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Could a single O'Neill Cylinder function on its own? —Preceding unsigned comment added by 76.184.133.222 ( talk) 02:18, 9 April 2010 (UTC)
Given the stated dimensions of 32km length and 4km radius, the hull of one of the cylinders would have a surface area of 900km2. Very conservatively assuming that a 1 m2 section of a cylinder has a mass of 1 tonne, and disregarding the mass of the contained air, a single cylinder would have a mass upwards of 900 million tonnes. This represents the LEO lifting capacity of 45 million Ariane V launchers. The biggest spacecraft ever seriously proposed, the H-Bomb-propelled "Super Orion", would require 112 round-trips to lift that much material. Assuming a space elevator could reduce the cost of lifting material to GEO to $10/kg, lifting one cylinder's worth would cost $9 trillion.-- 174.118.10.147 ( talk) 09:12, 21 February 2011 (UTC)
Shouldn't the sentence "They rotate so as to provide artificial gravity via centrifugal force on their inner surfaces," instead list "centripetal force"? On its article page, centrifugal force is listed as "represent[ing] the effects of inertia that arise in connection with rotation and which are experienced as an outward force away from the center of rotation." In other words, centrifugal is the motion after an object in centripetal motion is released- the motion tangential to the point of release along the circular path of motion. 68.10.137.78 ( talk) 02:05, 27 May 2011 (UTC)
Would it be enough to protect against a super flare, like the one that occurred in 1859? 108.23.147.17 ( talk) —Preceding undated comment added 06:57, 30 September 2011 (UTC).
Not only the numbers sounded really exotic, since 24kg of steel per square metre means a mere 3 mm total thickest since a cubic metre of steel is 7800 kg and 24/7800 of a metre is about 3mm. It is essentially comparing apple with oranges. It is also using the most inefficient design (island 1) as a compare.(which does not even have even distribution of gravity.) Having a chain of small balls also pose a very inconvenient traveling infrastructure, and the essential materials needed to build an equivalent living area of an island 3 is likely to be much more with added material for connection, travel, radiation shielding and safety issues. If you need the most flat surface area from such a ball, you get a 314 square metre from each(no one wants to live on a curved 10 metre diameter surface.). The Island 3 gives you a total of 804 square kilometre area, and 402 minus the "rivers", which is 402000000 square metre, and one would need 1280649.2 balls(10m diameter) to have the same comparison. If each ball really only need 24 kg of steel per square metre (which I assume to be related to surface area, and surface area of a 10m ball is about 1257 square metre), each will weight about 30 tons(rounded down), so the complete structure, with same living area(but much less radiation shielding and safety net since you are holding 314 square metre of objects with 3mm walls) will weight about 1280650 X 30 (you can't have 0.2 of a ball in the chained structure), 38419500 metric tons. (if the island 3 had a 10 metre thick hull, it would weight something like 62712000000 metric tons though) This is without and structural weight to sustain the chain, and you need structural weight between each ball to sustain about 300kN+double of its own weight of force for a static loading, safety factor of 1, that is another few cubic metres of steel per ball(needed for both sides), and now you really need to thicken the walls of the balls since the 3mm thickness cannot sustain the force between each ball. Since the claim is so exotic, you need an extremely reliable source to support it. (see WP:OR, WP:RS and WP:undue as well) I was just about to ask for a source with a citation tag, but the 3mm thickness really worries me and seemed unrealistic, so I am hiding the whole section before anyone can give a reliable source. Also, think carefully why could someone build a 10 metre thick hull structure with a 3mm thick hull. —Preceding signed comment added by MythSearcher talk 15:18, 11 December 2011 (UTC) P.S. a 3mm hull would also have a really great loss of air and water. The more you think about it, the more you feel like that section was written by someone with minimal knowledge of craft/building design, or I must have made an error up there. —Preceding signed comment added by MythSearcher talk 15:30, 11 December 2011 (UTC)
An O'Neill Tube can be seen in level 4 of the SNES game Super Earth Defense Force. For example, skip to about halfway through this video: http://www.youtube.com/watch?v=dJCt1F2dEzM
I wasn't sure whether it was kosher to post a screenshot of the game as fair use, or if it would even be considered a good addition to the article, so I'm just mentioning it here instead. -- 24.22.37.178 ( talk) 04:56, 7 May 2012 (UTC)
The Citadel in Mass Effect is an example of an O'Neill Cylinder. This section may be possible.
Blumin (
talk) 00:26, 5 June 2012 (UTC)
This is the
talk page for discussing improvements to the
Island Three redirect. This is not a forum for general discussion of the article's subject. |
Article policies
|
Find sources: Google ( books · news · scholar · free images · WP refs) · FENS · JSTOR · TWL |
This redirect does not require a rating on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||||||||||||||||||||||||
|
Could a single O'Neill Cylinder function on its own? —Preceding unsigned comment added by 76.184.133.222 ( talk) 02:18, 9 April 2010 (UTC)
Given the stated dimensions of 32km length and 4km radius, the hull of one of the cylinders would have a surface area of 900km2. Very conservatively assuming that a 1 m2 section of a cylinder has a mass of 1 tonne, and disregarding the mass of the contained air, a single cylinder would have a mass upwards of 900 million tonnes. This represents the LEO lifting capacity of 45 million Ariane V launchers. The biggest spacecraft ever seriously proposed, the H-Bomb-propelled "Super Orion", would require 112 round-trips to lift that much material. Assuming a space elevator could reduce the cost of lifting material to GEO to $10/kg, lifting one cylinder's worth would cost $9 trillion.-- 174.118.10.147 ( talk) 09:12, 21 February 2011 (UTC)
Shouldn't the sentence "They rotate so as to provide artificial gravity via centrifugal force on their inner surfaces," instead list "centripetal force"? On its article page, centrifugal force is listed as "represent[ing] the effects of inertia that arise in connection with rotation and which are experienced as an outward force away from the center of rotation." In other words, centrifugal is the motion after an object in centripetal motion is released- the motion tangential to the point of release along the circular path of motion. 68.10.137.78 ( talk) 02:05, 27 May 2011 (UTC)
Would it be enough to protect against a super flare, like the one that occurred in 1859? 108.23.147.17 ( talk) —Preceding undated comment added 06:57, 30 September 2011 (UTC).
Not only the numbers sounded really exotic, since 24kg of steel per square metre means a mere 3 mm total thickest since a cubic metre of steel is 7800 kg and 24/7800 of a metre is about 3mm. It is essentially comparing apple with oranges. It is also using the most inefficient design (island 1) as a compare.(which does not even have even distribution of gravity.) Having a chain of small balls also pose a very inconvenient traveling infrastructure, and the essential materials needed to build an equivalent living area of an island 3 is likely to be much more with added material for connection, travel, radiation shielding and safety issues. If you need the most flat surface area from such a ball, you get a 314 square metre from each(no one wants to live on a curved 10 metre diameter surface.). The Island 3 gives you a total of 804 square kilometre area, and 402 minus the "rivers", which is 402000000 square metre, and one would need 1280649.2 balls(10m diameter) to have the same comparison. If each ball really only need 24 kg of steel per square metre (which I assume to be related to surface area, and surface area of a 10m ball is about 1257 square metre), each will weight about 30 tons(rounded down), so the complete structure, with same living area(but much less radiation shielding and safety net since you are holding 314 square metre of objects with 3mm walls) will weight about 1280650 X 30 (you can't have 0.2 of a ball in the chained structure), 38419500 metric tons. (if the island 3 had a 10 metre thick hull, it would weight something like 62712000000 metric tons though) This is without and structural weight to sustain the chain, and you need structural weight between each ball to sustain about 300kN+double of its own weight of force for a static loading, safety factor of 1, that is another few cubic metres of steel per ball(needed for both sides), and now you really need to thicken the walls of the balls since the 3mm thickness cannot sustain the force between each ball. Since the claim is so exotic, you need an extremely reliable source to support it. (see WP:OR, WP:RS and WP:undue as well) I was just about to ask for a source with a citation tag, but the 3mm thickness really worries me and seemed unrealistic, so I am hiding the whole section before anyone can give a reliable source. Also, think carefully why could someone build a 10 metre thick hull structure with a 3mm thick hull. —Preceding signed comment added by MythSearcher talk 15:18, 11 December 2011 (UTC) P.S. a 3mm hull would also have a really great loss of air and water. The more you think about it, the more you feel like that section was written by someone with minimal knowledge of craft/building design, or I must have made an error up there. —Preceding signed comment added by MythSearcher talk 15:30, 11 December 2011 (UTC)
An O'Neill Tube can be seen in level 4 of the SNES game Super Earth Defense Force. For example, skip to about halfway through this video: http://www.youtube.com/watch?v=dJCt1F2dEzM
I wasn't sure whether it was kosher to post a screenshot of the game as fair use, or if it would even be considered a good addition to the article, so I'm just mentioning it here instead. -- 24.22.37.178 ( talk) 04:56, 7 May 2012 (UTC)
The Citadel in Mass Effect is an example of an O'Neill Cylinder. This section may be possible.
Blumin (
talk) 00:26, 5 June 2012 (UTC)