Hollow Moon

[[File:Main lunar core en.jpg|right|200px|thumb|What the inside of the Moon ''actually'' looks like. Nearly 1,737.5 km<ref>https://www.space.com/18135-how-big-is-the-moon.html</ref> of solid mantle isn't exactly '''hollow''', now is it?]]{{pseudoastronomy}}

The '''Hollow Moon''' theory, also known as the '''Spaceship Moon''' theory, is the sister of the [[Hollow Earth]] theory. It proposes that the [[Moon]] is hollow, and of course a ''huge'' spaceship produced by [[alien]]s. Like the former, it is a [[Pseudoscience|pseudoscientific]] belief supported by zero [[evidence]], ripe for believers in [[NASA]] conspiracy theories.

The first suggestion of the Moon being hollow in [[science fiction]] was in H. G. Wells' ''The First Men in the Moon'', published in the year 1901.<ref name=sservi>{{cite web |url=http://sservi.nasa.gov/?question=hollow-moon |title=Hollow Moon |work=Solar System Exploration Research Virtual Institute |date=2 February 2009}}</ref><ref name=armhol>{{cite web |url=http://www.armaghplanet.com/blog/is-the-moon-hollow.html |title=Is the Moon Hollow? |work=Armagh Planetarium |date=22 May 2015}}</ref><ref name=colspa>{{cite web |url=http://www.jasoncolavito.com/blog/spaceship-moon-and-soviet-scientific-politics |title="Spaceship Moon" and Soviet Scientific Politics |work=[[Jason Colavito|JasonColavito.com]] |date=23 September 2012}}</ref>

==Origins of the belief==
In the 1970s, [[USSR|Soviet]] scientists Michael Vasin and Alexander Shcherbakov proposed that the Moon is a massive space station built by some unknown alien beings<ref name=colspa /> in an article called ''Is the Moon the Creation of Alien Intelligence?''. It was not published in any [[peer-review]]ed journals, but on what was basically the Soviet equivalent of the ''Reader's Digest''.<ref name=armhol/><ref>{{cite book |url=https://books.google.com/books?id=s3iukQc_DBEC&pg=PA34 |title=Cold War Space Sleuths |editor= Dominic Phelan |publisher=Springer-Praxis |date=2013 |page=34|isbn=9781461430520 }}</ref><ref name=inqspa /> Vasin and Shcherbakov also cited earlier speculation by astrophysicist {{wpl|Iosif Shklovsky||,}} who believed that the [[Mars|Martian]] moon Phobos was a hollow, artificial satellite, which we now know is ''certainly'' not the case.  This should say it all about just how credible this [[hypothesis]] is.

The belief relies heavily on the asinine suggestion that since large lunar craters (which scientists generally agree were formed from [[asteroid]]/[[comet]]ary impact) are generally quite shallow with flat or even convex bottoms, ergo these meteors are allegedly creating a cup-shaped dent in the rocky surface of the moon- while the larger meteors, it argues, are drilling through a rocky layer and hitting some armored metal "hull" underneath that conceals a [[Fun:Star Wars|Death Star]]-like [[UFO]] underneath. Hollow-mooners may also try to explain why almost all of the Moon's dried lava flows are on the side that always faces Earth by arguing that these "seas" (or "mares"), currently known to be plains of solidified lava that oozed from the Moon's interior billions of years ago, are some sort of reinforcement to better endure such impacts.<ref name=inqpar>{{cite news |url=http://www.inquisitr.com/1917650/our-moon-is-an-alien-ufo-spaceship-parked-in-orbit-around-earth-ufologists-claim/ |title=Our Moon Is An Alien UFO Spaceship Parked In Orbit Around Earth, UFOlogists Claim |date=12 March 2015}}</ref>

However, as pointed out by [[skeptic]] writer [[Jason Colavito]], the "evidence" cited by Vasin and Shcherbakov is only circumstantial at best suggesting also the officially [[atheist]] Soviet Union promoted such kind of theories about [[ancient astronauts]] attempting to undermine the faith in [[religion]] of the western world,<ref name=colspa/> and the apparent shallowness of lunar craters, which is also present in other [[Solar System]] planets and moons can be explained by the mechanisms of impact crater formation.{{efn|See {{wpl|Impact_crater#Crater_formation|the other Wiki}}. Long history short, the crater is initially much deeper but such cavity collapses almost immediately when attempting to return to a state of gravitational equilibrium, both uplifting its center and its rim collapsing. See also {{wpl|Complex_crater|here}}, and note too that some lunar craters have had their floor filled with lava and/or ejecta from nearby impacts burying it and contributing even more to its shallowness}} 

Another major problem is how such spacecraft would be able to withstand impacts as great as those which formed the {{wpl|Orientale basin|Orientale,}} {{wpl|Imbrium basin|Imbrium,}} and {{wpl|South Pole-Aitken basin|South Pole-Aitken}} basins – the latter of which is believed to have been powerful enough to completely destroy the Moon, had impact conditions been different.{{efn|And these are the largest impacts known to have been suffered by the Moon, as there have been proposals of [https://the-moon.us/wiki/Procellarum_Basin way] [https://link.springer.com/article/10.1007/s11038-007-9225-8 larger] ones.}} Were Luna actually hollow, it is likely that the impact force would have been more than sufficient for this to happen.<ref name=spa>[http://www.psrd.hawaii.edu/July98/spa.html The Biggest Hole in the Solar System]</ref>

==Some common hollow-Mooner arguments (and why they fail)==
Seismometers installed on the Moon from 1972 to 1977 by the Apollo missions have recorded "moonquakes", demonstrating that the [[Earth]] exerts tidal forces on the Moon — something that would only be possible if there were solid [[Mass (physics)|mass]] inside and beneath the moon's crust — which, in response to the Moon being slightly squeezed by tidal forces, will slide against each other and cause the quakes. One hollow-Mooner argument tries to explain this away by asserting that the Moon was "ringing like a bell" during some of those tremors (specifically the shallow ones).<ref name=nasmoo>{{cite web |url=http://www.nasa.gov/exploration/home/15mar_moonquakes.html |title=Moonquakes |work=[[NASA]] |date=15 March 2006}}</ref> The same assertion was also made when Apollo 12 deliberately crashed the Ascent Stage of its Lunar Module into the Moon's surface, followed by a further assertion that the Moon must be "hollow like a bell".<ref name=armhol/> However, lunar seismology experiments conducted during the Apollo missions have since shown that the lunar body has shallow quakes that act differently than those on Earth, due to differences in texture, type, and density between the two bodies. However, there is no evidence of any massive empty chasm inside the Moon that encompasses a super-colossal portion of its interior volume.<ref name=nasmoo/>

Yet another assertion tries to offer the existence of a massive hollow within the Moon as an explanation for why the Moon, with a density is 3.3 g/cm<sup>3</sup>, is less dense than the Earth (whose density is 5.5 g/cm<sup>3</sup>).<ref name=inqpar/> The fact that the Moon is made up primarily of rocky material that has such density can be easily explained by the {{wpl|Giant-impact hypothesis|Giant impact hypothesis|,}} which suggests that the Moon was formed out of material from the Earth's crust and mantle that was blasted into orbit by a Mars-sized protoplanet's impact with the early Earth, leaving it with just enough iron to have a {{wpl|Internal structure of the Moon|small, iron-rich core|,}} unlike {{wpl|Structure of Earth#Core|Earth|.}}{{efn|{{wpl|Ganymede (moon)|Ganymede}} and [[Titan (moon)|Titan]], the largest moons in the [[Solar System]], have crusts that mainly consist of a thick layer of ice with underground oceans of liquid water, meaning that they have a much lower density than our Moon — without being hollow at all. And that's not even taking into account the much, much deeper layers of rock below the ice/water layer. Other moons of outer Solar System gas giants, like Saturn's icy 
Death Star
 moon {{wpl|Tethys (moon)|Tethys|,}} and even more distant dwarf planets like Sedna and the [[Pluto]]/Charon binary system, have much lower densities - being composed almost ''entirely'' of water ice (which also explains why Pluto and Sedna's surfaces appear blood red from chemical changes that occur when ultra-cold water ice is blasted with cosmic rays) — and yet all of these bodies still manage to not be entirely hollow.}}

Some authors (such as Don Wilson in his book ''Our Mysterious Spaceship Moon''), also claim that such spacecraft would have come here a few millennia ago (around between 13,000 and 11,500 years ago), in an attempt to explain why some cultures have legends about a past in which either no Moon shone in the sky or there was a second one, citing in the latter case a [[Welteislehre|theory]] of the [[Engineer woo|engineer]] Hanns Hörbiger back in the first decades of the 20st Century that proposes among other nonsense there existed another Moon before the one we know and love{{efn|Actually ''several'' Moons, as each satellite ended up crashing into Earth being replaced by another. In Hörbirger's theory the one that was replaced by the current Moon caused when collided with Earth the [[Global Flood]]}}. One has to wonder what became of [[No True Scotsman|the "real", natural Moon]], and why these ancient aliens who allegedly visited the Earth system were so clumsy to allow whatever made it disappear even if Don Wilson suggests they would have gone away in the old Moon which conveniently was also another big spaceship leaving here theirs, not ''all'' cultures have myths about either no or two moons shining in the sky, and especially where the exhausts of the ''massive'' engines needed to propel such humongous spacecraft are
, plus the equatorial trench, the superlaser dish, and that pesky thermal exhaust port
.<ref>[https://books.google.es/books?id=OPilswEACAAJ&dq=mysterious+spaceship+moon&hl=es&sa=X&ved=2ahUKEwi0_cehvLDtAhURAWMBHdIsCscQ6AEwAHoECAEQAQ Our Mysterious Spaceship Moon]</ref> 

On the former case, the arguments in support of no Moon in the sky include besides those legends claims by [[Immanuel Velikovsky]], which should give a hint of their credibility, Assyrian texts, {{bible|Psalm|72|5}} in the [[Bible]] suggesting that, the works of the [[Pseudoarcheology|pseudoarcheologist]] and crank {{wpl|Hans Schindler Bellamy||,}} who also claims the city of [[Tiwanaku]] in [[Bolivia]] and whose name for him means "City of the Dying Moon", was founded around 14,000-12,000 years ago by [[Ancient astronauts|people who came from the sky in shining chariots]], presumably from the spaceship that would become our Moon, and finally claims of no cave paintings showing both no Moon and no stars even if there's research that suggests some were actually lunar calendars painted 20,000 years ago during the Ice Age.<ref>[https://www.artnews.com/art-news/news/amateur-archaeologist-decodes-ice-age-calendar-cave-paintings-animals-1234652741/ Amateur Archaeologist Decodes Ice Age Calendar Tracking Animal Reproductive Cycles]</ref> All of these arguments, however, ignore the presence of {{wpl|Rhythmite|tidal rhythmites}} that show how tides, thus the Moon being around as solar tides are weaker and they alone would have left a very different register (same if there had been more than just one Moon around, at least another large enough to produce detectable tides), were being produced hundreds of millions of years ago.<ref>[https://www.sciencedirect.com/science/article/abs/pii/S0012825204000923 Tidal rhythmites and their implications]</ref>

[[Cranks]] who support the hypothesis include [[David Icke]]<ref name=inqspa>{{cite news |url=http://www.inquisitr.com/3142772/the-moon-is-an-alien-ufo-spaceship-parked-in-orbit-around-earth-conspiracy-theorist-david-icke-says-video/ |title=The Moon Is An Alien UFO Spaceship Parked In Orbit Around Earth, Conspiracy Theorist David Icke Says |date=28 May 2016}}</ref> (because [[Crank magnetism|of fucking course he does]]), the writers of ''[[Who Built the Moon?]]'', and, as stated above, Don Wilson — who both the mentioned book and in a later one, ''Secrets of Our Mysterious Spaceship Moon'',<ref>[https://archive.org/details/SecretsOfOurSpaceshipMoon/mode/2up Secrets of Our Mysterious Spaceship Moon]</ref> claims astronauts of the Apollo spacecrafts saw 
TIE fighters, ports for Spelljammer ships in the far side, and the Drow goddess Eilistraee dancing skyclad there
 UFOs in the Moon, alien ships parked there watching them, and that it is a sort of interplanetary [[Noah's Ark]] employing as usual what looks like a mix of [[quote mining]], [[cherry-picking]], trusting in the work of other cranks, and [[argument from authority]] as the most suitable ones to also explain why [[NASA]] has not come back to the Moon at least with manned missions (until the {{wpl|Artemis program||,}} that is.)

The idea of a hollow Moon appeared back in the 1970s, when there were three different theories for how the Moon was formed: [[Origin of the Moon#Hypothesis 2: Capture|That it was an independent dwarf planet until it was captured by Earth's gravity]], [[Origin of the Moon#Hypothesis 1: Fission|that the Earth was spinning so fast that part of it broke off and formed the Moon]], and [[Origin of the Moon#Hypothesis 3: Accretion|that the Moon was accreted]] from the same accretion disk that formed 
the Solar System's largest madhouse
 our planet. However, all of these had failed to explain its origin.{{efn|Back in those days, some astronomers half-jokingly said the Moon did not exist, as such hypotheses had weaknesses (Wilford, 1971).}} This was before the currently [[Origin of the Moon#Giant Impact Hypothesis|most accepted one]] had been embraced by the scientific community, when all of these hypotheses were discredited when refined analysis of the lunar rocks brought back by the Apollo missions was found to be very similar to rocks found on Earth — which also disproved claims that lunar rocks were older than Earth's oldest known ones. This indicated that a) the Moon either formed from the same accretion disk as Earth or was formed from the debris of a giant impact with it, and that b) the Moon is not a captured dwarf planet.

==What the real, actual science says about the Moon's interior==
As noted in the picture at the top of this article, the current, established [[scientific consensus]] points to a Moon that is mostly solid, with at most a possible fluid outer core and partial melt at the bottom of its mantle.<ref>{{wpa|Internal structure of the Moon}}</ref> This is supported by both the network of seismometers set up on the Moon's surface and its {{wpl|moment of inertia factor||}} — which is perfectly normal for a solid celestial body with a non-hollow, rocky/metallic interior.<ref name=lunpro>{{cite journal |author1= AS Konopliv |author2=AB Binder |author3=LL Hood |author4=AB Kucinskas |author5=WL Sjogren |author6=JG Williams |title=Improved Gravity Field of the Moon from Lunar Prospector |journal=Science |pmid=9727968 |date=1998 |volume=281 |issue=5382 |pages=1476–80 |doi=10.1126/science.281.5382.1476 |bibcode = 1998Sci...281.1476K|doi-access=free }}</ref><ref>{{cite web |url=http://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html |title=Moon Fact Sheet |work=NASA |date=19 April 2016}}</ref>

Another gaping hole (badum-tssh!) in this hypothesis is how unstable our Moon, with the mass and [[Gravity|gravitational]] pull that it has, would be if it were hollow — especially given that Earth's tidal pull on it is already so immense that only one side of the moon ever faces towards its host planet, and was also strong enough to pull almost all lava flows to the side of the Moon that faces us when it was still geologically active.

==Legitimately hollow Solar System objects==

[[File:Inside rubble pile asteroid.jpeg|250px|right|thumb|The inside of a "rubble pile" asteroid. Notice how its interior is ''somewhat'' hollow.]]
Even though the Hollow Moon theory is clearly bollocks, a significant number of Solar System asteroids are either known or believed to be "{{wpl|rubble pile|rubble piles}}", formed by many smaller chunks held together by [[gravity]], and in rare cases, magnetism if they contain large amounts of iron<ref>[https://arstechnica.com/science/2014/08/weak-forces-hold-rubble-pile-asteroids-together/ Weak forces hold rubble pile asteroids together.] ''Ars Technica Science.''</ref>) — leaving behind many gaps in between the pieces of gravel that make up such asteroids — not like the super-colossal [[Australia]]-sized chasm that hollow-Mooners believe to lie within Earth's moon, but more in the form of caverns and tiny spaces between the rocks. In addition to these gravelly [[asteroid]]s, the legitimately hollow objects in our Solar System also include:
*{{wpl|Phobos (moon)|Phobos|:}} the larger of [[Mars]]' two moons that is believed, due to its trajectory that is gradually pulling it closer and closer to the 
future doomsday for our descendants who will live on and have gone through so much trouble to terraform
 the Red Planet and the fact that it orbits in the wrong direction, to be an asteroid captured by Mars' gravity. Its surface is very fractured and stripey due to tidal stress — which is already so bad that if you made even just a small jump off of Phobos, you could fall into Mars. Indeed, the 2008 Mars Express Satellite has found that Phobos, too, is a beanbag-like rubble pile, held together by a thick, strong dust layer.<ref>[https://www.newscientist.com/article/dn28426-mars-is-ripping-its-beanbag-moon-phobos-apart/ Mars is ripping its beanbag moon Phobos apart]. ''NewScientist Space.'' 30 October 2015.</ref>
*[[Saturn]]'s spongy, geode-like moon {{wpl|Hyperion (moon)|Hyperion|.}}

==In popular culture==
The idea of Luna being hollow is central to [[Roland Emmerich]]'s 2022 movie ''Moonfall''. Like other flicks from the same director, scientific accuracy takes a long break as supposedly for example the Moon's insides contain a {{wpl|White dwarf}} star without Earth being affected at all by it and despite even the [https://www.nature.com/articles/s41586-021-03615-y smallest white dwarf known to date] (thus very massive by such dead stars' standards, as {{wpl|Chandrasekhar limit|the smaller the white dwarf the more massive it is}}) being similar in size to Luna.

==See also==
*[[Hollow Earth]], basically the same thing but for Earth
*[[Flat Earth]], a similar conspiracy theory
*[[Pseudoastronomy]]

==External links==
*[https://www.youtube.com/watch?v=3bUUXFuOvfo Ancient Aliens episode on YouTube discussing the theory]
*[https://spacetech.freeforums.net/board/1/general-discussion Australian hollow moon theory]

==Notes==
{{reflist|group=note}}

==References==
{{reflist|2|80%}}

[[Category:Conspiracy theories]]
[[Category:Moon]]
[[Category:Pseudoscience]]
[[Category:Ufology]]

Categories: Conspiracy theories, Moon, Pseudoscience, Ufology