Wikipedia:Reference desk/Archives/Miscellaneous/2022 January 11

= January 11 =

Longest straight flight only in a single nation's airspace plus international waters.
Thinking about the North Korea Missile Launch, I was wondering what nation could do the longest straight flight from a point in their country travelling only over their own country and international waters. The US seems to be able to be one of the best launching from Northern Alaska to the South South East avoiding Easter Island and the Galapagos and ending where the Antarctic Treaty starts 60 degrees south. I guess the Chileans could launch something along a similar track but I don't think it would be that long. Could we get from Western Russia over the pole/Siberia staying north of Japan and ending *somewhere* in the Pacific that would be longer? I'm not sure you can thread the needle down the Atlantic though. (And I don't think Eastern Australia heading west south west and landing near the falklands works.Naraht (talk) 15:26, 11 January 2022 (UTC)


 * WHAAOE: World's longest domestic flight. Clarityfiend (talk) 17:18, 11 January 2022 (UTC)


 * Surely the answer would have to be this path over water, continued across eastern Russia until it hits the border with Mongolia or Kazakhstan. --Amble (talk) 17:55, 11 January 2022 (UTC)


 * WDHAAOE. Okay, I see that this is a theoretical question. So you can start and end in the drink? My guess would be starting just off the coast of Greenland, across Russia and over the Pacific to just off the west coast of the United States or Canada. Clarityfiend (talk) 21:20, 11 January 2022 (UTC)


 * If you had to begin on land, then my Mark I eyeball would say start from Murmansk to maximize the distance across the Pacific. Clarityfiend (talk) 21:32, 11 January 2022 (UTC)


 * That's also what I thought, before I saw the all-water path that I linked. It is quite a remarkable great circle path over water -- it goes from the coast of Pakistan down around Africa and South America, threading inside of Madagascar and Antarctica, then back up the Pacific to Russia. The part of the great circle that's over land is mostly Russia. I would be amazed if it can be beat. Here's another view: . If I understand correctly, this path is already 80% of a great circle continuously over water, and it should be more like 90% once you include the part over Russia. I took the rules to be based on the ballistic missile test scenario, where your launcher is land-based, splashdown is OK, and you just want to be able to tell other countries to mind their own business. --Amble (talk) 21:44, 11 January 2022 (UTC)
 * That's not straight, though. Clarityfiend (talk) 22:44, 11 January 2022 (UTC)
 * Sure it is: it's a great circle, which is a geodesic on the sphere. --Amble (talk) 22:48, 11 January 2022 (UTC)
 * 😲 Clarityfiend (talk) 22:55, 11 January 2022 (UTC)
 * Here's a version where I tried to pick about the best point on the Russia-Mongolia border: . The great circle has a total length of 39941 km, with 36237 km over ocean + Russia, and another 3704 km over Mongolia, Pakistan, and other countries. --Amble (talk) 23:14, 11 January 2022 (UTC)
 * Earth's surface is curved, not flat.[citation not needed] This means the rules of Euclidean geometry don't apply. A geodesic is just a geometry thing: the generalization of "straight line", or shortest distance, to any general geometric surface, including non-Euclidean ones. Suggested reading: . As shown, on a sphere, the angles of a triangle sum up to more than 180 degrees. --47.155.96.47 (talk) 00:56, 12 January 2022 (UTC)
 * If the planet was tilted so that that great circle route was the Equator, what would be the lat/long of the poles? I think one of the poles would be around Bermuda???Naraht (talk) 23:15, 12 January 2022 (UTC)
 * The poles seem to be in the north Atlantic northeast of Bermuda, and near Sydney. Unfortunately the great circle plotting site I used doesn't directly show this, but you can get a good guess by switching to the azimuthal-equidistant map projection. --Amble (talk) 00:34, 13 January 2022 (UTC)
 * I don't see how to switch to the other map projection. Can you put in the URL after you switch?Naraht (talk) 06:27, 13 January 2022 (UTC)
 * "North pole": ; "South pole": . --Amble (talk) 17:35, 13 January 2022 (UTC)
 * Other than seaplanes, don't all flights begin on land? --  Jack of Oz   [pleasantries]  22:11, 11 January 2022 (UTC)
 * No and no. Clarityfiend (talk) 22:49, 11 January 2022 (UTC)
 * OP said missile, not aircraft. Submarine-launched ballistic missiles exist too. --Amble (talk) 22:51, 11 January 2022 (UTC)


 * The most northerly part of Norway is Rossøya, a lot further north than anywhere in Alaska, and Queen Maud Land ends at the South Pole, so assuming that it was a civilian missile (descending harmlessly by parachute) it would be hard to beat I think. It might need some course corrections on the way to keep it over the water, but Norwegians are clever people. Alansplodge (talk) 23:52, 11 January 2022 (UTC)
 * If it needs course corrections, it is not a straight flight. --Lambiam 10:20, 12 January 2022 (UTC)
 * Claims to national territory in Antarctica are not very sturdy. Hayttom (talk) 17:00, 12 January 2022 (UTC)
 * Launch from Thule Island (British) 59°27′S 27°18′W and fly straight East as far as you like. Philvoids (talk) 17:15, 12 January 2022 (UTC)
 * That makes sense. Just pick an island with nothing else along the same longitude and you can circumnavigate the world as many times as you want as long as the fuel lasts. Clarityfiend (talk) 22:09, 12 January 2022 (UTC) Having nothing else along the same latitude would be more helpful. Philvoids (talk) 14:53, 15 January 2022 (UTC)
 * but lines of constant latitude are not straight (except when that latitude is zero). Lines of constant longitude are straight. --Trovatore (talk) 19:41, 15 January 2022 (UTC) : But ? But ? - please rest your cursor on a "But".  Philvoids (talk) 00:39, 16 January 2022 (UTC)
 * but nothing. On a perfect sphere, lines of constant longitude are straight; lines of constant latitude (except the equator) are not.  To fly at a constant latitude going east, you either always have to be banking the plane left (if you're in the Northern Hemisphere) or right (in the Southern).  To fly a line of constant longitude, you don't have to bank it at all. --Trovatore (talk) 17:30, 18 January 2022 (UTC)
 * That's not a "straight line", it's powered flight in a circle. --Amble (talk) 22:28, 12 January 2022 (UTC)
 * Pedantically, every flight is curved, simply because of the curvature of the Earth (plus takeoff and landing). HiLo48 (talk) 06:58, 13 January 2022 (UTC)
 * A great circle path is a straight line in a certain sense &mdash; it's a geodesic in the appropriate manifold. Not only is it the shortest path, but the covariant derivative of the tangent vector is zero, so it keeps the "same direction" in the sense of the intrinsic geometry of the surface.  Try to out-pedantic me, I dare you! --Trovatore (talk) 07:21, 13 January 2022 (UTC)
 * Great-circle navigation gives both the shortest and the longest paths on the surface of a sphere between any given pair of different locations. My proposal to launch from Thule answers the OP's question by flying a less-than-great circle. A geometrically straight flight path would shortly exit the atmosphere so I presume the "longest straight flight in...airspace" can be flown at a constant altitude which means it follows the curvature of the Earth. I anticipate an objection to my infinitely recycling route that keeps returning over the launch site by changing "fly straight East" i.e. 90° to "fly bearing 89° 59' 59". This makes the flight route a tight spiral Rhumb line that never retraces itself and can go a very considerable distance before reaching a non-British airspace. Philvoids (talk) 12:11, 13 January 2022 (UTC)
 * Well, my point is that "geometrically straight" depends on which geometry you're talking about. If you mean the 3D approximately-Euclidean geometry of the containing space, then yes.  But if you mean the 2D geometry of the surface of the Earth (or rather the geoid), then a great circle is a straight line in the appropriate sense. --Trovatore (talk) 19:00, 13 January 2022 (UTC)
 * To make the distinction clearly, "flying straight east" is not "straight" except at the equator (let's assume a spherical Earth for simplicity). If you're in the Northern Hemisphere, to fly straight east, you have to keep turning left.  In the Southern Hemisphere, you have to keep turning right. --Trovatore (talk) 19:06, 13 January 2022 (UTC)

Reggie Kray's glasses - what type/brand were they?
Question as title. If you've seen pictures of him, his glasses had thick lenses and a thick frame, but only along the top. Was discussing this with someone today who said they were "Michael Caine glasses", but they definitely weren't. No, Caine's glasses were thick frames all the way around. Anyone have any idea what Reggie's specs were called? --Iloveparrots (talk) 23:16, 11 January 2022 (UTC)
 * The type is 'browline glasses'. --107.15.157.44 (talk) 23:25, 11 January 2022 (UTC)
 * Hard to believe that Sir Michael is older than the twins. But of course he was born in lovely, leafy Rotherhithe, not awful, 'orrble, 'Aggerston. But Michael must be a bit hard up, as he's putting his own "iconic specs" up for sale. "Not a lot of people know that." Martinevans123 (talk) 18:33, 12 January 2022 (UTC)