text:
United States Numbered Highway System

The United States Numbered Highway System (often called U.S. Routes or U.S. Highways) is an integrated network of roads and highways numbered within a nationwide grid in the contiguous United States. As the designation and numbering of these highways were coordinated among the states, they are sometimes called Federal Highways, but the roadways were built and have always been maintained by state or local governments since their initial designation in 1926.

The route numbers and locations are coordinated by the American Association of State Highway and Transportation Officials (AASHTO). The only federal involvement in AASHTO is a nonvoting seat for the United States Department of Transportation. Generally, most north-to-south highways are odd-numbered, with the lowest numbers in the east and the highest in the west, while east-to-west highways are typically even-numbered, with the lowest numbers in the north, and the highest in the south, though the grid guidelines are not rigidly followed, and many exceptions exist. Major north–south routes generally have numbers ending in "1", while major east–west routes usually have numbers ending in "0". Three-digit numbered highways are generally spur routes of parent highways; for example, U.S. Route 264 (US 264) is a spur off US 64. Some divided routes, such as US 19E and US 19W, exist to provide two alignments for one route. Special routes, which can be labeled as alternate, bypass or business, depending on the intended use, provide a parallel routing to the mainline U.S. Highway.

Before the U.S. Routes were designated, auto trails designated by auto trail associations were the main means of marking roads through the United States. These were private organizations, and the system of road marking at the time was haphazard and not uniform. In 1925, the Joint Board on Interstate Highways, recommended by the American Association of State Highway Officials (AASHO), worked to form a national numbering system to rationalize the roads. After several meetings, a final report was approved by the U.S. Department of Agriculture in November 1925. After getting feedback from the states, they made several modifications; the U.S. Highway System was approved on November 11, 1926.

Expansion of the U.S. Highway System continued until 1956, when the Interstate Highway System was laid out and began construction under the administration of President Dwight D. Eisenhower. After the national implementation of the Interstate Highway System, many U.S. Routes that had been bypassed or overlaid with Interstate Highways were decommissioned and removed from the system. In some places, the U.S. Routes remain alongside the Interstates and serve as a means for interstate travelers to access local services and as secondary feeder roads or as important major arteries in their own right. In other places, where there are no nearby Interstate Highways, the U.S. Routes often remain as the most well-developed roads for long-distance travel. While the system's growth has slowed in recent decades, the U.S. Highway System remains in place to this day and new routes are occasionally added to the system.

System details
In general, U.S. Routes do not have a minimum design standard, unlike the later Interstate Highways, and are not usually built to freeway standards. Some stretches of U.S. Routes do meet those standards. Many are designated using the main streets of the cities and towns through which they run. New additions to the system, however, must "substantially meet the current AASHTO design standards". As of 1989, the United States Numbered Highways system had a total length of 157724 mi.

Except for toll bridges and tunnels, very few U.S. Routes are toll roads. AASHTO policy says that a toll road may only be included as a special route, and that "a toll-free routing between the same termini shall continue to be retained and marked as a part of the U.S. Numbered System." U.S. Route 3 (US 3) meets this obligation; in New Hampshire, it does not follow tolled portions of the Everett Turnpike. However, US Routes in the system do use parts of five toll roads:
 * US 51 uses part of the Jane Addams Memorial Tollway in Illinois; the old road is Illinois Route 251.
 * US 278 uses the tolled Cross Island Parkway in South Carolina; the old road is US 278 Business. The tolls were removed in July 2021.
 * US 301 is a toll road through Delaware; the former routing is a free road and uses several Delaware state routes.
 * US 412 uses the Cimarron Turnpike in Oklahoma; the old road is US 64.
 * US 412 also uses the Cherokee Turnpike in Oklahoma; the old road is US 412 Alternate.

Numbering
U.S. Routes in the contiguous United States follow a grid pattern, in which odd-numbered routes run generally north to south and even-numbered routes run generally east to west, though three-digit spur routes can be either-or. Usually, one- and two-digit routes are major routes, and three-digit routes are numbered as shorter spur routes from a main route. Odd numbers generally increase from east to west; U.S. Route 1 (US 1) follows the Atlantic Coast and US 101 follows the Pacific Coast. (US 101 is one of the many exceptions to the standard numbering grid; its first "digit" is "10", and it is a main route on its own and not a spur of US 1.) Even numbers tend to increase from north to south; US 2 closely follows the Canadian border, and US 98 hugs the Gulf Coast. The longest routes connecting major cities are generally numbered to end in a 1 or a 0; however, extensions and truncations have made this distinction largely meaningless. These guidelines are very rough, and exceptions to all of the basic numbering rules exist.

The numbering system also extended beyond the borders of the United States in an unofficial manner. Many Canadian highways were renumbered in the 1940s and 1950s to adopt the same number as the U.S. Route they connected to – mostly in the western provinces. Examples include British Columbia's highways 93, 95, 97, and 99; Manitoba's highways 59, 75, and 83; or 71. The reverse happened with U.S. Route 57, originally a Texas state highway numbered to match Mexican Federal Highway 57.

In the 1950s, the numbering grid for the new Interstate Highway System was established as intentionally opposite from the US grid insofar as the direction the route numbers increase. Interstate Highway numbers increase from west-to-east and south-to-north, to keep identically numbered routes geographically apart in order to keep them from being confused with one another, and it omits 50 and 60 which would potentially conflict with US 50 and US 60.

In the US Highway system, three-digit numbers are assigned to spurs of one or two-digit routes. US 201, for example, splits from US 1 at Brunswick, Maine, and runs north to Canada. Not all spurs travel in the same direction as their "parents"; some are connected to their parents only by other spurs, or not at all, instead only traveling near their parents, Also, a spur may travel in different cardinal directions than its parent, such as US 522, which is a north–south route, unlike its parent US 22, which is east–west. As originally assigned, the first digit of the spurs increased from north to south and east to west along the parent; for example, US 60 had spurs, running from east to west, designated as US 160 in Missouri, US 260 in Oklahoma, US 360 in Texas, and US 460 and US 560 in New Mexico. As with the two-digit routes, three-digit routes have been added, removed, extended and shortened; the "parent-child" relationship is not always present.

AASHTO guidelines specifically prohibit Interstate Highways and U.S. Routes from sharing a number within the same state. As with other guidelines, exceptions exist across the U.S.

Some two-digit numbers have never been applied to any U.S. Route, including 37, 39, 47, 86 and 88.

Signage
Route numbers are displayed on a distinctively-shaped white shield with large black numerals in the center. Often, the shield is displayed against a black square or rectangular background. Each state manufactures their own signage, and as such subtle variations exist all across the United States. Individual states may use cut-out or rectangular designs, some have black outlines, and California prints the letters "US" above the numerals. One- and two-digit shields generally feature the same large, bold numerals on a square-dimension shield, while 3-digit routes may either use the same shield with a narrower font, or a wider rectangular-dimension shield. Special routes may be indicated with a banner above the route number, or with a letter suffixed to the route number. Signs are generally displayed in several different locations. First, they are shown along the side of the route at regular intervals or after major intersections (called reassurance markers), which shows the route and the nominal direction of travel. Second, they are displayed at intersections with other major roads, so that intersecting traffic can follow their chosen course. Third, they can be displayed on large green guide signs that indicate upcoming interchanges on freeways and expressways.

Divided and special routes
Since 1926, some divided routes were designated to serve related areas, and designate roughly-equivalent splits of routes. For instance, US 11 splits into US 11E (east) and US 11W (west) in Bristol, Virginia, and the routes rejoin in Knoxville, Tennessee. Occasionally only one of the two routes is suffixed; US 6N in Pennsylvania does not rejoin US 6 at its west end. AASHTO has been trying to eliminate these since 1934; its current policy is to deny approval of new split routes and to eliminate existing ones "as rapidly as the State Highway Department and the Standing Committee on Highways can reach agreement with reference thereto".

Special routes—those with a banner such as alternate or bypass—are also managed by AASHTO. These are sometimes designated with lettered suffixes, like A for alternate or B for business.

Naming
The official route log, last published by AASHTO in 1989, has been named United States Numbered Highways since its initial publication in 1926. Within the route log, "U.S. Route" is used in the table of contents, while "United States Highway" appears as the heading for each route. All reports of the Special Committee on Route Numbering since 1989 use "U.S. Route", and federal laws relating to highways use "United States Route" or "U.S. Route" more often than the "Highway" variants. The use of U.S. Route or U.S. Highway on a local level depends on the state, with some states such as Delaware using "route" and others such as Colorado using "highway".

Early auto trails
In 1903, Horatio Nelson Jackson became the first documented person to drive an automobile from San Francisco to New York using only a connection of dirt roads, cow paths, and railroad beds. His journey, covered by the press, became a national sensation and called for a system of long-distance roads.

In the early 1910s, auto trail organizations—most prominently the Lincoln Highway—began to spring up, marking and promoting routes for the new recreation of long-distance automobile travel. The Yellowstone Trail was another of the earliest examples. While many of these organizations worked with towns and states along the route to improve the roadways, others simply chose a route based on towns that were willing to pay dues, put up signs, and did little else.

Planning
Wisconsin was the first state in the U.S. to number its highways, erecting signs in May 1918. Other states soon followed. In 1922, the New England states got together to establish the six-state New England Interstate Routes.

Behind the scenes, the federal aid program had begun with the passage of the Federal Aid Road Act of 1916, providing 50% monetary support from the federal government for improvement of major roads. The Federal Aid Highway Act of 1921 limited the routes to 7% of each state's roads, while 3 in every 7 roads had to be "interstate in character". Identification of these main roads was completed in 1923.

The American Association of State Highway Officials (AASHO), formed in 1914 to help establish roadway standards, began to plan a system of marked and numbered "interstate highways" at its 1924 meeting. AASHO recommended that the Secretary of Agriculture work with the states to designate these routes.

Secretary Howard M. Gore appointed the Joint Board on Interstate Highways, as recommended by AASHO, on March 2, 1925. The Board was composed of 21 state highway officials and three federal Bureau of Public Roads officials. At the first meeting, on April 20 and 21, the group chose the name "U.S. Highway" as the designation for the routes. They decided that the system would not be limited to the federal-aid network; if the best route did not receive federal funds, it would still be included. The tentative design for the U.S. Route shield was also chosen, based on the shield found on the Great Seal of the United States.

The auto trail associations rejected the elimination of the highway names. Six regional meetings were held to hammer out the details—May 15 for the West, May 27 for the Mississippi Valley, June 3 for the Great Lakes, June 8 for the South, June 15 for the North Atlantic, and June 15 for New England. Representatives of the auto trail associations were not able to formally address the meetings. However, as a compromise, they talked with the Joint Board members. The associations finally settled on a general agreement with the numbering plans, as named trails would still be included. The tentative system added up to 81,000 miles (130,000 km), 2.8% of the public road mileage at the time.

The second full meeting was held August 3 and 4, 1925. At that meeting, discussion was held over the appropriate density of routes. William F. Williams of Massachusetts and Frederick S. Greene of New York favored a system of only major transcontinental highways, while many states recommended a large number of roads of only regional importance. Greene in particular intended New York's system to have four major through routes as an example to the other states. Many states agreed in general with the scope of the system, but believed the Midwest to have added too many routes to the system. The group adopted the shield, with few modifications from the original sketch, at that meeting, as well as the decision to number rather than name the routes. A preliminary numbering system, with eight major east–west and ten major north–south routes, was deferred to a numbering committee "without instructions".

After working with states to get their approval, the committee expanded the highway system to 75,800 miles (122,000 km), or 2.6% of total mileage, over 50% more than the plan approved August 4. The skeleton of the numbering plan was suggested on August 27 by Edwin Warley James of the BPR, who matched parity to direction, and laid out a rough grid. Major routes from the earlier map were assigned numbers ending in 0, 1 or 5 (5 was soon relegated to less-major status), and short connections received three-digit numbers based on the main highway from which they spurred. The five-man committee met September 25, and submitted the final report to the Joint Board secretary on October 26. The board sent the report to the Secretary of Agriculture of October 30, and he approved it November 18, 1925.

Disagreement and refinement, 1925–26

The new system was both praised and criticized by local newspapers, often depending on whether that city was connected to a major route. While the Lincoln Highway Association understood and supported the plan, partly because they were assured of getting the US 30 designation as much as possible, most other trail associations lamented their obsolescence. At their January 14–15, 1926 meeting, AASHO was flooded with complaints.

In the Northeast, New York held out for fewer routes designated as US highways. The Pennsylvania representative, who had not attended the local meetings, convinced AASHO to add a dense network of routes, which had the effect of giving six routes termini along the state line. (Only US 220 still ends near the state line, and now it ends at an intersection with future I-86.) Because US 20 seemed indirect, passing through Yellowstone National Park, Idaho and Oregon requested that US 30 be swapped with US 20 to the Pacific coast.

Many local disputes arose related to the committee's choices between designation of two roughly equal parallel routes, which were often competing auto trails. At their January meeting, AASHO approved the first two of many split routes (specifically US 40 between Manhattan, Kansas and Limon, Colorado and US 50 between Baldwin City, Kansas and Garden City, Kansas). In effect, each of the two routes received the same number, with a directional suffix indicating its relation to the other. These splits were initially shown in the log as—for instance—US 40 North and US 40 South, but were always posted as simply US 40N and US 40S.

The most heated argument, however, was the issue of US 60. The Joint Board had assigned that number to the Chicago-Los Angeles route, which ran more north–south than west–east in Illinois, and then angled sharply to the southwest to Oklahoma City, from where it ran west to Los Angeles. Kentucky strongly objected to this designated route, as it had been left off any of the major east–west routes, instead receiving the US 62 designation. In January 1926, the committee designated this, along with the part of US 52 east of Ashland, Kentucky, as US 60. They assigned US 62 to the Chicago-Los Angeles route, contingent on the approval of the states along the former US 60. But Missouri and Oklahoma did object—Missouri had already printed maps, and Oklahoma had prepared signs. A compromise was proposed, in which US 60 would split at Springfield, Missouri, into US 60E and US 60N, but both sides objected. The final solution resulted in the assignment of US 66 to the Chicago-Los Angeles portion of the US highway, which did not end in zero, but was still seen as a satisfyingly round number. Route 66 came to have a prominent place in popular culture, being featured in song and films.

With 32 states already marking their routes, the plan was approved by AASHO on November 11, 1926. This plan included a number of directionally split routes, several discontinuous routes (including US 6, US 19 and US 50), and some termini at state lines. By the time the first route log was published in April 1927, major numbering changes had been made in Pennsylvania in order to align the routes to the existing auto trails. In addition, U.S. Route 15 had been extended across Virginia.

Much of the early criticism of the U.S. Highway System focused on the choice of numbers to designate the highways, rather than names. Some thought a numbered highway system to be cold compared to the more colorful names and historic value of the auto trail systems. The New York Times wrote, "The traveler may shed tears as he drives the Lincoln Highway or dream dreams as he speeds over the Jefferson Highway, but how can he get a 'kick' out of 46, 55 or 33 or 21?" (A popular song later promised, "Get your kicks on Route 66!") The writer Ernest McGaffey was quoted as saying, "Logarithms will take the place of legends, and 'hokum' for history."

Expansion and adjustment, 1926–1956

When the U.S. numbered system was started in 1925, a few optional routings were established which were designated with a suffixed letter after the number indicating "north", "south", "east", or "west". While a few roads in the system are still numbered in this manner, AASHO believes that they should be eliminated wherever possible, by the absorption of one of the optional routes into another route.

In 1934, AASHO tried to eliminate many of the split routes by removing them from the log, and designating one of each pair as a three-digit or alternate route, or in one case US 37. AASHO described its renumbering concept in the October 1934 issue of American Highways: "'Wherever an alternate route is not suitable for its own unique two-digit designation, standard procedure assigns the unqualified number to the older or shorter route, while the other route uses the same number marked by a standard strip above its shield carrying the word 'Alternate'.'"Most states adhere to this approach. However, some maintain legacy routes that violate the rules in various ways. Examples can be found in California, Mississippi, Nebraska, Oregon, and Tennessee. In 1952, AASHO permanently recognized the splits in US 11, US 19, US 25, US 31, US 45, US 49, US 73, and US 99.

For the most part, the U.S. Routes were the primary means of inter-city vehicle travel; the main exceptions were toll roads such as the Pennsylvania Turnpike and parkway routes such as the Merritt Parkway. Many of the first high-speed roads were U.S. Highways: the Gulf Freeway carried US 75, the Pasadena Freeway carried US 66, and the Pulaski Skyway carries US 1 and US 9.

Interstate era, 1956–present

The Federal Aid Highway Act of 1956 appropriated funding for the Interstate Highway System, to construct a vast network of freeways across the country. By 1957, AASHO had decided to assign a new grid to the new routes, to be numbered in the opposite directions as the U.S. Highway grid. Though the Interstate numbers were to supplement—rather than replace—the U.S. Route numbers, in many cases (especially in the West) the US highways were rerouted along the new Interstates. Major decommissioning of former routes began with California's highway renumbering in 1964. The 1985 removal of US 66 is often seen as the end of an era of US highways.

A few major connections not served by Interstate Highways include US 6 from Hartford, Connecticut, to Providence, Rhode Island and US 93 from Phoenix, Arizona to Las Vegas, Nevada, though the latter is planned to be upgraded to Interstate 11. Three state capitals in the contiguous U.S. are served only by U.S. Routes: Dover, Delaware; Jefferson City, Missouri; and Pierre, South Dakota.

In 1995, the National Highway System was defined to include both the Interstate Highway System and other roads designated as important to the nation's economy, defense, and mobility.

AASHTO is in the process of eliminating all intrastate U.S. Highways less than 300 mi in length "as rapidly as the State Highway Department and the Standing Committee on Highways of the American Association of State Highway and Transportation Officials can reach agreement with reference thereto". New additions to the system must serve more than one state and "substantially meet the current AASHTO design standards". A version of this policy has been in place since 1937.

The 1925 routes
The original major transcontinental routes in 1925, along with the auto trails which they roughly replaced, were as follows:

 * US 1, Fort Kent, Maine, to Miami, Florida: Atlantic Highway
 * US 11, Rouses Point, New York, to New Orleans, Louisiana
 * US 21, Cleveland, Ohio, to Jacksonville, Florida (where it met US 1)
 * US 31, Mackinaw City, Michigan, to Mobile, Alabama
 * US 41, Copper Harbor, Michigan, to Naples, Florida: Dixie Highway
 * US 51, Hurley, Wisconsin, to New Orleans, Louisiana
 * US 61, Canadian border north of Grand Portage, Minnesota, to New Orleans, Louisiana
 * US 71, International Falls, Minnesota, to Baton Rouge, Louisiana (where it met US 61): Jefferson Highway
 * US 81, Canadian border north of Pembina, North Dakota, to Laredo, Texas: Meridian Highway
 * US 91, Great Falls, Montana, to south of Las Vegas, Nevada
 * US 101, Port Angeles, Washington, to San Diego, California: Pacific Highway

 * US 2, Houlton, Maine, to Bonners Ferry, Idaho
 * US 10, Detroit, Michigan, to Seattle, Washington: National Parks Highway
 * US 20, Boston, Massachusetts, to Newport, Oregon
 * US 30, Atlantic City, New Jersey: White Horse Pike, to Salt Lake City, Utah: Lincoln Highway
 * US 40, Atlantic City, New Jersey: Black Horse Pike, to San Francisco, California: Victory Highway
 * US 50, Annapolis, Maryland, to Wadsworth, Nevada (where it met US 40)
 * US 60, Chicago, Illinois, to Los Angeles, California
 * US 70, Morehead City, North Carolina, to Holbrook, Arizona (where it met US 60)
 * US 80, Savannah, Georgia, to San Diego, California: Dixie Overland Highway
 * US 90, Jacksonville, Florida to Van Horn, Texas, (where it met US 80): Old Spanish Trail

US 10, US 60, and US 90 only ran about two thirds of the way across the country, while US 11 and US 60 ran significantly diagonally. US 60's violation of two of the conventions would prove to be one of the major sticking points; US 60 eventually was designated as US 66 in 1926, and later it became a part of popular culture. US 101 continues east and then south to end at Olympia, Washington. The western terminus of US 2 is now at Everett, Washington.

title: United States Numbered Highway System


text:
Talk:Hollow Earth

Expedition
I have no affiliation with the PSF and I was the original contributor of the expedition information. 72.150.123.48 claims that the website contains inaccurate scientific data, but after looking at the PSF website, I found no such claims. Although the website is a bit amateur-ish for a scientific organization, I guess we will find out the truth by July 2007 when this expedition is supposed to take place. I would like to put this section to a vote, but I'm not sure how. Templeofthedog7 02:15, 12 December 2006 (UTC)

 * , so what came out 10½ years ago? --Thnidu (talk) 18:27, 20 January 2018 (UTC)

hollow moon
I wonder if some of the more experienced debunkers might help out with Hollow moon. The theory existed in a highly PoV fashion for several weeks on wp. I had never heard of the "theory" but I looked it up a little, and there's still quite a bit of misinformation out there (mostly on hollow earth pages). For that reason I oppose a delete. Anyone want to step up with some debunking goodness? Charles (Kznf) 22:41, 8 March 2007 (UTC)

 * I did stumble across this and blogged it up and while I don't consider it very likely all I can offer is more details to support the contention. Of course, even the weirdest things need to have balanced coverage I suppose. (Emperor 00:50, 9 March 2007 (UTC))

There was this joke explaining how Space: 1999 was able to explode an Eagle spacecraft at least once every episode. The moon was hollow and filled with these Eagles.

Not NPOV
I don't think that this article is NPOV. It's a huge article explaining various fringe theories and then two paragraphs (poorly) refuting it and a sentence in the introduction saying it's false. The large majority of the article is also unsourced. Perhaps a section could be added on views against Hollow Earth. —  Pious 7  21:36, 7 July 2007 (UTC)

 * You're kidding, right? It's clear from the start of the article that the idea is bunk
 * ("the hypothesis of a Hollow Earth has long been contradicted by overwhelming evidence as well as by the modern understanding of planet formation, and the scientific community now dismisses the notion as pseudoscience") The article discusses what proponents thought and/or argued, it doesn't *support* those ideas. I'm removing the tag. - DavidWBrooks 00:34, 21 August 2007 (UTC)

 * that sentence is missing in current version. I added it back in. Lot49a (talk) 22:29, 21 April 2008 (UTC)

Why should it be NPOV? It's obviously a load of rubbish. Should I make a page about the flying spaghetti monster and demand it be NPOV? This is an encyclopaedia, encyclopaedias are supposed to be educational. How is giving an absolute load of gobbledy-gook such as the hollow-Earth 'theory' a NPOV educational? You people who want balance for balance's sake are absolute idiots.
 * You are responding to a 2 1/2-year-old comment that is no longer relevant to the article. Just thought you'd like to know, because you are, of course, not an absolute idiot. - DavidWBrooks (talk) 16:34, 8 December 2010 (UTC)

 * Just wanted to comment, on the above, very old comment. As much as I may not believe in a hollow earth, and you may find those that do "idiots," it is possible that there are some out there who may believe this kind of thing, or entertain the notion. Such people might find a disparaging comment insulting. Is it likely there are many of them? Probably not. Does consensus equate to reality? No, I do not think that it does. And further, society typically dictates that we should have respect or sensitivity toward the beliefs of others that differ from our own. Or do you think that sensitivity is the rightful reaction to SOME ideas, viewpoints, or theories, and not others?

Note for Michaelbusch
You might want to be more careful in your deletions, and your characterizations of the material deleted. You recently reverted an edit of mine as "misleading and nonsensical." I saw nothing to warrant such a characterization, and so restored it. I notice you have made another deletion with the same characterization, this time of one sentence in the entry preceding my addition to the list. I had edited that entry at the same time I added mine to move the title of the item to a more sensible place; the statement objected to was pre-existing, and having no knowledge one way or another of whether its characterization of some people's belief was accurate I let it stand. Since your problem appears to have been with that sentence, you ought to have limited your original deletion (and characterization) to that sentence alone, and left the valid material alone. Just a little friendly advice.BPK 19:15, 8 September 2007 (UTC)

Notable?
I removed these two paragraphs as they appear to be about an idea of limited notability:

 * In 2001 the Australian father-and-son team Kevin and Matthew Taylor self-published the book The Land of No Horizon (direct link National Library of Australia ISBN 0-646-41057-1). Among other things it proposes an expanding and hollow Earth (as well as other planetary bodies) which eventually reached equilibrium. The book also looks at a range of topics including but not limited to evolution, human physiology, impact craters and other geology in light of such a hollow Earth.

 * Kevin and Matthew Taylor's view of a hollow planet envisages a hollow globe with a small (depending on planet size) central sun ignited by radiation from the inner surface. They use this view both to explain Earth's magnetic field (replacing the dynamo theory) and the origin and ignition of stars.

I refer to WP:FRINGE, WP:V, WP:RS, etc. for why this text doesn't belong in the article.

24.199.99.169 22:54, 29 September 2007 (UTC)
 * Concur. Thanks for catching it. Michaelbusch 23:55, 29 September 2007 (UTC)

Mentioning disclaimers(?)
Regarding Obruchev's Plutonia (and probably other "hollow Earth" books by other authors) - it might be worth noting in the article that the book's author himself did not believe the Earth to be hollow. Obruchev explained in preface that the Earth is hollow in the book only because he wanted to write an educational story about dinosaurs, and there already wasn't much unexplored territory left on Earth for such story to take place. He did, however, recieve considerable amount of correspondence that indicated how few people actually read prefaces.

fiction and culture
I like "references in culture" sections in articles, but this one has gotten way out of hand and should, I think, be removed. It has become an enormous list, which is one of the things that wikipedia is not. I guess the hollow-earth concept is too widespread to be listed out. Instead I think we need a paragraph or two that talks about the fact that it's a commonly used plot device, and that's all.

I thought I'd mention this here first, before making such a drastic change. Any thoughts? - DavidWBrooks (talk) 00:04, 12 December 2007 (UTC)

 * I approve culling the example farm, but a few specific examples should be kept. In particular, Edgar Rice Burroughs' books. Michaelbusch (talk) 01:08, 12 December 2007 (UTC)

 * What should we use to separate the wheat from the chaff, then? Once you let in Edgar Rice Burroughs, why not the scads of other scifi/fantasy authors listed? If we keep any list, we need a good argument to prevent it from growing back to this size. - DavidWBrooks (talk) 01:30, 12 December 2007 (UTC)

 * I would apply common sense and WP:N. Michaelbusch (talk) 02:59, 12 December 2007 (UTC)
 * Which translates into "constantly removing rubbish for the rest of eternity", alas. That's one of the advantages of completely removing a list. - DavidWBrooks (talk) 12:02, 12 December 2007 (UTC)
 * Well, I took out all the comic/cartoon/videogame references. Let's see what happens. - DavidWBrooks (talk) 19:51, 15 December 2007 (UTC)
 * It's creeping back up, two months later - 21 books and 7 "other" references. - DavidWBrooks (talk) 15:54, 26 February 2008 (UTC)

North pole expedition
Some clown named Agnew Brooks is perpetuating the theory and organizing a new North Pole expedition to go inside the earth again. The radio talks and some videos are up on youtube as well. There ought to be a section on it. Its been in a few newspapers as well. —Preceding unsigned comment added by Savuporo (talk • contribs) 17:52, 15 December 2007 (UTC)
 * Brooks Agnew, actually. - DavidWBrooks (talk) 19:52, 15 December 2007 (UTC)

a.k.a The Inner Earth Expedition Part One. This is absolute non sense... :-( --Pascal Boulerie (talk) 17:14, 21 August 2008 (UTC)

admiral byrd's flight
Why is there no information on Admiral Byrd? I've read a great deal about his flight logs and such. —Preceding unsigned comment added by Sir tetra (talk • contribs) 08:00, 19 December 2007 (UTC)
 * Byrd's "lost diary" has been proven to be a myth, but it gets discussed ad nauseum. I think there should be some kind of text mentioning it in this article, and that it's purely a myth. --98.232.181.201 (talk) 03:52, 27 June 2009 (UTC)
 * Regardless of his "lost Diary" having been "proven" to be a myth - which it was not proven beyond a doubt to be a myth, there should ABSOLUTELY be some kind of text in this article about Admiral Byrd, as his information, whether it be lore or fact or in between, was very very popular and he is still talked about to this day, and many consider him to be one of the main modern day references to the subject, then they study further, more verifiable sources. (talk) 11:20, 16 March 2915 (UTC)

Introduction and reference to 15 miles of drilling
"thus direct knowledge of the Earth's structure extends only that far."

That's a misrepresentation of what's meant by "direct knowledge." Information gained from sources other than visual still counts as "direct." I'm changing the wording to "visual," since that's as strong/truthful a description as could be in the context of the article. Ryanluck (talk) 17:00, 1 March 2008 (UTC)

Ufology
Why does the article have a ufology-box at the bottom? I can't see the connection with hollow earth! --83.72.7.63 (talk) 19:40, 9 March 2008 (UTC)

Some branches of UFOlogy maintain that UFOs originate in the hollow of the earth. —Preceding unsigned comment added by 209.78.16.118 (talk) 01:15, 24 March 2008 (UTC)

Books by Adam Seaborn "Symzonia" and Professor Symmes "Symmes theory...."
At one time I owned a store called Cachivaches y otros adefecios ilimitada, a used goods and antique shop in Lima Peru and the two books were sold to me and by me. The Seaborn book was dated 1829 and the Symmes theory of concentric circles proving that the earth is hollow and habitable within was 1832 ie three years after the novel which has stuck in my memory as also the Z in Symzonia. If I remember rightly I mentioned them in a letter to Martin Gardner. Are other copies of the books extant? Prof Symmes has a dedication to the Emperor Napoleon the third by Symmes widow on the fly .92.234.53.41 (talk) 03:20, 20 March 2008 (UTC)

Myths and hints
The oldest claims of the hollow earth are Tibetian myths. Those myths report of 3 openings into the earth: 2 near the poles and 1 in the Himalaya. The Thule society, which was closely known by Adolf Hitler, reported much about those myths. There is even the theory that Hitler ordered a research journey for such an opening in the Antarctica. This theory is based on a speech of admiral Dönitz in front of the German submarine in 1944. During that speech, Dönitz claims, “The German submarine fleet is proud of having built an invinsible fortification for the Führer, anywhere in the world.” During the Nuremberg Trials, Dönitz spoke of “an invinsible fortification, inmidst of the eternal ice.” These are the only serious hints of the theory of the hollow earth.

I request you to discuss this part of the article, which was deleted. I think this is in no way "spiritual" or "esoteric", but rather serious, since I also gave serious sources. What's your opinion? Should this be a part of the article? —Preceding unsigned comment added by 217.185.234.196 (talk) 11:34, 2008 April 20 (UTC)

 * This has apparently been removed and readded before, but I removed this on the basis that 1) It was nonsense 2) It had no sources 3) Donitz never said any of that. If you can find some sources please forgive me and add it in again. :)--Andrews Palop (talk) 11:08, 27 July 2008 (UTC)

There is a serious and reliable source: http://www.hi-story.de/themen/schwab/schwab.htm There is also an English version; a historian writes a serious essay about the myth of the Nazis in Antarctica. There are also the few sentences, my text is about. Please, read this. —Preceding unsigned comment added by 217.185.234.200 (talk) 09:56, 2 August 2008 (UTC)

 * I don't know how serious the hi-story page is, but it has since vanished (took a look with archive.org). If the quote is genuine, I would really like to have it confirmed. The given date varies, sometimes it's 1943 and sometimes 1944. Also, what is not mentioned here is the name he (allegedly) gives the secret base: "Die deutsche U-Boot Flotte ist stolz darauf, dass sie für den Führer in einem anderen Teil der Welt ein Shangri-La gebaut hat, eine uneinnehmbare Festung." A Shangri-La in another part of the world, what would that be supposed to mean? I can think of plenty of explanations other than one in Antarctica and/or inside a hollow Earth, including the simple fact that the U-Boots themselves are (comparably) unreachable, and that the "Teil der Welt" in question would simply be the deep sea. Hexmaster (talk) 12:37, 4 August 2010 (UTC)

Literature
I believe H. P. Lovecraft also wrote a hollow earth story called The Mound, and several others written by him have similar themes. I don't know if you really want the literature section to be any longer, but seeing how there's a reference to a Scrooge McDuck comic in there... 75.209.146.71 (talk) 21:41, 18 May 2008 (UTC)

"The hypothesis of a Hollow Earth has long been contradicted by overwhelming evidence"
It is claimed that there is "overwhelming evidence" which contradicts the hollow earth theory. However there is no evidence cited within the article and there are no links to such evidence. This statement should be removed unless substantiated. —Preceding unsigned comment added by DinosaurDon (talk • contribs) 13:48, 19 September 2008 (UTC) DinosaurDon (talk) 14:03, 19 September 2008

 * Don't remove it, since it's a statement of obvious fact that casual readers need. But you're right: We need, a good short discussion about why the hypothesis runs afoul of modern geological knowledge. Help needed from knowledgeable editors! - DavidWBrooks (talk) 15:14, 19 September 2008 (UTC)

 * "Overwhelming evidence"? All knowledge of what's below the deepest drilling hole (~20 miles, I believe) is based exclusively on seismology measurements and volcanic eruptions. I wouldn't discount this theory just yet.  Hmaier (talk) 02:15, 6 November 2008 (UTC)

Um, the theory also says that the entire universe is contained within what we think of as the surface of the earth. This is completely at odds with ALL astrophysics, geometric understanding, gravity, and so many other things the list would take days to write. The only way this theory is "correct" is if all scientific understanding is incorrect and the universe functions in metaphysical terms instead of physical terms. Such abandonment of rationality is hardly appropriate for an encyclopedia devoted to collecting objective information and presenting it in an organized and intellectual manner. While this belief is certainly influencial in human history and worth of philosophical consideration, it would hardly be appropriate to depict it as any thing other than a disproved notion of a less informed time, like the flat earth theory.98.28.114.217 (talk) 05:37, 2 January 2009 (UTC)

I'm surprised there is no mention of moment of inertia as evidence against a hollow earth. Astronomers define a quantity called the 'moment of inertia factor' defined as the polar moment of inertia divided by the mass and the square of the average radius. For a uniform solid sphere this is 0.4 and for a spherical shell 2/3 or about 0.67. The value measured for the earth is about 0.33, indicating density increases in the interior.Daviddlm (talk) 21:35, 17 June 2021 (UTC)

Newtonian gravity and a hollow Earth
This section explains how inhabitants on the inside would be pulled outwards by the centrifugal force, but does it really work like that? If there is no gravity to pull the inhabitants towards the surface, how would they be affected by the rotation? —Preceding unsigned comment added by 130.243.171.135 (talk) 16:48, 21 October 2008 (UTC)

 * Friction. If you were to bump into the inner surface, friction would start you rotating with the Earth, and then the centrifugal force would push you outwards to bump the surface again, and then friction would pull you some more; this process would continue until you were resting against the inner surface, moving at the same velocity and being pressed very weakly against it.  If there were atmosphere inside the shell, friction would also cause the air to rotate with the Earth, precluding you from simply floating motionless without touching the surface. —Steven G. Johnson (talk) 04:43, 6 November 2008 (UTC)

visual knowledge
What is the case for including this? It seems totally irrelevant to me; we know the Earth isn't hollow.71.240.67.58 (talk) 02:29, 22 November 2008 (UTC)

 * It's a piece of information that answers a question many readers will have. It doesn't interfere with the article, or make it lop-sided - there's information elsewhere about non-visual methods of determining the non-hollowness of the planet. It also doesn't say that visual information is the only information possible. I think it's fine; maybe it could be moved lower down in the story. - DavidWBrooks (talk) 12:18, 27 November 2008 (UTC)
 * I have moved it way down. - DavidWBrooks (talk) 21:21, 2 December 2008 (UTC)

Way too many fiction references
We now have 27 books/stories in the Literature section, which is ridiculous. The point of such sections is to demonstrate that the article topic has a certain presence in popular culture, not to list every such reference in a pointless bludgeon-the-reader attack. This issue was discussed a while ago (it's in the Talk page Archive), with the agreement that we had too many but nobody (including me) ready to pare them down. It has only grown since. So ... what the heck ... i'm going to remove them all and replace them with a summary paragraph, and see what people think. - DavidWBrooks (talk) 21:21, 2 December 2008 (UTC)
 * Argh - I just can't remove those interesting 18th- and 19th-century examples! We need to think of a way to keep those but cut all the recent dross. - DavidWBrooks (talk) 21:26, 2 December 2008 (UTC)

removed fiction items
The "Hollow Earths in fiction" list is still enormous. I just removed a few items, trying to keep them only to fiction about the Earth itself being hollow, not other planets or fake planets - like Dyson spheres (the Halo book), or hollow Moon (Neznaika on the Moon (Незнайка на Луне)), or Matter (2008) by Iain M Banks describes a "shell world" ... the iffiest cut was James De Mille's novel A Strange Manuscript Found in a Copper Cylinder'' (1888) is a Victorian satire, because he thinks he's in a hollow Earth but really isn't. I also removed an "independent sci/fi" film because there are a bazillion independent films out there, maybe that was excessive on my part. - DavidWBrooks (talk) 16:27, 8 January 2009 (UTC)
 * All of this makes sense. If no one can bear to cut things, is it worth splitting off the list? Hollow Earth is a very popular and common theme. Lot   49a talk 18:12, 8 January 2009 (UTC)

 * That's an interesting idea. If we do it, it should cover all hollow-planet stories and movies, not just hollow Earth. Hollow planets in fiction would cover Dyson spheres, I think. - DavidWBrooks (talk) 19:16, 8 January 2009 (UTC)

 * Perhaps better would be Hollow worlds in fiction? "Planet" is too restrictive, it seems to me, excluding moons, etc. And too general, as I think the interest is in inhabited (if only by animals) places, I guess? TomS TDotO (talk) 19:41, 8 January 2009 (UTC)

 * I like Hollow Worlds in Fiction myself. It has a nice ring to it. Lot   49a talk 21:57, 8 January 2009 (UTC)
 * "Worlds" is much better. - DavidWBrooks (talk) 22:43, 8 January 2009 (UTC)
 * I just noticed that there is an article Subterranean fiction. Perhaps the proper thing would be to expand upon that article? TomS TDotO (talk) 15:24, 14 January 2009 (UTC)
 * Perfect! We can do some cut and paste from here to there, then reduce the section here to a few sentences and a "main article" link to Subterranean fiction, and voila. - DavidWBrooks (talk) 17:02, 14 January 2009 (UTC)

Seven months later, I did just that, since nobody seemed to care much. - DavidWBrooks (talk) 19:54, 24 August 2009 (UTC)
 * Ha! I was just coming back here because I remembered about this. Nice work. Lot   49a talk 15:44, 9 September 2009 (UTC)

part about gravity
The part about gravity is entirely incorrect. It's been mathematically proven and well known that gravity on the inside of a sphere would allow you to walk on the outside shell, much like the picture shown. Also, there is no such thing a "centrifugal force." It should not even be mention as it makes no sense. Mbaboy (talk) 01:42, 26 January 2009 (UTC)

 * I agree that the section is probably incorrect, but not quite as you say. Walking on the outermost shell would be the same as walking on a solid sphere of a proportional density.  Inside the shell, its gravitational effects would be cancelled, but one would be able to walk on any inner shells in exactly the same manner.  Centrifugal force does exist, it just depends on your frame of reference. 218.143.30.1 (talk) 08:48, 30 July 2009 (UTC)

The proof that a the gravitational force inside of a hollow shell is zero (from the shell, although other bodies may exert a force) has been well-established since Newton. Your claims are bogus.

As for the centrifugal force, it's a totally standard and useful way to represent motion in a non-inertial reference frame (like a rotating sphere).

— Steven G. Johnson (talk) 01:52, 31 July 2009 (UTC)

It's never been proven that you can walk on the inside of a hollow shell planet solely by gravitational attraction. Newton's Shell Theorem on the other hand demands that the total gravitational potential inside the shell be zero everywhere inside. Also, Newton's law of gravity is formally analogous to the classical law of the electric force. The Shell Theorem applies also to electric fields; the interior of a hollow, spherical, conducting sphere is predicted to have an electrical potential of zero everywhere. This is easily demonstrated, and is commonly demonstrated in college classrooms.

It also doesn't matter if you don't like the term "centrifugal" force. Whatever you call it, it's what presses riders against the interior surface of a common carnival centrifuge. The same would happen inside a hollow, spinning Earth.

Reversion of edits arguing about physics
I have reverted this. There are many things wrong with it: Cardamon (talk) 06:47, 18 September 2009 (UTC)
 * 1) Its tone is argumentative, which is wrong for Wikipedia
 * 2) It is sourced to largely to a web site that is not a wp:reliable reference
 * 3) The website it is sourced to doesn't even support it
 * 4) The physics is incorrect. For example, the center of mass of a hollow uniform spherical  shell is at the center of the sphere.
 * And, most importantly, Wikipedia is not a hosting service for wp:Original Research.

Gravity section
Hi guys,

I've just tried to tighten up the section about the forces experienced by an observer standing on the interior of the shell. I have also moved the last bit, about the observed mass of the Earth, closer to the first bit (about stability reasons for the infeasibility of a hollow Earth) as they seem closer together in spirit than the bit about the forces does to them both. PatBuckles (talk) 23:42, 11 February 2010 (UTC)

 * I think the older version was clearer (it was also shorter, so I'm not sure what you mean by "tighten up"). — Steven G. Johnson (talk) 00:57, 12 February 2010 (UTC)

Hi Steven. I'm sorry to see that you deleted my section. This is what I meant:

-The original version states that 'Someone one the inside would not experience an outward pull' and then contradicts itself a couple of lines later by stating that there would actually be an outward pull due to the the ellipticity of the Earth's surface and the influence of other astrophysical bodies.

-The original version contradicts itself again by saying that one would be 'nearly' weightless and then goes off onto a tangent about the shell-theorem. Only after talking about the shell theorem does it mention why it is 'nearly' weightless and not totally weightless.

The relation between the shape of the shell, the gravity, and the influence of other bodies is not coherently laid out as is.

-It is not true that one instantaneously co-moving with the Earth's rotation at the shell would feel always feel a centrifugal force, hence my comment about the necessity of the person not lying on either of the two points of the shell that meet the Earth's axis of rotation. If one is one the axis of rotation then the is no force. One simply would stay where one was (assuming there is no mass interior to the shell. PatBuckles (talk) 01:40, 12 February 2010 (UTC)

Hi Steven,

Also if you need a bit of help with the physics, this is a good book in my view: `An Introduction To Mechanics' by Kleppner and Kolenkow (McGraw-Hill Inc.,US.). It covers things like Newton's theory of gravity and centrifugal and centripetal forces. PatBuckles (talk) 04:37, 12 February 2010 (UTC)

 * Regarding the first sentence, the addition of the word "significant" fixes the problem with "would not experience an outward pull". "nearly weightless" is correct.  I don't see how the shell theorem is a tangent: it is the reason why a person would be nearly weightless.  Your comment about a lack of coherence is not clear. One still feels a centrifugal force if one is on the axis of rotation assuming that you don't have zero size (though yes, on the axis there is no net force on a symmetrical person), although of course the maximum force is at the equator as stated.  Anyway, this seems like a pointless quibble: the whole point is that the centrifugal force is tiny, even at the equator.  I'm not sure why you think I need "help with the physics"; I'm quite familiar with K&K (I have a PhD in physics). — Steven G. Johnson (talk) 04:41, 12 February 2010 (UTC)

Looks like everybody forgot within the fiction section about Jules Verne book "trip to the center of the earth". —Preceding unsigned comment added by 71.139.14.2 (talk) 04:41, 18 August 2010 (UTC)

Caption for Euler's "thought experiment"
The text itself does not suggest that Euler proposed the earth was that way as a thought experiment. Thus I intend to change the caption to "purported theory"; however I've never heard of this myself (it doesn't fit in with how I envisage Euler) and so have only the main article to go on. Thus, before I do so, I invite comments. Egg Centric (talk) 18:52, 22 January 2011 (UTC)
 * I have subsequently found a pdf here about the subject, suggesting it was indeed a thought experiment. The problem, therefore, lies with the text. I'm not certain what to do at this point. Input, as ever, is welcome. Egg Centric (talk) 18:56, 22 January 2011 (UTC)

Relative density
Nothing here about relative density? Consider that atmosphere has a certain density which life could float on top of, imagining that nothing could live within. 71.198.129.20 (talk) 07:11, 15 March 2011 (UTC)
 * Sorry, not sure I followed that ... could you explain it? - DavidWBrooks (talk) 13:28, 15 March 2011 (UTC)

Noises from inside the earth
I have been studying the Hollow Earth and one of the claims I have come across, is that noises etc have been heard underground. See for example this here: Link

Any opinions? Should we mention this on the article? Earthisalive (talk) 22:24, 19 September 2011 (UTC)
 * I don't really see how claims of noises underground, even if true, are relevant to the article. Similarly, I don't see how claims of single caves or caverns, which are tiny compared to the size of the earth, are all that relevant. Cardamon (talk) 09:27, 20 September 2011 (UTC)

 * Regarding the hollow earth theory, it has many aspects. Not all hollow earth believers claim that the whole of the earth is hollow, some claim just some of it, others just a small part. Theres ancient myths all around the world saying that ancient peoples had originated from coming out of caves from inside the earth. Regarding the noises, if you look at many of the early hollow earth writers (you may not know about them) well many of them have written about noises underground, as evidence for people living inside of the earth or UFOs. Earthisalive (talk) 20:53, 20 September 2011 (UTC)
 * I agree that there are myths concerning underground origins of various peoples, and that  some of them are appropriate.  For example, if I remember correctly (the relevant books are packed in boxes) the Navajos have a myth that their ancestors emerged from a cave, after passing thru the sky of another world.  However, I would suggest that underground cavities smaller than, say, the Chicago Tunnel Company, or the tunnels that Colonel Gaddafi had excavated, would not be appropriate in this article.  (They might be appropriate in some other article).

 * If someone has used reports of caverns or noises or whatever to argue that the earth either is hollow, or has truly extensive systems of tunnels in it, and their argument is notable, we can write about their arguments. But we shouldn't collect reports of odd things underground to support a hollow earth.  That would be getting close to Wikipedia calls wp:synthesis; also there would be the potential of over-filling the article with allegations of odd things underground. Cardamon (talk) 21:43, 20 September 2011 (UTC)

Requested Move
Would there be support to swap this page with Hollow Earth theory since that's what it is? This page should be the redirect, not Hollow Earth theory. Thanks  J e n o v a  20 09:49, 16 April 2012 (UTC)
 * This would go against the established practice of dropping non-essential words from a title, unless a longer form is preferable for some particular reason. There is no habit to include the word "theory" to theories' titles, see e.g. Big Bang. Incnis Mrsi (talk) 11:00, 16 April 2012 (UTC)
 * Fair point, i was using Evolution as my basis but since that title agrees with you i now agree a move wouldn't be appropriate. Thanks  J e n o v a  20 11:13, 16 April 2012 (UTC)

Possible copyright problem
This article has been revised as part of a large-scale clean-up project of multiple article copyright infringement. Earlier text must not be restored, unless it can be verified to be free of infringement. For legal reasons, Wikipedia cannot accept copyrighted text or images borrowed from other web sites or printed material; such additions must be deleted. Contributors may use sources as a source of information, but not as a source of sentences or phrases. Accordingly, the material may be rewritten, but only if it does not infringe on the copyright of the original or plagiarize from that source. Please see our guideline on non-free text for how to properly implement limited quotations of copyrighted text. Wikipedia takes copyright violations very seriously. IRWolfie- (talk) 21:04, 20 June 2012 (UTC)

 * You removed one short-ish declaratory sentence talking about a single book. Even if that's from somewhere else, that's not enough to be a plagiarism issue - and while the book it discusses is looney-tunes, it seems a legitimate addition to the article - so I've restored it. If you can point to an actual location that it's copied from, or if others have a concern, we can discuss it. - DavidWBrooks (talk) 10:56, 21 June 2012 (UTC)

 * Sorry, I am no copyright-specialist. But tell me: Is it really forbidden to simple talk about the mere (?) existence of a book? --185.81.138.26 (talk) 21:14, 16 August 2016 (UTC)

A large is section is copied from http://www.crystalinks.com/hollowearth.html or possibly it's the other way round. WikipediaUserCalledChris (talk) 09:20, 20 December 2016 (UTC) WikipediaUserCalledChris (talk) 09:20, 20 December 2016 (UTC)

Question about the theory
Hi, I have recently heard about this theory while watching the History Channel and I think there are a few technical problems in this theory (fix me if I wrong):

If there is an hollow space between the core to the outer stratum (where we live), provably as a stratum, there might be a few "bridges" which hold those stratums, unless the fact that the outer stratum is in space and the fact the core of earth applies a gravity force, that its field reaches the outer stratum (and the atmosphere) - so the distance between them is always the same and they are both spin at the same speed (and are synchronized to each other).

Other problem might be - in what stratum does the magma located? It should be more near to the core, but this way, according to the theory, volcanos shouldn't have magma inside them and the Tectonic plates shouldn't be affected by the magma. If not, it should be in one of the stratums which are nearer to the outer stratum. Galzigler (talk) 18:03, 20 October 2012 (UTC)

Concave hollow Earth and the "centre" of the Earth
In the Concave hollow Earths section, the very salient point is made that if the distance metric of the universe was configured in an extremely particular way, we would be unable to discriminate between a concave hollow Earth and standard cosmology. Does this mean that if this picture was zoomed out, we should be seeing an outer ring of the crust, an even outer ring for the outer core, and finally the "inner" core stretching out to infinity (from our non-projective point of view), à la azimuthal equidistant projection (where the circumference of the map corresponds to just one point, i.e. the South Pole)? I think this is an interesting consequence of the "theory" but I'm wary of adding it to the section due to WP:NOR concerns. --Anagogist (talk) 11:32, 15 June 2013 (UTC)

shin megami tensei nocturne
In fiction This game has a hollow world map. — Preceding unsigned comment added by RoodNv (talk • contribs) 02:32, 1 November 2014 (UTC)

Verne's A Journey to the Center of the Earth
I haven't read this in a long time. If I remember correctly, Verne imagines a vast underground sea, stretching from Iceland to the Mediterranean, with internal sources of light. I got the impression that he intended a vast cavern, not the interior of a spherical earth, nor the exterior of another spherical body inside. Maybe this article should distinguish cavern narratives from inverted-world hollow earth narratives. 108.48.94.155 (talk) 01:38, 28 October 2015 (UTC)

Split article up!
This article talks about two vastly different theories, one being that planet earth would be hollow, and the other being that the entire universe would be inside-out. Theory #1 is just silly, whereas theory #2 is scientifically irrefutable (but can be refuted by means of Occam's razor). The only thing the two theories have in common is that people mistakenly use the same names for it. Thus, the article should be split up. --79.242.222.168 (talk) 18:29, 10 June 2016 (UTC)

Inaccurate contrary evidence
The contrary evidence saying "The solid sphere is the best way in which to minimize the gravitational potential energy" really only applies to non-rotating matter. The rotation effect creates a centrifugal force that pushes matter to the surface and this would partially counteract the force of gravity. the honeycomb earth theory is based on the effect of both forces Normana400 (talk) 02:47, 14 June 2017 (UTC)

It is technically inaccurate, but really only pedantically. The form that minimizes gravitational potential energy, accounting for pressure and the centrifugal potential, is a solid oblate spheroid. I'll add a clarification. Justin Kunimune (talk) 02:43, 3 January 2020 (UTC)

theory by Amico-Roxas deleted
this section has been deleted: --- The mathematician and physicist Paolo Emilio Amico-Roxas in his books Il problema dello spazio e la concezione del mondo: la teoria endosferica del campo o sistema cosmocentrico (1960) and La suprema armonia dell'universo: la teoria endosferica del campo (1990) he develops a cosmogonic theory partially based on the hollow earth theory but giving a strong scientific basis. With the aims to resolve some problems of standard cosmogony (like energy conservation in an expanding universe), with geometric exactitude the author exposes an alternative cosmogonic model based on non-Euclidean geometry, in whitch the Earth is shaped within an hollow sphere that contains the whole universe and that subject to field laws, but that the human being perceives it as described by standard cosmogony through his own sensory experience. He highlights, according to Einstein's Theory of relativity, that the universe is not Euclidean and the propagation of the light is rectilinear in a non-Euclidean sense (the light rays run on geodetics, which in the Euclidean sense are curviline). Through the application of the transformation by reciprocal vector rays the author shows how it's possible the passage from a convex sphere (called exosphere) to a concave sphere (defined endosphere). ---

NewEnglandYankee deleted it with the follow reason: "OK, I read it two times. It was gibberish the second time, too." So, the question is: beyond the fact that this model is real or not (because in this view the entire wiki hollow earth article could be considered nonsense), it is really gibberish or, is it difficult to understand because some basic physics and mathematics are needed? Amico-Roxas' model of the Earth is essentially based on non-Euclidean geometry, on the physical concept of the field, on the curvature of Einstein's space in which the propagation of light is not straight (the light in this model follows the lines of a field) and on the transformation by reciprocal vector rays, that is used for switching from euclidean to non-euclidean spaces. So, for understand how the model works is needed, at least, to know these:

Non-Euclidean geometry - Field (physics) - Einstein field equations - and for the transformation by reciprocal vector rays: "Liouville, Joseph." Complete Dictionary of Scientific Biography. Encyclopedia.com. (July 7, 2018). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/liouville-joseph also called Circular Inversion (see Inversive geometry) This paragraph need to be reviewed by someone has knowledge of math & physics, because reviewers without that skills should not delete (so lightly) all that they doesn't understand. Is this statement correct? Thanks.

 * Just as importantly, it's a peripheral argument from a single person that has too little importance to be cited in this article. Mathematical models of physical systems are a dime a dozen - a lire a dozen, in this case - and not worthy of mention by themselves unless they've had some impact. - DavidWBrooks (talk) 12:49, 9 July 2018 (UTC)

thanks for your good answer. Reading that (from the article):

--- In one chapter of his book On the Wild Side (1992), Martin Gardner discusses the Hollow Earth model articulated by Abdelkader. According to Gardner, this hypothesis posits that light rays travel in circular paths, and slow as they approach the center of the spherical star-filled cavern. No energy can reach the center of the cavern, which corresponds to no point a finite distance away from Earth in the widely accepted scientific cosmology. A drill, Gardner says, would lengthen as it traveled away from the cavern and eventually pass through the "point at infinity" corresponding to the center of the Earth in the widely accepted scientific cosmology. Supposedly no experiment can distinguish between the two cosmologies.

Gardner notes that "most mathematicians believe that an inside-out universe, with properly adjusted physical laws, is empirically irrefutable". Gardner rejects the concave Hollow Earth hypothesis on the basis of Occam's razor.[48]

Purportedly verifiable hypotheses of a "Concave Hollow Earth" need to be distinguished from a thought experiment which defines a coordinate transformation such that the interior of the Earth becomes "exterior" and the exterior becomes "interior". (For example, in spherical coordinates, let radius r go to R2/r where R is the Earth's radius.) The transformation entails corresponding changes to the forms of physical laws. This is not a hypothesis but an illustration of the fact that any description of the physical world can be equivalently expressed in more than one way.[49] --- At this point I would ask: who decided that this one, that refers to a work made by a single person (Martin Gardner), has enough importance to be cited in this wiki article and is not only one of the "a dime a dozen - a lire a dozen" (as you wrote) of Mathematical models of physical systems? Because the only cited source about Martin Gardner idea is the book itself by him wrote, who decided that it is worthy of mention by themselves or that it has had some impact? Thanks. — Preceding unsigned comment added by 105.155.186.219 (talk) 13:46, 9 July 2018 (UTC)

 * Please sign your posts - type in four tildes at the end. It's very confusing otherwise to know who's saying what, and when. (the SineBot just did it for you, but you should do it yourself.)
 * As for who decides, the people who edit the article decide as we proceed, and that decision may change over time. That's how wikipedia works. So far, you're the only person who thinks this one hypothesis is worthy of mention. Martin Gardner is internationally known and his works have been commented on and reported on and analyzed by many, many people. - DavidWBrooks (talk) 13:51, 9 July 2018 (UTC)

Soapboxing
, and  violated WP:SOAP. Tgeorgescu (talk) 02:54, 8 February 2020 (UTC)

Language problem
Add many languages in this site Sri creation (talk) 12:18, 2 April 2021 (UTC)
 * , click here. Dam222 🌋 (talk) 12:23, 2 April 2021 (UTC)

Start of History Section is not really about "Hollow Earth"
The first section of the "History" section is not about the theory/myth of the whole earth being hollow, but about subterranean spaces of various sort. The name should refer properly only to theories of the Earth being mostly a self-supporting empty shell, without support from some core. I would think that Halley's theory still qualifies because the inner shells would be disconnected from the outer one. --Jorge Stolfi (talk) 05:09, 10 April 2021 (UTC)

Agartha Conspiracy Theory
''Hollow Earth also recurs in conspiracy theories such as the underground kingdom of Agartha and is often said to be inhabited by mythological figures or political leaders. ''

Why is this labeled as a conspiracy theory? The Agartha article simply referrers to this as a legend. 57.135.233.22 (talk) 22:17, 4 November 2023 (UTC)

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Talk:Hollow Earth


text:
Erlenmeyer flask

An Erlenmeyer flask, also known as a conical flask (British English) or a titration flask, is a type of laboratory flask with a flat bottom, a conical body, and a cylindrical neck. It is named after the German chemist Emil Erlenmeyer (1825–1909), who created it in 1860.

Erlenmeyer flasks have wide bases and narrow necks. They may be graduated, and often spots of ground glass or enamel are used where they can be labeled with a pencil. It differs from the beaker in its tapered body and narrow neck. Depending on the application, they may be constructed from glass or plastic, in a wide range of volumes.

The mouth of the Erlenmeyer flask may have a beaded lip that can be stoppered or covered. Alternatively, the neck may be fitted with ground glass or other connector for use with more specialized stoppers or attachment to other apparatus. A Büchner flask is a common design modification for filtration under vacuum.

In chemistry
The slanted sides and narrow neck of this flask allow the contents of the flask to be mixed by swirling, without risk of spillage, making them suitable for titrations by placing it under the buret and adding solvent and the indicator in the Erlenmeyer flask. Such features similarly make the flask suitable for boiling liquids. Hot vapour condenses on the upper section of the Erlenmeyer flask, reducing solvent loss. Erlenmeyer flasks' narrow necks can also support filter funnels.

The final two attributes of Erlenmeyer flasks make them especially appropriate for recrystallization. The sample to be purified is heated to a boil, and sufficient solvent is added for complete dissolution. The receiving flask is filled with a small amount of solvent, and heated to a boil. The hot solution is filtered through a fluted filter paper into the receiving flask. Hot vapors from the boiling solvent keep the filter funnel warm, avoiding the premature crystallization.

Like beakers, Erlenmeyer flasks are not normally suitable for accurate volumetric measurements. Their stamped volumes are approximate within about 5% accuracy.

In biology
Erlenmeyer flasks are also used in microbiology for the preparation of microbial cultures. Erlenmeyer flasks used in cell culture are sterilized and may feature vented closures to enhance gas exchange during incubation and shaking. The use of minimal liquid volumes, typically no more than one fifth of the total flask volume, and baffles molded into the flask's internal surface both serve to maximize gas transfer and promote chaotic mixing when the flasks are orbitally shaken. The oxygen transfer rate in Erlenmeyer flasks depends on the agitation speed, the liquid volume, and the shake-flask design. The shaking frequency has the most significant impact on oxygen transfer.

Oxygenation and mixing of liquid cultures further depend on rotation of the liquid "in-phase", meaning the synchronous movement of the liquid with the shaker table. Under certain conditions the shaking process leads to a breakdown of liquid motion – called "out-of-phase phenomenon". This phenomenon has been intensively characterized for shake flask bioreactors. Out-of-phase conditions are associated with a strong decrease in mixing performance, oxygen transfer, and power input. Main factor for out-of-phase operation is the viscosity of the culture medium, but also the vessel diameter, low filling levels and/or a high number of baffles.

Legal restriction
To impede illicit drug manufacturers, the state of Texas previously restricted the sale of Erlenmeyer flasks to those who have the requisite permits. On September 1, 2019, SB 616 amended the law so that permits are no longer required, but accurate inventory of this and certain other pieces of lab equipment must still be maintained, loss or theft must still be reported, and the owner must still allow audits of their records and equipment to be made.

title: Erlenmeyer flask


text:
Laboratory glassware

Laboratory glassware refers to a variety of equipment used in scientific work, and traditionally made of glass. Glass can be blown, bent, cut, molded, and formed into many sizes and shapes, and is therefore common in chemistry, biology, and analytical laboratories. Many laboratories have training programs to demonstrate how glassware is used and to alert first–time users to the safety hazards involved with using glassware.

Ancient era
The history of glassware dates back to the Phoenicians who fused obsidian together in campfires making the first glassware. Glassware evolved as other ancient civilizations including the Syrians, Egyptians, and Romans refined the art of glassmaking. Mary the Jewess, an alchemist in Alexandria during the 1st century AD, is credited for the creation of some of the first glassware for chemical such as the kerotakis which was used for the collection of fumes from a heated material. Despite these creations, glassware for chemical uses was still limited during this time because of the low thermal stability necessary for experimentation and therefore was primarily made using copper or ceramic materials.

Early modern era
Glassware improved once again during the 14th-16th century, with the skill and knowledge of glass makers in Venice. During this time, the Venetians gathered knowledge about glassmaking from the East with information coming from Syria and the Byzantine Empire. Along with knowledge about glassmaking, glassmakers in Venice also received higher quality raw materials from the East such as imported plant ash which contained higher soda content compared to plant ash from other areas. This combination of better raw materials and information from the East led to the production of clearer and higher thermal and chemical durability leading towards the shift to the use of glassware in laboratories.

Modern era
Many glasses that were produced in bulk in the 1830s would quickly become unclear and dirty because of the low quality glass being used. During the 19th century, more chemists began to recognize the importance of glassware due to its transparency, and the ability to control the conditions of experiments. Jöns Jacob Berzelius, who invented the test tube, and Michael Faraday both contributed to the rise of chemical glassblowing. Faraday published Chemical Manipulation in 1827 which detailed the process for creating many types of small tube glassware and some experimental techniques for tube chemistry. Berzelius wrote a similar textbook titled Chemical Operations and Apparatus which provided a variety of chemical glassblowing techniques. The rise of this chemical glassblowing widened the availability of chemical experimentation and led to a shift towards the dominant use of glassware in laboratories. With the emergence of glassware in laboratories, the need for organization and standards arose. The Prussian Society for the Advancement of Industry was one of the earliest organizations to support the collaborative improvement of the quality of glass used.

Following the development of borosilicate glass by Otto Schott in the late 19th century, most laboratory glassware was manufactured in Germany up until the start of World War I. Before World War I, glass producers in the United States had difficulty competing with German laboratory glassware manufacturers because laboratory glassware was classified as educational material and was not subject to an import tax. During World War I, the supply of laboratory glassware to the United States was cut off.

In 1915 Corning Glassworks developed their own borosilicate glass, introduced under the name Pyrex. This was a boon to the war effort in the United States. Though many laboratories turned back to imports after the war ended, research into better glassware flourished. Glassware became more resistant to thermal shock while maintaining chemical inertness.

Laboratory glassware selection
Laboratory glassware is typically selected by a person in charge of a particular laboratory analysis to match the needs of a given task. The task may require a piece of glassware made with a specific type of glass. The task may be readily performed using low cost, mass-produced glassware, or it may require a specialized piece created by a glass blower. The task may require controlling the flow of fluid. The task may have distinctive quality assurance requirements.

Type of glass
Laboratory glassware may be made from several types of glass, each with different capabilities and used for different purposes. Borosilicate glass is a type of transparent glass that is composed of boron oxide and silica, its main feature is a low coefficient of thermal expansion making it more resistant to thermal shock than most other glasses. Quartz glass can withstand very high temperatures and is transparent in certain parts of the electromagnetic spectrum. Darkened brown or amber (actinic) glass can block ultraviolet and infrared radiation. Heavy-wall glass can withstand pressurized applications. Fritted glass is finely porous glass through which gas or liquid may pass. Coated glassware is specially treated to reduce the occurrence of breakage or failure. Silanized (siliconized) glassware is specially treated to prevent organic samples from sticking to the glass.

Scientific glass blowing
Scientific glass blowing, which is practiced in some larger laboratories, is a specialized field of glassblowing. Scientific glassblowing involves precisely controlling the shape and dimension of glass, repairing expensive or difficult-to-replace glassware, and fusing together various glass parts. Many parts are available fused to a length of glass tubing to create highly specialized piece of laboratory glassware.

Controlling fluid flow
When using glassware it is often necessary to control the flow of fluid. It is commonly stopped with a stopper. Fluid may be transported between connected pieces of glassware. Types of interconnecting components include glass tubing, T-connectors, Y-connectors, and glass adapters. For a leak-tight connection a ground glass joint is used (possibly reinforced using a clamping method such as a Keck clips). Another way to connect glassware is with a hose barb and flexible tubing. Fluid flow can be switched selectively using a valve, of which a stopcock is a common type fused to the glassware. Valves made entirely of glass may be used to restrict fluid flows. Fluid, or any material which flows, can be directed into a narrow opening using a funnel.

Metrology
Laboratory glassware can be used for high precision volumetric measurements. With high precision measurements, such as those made in a testing laboratory, the metrological grade of the glassware becomes important. The metrological grade then can be determined by both the confidence interval around the nominal value of measurement marks and the traceability of the calibration to an NIST standard. Periodically it may be necessary to check the calibration of the laboratory glassware.

Dissolved silica
Laboratory glassware is composed of silica, which is considered insoluble in most substances, with a few exceptions such as hydrofluoric acid. Though insoluble, a minute quantity of silica will dissolve, which may affect high precision, low threshold measurements of silica in water.

Cleaning
Cleaning laboratory glassware is sometimes necessary and may be done using multiple methods. Glassware can be soaked in a detergent solution to remove grease and loosen most contaminations. These contaminations are then scrubbed with a brush or scouring pad to remove particles which cannot be rinsed. Sturdy glassware may be able to withstand sonication as an alternative to scrubbing. For certain sensitive experiments glassware may be soaked in solvents, such as aqua regia or mild acids, to dissolve a trace quantities of specific contaminations known to interfere with an experiment. When cleaning is finished it is common practice to triple rinse glassware before suspending it upside down on drying racks.

Examples
There are many different kinds of laboratory glassware items:

Examples of glassware containers include:
 * Beakers are simple cylindrical shaped containers used to hold reagents or samples.
 * Flasks are narrow-necked glass containers, typically conical or spherical, used in a laboratory to hold reagents or samples. Examples flasks include the Erlenmeyer flask, Florence flask, and Schlenk flask.
 * Reagent bottles are containers with narrow openings generally used to store reagents or samples. Small bottles are called vials.
 * Jars are cylindrical containers with wide openings that may be sealed. Bell jars are used to contain vacuums.
 * Test tubes are used by chemists to hold, mix, or heat small quantities of solid or liquid chemicals, especially for qualitative experiments and assays
 * Desiccators of glass construction are used to dry materials or keep material dry.
 * Glass evaporating dishes, such as watch glasses, are primarily used as an evaporating surface (though they may be used to cover a beaker.)
 * The Petri dish is a flat dish filled with a nutritious gelatin that allows for microorganisms to quickly grow, its named after its inventor Julius Petri in the 1880s.
 * Microscope slides are thin strips used to hold items under a microscope.

Examples of glassware used for measurements include:
 * Graduated cylinders are thin and tall cylindrical containers used for volumetric measurements.
 * Volumetric flasks are for measuring a specific volume of fluid.
 * Burettes are similar to graduated cylinders but have a valve at the end used to disperse precise amounts of liquid reagents often for titrations.
 * Glass pipettes are used to transfer precise quantities of fluids.
 * Glass Ebulliometers are used to accurately measure the boiling point of liquids.

Other examples of glassware includes:
 * Stirring rods are glass rods used to mix chemicals.
 * Condensers are used to condense vapors by cooling them down and turning them into liquids.
 * Glass retorts are used for distillation by heating, they have a bulb with a long curved spout.
 * Drying pistols are used to free samples from traces of water, or other impurities.

title: Laboratory glassware


text:
Beaker

Beaker may refer to:

Containers

 * Beaker (drinkware), a beverage container
 * Beaker (laboratory equipment), a glass container used for holding liquids in a laboratory setting
 * Beaker (archaeology), a prehistoric drinking vessel
 * Beaker culture, the archaeological culture often called the Beaker people
 * Sippy cup, referred to as a beaker in UK English

Other uses

 * Beaker (Muppet), the hapless assistant of Dr. Bunsen Honeydew on The Muppet Show
 * Tracy Beaker, a fictional character
 * Norman Beaker, British guitarist born Norman Hume in 1950
 * Beaker (album), an album by the band 22 Brides
 * Beaker (web browser), a peer-to-peer browser with tools to create and host websites

title: Beaker