Episode Transcript
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(00:00):
What is a moonquake? Earth's Moonmight appear to be dead, calm and
still on the outside, but belowthe surface, the Moon is an active,
vibrating body. We know this becausehumans have caused moonquakes ourselves with the
Apollo missions, and the remains ofthat technology are still causing tremors on the
(00:20):
Moon as we speak. So todaywe are going to investigate the truth behind
the mysterious moonquake. This is thespace race. On November nineteenth, nineteen
sixty nine, the Apollo twelve mission, commanded by Pede Conrad and albeen,
landed on the surface of the Moonin a region known as the Ocean of
(00:41):
Storms. Part of their mission wasto deploy a payload known as the Apollo
Lunar Surface Experiment Package, a collectionof scientific instruments that included a remote seismic
monitoring station, the kind of devicethat we would typically use to detect an
earthquake. After complete eating their moonwalkand returning to the command module, Apollo
(01:03):
twelve released their lunar ascent stage ona trajectory back to the Moon's surface.
They purposefully crashed the vehicle into theMoon. It impacted the surface forty miles
away from the landing site with theforce of about one ton of TNT.
The seismic monitoring station was then ableto measure the resulting shockwave from that impact.
(01:23):
It took eight minutes for the moonquaketo build up and reach its peak,
and then another hour for the tremorto fully dissipate. A similar event
happened on Apollo thirteen. They neverlanded on the Moon due to a technical
failure en route, but one thingthat Apollo thirteen did accomplish was generating a
massive moonquake. As part of theirmission profile, the third stage of the
(01:46):
Saturn five rocket, known as theS four B, would be deployed on
a crash course for the Moon.The S four B was a hydrogen propulsion
stage that consisted of two large fueltanks and a J two rocket, an
engine much larger and heavier than thelunar ascent vehicle, so when this thing
hit the Moon, it generated theforce of eleven and a half tons of
(02:07):
TNT, creating shockwaves thirty times greaterand lasting four times longer than the Apollo
twelve impact. In both of theseexperiments, the vibrations recorded by the remote
seismic monitoring station lasted much longer thanscientists had expected, far longer than any
(02:27):
equivalent vibrations on the Earth, andthis observation led NASA officials to comment that
the moon quote rang like a bell. Those particular words would go on to
birth one of the more fringe conspiracytheories out there, known as the hollow
Moon. The idea is that sincethe moon rang like a bell, and
bells are hollow, then the moonmust therefore also be hollow. The generally
(02:51):
agreed upon explanation for the hollow moonis that we are actually being orbited by
an ancient alien spaceship. So,first of all, an object does not
need to be hollow in order tovibrate or even to ring. Case in
point, the glockenspiel, which usessolid metal bars to create sustaining bell like
tones, or even its more primitivesister instrument, the xylophone, which creates
(03:13):
ringing musical notes from blocks of wood. And second off, the moon isn't
hollow anyway. We'll get to thereal reason that the moon rings like a
bell in a little bit, butfirst let's talk about some natural tremors on
the Moon that are not created byhumans crashing stuff into it. The Apollo
Lunar Surface Experiment packages that were deployedon the Moon between nineteen sixty nine and
(03:35):
nineteen seventy two continued to operate andmonitor activity for several years until they were
remotely shut down in nineteen seventy seven, and in that time NASA was able
to record a large amount of dataabout the natural seismic activity of the Moon.
This is fascinating information to have becausewe know that earthquakes are caused by
the movement of tectonic plates that makeup the surface of the Earth, but
(03:59):
the the Moon does not have tectonicplates. The surface is all one continuous
shell. So what causes moonquakes well. One known variety of lunar activity is
the emergent thermal quake. This isthe easiest one to understand because we know
that each half of the Moon willexperience fourteen days of continuous sunlight followed by
fourteen days of continuous darkness, andsince the Moon has no atmosphere to insulate
(04:25):
the surface and maintain a consistent temperature, the surface can range from positive two
hundred and fifty degrees fahrenheit during thedaylight periods to negative two hundred and eight
fahrenheit during the night time periods,and just like any other solid material that
is exposed to these drastic temperature swings, the surface of the Moon will actually
expand and contract as it moves fromday to night. This movement causes significant
(04:48):
vibrations to travel through the surface ofthe Moon. Another common seismic activity on
the Moon is the tidal moonquake.On Earth, we experience the physical effect
of the Moon's gravity in the risingand falling of the ocean tides. By
the same measure, the gravity ofthe Earth will also have an effect on
the surface of the Moon, pullingand stretching the surface material. This will
(05:11):
also cause some residual seismic activity.And then, of course, the Moon
also experiences a pretty high frequency ofnatural impacts. In addition to humans throwing
chunks of spaceships at it, theMoon gets hit by asteroids of varying sizes
all the way from micrometeorites to metalboulders, each one leaving behind a seismic
(05:32):
footprint. We know all of thisinformation because of the scientific instruments left behind
by Apollo Missions twelve and beyond.With Apollo seventeen, the final crude lunar
mission carrying the most advanced instruments ona payload named the Lunar Seismic Profiling Experiment.
At the time, this was cuttingedge research, but it was also
(05:54):
the nineteen seventies, so the communicationbetween the instruments on the Moon and the
receivers on Earth was relatively low bandwidthby modern standards. However, in twenty
twenty three, researchers at the CaliforniaInstitute of Technology found a way to extract
more detail from the Lunar Seismic ProfilingExperiment data. They used artificial intelligence and
(06:15):
machine learning algorithms to fill in themissing pieces of the seismic recordings. This
AI upscaling gave the researchers enough detailto begin separating naturally occurring moonquakes from external
influences. One of the more amazingdiscoveries was that the Apollo seventeen lunar lander,
which was left behind only around onehundred meters from the seismic measuring equipment,
(06:40):
is actually causing moonquakes itself. Sowhat's been happening is that the lander
has been traveling through the lunar dayand night cycle for years, and as
the temperatures swing from one extreme tothe other, the metal structure has been
expanding and contracting. That movement ofthe metal over the ground was enough to
cause vibrations that traveled through the surfaceand reached the monitoring equipment. Now,
(07:04):
this is an incredibly subtle tremor.If you were standing on the Moon next
to the lander, you wouldn't activelynotice the vibration. But the fact that
these micro moonquakes were present enough tobe extracted from fifty year old recording data
just reinforces the fact that the Moon'ssurface is a very strong conductor of vibrations,
(07:26):
even very tiny ones. So doesthis new discovery lend any more credibility
to the hollow moon theory? Howcould the moon be so incredibly resonant without
being a hollow bell after all?Well, let's go back to the xylophone
for a minute. The keys ofthe instrument are made from simple wooden blocks
that are sized to create a specificpitch. But not every type of wood
(07:47):
is suitable to make a xylophone block. Only hardwood varieties that have been thoroughly
dried out can resonate freely enough tobe musical. A soggy, softwood is
going to deaden the vibration before itcan ring out. If we think about
the surface of the Earth, it'scovered in a lot of water. The
more moisture there is present in thesurface materials, the less dense their structure
(08:11):
will be. This damp material workslike a sponge to absorb and deaden the
vibrations created by an earthquake. Ithelps to keep the most severe effect localized
to one area. If we thinkabout the surface of the Moon, it
is totally dry. No moisture existson the Moon. The entire crust of
the Moon is one continuous, cold, and rigid structure. So even if
(08:35):
a moonquake is less intense than anearthquake, there is nothing to deaden the
vibrations on the Moon. They justcontinue to move back and forth through the
body of the Moon like a ringingbell until the solid stone eventually stops them.
Okay, so the Moon might notbe hollow, but it definitely is
unusual, at least by Earth's standards, and this, unfortunately, is something
(08:58):
that we are going to have tobe considered of as we move forward with
the eventual settlement and colonization of theMoon. We know that mining and long
term construction on the Moon is aneventual goal of Mass's Artemis program. We
know that China and their allies alsowant to establish a permanent base on the
Moon. What we don't know ishow this massive increase in surface activity is
(09:20):
going to affect the environment of theMoon. If one relatively small lunar lander
scraping back and forth over a fewmillimeters of surface as it expands and contracts
with the temperature, can create enoughvibration through the Moon's surface to be detectable
with a primitive seismograph, then whatdo we think that a mining operation is
(09:41):
going to do. Or the frequentlanding and takeoff of a giant vehicle like
the SpaceX starship. We are goingto have to accept the fact that a
colonized Moon will end up going intoa constant state of seismic activity, a
permanent moonquake, in addition to allof the naturally occurring moonquakes. So just
(10:01):
one of the many obstacles that humanitywill need to overcome on a very long
and difficult journey to becoming a multiplanetarycivilization.
What is a moonquake? Earth's Moonmight appear to be dead, calm and
still on the outside, but belowthe surface, the Moon is an active,
vibrating body. We know this becausehumans have caused moonquakes ourselves with the
Apollo missions, and the remains ofthat technology are still causing tremors on the
(00:20):
Moon as we speak. So todaywe are going to investigate the truth behind
the mysterious moonquake. This is thespace race. On November nineteenth, nineteen
sixty nine, the Apollo twelve mission, commanded by Pede Conrad and albeen,
landed on the surface of the Moonin a region known as the Ocean of
(00:41):
Storms. Part of their mission wasto deploy a payload known as the Apollo
Lunar Surface Experiment Package, a collectionof scientific instruments that included a remote seismic
monitoring station, the kind of devicethat we would typically use to detect an
earthquake. After complete eating their moonwalkand returning to the command module, Apollo
(01:03):
twelve released their lunar ascent stage ona trajectory back to the Moon's surface.
They purposefully crashed the vehicle into theMoon. It impacted the surface forty miles
away from the landing site with theforce of about one ton of TNT.
The seismic monitoring station was then ableto measure the resulting shockwave from that impact.
(01:23):
It took eight minutes for the moonquaketo build up and reach its peak,
and then another hour for the tremorto fully dissipate. A similar event
happened on Apollo thirteen. They neverlanded on the Moon due to a technical
failure en route, but one thingthat Apollo thirteen did accomplish was generating a
massive moonquake. As part of theirmission profile, the third stage of the
(01:46):
Saturn five rocket, known as theS four B, would be deployed on
a crash course for the Moon.The S four B was a hydrogen propulsion
stage that consisted of two large fueltanks and a J two rocket, an
engine much larger and heavier than thelunar ascent vehicle, so when this thing
hit the Moon, it generated theforce of eleven and a half tons of
(02:07):
TNT, creating shockwaves thirty times greaterand lasting four times longer than the Apollo
twelve impact. In both of theseexperiments, the vibrations recorded by the remote
seismic monitoring station lasted much longer thanscientists had expected, far longer than any
(02:27):
equivalent vibrations on the Earth, andthis observation led NASA officials to comment that
the moon quote rang like a bell. Those particular words would go on to
birth one of the more fringe conspiracytheories out there, known as the hollow
Moon. The idea is that sincethe moon rang like a bell, and
bells are hollow, then the moonmust therefore also be hollow. The generally
(02:51):
agreed upon explanation for the hollow moonis that we are actually being orbited by
an ancient alien spaceship. So,first of all, an object does not
need to be hollow in order tovibrate or even to ring. Case in
point, the glockenspiel, which usessolid metal bars to create sustaining bell like
tones, or even its more primitivesister instrument, the xylophone, which creates
(03:13):
ringing musical notes from blocks of wood. And second off, the moon isn't
hollow anyway. We'll get to thereal reason that the moon rings like a
bell in a little bit, butfirst let's talk about some natural tremors on
the Moon that are not created byhumans crashing stuff into it. The Apollo
Lunar Surface Experiment packages that were deployedon the Moon between nineteen sixty nine and
(03:35):
nineteen seventy two continued to operate andmonitor activity for several years until they were
remotely shut down in nineteen seventy seven, and in that time NASA was able
to record a large amount of dataabout the natural seismic activity of the Moon.
This is fascinating information to have becausewe know that earthquakes are caused by
the movement of tectonic plates that makeup the surface of the Earth, but
(03:59):
the the Moon does not have tectonicplates. The surface is all one continuous
shell. So what causes moonquakes well. One known variety of lunar activity is
the emergent thermal quake. This isthe easiest one to understand because we know
that each half of the Moon willexperience fourteen days of continuous sunlight followed by
fourteen days of continuous darkness, andsince the Moon has no atmosphere to insulate
(04:25):
the surface and maintain a consistent temperature, the surface can range from positive two
hundred and fifty degrees fahrenheit during thedaylight periods to negative two hundred and eight
fahrenheit during the night time periods,and just like any other solid material that
is exposed to these drastic temperature swings, the surface of the Moon will actually
expand and contract as it moves fromday to night. This movement causes significant
(04:48):
vibrations to travel through the surface ofthe Moon. Another common seismic activity on
the Moon is the tidal moonquake.On Earth, we experience the physical effect
of the Moon's gravity in the risingand falling of the ocean tides. By
the same measure, the gravity ofthe Earth will also have an effect on
the surface of the Moon, pullingand stretching the surface material. This will
(05:11):
also cause some residual seismic activity.And then, of course, the Moon
also experiences a pretty high frequency ofnatural impacts. In addition to humans throwing
chunks of spaceships at it, theMoon gets hit by asteroids of varying sizes
all the way from micrometeorites to metalboulders, each one leaving behind a seismic
(05:32):
footprint. We know all of thisinformation because of the scientific instruments left behind
by Apollo Missions twelve and beyond.With Apollo seventeen, the final crude lunar
mission carrying the most advanced instruments ona payload named the Lunar Seismic Profiling Experiment.
At the time, this was cuttingedge research, but it was also
(05:54):
the nineteen seventies, so the communicationbetween the instruments on the Moon and the
receivers on Earth was relatively low bandwidthby modern standards. However, in twenty
twenty three, researchers at the CaliforniaInstitute of Technology found a way to extract
more detail from the Lunar Seismic ProfilingExperiment data. They used artificial intelligence and
(06:15):
machine learning algorithms to fill in themissing pieces of the seismic recordings. This
AI upscaling gave the researchers enough detailto begin separating naturally occurring moonquakes from external
influences. One of the more amazingdiscoveries was that the Apollo seventeen lunar lander,
which was left behind only around onehundred meters from the seismic measuring equipment,
(06:40):
is actually causing moonquakes itself. Sowhat's been happening is that the lander
has been traveling through the lunar dayand night cycle for years, and as
the temperatures swing from one extreme tothe other, the metal structure has been
expanding and contracting. That movement ofthe metal over the ground was enough to
cause vibrations that traveled through the surfaceand reached the monitoring equipment. Now,
(07:04):
this is an incredibly subtle tremor.If you were standing on the Moon next
to the lander, you wouldn't activelynotice the vibration. But the fact that
these micro moonquakes were present enough tobe extracted from fifty year old recording data
just reinforces the fact that the Moon'ssurface is a very strong conductor of vibrations,
(07:26):
even very tiny ones. So doesthis new discovery lend any more credibility
to the hollow moon theory? Howcould the moon be so incredibly resonant without
being a hollow bell after all?Well, let's go back to the xylophone
for a minute. The keys ofthe instrument are made from simple wooden blocks
that are sized to create a specificpitch. But not every type of wood
(07:47):
is suitable to make a xylophone block. Only hardwood varieties that have been thoroughly
dried out can resonate freely enough tobe musical. A soggy, softwood is
going to deaden the vibration before itcan ring out. If we think about
the surface of the Earth, it'scovered in a lot of water. The
more moisture there is present in thesurface materials, the less dense their structure
(08:11):
will be. This damp material workslike a sponge to absorb and deaden the
vibrations created by an earthquake. Ithelps to keep the most severe effect localized
to one area. If we thinkabout the surface of the Moon, it
is totally dry. No moisture existson the Moon. The entire crust of
the Moon is one continuous, cold, and rigid structure. So even if
(08:35):
a moonquake is less intense than anearthquake, there is nothing to deaden the
vibrations on the Moon. They justcontinue to move back and forth through the
body of the Moon like a ringingbell until the solid stone eventually stops them.
Okay, so the Moon might notbe hollow, but it definitely is
unusual, at least by Earth's standards, and this, unfortunately, is something
(08:58):
that we are going to have tobe considered of as we move forward with
the eventual settlement and colonization of theMoon. We know that mining and long
term construction on the Moon is aneventual goal of Mass's Artemis program. We
know that China and their allies alsowant to establish a permanent base on the
Moon. What we don't know ishow this massive increase in surface activity is
(09:20):
going to affect the environment of theMoon. If one relatively small lunar lander
scraping back and forth over a fewmillimeters of surface as it expands and contracts
with the temperature, can create enoughvibration through the Moon's surface to be detectable
with a primitive seismograph, then whatdo we think that a mining operation is
(09:41):
going to do. Or the frequentlanding and takeoff of a giant vehicle like
the SpaceX starship. We are goingto have to accept the fact that a
colonized Moon will end up going intoa constant state of seismic activity, a
permanent moonquake, in addition to allof the naturally occurring moonquakes. So just
(10:01):
one of the many obstacles that humanitywill need to overcome on a very long
and difficult journey to becoming a multiplanetarycivilization.
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