Original subtitles

William shatner: A shining wonder that brightens our nights,

measures our days,

and may possess incredible powers.

The moon. Look at it.

Is there anything more marvelous,

more inspiring,

than this glowing orb that hangs in the night sky?

But is the moon just a giant rock in space,

or does it hold profound secrets?

Could it harbor signs of life,

or perhaps evidence

of an ancient civilization?

That is what we'll try and find out.

? ?

each fall, the people of this city gather along

the banks of the qiantang river

to see something extraordinary:

A massive wave that barrels upstream

and keeps surging for miles and miles up the river.

The wave's rapid speed, loud roaring sound,

and white crests have earned it a fitting nickname:

The silver dragon.

A hundred miles southwest of shanghai,

every year there is this really interesting tidal phenomena

that happens that's very much related to the moon.

The silver dragon is a 30-foot-tall,

25-mile-an-hour wave,

so it draws a massive crowd.

Over a 100,000 people annually come out to watch this wave,

and people even surf on it.

Michael dennin: It's huge, it comes down and it can

flood to the side, and it's actually quite dangerous,

and people often get way too close.

Teitel: We're used to seeing tides at beaches on the ocean,

they go in and out, but it's never this dramatic.

This is an extremely tangible thing you can point to and say,

"this is the moon's effect on the earth,

happening now as we see it."

michio kaku: The gravity of the moon lifts the water up

to give you high tide,

and when the moon passes, it drops, giving you low tide.

Think of that: The entire planet earth's water

being lifted several feet.

And that tremendous cosmic energy

comes from the gravitational pull of the moon.

Shatner: Today, the process by which the moon

generates earth's ocean tides is widely understood.

But what is less commonly known

is how the moon causes a phenomenon

like the silver dragon.

Well, scientists have a name

for this kind of strange occurrence.

It's called a tidal bore.

One of the most amazing things the moon does,

from my perspective, is create tidal bores.

And the way to think about it is

the tide rises the oceans a certain height,

and if you have the right combination

of the shape of the connection of the ocean into a river,

you can actually funnel all of that height

into a narrow, extra high, massive wave.

And then that will run up a gorge or a river.

It's kind of a fascinating interaction between moon, water,

nature and then people and what we do in response to it.

Shatner: Tidal bores are a striking example

of the power that the moon exerts on the earth.

But, according to scientists,

creating tides is just one of many effects

that the moon has on our planet.

For instance, as the moon circles the earth,

its gravitational force causes molten liquids

deep within the earth's core to swirl,

a process which some experts refer to as "churning."

we now realize that the orbit of the moon

creates churning inside the earth.

The moon churns the inside of the earth

by tidal forces,

causing currents in the form of electricity,

which creates the earth's magnetic field.

We depend upon a magnetic shield

to protect us against solar flares from the sun.

And we think that's where the moon comes in.

If it wasn't for the presence of the moon,

you go outside, you get a sunburn

within just a matter of a few minutes.

Shatner: A sunburn within a few minutes?

It's enough to make you wonder what else could happen

if the unimaginable occurred

and the moon...

Just disappeared?

One of the questions I get asked a lot is, you know,

can we survive without the moon?

If the moon suddenly disappeared,

I think not.

The result on earth would be

catastrophic and very, very rapid.

The tides would stop working.

The earth would start slowing down.

As the earth slows down,

it can start wobbling on its axis.

If it wobbles very far,

this would melt the polar ice caps,

and sea levels would rise radically.

Also, a place like las vegas

could be freezing in winter

and yet boiling in summer.

There's all sorts of things that could

cause trouble for life on earth.

Brian keating: The moon is sort of the earth's bodyguard

because the moon has protected us

from asteroid impacts.

All the craters that we see on the moon

are the result of impacts of asteroid fragments.

And all those craters,

they could have been impacts on earth.

Kaku: So we have this cosmic coincidence.

All the characteristics to the moon are just so

that we have life on the planet earth.

So, in other words, we hit the jackpot.

We have this cosmic lottery, and we hit the jackpot.

We got a moon that makes

possible conditions on the earth compatible with life.

Shatner: The fact that the moon is so vital

to life on earth raises some intriguing questions.

Such as, is there something special

about our moon that enables it to make life on earth possible?

And, if our moon is unique,

what makes it different

from the more than 200 other moons in our solar system?

Keating: A moon is just what we call a natural satellite,

a satellite that's not human-made

that orbits around a planet.

Other planets, such as the massive gas planets

like jupiter and saturn,

have many, many dozens of moons.

We're the only planet in the solar system

that has only one moon.

And our moon is actually the fifth largest moon

in the solar system, it's quite large.

Teitel: It's really big compared to the planet.

It's a very unique setup.

Usually moons are significantly smaller,

but our moon is relatively large compared to our planet.

Mike bara: It's very bizarre.

It's basically a double planet system.

The moon is so big and so close.

And there is no other example

anywhere in the observable universe like this.

Lynn picknett: Because it's so big

and it has so many effects on the earth,

the moon is always fascinating.

There's something inherently amazing and mesmerizing

about how big and how powerful it is.

I mean, there it is, hanging in our skies,

this extraordinary spherical object,

just this amazing orb in the sky.

Shatner: Scientists have observed

that there is another strange aspect

of the moon's dimensions.

It is precisely the right size

and distance from the sun

to occasionally create...

A total solar eclipse.

If you look at the moon and you look at the sun,

the sun is actually 400 times the diameter of the moon,

but the moon happens to be 400 times closer to the earth.

This means that the sun and the moon look as if

they're the same size in the sky.

That means that when the moon goes in front of the sun,

it totally blocks off the sun.

I've been very lucky,

and I've seen two total eclipses of the sun,

and they are magical.

They literally blew my socks off.

Bara: The fact is, the moon is exactly the right size

and exactly the right distance from the earth

to create perfect solar eclipses.

Some people think that's a coincidence.

I don't think it's a coincidence.

There has to be something very special

and very mysterious about the moon itself.

Shatner: The unique size relationship

between the moon and earth may help explain

why the moon has such a strong impact on our planet.

But does the moon's gravity only affect the earth?

Or could it also have a direct influence

on human beings?

Perhaps the answers can be found

by examining how the moon alters not just our planet

but also...

Our minds.

How does a full moon make you feel?

A little nervous?

Afraid, perhaps?

Well, maybe you should be.

After all, the word "lunatic" comes from the notion

that when the full moon rises,

it causes insanity, mayhem,

and even murder.

But are-are these just stories?

Or does the moon actually have the power

to make people crazy, and drive them to kill?

(thunder rumbles)

picknett: The word "lunatic"

means "the moon has made you mad."

the word "luna" is latin...

Is roman, essentially... for "moon."

so, clearly, over the millennia,

the moon has been associated

with a rise in madness,

or manifestations of mental disturbance,

emotional disturbance.

Young: The dancing in the moonlight, the witchcraft,

the ceremonies of the occult,

somehow are related to the moon.

You take something like the werewolf.

The moon comes up,

out comes the werewolf.

Some powerful alter ego.

Eric hickey: Way back in victorian England

people would claim, "it wasn't my fault.

"the moon made me do it, it was a moon madness,

it was lunacy."

and so people could actually be institutionalized

rather than be hung because

they were crazy, it was not their fault.

That's how strong

the belief was in-in the moon.

Shatner: The connection between the full moon,

insanity and violence

is not merely an antiquated fantasy.

In fact, similar stories about the moon

persist into modern times.

Picknett: It's well known people who work

for emergency services...

Paramedics, or the police, for example,

and they all report

the numbers go up at full moon,

of people in accidents or suffering from violence.

But science has challenged these stories.

Young: That's myth, that is legendary talk.

We don't have science to back that up and yet,

when we look at the night sky, the big object is the moon.

It is the dominant sighting in the heavens.

When the moon is full,

poetically, there are lots of effects.

Shatner: Humanity has long expressed a belief that the moon

can influence our minds.

But is that all just a figment of our collective imagination?

Or is it possible to scientifically prove

that the moon can affect the mind?

Psychiatrist dr. David avery

is counseling a 35-year-old man

who suffers from bipolar disorder

and has experienced a number

of sleepless nights.

He had bipolar disorder,

sometimes known as manic-depressive illness.

He was typical in that

he had a history of these episodes...

...Of having short sleep,

manic symptoms,

hyperactivity, thoughts going very fast,

and might get only one or two hours of sleep

during the manic phase.

Shatner: The patient, an engineer by trade,

kept detailed records of his sleep habits,

noting the dates and times when he had trouble falling asleep.

When dr. Avery studied the log,

he made a startling connection

between the patient's sleeplessness and the moon.

It was very clear these short sleep periods

were correlated both with the full moon and the new moon.

And so my jaw kind of dropped

when I saw the regularity of the pattern

and the fact that this was associated

with changes of the moon.

Shatner: The evidence showed a pattern that suggested

that the lunar cycle may be responsible

for causing some people to become restless,

to the point where they can't sleep.

I saw this, um, pattern in 2004,

but it was a sample size of one,

which scientifically is not all that strong.

But in 2017, dr. Thomas wehr

from the national institute of mental health

published a paper in which he had

17 rapid-cycling bipolar patients

who had synchrony with the lunar tidal cycles.

I realized at that point that my patient

um, was not the only one.

Shatner: In 2018, dr. Avery and dr. Wehr

joined forces and published their findings on the connection

between moon cycles and sleeplessness.

They theorized that the moon has this effect on some people

because they are particularly sensitive

to its gravitational pull.

We have a vestibular system in the ears

that helps us with balance.

And in the vestibular system,

there are tiny stones that are on the end of small filaments

that move around with gravity.

These filaments send signals to parts of the brain

that are involved with our body clocks and sleep.

So it's conceivable that, in some way,

changes in gravity generated by the moon

are affecting these filaments,

perhaps influencing the body clock,

then influencing sleep and mood.

When I think of the moon, I think

of the gravitational changes that it creates.

It may be that these gravitational forces

have a greater impact on our sleep than you might expect.

These are all questions that I think, uh,

should be answered.

Shatner: It seems that the more we study the moon,

the more we realize that there is much about it

that remains a mystery.

For instance, it wasn't that long ago that we believed

the moon was just a huge rock floating in space...

Until scientists were surprised to discover

that part of our attraction to the moon

may be due to the fact that it's actually magnetic.

Shatner: A group of scientists publish the results

of a remarkable study on the moon.

By analyzing information collected by nasa space probes,

the team discovered that an enormous mass of metal

is buried beneath the surface of the moon.

This mysterious mass is 1,200 miles in diameter,

and, because it's hidden deep underground,

before this paper was published,

scientists had no idea the metal was there.

Kaku: What happened is we have satellites

that go around the moon,

and it turns out that the gravitational pull increased,

indicating the presence of a massive, dense object

underneath the surface of the moon.

Keating: According to the scientists

who made this discovery,

it's made of metals, very dense, very heavy metals

like iron, cobalt, nickel,

which are also highly magnetic.

Aderin-pocock: Now, the question is how did it get there?

How did this blob of iron get to the moon?

There were sort of a few theories afoot, but I think

the one that makes most sense is that it was an asteroid strike.

And it seems quite likely that a metal asteroid

came and hit the moon's surface with huge impact.

It sort of melted into the moon's surface,

and then magma from the moon covered it over,

so that's why we hadn't discovered it before.

Shatner: One reason why the discovery of metal on the moon

came as such a surprise

is because it's easy to assume that we already know

most of what there is to know about the moon.

After all, we've photographed it,

studied it, and sent astronauts to walk on its surface.

But despite everything we've learned,

the moon still holds many secrets.

The moon is so fascinating because it's mysterious.

It's close to us, and yet, it's very inscrutable.

There are places and parts of the moon

we know almost nothing about,

that are completely unexplored and unexplained.

There's so many mysteries about our nearest celestial neighbor.

For example, what's inside the moon?

What's on the far side of the moon?

It's amazing that we've sent space probes to saturn,

jupiter, uranus, neptune, even past pluto,

and yet there's so many things we don't know about the moon.

Shatner: The detection of metal on the moon

was followed by an even more extraordinary discovery.

In October of 2020,

nasa's stratospheric observatory for infrared astronomy

announced that they had detected water

on the sunlit surface of the moon.

And in other studies, scientists have found evidence

of ice on the north pole of the moon.

Aderin-pocock: Many people assumed that the moon was dry.

And, looking at the environment, it wasn't so surprising

that they sort of concluded this.

But one thing we have got confirmation of

is large volumes of frozen water

in these craters which never see sunlight.

These craters are some of the coldest places

in the solar system.

And so substances like water can condense.

Dennin: When you look at the water on the moon,

there's a shockingly large amount of water

compared to what we think of it.

Now it's water in frozen form, it's ice.

But it still was fascinating just to know that there was

something we were wrong about the moon.

Shatner: As a result of these findings, scientists have been compelled

to reexamine the belief that the moon is inert,

and to ask whether it can harbor life.

Whether or not we can have life on the moon,

that's, of course, a big question mark.

Today, when you think of the moon,

you think of a lifeless environment.

But that's not always true.

We think that in the early days of the moon,

perhaps there was a thicker atmosphere to the moon,

and that's what's required to create life on a planet.

So if we drill deep into the lunar soil,

perhaps we'll pick up evidence

of ancient microbial life that existed

billions of years ago

when the atmosphere was quite different on the moon.

Shatner: Was the moon a place in which life

could actually thrive in the distant past?

Well, according to some researchers,

there is photographic evidence not only of life on the moon

but of something much more profound.

Nasa launches ranger 7,

a lunar probe designed to take

the first close-up photographs of the lunar surface.

The landmark images fascinated the world,

and since that time, other nations have sent

probes to capture more images of the moon.

Over the years, researchers have identified

strange anomalies in these photographs.

Anomalies that look an awful lot

like artificial structures.

Bara: In one picture you see a rectangular structure

with some structure on top of it

that looks almost like the spires of a roof,

as if there was a glass dome over this at one time

that has a few girders left that used to hold it up.

Now, there is nothing in natural lunar geology

that can account for that as a real extant possibility

on the surface of the moon.

And in another image taken is a gigantic spire or tower.

It almost looks exactly like a gigantic egyptian obelisk.

The way this thing is sticking up,

it simply defies explanation.

The fact that it even exists in the image

is absolute de facto proof

that there is ancient extraterrestrial technology

on the lunar surface.

Shatner: Giant structures left behind

by an extraterrestrial civilization?

It's certainly a provocative theory

and one that is hard to prove.

But if these anomalies

are the ruins of an advanced civilization,

is it possible...

They were intentionally left there for us to find?

Keating: The moon has properties that make it ideal

for conducting research into the deep past

and even, potentially, very speculatively,

for the presence of-of potentially finding

alien artifacts, which is a very fascinating prospect,

that an alien civilization might want to leave a marker,

a time capsule attesting to their existence, for us to find,

and it would be perfectly preserved for billions of years.

Shatner: Are there "time capsules" on the moon?

Tangible pieces of evidence which suggest

that we might not be alone in the universe?

Perhaps the answers can be found by taking a closer look

at the apollo missions...

...And what the astronauts discovered

while walking on the moon.

On July 20th, 1969 history was made

when american neil armstrong

became the first man to walk on the moon.

For the united states, it was a moment of immense

national pride, a triumph over the soviets

in the space race.

But is that what going to the moon was all about?

Bragging rights?

Or did the apollo program have a hidden agenda?

And, if so,

what was the mission's real objective?

Mission control: Ten, nine. Ignition sequence starts.

Shatner: Four days after taking off from earth,

the apollo 11 astronauts landed on the surface of the moon.

And over a billion people around the world

tuned in to watch.

Teitel: This was such a pivotal moment in human history.

It was just the culmination

of incredible technological ingenuity

and engineering prowess

that we actually managed to send three people to the moon

and two of them were going to walk on its surface.

Keating: If you look at the plaque that was on the apollo 11

eagle lander, it said, "we came in peace for all mankind."

nowadays, we use that as the calibration

for the greatness that mankind can achieve.

Kaku: I still remember when the apollo spacecraft

was approaching a landing site on the moon.

Scientists were asked, "what do we expect to find on the moon?"

and the answer is: We're clueless.

We didn't know how solid the surface was.

Perhaps the lunar module,

as it lands on the moon, will sink.

So we simply kept our fingers crossed

and hoped that the surface of the moon was solid

and not basically made out of dust.

So, back then in 1969, it was a crapshoot.

We really didn't know what we were going to find on the moon.

Shatner: The gamble paid off,

and, for the first time,

humanity was able to explore earth's closest neighbor.

There were many questions that nasa was hoping to answer

on the apollo missions,

but perhaps none were more important

than solving the moon's most enduring mystery:

How did it get there in the first place?

There had been a number of theories

about how the moon was formed.

Uh, one idea was that the moon was an asteroid drifting past

and got caught up by the earth's gravity.

Now, looking at the size of the moon,

this seems an unlikely scenario.

Another idea is when the solar system was being formed,

the planets formed and maybe the moon

formed at the same time as the earth.

But, again, looking at the size of the moon and sort of

the dynamics of that, it doesn't really add up.

Shatner: At the time, each of the commonly proposed theories

was ultimately rejected by scientists.

So nasa sent six manned missions to the moon

to try and find the answer as to how the moon came into being.

Astronauts collected more than 800 pounds of lunar rocks...

...Took atmospheric samples,

and drilled into the moon's surface.

Teitel: Right after the crew splashdown,

the rocks were actually quarantined

to keep all of their germs inside.

They went right into a converted airstream trailer

that was their mobile quarantine facility.

That was then airlifted

to the mainland united states

and transported to houston where they were then

deposited into the lunar receiving lab,

which was a custom-built facility

to deal with everything coming back from the moon.

Shatner: When scientists carefully examined the composition

of the lunar rocks gathered on the apollo missions,

they proposed a dramatic new theory

about the moon's origins.

The current leading theory about the moon's creation

is the so-called giant-impact theory.

This theory posits that a large, mars-sized body

called theia hit the earth when it was young...

...And all of that debris from that impact

coalesced around the planet and eventually formed the moon.

Shatner: The theory that the moon

is the result of a massive collision

is one that is widely supported.

But there's just one problem.

Some scientists are still not convinced.

Aderin-pocock: Now, if this theory is correct,

then what we'd expect is for, um, the moon

should be made out of this sort of a mars-like planet,

which we called theia, and to have some earth in it.

But one of the crazy things we found is that,

when we went to the moon, the composition of the moon

and the composition of earth are very, very similar.

Kaku: It turns out the composition of moon rocks

and the composition earth rocks

is uniformly the same, which shouldn't be.

And so the collision theory has a problem.

We should find remnants of the original asteroid

which created the moon.

And we don't find that. And so that's still a mystery.

Teitel: It's fascinating to think that,

even though we've been studying the moon very closely,

we still don't have this one basic key mystery solved.

There's so much more to learn.

Shatner: The apollo program brought us much closer

to knowing how the moon was created,

even if we still don't have the final answer.

But nasa had other goals in mind for the apollo missions,

some of which are not as well known by the public.

They conducted experiments which were intended

to learn more, not about the lunar surface,

but about what's inside the moon.

Shatner: Less than four months after the success of apollo 11,

nasa launches apollo 12,

its second manned mission to the moon.

On this mission, one of the key objectives was

to learn more about what's below the surface of the moon.

One of the big lunar mysteries that the apollo astronauts

were hoping to at least answer in part

was what is inside the moon.

We're limited in how much we can really look at the moon

and look into the moon to understand its interior

from the earth.

Keating: The astronauts on apollo 12

left seismometers just like

we use on earth to detect earthquakes on earth.

They wanted to see if the moon had these

quaking type behaviors called moonquakes.

And they wanted to see how did the moon behave?

What kind of resonances does it have?

And those are related to its properties,

its inner structure, its core.

And these are things that you can learn about only

from placing these seismometers on the moon's surface.

Teitel: To understand what's going on inside the moon,

the apollo astronauts and the scientists at nasa

came up with a really interesting experiment...

...Which was to crash things into the moon

and measure their impact with seismometers.

The idea being if you smash a known mass

into the lunar surface, that allows you to understand

exactly the seismic data that you're seeing.

Shatner: After the astronauts had safely left the moon's surface,

they intentionally sent their ascent stage module,

which they no longer needed,

crashing into the moon.

When apollo 12 sent its lunar module ascent stage

hurtling into the moon, it hit...

...And the scientists on earth saw the seismic data,

but it didn't do what anyone was expecting.

The signal seemed to be going back and forth inside the moon

almost like it was a bell that was ringing.

And it went on for an hour.

And no one has been able to understand why.

Shatner: The moon rang...

Like a bell?

The discovery came as a shock, and it opened

the door to new, thought-provoking possibilities.

Dennin: The oscillations lasted for a very long time,

much longer than we expected.

And that's surprising fundamentally because we're just

really used to the way the earth vibrates.

And the moon just behaves differently,

and it let us know that the structure of the moon

is very different than the structure of the earth.

Some people thought that might mean the moon is hollow.

Bara: The moon basically resonated,

and to put it the way nasa put it,

it rang like a bell,

which doesn't really make any sense if the moon is solid.

Now this can only happen if there were vast empty spaces

inside the moon

where these sound waves

would be bouncing around for hours and hours afterwards.

It was not a result they expected.

So, it's possible what we're looking at here

is that there are interior portions of the moon

which are hollowed out.

Shatner: Did the apollo 12 mission actually reveal

that the moon is hollow?

While that may sound like a farfetched notion,

many researchers believe that the answer is yes.

And for further evidence,

they point to a classified experiment that was conducted

on the apollo 17 mission in 1972.

Bara: On apollo 17, there was a nasa experiment

called chapel bell, which was classified.

If you think about the name chapel bell,

it implies something to do with sound waves

and the ringing of a bell.

But nobody knows what chapel bell is.

It's 50 years later, the test itself is still classified.

There's a lot of secrecy that seems unnecessary,

especially 50 years later.

It doesn't make any sense.

The only reason it makes sense

for the chapel bell experiment, the separate experiment,

to be classified is if the results

were something extraordinary,

something unexpected, and something that implied

that the moon was far, far different

than nasa had been telling us.

Shatner: What was the chapel bell experiment?

And what were its results?

Could it have provided more evidence

to suggest that the moon is hollow?

And, if so, has nasa deliberately withheld

this information for 50 years?

Perhaps the answers can be found by examining bold new plans,

proposed by space agencies from around the world,

for future missions that will send astronauts

back to the moon.

Shatner: The moon is the most visible object in the night sky.

For thousands of years, humanity has looked up

at this shining celestial body with a sense of wonder.

But when we look at the moon,

we only ever see one side of it, because, as it turns out,

the far side of the moon

never faces earth.

Aderin-pocock: Many people don't realize,

but we only see one face of the moon.

As the moon orbits around the earth,

what happens is that it spins, so the same face of the moon

is always facing towards the earth.

Kaku: Every night we can look at it, and it's the same moon

that you've seen ever since you were a child.

You've never seen the backside of the moon

unless you've seen pictures from the space program.

Shatner: Why does the far side of the moon

never face towards the earth?

Well, the time that it takes for the moon to do

one complete spin on its axis,

is the same length of time

it takes to orbit the earth: 27 days.

This effect is known as "synchronous rotation."

keating: The moon is rotating

and always presents the same face to the earth.

The question is: Why does that occur?

And it occurs because the moon and the earth share energy,

we transfer energy between one another,

and the moon exerts force on the earth,

and the earth exerts a force on the moon, as well.

That reaction on the moon has caused it to become

what's called "tidally locked."

so, for that reason, you'll always see

the same side of the moon.

Shatner: Because the far side of the moon

is not visible from earth,

it is much harder to study than the moon's near side.

In fact, nasa has never landed a spacecraft

on the far side of the moon.

But on January 2, 2019,

the chinese government did.

The change'e 4 lunar lander,

part of the chinese lunar exploration program,

became the first space vehicle

to achieve this historic accomplishment.

Teitel: China recently landed

a robotic mission on the far side of the moon,

which is a really incredible feat

because you don't have communications

with the earth on the far side.

You have to do it completely autonomously.

Dennin: The far side of the moon,

or what we call the dark side of the moon,

it's always been a mysterious place.

We don't expect it to be radically different

than the side that you can see,

but it's still an interesting question of what's there.

So it's an exciting and very important thing to explore.

And what's more, china was doing this,

in part, to prepare for a human mission to the moon.

It's bringing to light a renewed interest

in sending humans to explore the moon.

Shatner: China is not the only country interested

in sending astronauts to the moon.

A growing list of nations are planning similar missions,

including india, israel,

japan, the european union,

- mission control: Ignition... - Shatner: And the united states.

Aderin-pocock: We're excited by the moon again.

Taking samples and getting a better understanding

of the moon is a big driver.

There's lots of science to be done on the moon.

There are so many mysteries that remain unresolved.

The renewed interest in the moon isn't just for science.

There's a whole new industry popping up

for space tourism.

There's also companies who are looking to mine the moon

for resources like helium-3 and other rare elements

that we don't have in abundance on earth,

but are in abundance on the moon.

There's a whole new wave of lunar exploration coming

largely to make money off it.

Shatner: The prospect of more trips to the moon

raises the possibility that humanity

will finally fulfill one of its long-held dreams:

Establishing permanent colonies on the moon.

Kaku: If you want to create a city on the moon,

the quickest way is to exploit lava tubes.

Ancient channels of molten lava that create a tube that can

shelter our astronauts, readymade.

It's a lunar base waiting to be inhabited.

Another possibility is why not take moon rock, melt it,

reform it to create the building blocks for a lunar city.

Dennin: A permanent moon base really is

a key steppingstone to exploring the rest of the solar system

and, eventually, the galaxy.

I'm an optimist at heart, and I really think the moon

is going to be a positive next step.

I'm really hopeful for that.

I think that's something we can do.

Right now, because of all the asteroids and comets

and-and other threats that may be out there,

our survival is in question.

Imagine if we could go to the moon back and forth

in just a few minutes. We could start building moon bases.

We could turn it into a second earth,

and we could ensure humanity's survival into the future.

Shatner: It seems that, in the near future,

some people will have the opportunity

to live on the moon.

But if given the choice between staying here on earth

or living on a moon colony...

...What would you do?

Would you stick to what you know?

Or are you drawn

to that luminous sphere,

compelled to learn its secrets,

and inspired to explore the surface of the moon

in order to explain...

The unexplained?