# Tell us an interesting random fact you stumbled across (Part 1) **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [April 13, 2020, 3:19am UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-1/851674 "2020-04-13T03:19:22Z")\ **Posts on this page:** 20\ **Page:** 422
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [December 23, 2023, 12:35am UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-1/851674/8431 "2023-12-23T00:35:29Z")
Is “sunk” really the right word? ---
**Author:** ![Elmer\_J.Fudd](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/elmer_j.fudd/32/1211_2.png) [@Elmer\_J.Fudd](https://boards.straightdope.com/u/Elmer_J.Fudd)\ **Post date:** [December 23, 2023, 12:49am UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-1/851674/8432 "2023-12-23T00:49:54Z")
> [@Jack\_Batty](#): > > In space, no one can hear you belch, because if you try you just vomit. Apparently, with gravity, the solids go down and the gases go up, but in zero-G it’s all a big, “chunky bubble,”\* according to one cite I read. I’m dubious. Farts travel downward and except for the rare lapse of judgement, there isn’t a chunky bubble. ---
**Author:** ![Zyada](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zyada/32/3028_2.png) [@Zyada](https://boards.straightdope.com/u/Zyada)\ **Post date:** [December 23, 2023, 2:41am UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-1/851674/8433 "2023-12-23T02:41:04Z")
Farts don’t travel downward, they travel in the direction they’re pused by the intestines. Once they’re out of the body they go staight up ---
**Author:** ![hajario](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hajario/32/171_2.png) [@hajario](https://boards.straightdope.com/u/hajario)\ **Post date:** [December 23, 2023, 2:54am UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-1/851674/8434 "2023-12-23T02:54:25Z")
Even in space? ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [December 23, 2023, 2:55am UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-1/851674/8435 "2023-12-23T02:55:35Z")
More to the point the colon and rectum are amazingly good at separating solids and liquids from gas, something the esophagus is far less skilled at. ---
**Author:** ![Askance](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/askance/32/8281_2.png) [@Askance](https://boards.straightdope.com/u/Askance)\ **Post date:** [December 23, 2023, 2:57am UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-1/851674/8436 "2023-12-23T02:57:37Z")
No shit? ---
**Author:** ![Zyada](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zyada/32/3028_2.png) [@Zyada](https://boards.straightdope.com/u/Zyada)\ **Post date:** [December 23, 2023, 3:08am UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-1/851674/8437 "2023-12-23T03:08:17Z")
Not in space, but Mr. Fudd said they travel downward, which I assumed he was talking about 1G conditions ---
**Author:** ![needscoffee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/needscoffee/32/1076_2.png) [@needscoffee](https://boards.straightdope.com/u/needscoffee)\ **Post date:** [December 23, 2023, 7:00am UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-1/851674/8438 "2023-12-23T07:00:56Z")
> [@Jack\_Batty](#): > > In space, no one can hear you belch, because if you try you just vomit. Apparently, with gravity, the solids go down and the gases go up, but in zero-G it’s all a big, “chunky bubble,”\* according to one cite I read. I find it hard to believe that every time a person in space belches, they vomit. How many times a day does the average person belch? ---
**Author:** ![Pardel-Lux](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pardel-lux/32/20182_2.png) [@Pardel-Lux](https://boards.straightdope.com/u/Pardel-Lux)\ **Post date:** [December 23, 2023, 9:00am UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-1/851674/8439 "2023-12-23T09:00:27Z")
I guess it is not difficult to find out: try belching while doing a handstand. I know you can swallow while doing a handstand, the [peristaltic movement reflex of the esophagus](https://en.wikipedia.org/wiki/Peristalsis#Esophagus) makes this possible. It should not be hard to find out whether peristalsis of the esophagus is strong enough to prevent involuntary regurgitation while fighting negative gravity: if it is, zero gravity should be doable too. Mind you: I am too old and stiff for this. But if somebody tries I’d be curious. ---
**Author:** ![Fiendish\_Astronaut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fiendish_astronaut/32/3295_2.png) [@Fiendish\_Astronaut](https://boards.straightdope.com/u/Fiendish_Astronaut)\ **Post date:** [December 23, 2023, 3:38pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-1/851674/8440 "2023-12-23T15:38:25Z")
> [@Askance](#): > > No shit? 👏 ---
**Author:** ![Pardel-Lux](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pardel-lux/32/20182_2.png) [@Pardel-Lux](https://boards.straightdope.com/u/Pardel-Lux)\ **Post date:** [December 25, 2023, 9:31am UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-1/851674/8441 "2023-12-25T09:31:27Z")
This is so unexpected for me that although [El País](https://elpais.com/ciencia/vacio-cosmico/2023-12-25/que-tiene-de-especial-el-mas-pequeno-de-los-planetas.html) (link in Spanish) is generally reliable I would like to ask @Chronos for confirmation. It is about the duration of Mercury’s day. As an introduction: Mercury’s orbit is a quite excentric ellipse close to the Sun, a Mercury year lasts 88 Earth days and the roation around its axis is such that after two years the planet has completed three revolutions (I guess the article means sideral days and not solar days here). So far nothing really strange. Now it seems, according to the article, that because of the high excentricity of Mercury’s orbit there is a short period of time around its perihelion, when Mercury is closest to the Sun, where for about two Earth days or so Mercury’s orbital speed relative to the Sun “overtakes” its rotational speed around its axis, so that the Sun would seem to go backwards, then forward again. This is explained with Kepler’s Laws, which state that planets move faster when they are closer to the sun. But this does change their sideral rotation rate. The article implies that if you were at the right meridian close to the terminator where the Sun is due to set around the time of the perihelion you would see the Sun touch the horizon, rebound, fall again and set definitively in the course of ~50 hours. And now the article talks about solar days, I reckon, but am not sure. This allegedly happens once every 88 days. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [December 25, 2023, 12:29pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-1/851674/8442 "2023-12-25T12:29:22Z")
If you stand in a different location on Mercury you could see it rise twice. ---
**Author:** ![Pardel-Lux](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pardel-lux/32/20182_2.png) [@Pardel-Lux](https://boards.straightdope.com/u/Pardel-Lux)\ **Post date:** [December 25, 2023, 1:17pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-1/851674/8443 "2023-12-25T13:17:38Z")
And if it is true, it will always happen on the same meridian, or the one 240° East of that, or 480° = 120° East of that, because of the 2:3 resonance, if I am picturing this correctly in my mind. And I think this is interesting because for it to happen the planet in question must be in an orbit with at least an excentricity of x, and very slow rotation rate wrt the length of the year. The slow rotation condition is easier to fulfill for the planets closer to the Sun, but those are the ones with the lowest excentricity - except Mercury. Only Pluto has a higher excentricity, says [NASA](https://nssdc.gsfc.nasa.gov/planetary/factsheet/). ETA: Now I wonder whether Mercury’s famous precession would slowly rotate the meridian in question around the planet and if so, whether this would be an easward or a westward rotation. ---
**Author:** ![Saint\_Cad](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saint_cad/32/18907_2.png) [@Saint\_Cad](https://boards.straightdope.com/u/Saint_Cad)\ **Post date:** [December 25, 2023, 2:31pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-1/851674/8444 "2023-12-25T14:31:44Z")
> [@Pardel-Lux](#): > > his is so unexpected for me that although [El País](https://elpais.com/ciencia/vacio-cosmico/2023-12-25/que-tiene-de-especial-el-mas-pequeno-de-los-planetas.html) (link in Spanish) is generally reliable I would like to ask @Chronos for confirmation. It is about the duration of Mercury’s day. That is absolutely true. In fact along the right line the Sun can rise, set then rise again. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [December 25, 2023, 4:57pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-1/851674/8445 "2023-12-25T16:57:30Z")
That’s not something I was familiar with, but I know how to do the calculations. Can’t right now, though, with Christmas stuff – I’ll get back to you on that. ---
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [December 25, 2023, 6:58pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-1/851674/8446 "2023-12-25T18:58:28Z")
Mercury was more interesting when I was a kid, when it was tidally locked and there was a permanent day side and a permanent night side. ---
**Author:** ![digs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/digs/32/14889_2.png) [@digs](https://boards.straightdope.com/u/digs)\ **Post date:** [December 25, 2023, 7:33pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-1/851674/8447 "2023-12-25T19:33:57Z")
You whippersnappers don’t even remember when the canals of Mars were remnants of glorious cities… ---
**Author:** ![Elmer\_J.Fudd](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/elmer_j.fudd/32/1211_2.png) [@Elmer\_J.Fudd](https://boards.straightdope.com/u/Elmer_J.Fudd)\ **Post date:** [December 25, 2023, 9:24pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-1/851674/8448 "2023-12-25T21:24:08Z")
In high school, a teacher projected the sun through a telescope onto the sidewalk. The shadow of Mercury was about the size of an ant. I really haven’t thought about it since. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [December 25, 2023, 10:07pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-1/851674/8449 "2023-12-25T22:07:40Z")
OK, Mercury’s orbit has a period of 88 days, which means that its average angular orbital rate \omega\_o is 0.0714 radians/day. Its sidereal (relative to the stars) rotational period is two thirds of that, 58.6 days, so an angular rotational rate \omega\_r of 0.1017 radians/day. For an orbit, \omega\_o^2r is a constant, and at its closest, it’s 0.8854 times its average distance. So at that point, its angular orbital rate is 1.06 times the average value, or 0.07588 radians/day. Which is still slower than the rotational rate, so no, you won’t get a Sundance. ---
**Author:** ![Pardel-Lux](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pardel-lux/32/20182_2.png) [@Pardel-Lux](https://boards.straightdope.com/u/Pardel-Lux)\ **Post date:** [December 25, 2023, 10:17pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-1/851674/8450 "2023-12-25T22:17:46Z")
Dang! Thanks for that. Once again El País has let me down, how disappointing (it ussually happens with biology, not astronomy). It’s good to ask someone who knows, but I had expected more from Ms Eva Villaver, whose titles include (as per the linked article she signed) “Director of the Space and Society Office of the Spanish Space Agency, and Research Professor at the Canary Islands Astrophysics Institute”. Space and Society Office sounds strange, come to think about it, wonder what is up with that. Anyway, sorry to you all, that was not an interesting random _ **fact** _ I stumbled across. [Previous page](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-1/851674.md?page=421) [Next page](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-1/851674.md?page=423)