Explain xkcd: It's 'cause you're dumb.
Title text: We actually divorced once over the airplane/treadmill argument. (Preemptive response to the inevitable threads arguing about it: you're all wrong on the internet.)
This comic shows Cueball and his significant other undergoing a domestic dispute. The debate is heated, enough to tear apart a romantic relationship, and although the end result is Cueball being thrown out of his other's house he resolves that he will stand by his point of view no matter what.
Of course, in the last panel we learn that the argument is over something that should be, in the context of romance, utterly trivial: Cueball has been thrown out simply because he believes that Pluto should never have been a planet.
Pluto was the ninth planet in our solar system between 1930 and 2006, during a time when "planet" had no formal definition. (Jupiter was thought to be the ninth planet from 1807 to 1845.) In 2006 the IAU created a formal definition for "planet"; Pluto didn't make the cut, and was swiftly reclassified as a dwarf planet. The reasons are complicated, but the basic issue is that like Ceres, Pallas, Juno, and Vesta, Pluto is too small to function as a planet in the solar system. Here is a good explanation.
In the title text, the airplane/treadmill argument starts when someone asks whether an airplane can take off while it is on a treadmill that is opposing its progress (pulling it backward). The question usually leads to arguments because it is posed ambiguously. Properly defining the question shows that the airplane can indeed take off (because its forward motion is provided by its propeller/jet engine, not its wheels, which are free to spin at any speed) and experiments (such as Mythbusters') bear this out. Randall also takes a crack at the issue here, and more info can be found here.
The statement about being wrong is likely a reference to 386: Duty Calls
- [Cueball laying on sidewalk outside a house, surrounded by his belongings.]
- She threw me out yelling, "You don't say those words. Not in this house."
- It's been two years. I thought the wounds had healed.
- But I stand by what I said.
- Pluto never should have been a planet.
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The explanation says: "... Pluto has been the ninth planet in our solar system until 2006 ...".
It should says 'the tenth' isn'it?
SioD (talk) 14:52, 30 August 2013 (UTC)
- Pluto was discovered in 1930, and has been since the ninth body to be discovered and classified as a "planet". The sentence is a temporal rather than spacial reference, if that clears up any confusion. Thokling (talk) 12:04, 24 September 2013 (UTC)
- Actually, no. Using the temporal definition, Pluto would be number 13. It was discovered after Ceres, Pallas, Juno and Vesta, which were discovered, named and classified, but then quickly demoted, all about 120 years before Pluto. This was due to the fact that telescopes of the day were strong enough to see quite a bit of the asteroid belt in a relatively short time, unlike with the "previously mythical" Kuiper belt.
- Also, if any thing, the spacial discrepancy should be between eighth and ninth, as Pluto's orbit is squeezed enough to be inside that of Neptune, but long enough to extend outside it. Charon, Pluto's "moon" may cause additional worry, but is usually ignored.
- Anonymous 01:11, 4 December 2013 (UTC)
- I think this interpretation is a bit deliberately obtuse. Ceres wasn't considered a planet at the same time that Pluto was, so Pluto was indeed the ninth planet for a period of time. There is no confusion here.
- On another note, the Dawn and New Horizons probes have now given us a large world covered in volatiles and weather, with internally driven geology, and a smaller, more obviously non-spherical cratered ball of rock. A common sense definition of a planet would probably leave Ceres out. As for Vesta, nobody has ever considered that a planet, not even the "Pluto should still be a planet" crowd. Again, being deliberately contrarian doesn't usually shed any light on scientific questions. 188.8.131.52 03:38, 18 April 2016 (UTC)
- I think we would all be happy if the astronomers would come up with a definition of a planet that reasonably included Pluto but reasonably excluded the other 'candidates' that have been found so far. You know, the ones without large moons. Or Pluto could just be grandfathered in. Exactly how would science be held back by this?? 184.108.40.206 00:00, 4 January 2014 (UTC)
- You don't think they tried to find a standard that included Pluto and excluded the others? Also grandfathering makes the idea of making a standard definition useless. 220.127.116.11 (talk) (please sign your comments with ~~~~)
The airplane/treadmill question is actually hard to define properly. In real case scenario, the plane would of course take off, but you can keep it in place if you assume really fast treadmill (much faster that the plane), friction in airplane wheels and that those wheels won't break off, catch fire or otherwise get destroyed under the stress much higher they are developed for. Oh, wait, actually the airplane WONT take off if the wheels break. :-) -- Hkmaly (talk) 12:01, 5 December 2013 (UTC)
- If you choose to model friction in the wheels, it would be simpler to model the airplane with NO wheels, and then ask whether it could take off. Well, 'Airplane!' notwithstanding, it couldn't. But that's not an interesting problem, right? And neither is the variation with friction in the wheels. 18.104.22.168 23:54, 3 January 2014 (UTC)
- Odd that carrier decks still have to be so long. In fact launching them from podiums would allow the use of on-deck hangars.
- Anyone know if this applies to helicopters?
I used Google News BEFORE it was clickbait (talk) 02:14, 31 January 2015 (UTC)