space.

[00:36:34]Underground caves or lava tubes act like natural bunkers, shielding anything inside from that radiation. This makes them the most promising places [music] to search for life. Because of that protection, astronauts might one day find signs of past life there or even fossils.

[00:36:52]To hunt for these hidden spaces, NASA brought in experts on underground structures and seismic activity from the US Geological Survey.

[00:37:00]In 2019, they released a detailed map [music] showing more than 1,000 possible cave entrances scattered all over Mars.

[00:37:08]There's a catch though. All of this data comes from spacecraft flying about 250 miles above the Martian surface. From that height, scientists [music] can spot holes, but they can't see how deep they go or what's underneath.

[00:37:23]Some may be true caves, while others could just be shallow dents in the rock.

[00:37:28]Other missions, including the European Space Agency's Mars Express, have also found signs of ancient lava tubes beneath Mars's long extinct volcanoes.

[00:37:38]But, what makes this newly released image stand out is that it clearly shows at least one hole that appears to lead into an unknown [music] underground layer. And if current plans come true, the earliest human astronauts could see this massive opening with their own eyes in the 2030s. And maybe they'll also be able to examine another Martian mystery.

[00:38:00]For more than 50 years, scientists have been puzzled by about 2 million dark streaks spread across the surface of Mars. These black marks look like long stains or shadows running downhill. It's almost like someone spilled ink on the planet. They were first spotted in the 1970s, >> [music] >> and for decades, no one could explain what caused them.

[00:38:22]These marks are called slope streaks.

[00:38:24]>> [music] >> They appear on steep slopes, crater walls, and ridges all over Mars. From far away, they look flat and dark.

[00:38:32]At first, scientists thought the streaks were caused by melting ice.

[00:38:35]>> [music] >> This could create muddy landslides similar to wet dirt sliding down a hill on Earth.

[00:38:41]Even today, researchers still believe the streaks come from landslides, but not the kind involving water.

[00:38:48]New research using data from NASA's Mars Reconnaissance Orbiter shows that most of these streaks are caused by dry landslides. Instead of mud or water, it's loose dust suddenly slipping downhill, more like dry sand pouring off a pile when it gets disturbed.

[00:39:04]>> [music] >> This explains how the streaks can form in Mars's cold, dry environment. One famous example is on [music] Apollinaris Mons. It's an extinct volcano south of Mars's equator. On one side of a ridge, hundreds of streaks run side by side, which [music] makes the surface look like a barcode. These streaks appeared sometime between 2013 and 2017.

[00:39:27]Scientists figured out a bit later that a nearby meteorite impact could have triggered [music] them. The impact didn't hit the ridge directly, but the shock shook the ground, and it was enough to send dust downhill.

[00:39:39]Now, because some streaks appeared after impacts, many scientists thought that meteoroids or Marsquakes were responsible for creating most slope streaks.

[00:39:49]But a new study shows that this idea is kind of wrong.

[00:39:52]>> [music] >> The study in question looked at about 2.1 million slope streaks. They were photographed by NASA's Mars Reconnaissance Orbiter over a long period from 2006 [music] to 2024.

[00:40:04]Scientists have estimated that Mars has around 1.6 million slope streaks in [music] total, but some streaks have been counted more than once because they appear in different image sets.

[00:40:15]So, after analyzing all this data, researchers have concluded that almost all new streaks form because of wind and dust, [music] not impacts or quakes.

[00:40:25]Look, seasons change on Mars and winds slowly move dust and sand. When that loose material suddenly slips downhill, it leaves behind [music] a dark streak.

[00:40:34]It's like brushing dust off a surface and revealing a darker layer underneath.

[00:40:39]Meteorite impacts and Marsquakes [music] do create some streaks, too, but only in very specific spots.

[00:40:46]Overall, they play a very small role.

[00:40:48]Less than 0.1% of new slope streaks are caused by impacts and Marsquakes.

[00:40:53][music] The analysis has also shown that slope streaks are not spread evenly across Mars. They're grouped into five main regions.

[00:41:05]In each of these areas, new streaks usually form during times of the year when winds are strongest.

[00:41:12]There's a key tipping point called the dust movement threshold. Once winds get strong enough to lift and move dust, the loose material on slopes becomes unstable.

[00:41:23]When that happens, dust can suddenly slide downhill, creating a dark streak.

[00:41:28]This is similar to how strong winds on Mars can kick up dust and form spinning columns called dust devils. They're like small tornadoes moving across the planet's flat plains.

[00:41:38]One reason this mystery took so long to solve is that these streaks form when scientists can't easily see them happen.

[00:41:46]The conditions that create new streaks usually occur around sunrise and sunset.

[00:41:51]And because this phenomenon happens in low light, no spacecraft has directly watched a streak form in real time.

[00:41:59]The study also calculated how often new streaks appear.

[00:42:03]On average, about 0.5 new streaks form each year for every existing streak. And since Mars has around 1.6 million slope streaks, that's roughly 80,000 new streaks forming every year. Most streaks seem to stick around for several decades before they slowly fade away. However, scientists don't yet have enough long-term data to be completely sure.

[00:42:25]Another cool discovery, even though slope streaks cover less than 0.1% of Mars' surface, they may be one of the biggest sources of dust in the Martian atmosphere.

[00:42:36]In other words, these small looking features may play a much larger role than we expected. That's why understanding how slope streaks move dust around Mars is important. Mars' dust affects weather, visibility, and even how much sunlight reaches the ground.

[00:42:51]That matters a lot for future human colonies, which would need stable conditions to survive and operate safely.

[00:43:10]>> This catapult-like system on the moon might bring us limitless energy. It's a launch system concept that was recently proposed by the Chinese scientists. It would work like a hammer throw, spinning a launch arm that flings objects. This arm is supposed [music] to be about 165 ft long. It will accelerate until it reaches the moon's escape velocity and then whoosh, the capsule is sent into space. [music] This crazy idea will cost around $18 billion.

[00:43:38]Ooh, pricey. But trust me, it's [music] totally going to be worth it. The system would be powered by solar panels and nuclear energy. It could also [music] recover more than 70% of the energy used after each launch.

[00:43:51]The moon has a very weak gravity.

[00:43:53]There's also barely any atmosphere, so the air doesn't weigh you down. This makes it so much easier to launch stuff there.

[00:44:01]But why do we even need this? The main purpose is to transport [music] helium-3.

[00:44:06]It's a really cool isotope of helium, and one of the most insane things about it is that it could become fuel for nuclear fission. This is the same process that happens in stars, including our sun.

[00:44:22]If we manage to recreate nuclear fusion here on Earth, we can make it a clean and basically limitless source of energy for power plants.

[00:44:31]But, helium 3 is super rare on Earth.

[00:44:35]We can sometimes find it in volcanic rock formations on the ocean floor.

[00:44:39]That's because it's a product of another rare element called tritium, the element we usually make in nuclear reactors and put in cool stuff like glow-in-the-dark paint. But, the catch of tritium is that it takes forever to decay and turn into helium 3.

[00:44:55]Now, there's a bunch of helium 3 on the moon, around 1 million tons. Just 20 tons of helium 3 could meet China's yearly electricity needs. [music] In fact, lunar soil has enough helium 3 to power the entire world for over a thousand years.

[00:45:10]But, why is there so much of helium 3 on the moon and barely none on our planet?

[00:45:15]Well, that's because helium 3 comes from the sun and travels in solar winds.

[00:45:19][music] Solar winds are like streams of dangerous particles. They're super radioactive. Our planet's thick atmosphere and magnetic fields serve as a shield for us. They almost fully protect [music] us from those particles.

[00:45:31]But, unfortunately, they also prevent the good stuff like helium 3 from getting here. The moon's atmospheric shields are super thin though, so it's under a constant shower of solar winds.

[00:45:43]So, helium 3 accumulated there over billions of years, and now it's just scattered around there.

[00:45:49]But, mining it and bringing back to Earth is no easy feat. It's super [music] expensive. Just think about it.

[00:45:59]Rockets need tons of fuel to break free from gravity. Every single bolt and screw on the spacecraft must be engineered to survive extreme conditions like radiation. [music] Not to mention, you need a team of rocket scientists, literally, working around the clock to make sure nothing goes wrong. You can't call a repair guy if something breaks on the moon. So, generally, it costs about a half a million dollars >> [music] >> to send 1 lb of payload to our satellite. That's based on estimates from NASA. To get some idea, let's calculate how much it would cost [music] to send an apple to the moon.

[00:46:32]A typical apple weighs about 0.4 lb. So, that funny mission would be at least $200,000.

[00:46:39]Now, for comparison, [music] the Chinese launch system weighs around 80 tons.

[00:46:47]Another problem is that the lunar surface is pretty harsh on the equipment. Like the freakish lunar dust, for example.

[00:46:53]You might recall this small thing that happened in the '60s [music] called the moon landings. But, when the Apollo astronauts came back from the moon, they found something weird was happening to them. Their throats were sore and their eyes watered. Luckily, it wasn't some scary moon sickness. Turns out, there's a lot of lunar dust clinging to their spacesuits. This dust seems harmless, but it's made up of sharp and abrasive particles, [music] much smaller than a human hair, yet sharp like glass. It contains silicate, a thing that can cause severe lung problems on Earth and is a common issue for miners.

[00:47:27]>> [music] >> So, it caused a lunar hay fever. At least, that's how NASA astronaut Harrison Schmitt called it.

[00:47:35]All 12 astronauts who walked on the moon were then sneezing and experiencing nasal congestion. Sometimes, it took days to fade away. The dust even got inside their spacecraft, smelling like burnt gunpowder. This nasty stuff can be harmful to both humans and equipment. It managed to damage spacesuit [music] boots and even ruin the seals on the containers used to bring back samples during the Apollo missions.

[00:47:59]As we mentioned, they're glass sharp and jagged. So, they start scratching, grinding, and wearing down any surfaces they come in contact with. They don't care if it's metal, glass, or humans.

[00:48:11]>> [music] >> And since there's so much dust, this causes equipment to malfunction and fail quite quickly. And that's just one of the possible hurdles with lunar missions. So, scientists really need to come up with some weird ideas to get that [music] precious helium-3.

[00:48:28]The Chinese scientist project [music] looks like a weird sci-fi invention, but it's a cost-effective way to transport materials back to us.

[00:48:35]It could throw stuff to Earth twice a day, and it would be 90% cheaper than current methods. Since it only needs electricity [music] and no fuel, the system would be small and easy to set up.

[00:48:47]Besides the beloved helium-3, this catapult would also help advance technologies in space mining and heavy launch vehicles.

[00:48:55]No lunar dust scares this thing. [music] It should last for at least 20 years. It would need to be transported to the moon using China's super heavy lift rocket.

[00:49:07]But, the idea is far from new. There was a novel called The Moon Is a Harsh Mistress >> [music] >> by Robert A. Heinlein. In the story, there's a lunar colony that uses an electromagnetic catapult to send weed and water ice back to Earth. It gets quite wild when the colonists, known as Loonies, eventually take control of this catapult. They threaten to launch rocks at Earth unless their colony is recognized as an independent world.

[00:49:33]Sounds kind of funny, but a large rock, if thrown at us from the moon, could wipe out a city.

[00:49:38]>> [music] >> The damage would be like from a meteorite strike, with fires, houses destroyed, and worse.

[00:49:44]But, scientists have been talking about this catapult idea for a while. For decades, they were trying to find a way to use electromagnetic systems >> [music] >> to send resources from the moon to Earth.

[00:49:57]There are also some challenges. For example, scientists forgot to mention how exactly helium 3 would be extracted from the lunar soil. Installing this launch system on the moon's rugged surface would be difficult as well.

[00:50:09]Also, they would need to make sure that the system remains [music] stable at high speeds and that it could withstand the moon's extreme temperature changes, cosmic [music] rays, and intense solar radiation. So, it take some time to develop. [music] China hopes to have the key components of the system ready by 2030. The full-scale operations might start by 2045.

[00:50:32]>> [music] >> China has tons of plans for the moon.

[00:50:35]For example, they want to build a research station at its [music] South Pole by 2035.

[00:50:40]But China's not the only one in this space race. Considering that NASA plans to send humans on Mars by that time, oh boy, the 2030s will be a crazy decade for space exploration.

[00:50:52]There's also an American startup that's part of the lunar economy.

[00:50:56]Oh, the ones that plan to land astronauts on the moon have people actually living on our satellite in a decade or two.

[00:51:03]One of the goals of this colony is to boost economic growth and create new jobs. Most of them will likely involve some mining activities. And if there'd be two space colonies, well, they'll have to figure something out.

[00:51:19]>> China's Yutu 2 is a robotic mission to the dark side of the moon, launched on December 7th, 2018. On January 3rd, 2019, it completes the first-ever soft landing on the lunar far side. It lands in the Von Karman crater, not far from the moon's South Pole. Scientists are interested in this area. Cold, permanently shadowed craters at the poles contain water ice. These ice patches are uneven and are likely to be ancient. In the south, most of the water ice is concentrated in craters and at the North Pole, it's spread more sparsely. In any case, this ice can be used once a long-term manned mission lands on the moon.

[00:52:02]Anyway, several days after Yutu-2 lands, it closes down its operating systems and hibernates through its first lunar night.

[00:52:11]It wakes up on January 29th, 2019. All its tools operate normally. The rover travels 390 ft during its first full lunar day. One lunar day lasts for about 14 days and a lunar night has the same duration.

[00:52:28]Moving and exploring during the day and switching off during the night becomes the rover's routine.

[00:52:34]It's the eighth lunar day when Yutu-2 stumbles across something incredible.

[00:52:40]This discovery makes the scientists put off all other plans for the mission.

[00:52:45]They focus on figuring out what the strange material found by the rover is.

[00:52:50]In the beginning, this lunar day is no different from any other. It begins on July 25th when the rover starts making its way through an area pockmarked with tiny impact craters. Yutu-2 is helped and monitored by the driver team [music] from the Beijing Aerospace Control Center.

[00:53:07]On July 28th, the team is preparing to shut the rover down for a midday nap.

[00:53:13]The sun is high in the sky. It means there are high levels of radiation and scorching [music] temperatures that can damage the machine. Before powering Yutu-2 down, the scientists are looking [music] through the pictures taken by the rover's main camera.

[00:53:28]That's when they spot it, a small crater filled with something [music] that looks shockingly different from the surrounding landscape. Unable to identify the gel-like substance, the team orders the rover to [music] check this bizarre finding.

[00:53:41]Yutu-2 cautiously nears the crater to examine the weirdly colored stuff.

[00:53:46]The machine uses special equipment [music] that detects the light reflected off the substance.

[00:53:51]It's supposed to help the researchers to [music] understand the structure of the material.

[00:53:56]Unfortunately, the nature of the unusually colored finding has remained [music] a mystery for over a year.

[00:54:03]No wonder that both the finding and the fact [music] that initially there were no images of the enigmatic stuff sparked curiosity all over the world. The only available [music] description of the substance was that it looked like a randomly colored shiny gel.

[00:54:19]Something that's rather odd for the dusty arid surface of the moon.

[00:54:24]But finally, the mystery seems to have been solved. The researchers have analyzed the information received from the rover's equipment. As expected, the substance turned out to be made up of rock, greenish and glistening breccia >> [music] >> in a sample no larger than 20 by 6 in.

[00:54:41]It's kind of like a geologic version of Jell-O salad with fruit inside. If you melt it down, it'll look glassy. [music] Breccia consists of sharp stones joined together by a chalky substance.

[00:54:54]>> [music] >> The sample found on the far side of the moon is made up of a mix of different minerals.

[00:55:00]The main [music] is a type of silicate that's one of the most common components in both the moon and Earth's crust.

[00:55:05][music] The piece also contains some glass, which means it could have formed during a volcanic eruption.

[00:55:12]But volcanic activity on the moon stopped more than 3 billion years ago.

[00:55:17]That's why [music] the researchers are almost sure it's unlikely to be the source of the unusual finding.

[00:55:24]The material could have been created by a massive asteroid, comet, [music] or meteorite that once hit the moon.

[00:55:31]During the collision, the pressure and temperature were so high that huge amounts of rock instantly [music] melted. Some pieces cooled down rapidly enough to form glass.

[00:55:41]The rest gathered at the center of the impact crater and grew colder more slowly, forming a new rock.

[00:55:48]The substance was likely not formed in the Von Karman crater, but in the nearby Finsen and Alder craters.

[00:55:55]The hollow where the rover made its finding was just 7 ft across.

[00:55:59]Whatever left [music] it had to be no wider than an inch. But then, it would be too small to create such a large piece of breccia.

[00:56:09]It's interesting [music] that the material is similar to the samples collected by the astronauts from NASA's Apollo missions.

[00:56:15]>> [music] >> One of those samples was made of dark broken shards of minerals glued together.

[00:56:21]It also contains some black shiny glass.

[00:56:24]It's not clear though whether it's the same as the stuff discovered by Yutu [music] 2.

[00:56:29]When the rover took photos and made its measurements, it was rather dark in the area. The quality of the images isn't that great.

[00:56:38]The experts also explained that the mission is examining a previously unexplored area of the moon. That's why they don't have any samples from that region to compare them with the greenish shiny substance Yutu 2 found.

[00:56:51]But, if their guesses turn out to be true, then the far side of the moon might have more in common with the Earth-facing one >> [music] >> than we used to think.

[00:57:00]But, what's so special about this dark [music] side of Earth's natural satellite? And why can't we see it?

[00:57:09]It's all because of the phenomenon known as tidal locking.

[00:57:13]Earth's only natural satellite rotates around its axis once in 27 days.

[00:57:18]It's the same amount of time it needs to go around our planet. That's why you always see the same face.

[00:57:25]To be precise, 59% of the moon's surface is visible to people.

[00:57:30]It means that you can catch glimpses of the satellite's far side at some times of the year.

[00:57:35]The moon's side we can't see is quite different from the one facing Earth. It doesn't have dark spots that are visible at night. Those are lunar basaltic plains called lunar maria. They were created by ancient volcanic eruptions.

[00:57:50]Those happened about 3 to 4 billion years ago. Instead of planes, the far surface of the moon has countless craters and tall mountains.

[00:58:00]One of the ideas about such a striking difference between the two sides is based on the collision theory. It claims that billions of years ago Earth collided with another planet or some other massive space body. After that, the debris from this collision crashed with something that would later form our moon. That's why the satellite's landscapes differ so greatly.

[00:58:22]>> [music] >> A more recent theory suggests that the Earth-facing part of the moon is warmer because of the heat radiated by our planet. During the period of volcanic eruptions, it was cooler on the farther side. That's why the minerals there became solid faster. They formed a protective layer shielding the moon's insides [music] against the meteorites.

[00:58:44]But each impact left an impressive crater. At the same time, a much softer crust on the front-facing side of the moon spewed lava every time a meteorite hit it. After this lava cooled down, it covered [music] the impact craters.

[00:59:00]Even though the far side is often called dark, both sides [music] get almost the same amount of sunlight. The side we see looks a bit brighter because of the glow coming from Earth.

[00:59:11]There are two reasons why people are interested in exploring the far side of the moon.

[00:59:16]After leaving our planet, many radio waves get blocked by Earth's natural satellite. If astronomers could build their radio and optical telescopes on the dark side, they would get much more data. There would be no problems [music] with any kind of interference. The telescopes would also be shielded from the glare of daylight coming from our planet.

[00:59:36]>> [music] >> If telescopes were set up inside craters, they would also be protected from solar radiation.

[00:59:42]Astronomers would be able to get an incredibly clear view of the far regions of the universe.

[00:59:47]Plus, scientists [music] believe there are great amounts of helium-3 on the opposite side of the moon.

[00:59:53]Earth is protected from solar winds that carry this [music] gas by its magnetic field. But our natural satellite doesn't have such a shield. That's why [music] experts believe the moon can be a perfect place for helium-3 mining.

[01:00:07]>> [music] >> This rare element can be later used as the fuel for fusion reactors.