# Tell us an interesting random fact you stumbled across (Part 2) **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [July 25, 2024, 3:06pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-2/1004785 "2024-07-25T15:06:02Z")\ **Posts on this page:** 20\ **Page:** 126
**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:** [May 26, 2025, 9:22pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-2/1004785/2501 "2025-05-26T21:22:23Z")
> [@Treppenwitz](#): > > I discovered yesterday that seminal rocker Little Richard was discovered by Sister Rosetta Tharpe. What?? I am incredulous that I didn’t know this. Don’t be. That “fact” always traces back to the liner notes on the record you linked to. None of the tracks are collaborations of the two, and the album is just a clever attempt to introduce Gospel fans to Little Richard and R&R fans to Sister Rosetta. I’m not saying the meeting couldn’t have happened (Richard was peddling snake oil at the time), but nothing written by a label flack should be taken at face value. ---
**Author:** ![Treppenwitz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/treppenwitz/32/3445_2.png) [@Treppenwitz](https://boards.straightdope.com/u/Treppenwitz)\ **Post date:** [May 26, 2025, 9:30pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-2/1004785/2502 "2025-05-26T21:30:28Z")
Goddam. Some things are just too good to be true. 🙁 Thanks for setting me straight. I’ve lost a chunk of faith in Jools Holland. j ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [May 26, 2025, 9:31pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-2/1004785/2503 "2025-05-26T21:31:36Z")
> [@Whack-a-Mole](#): > > Everything in orbit is under constant acceleration. Then how to you explain the accelerometer in orbit measuring zero? > [@Whack-a-Mole](#): > > Maybe we are talking past each other. Yes. I believe you’re using a Newtonian interpretation, in a circumstance that it doesn’t explain the evidence. An object in orbit is following a geodesic. There are no forces on it, and no acceleration. To make the object deviate from the geodesic requires a force be applied to it, and then it will accelerate. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [May 26, 2025, 9:35pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-2/1004785/2504 "2025-05-26T21:35:28Z")
> [@Pleonast](#): > > Then how to you explain the accelerometer in orbit measuring zero? Acceleration in physics (AIUI) is more nuanced than our everyday understanding of “speeding up” (or “slowing down”) - it’s really about any change in the velocity vector, whether that’s magnitude, direction, or both. An object in orbit certainly has a change in its vector at all times in its orbit. ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [May 26, 2025, 9:37pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-2/1004785/2505 "2025-05-26T21:37:23Z")
Compare the accelerometer sitting on a kitchen table. Its motion is not following a geodesic, therefore it is undergoing a net force and it is accelerating. As confirmed by its nonzero measurement. (The net force is electromagnetic from the kitchen table, which is preventing it from falling through the floor, as it’s geodesic path would take it.) ---
**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:** [May 26, 2025, 9:38pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-2/1004785/2506 "2025-05-26T21:38:32Z")
> [@Pleonast](#): > > > [@Whack-a-Mole](#): > > > > Everything in orbit is under constant acceleration. > > Then how to you explain the accelerometer in orbit measuring zero? > > > [@Whack-a-Mole](#): > > > > Maybe we are talking past each other. > > Yes. I believe you’re using a Newtonian interpretation, in a circumstance that it doesn’t explain the evidence. > > An object in orbit is following a geodesic. There are no forces on it, and no acceleration. To make the object deviate from the geodesic requires a force be applied to it, and then it will accelerate. Which gets back to the original controversy: whether gravity, which indeed is bending satellites in circular path, is a “force” as least as far as Newton was concerned. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [May 26, 2025, 9:39pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-2/1004785/2507 "2025-05-26T21:39:29Z")
[Centripetal acceleration](https://courses.lumenlearning.com/suny-physics/chapter/6-2-centripetal-acceleration/) is not acceleration? And the Equivalence Principle does not apply? ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [May 26, 2025, 10:00pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-2/1004785/2508 "2025-05-26T22:00:08Z")
> [@Whack-a-Mole](#): > > An object in orbit certainly has a change in its vector at all times in its orbit. You’re using a Newtonian frame of reference. That works for many things, like most orbital calculations. But it does _not_ explain why the accelerometer in orbit measures zero. For that, you need to use a space-time metric that correctly describes the local geometry. In that geometry, the orbiting object has a constant velocity (both speed and direction). And thus explains the zero measurement. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [May 26, 2025, 10:15pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-2/1004785/2509 "2025-05-26T22:15:12Z")
> [@Pleonast](#): > > But it does _not_ explain why the accelerometer in orbit measures zero. Because the accelerometer is in that same reference frame. The accelerometer reads zero because it’s measuring acceleration relative to its own freely-falling reference frame, not relative to an external inertial frame. ---
**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:** [May 26, 2025, 10:37pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-2/1004785/2510 "2025-05-26T22:37:53Z")
No, it’s not. If things in orbit were accelerating, they’d be traveling in curved paths. They’re not: They’re following geodesics. ---
**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:** [May 26, 2025, 11:24pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-2/1004785/2511 "2025-05-26T23:24:57Z")
If an accelerometer could be constructed entirely of iron and allowed to freely move in a strong magnetic field, would it register acceleration? I say no because all of its atoms would be responding equally to the magnetic field (ideally). There would be no internal strain to register an acceleration. ---
**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:** [May 26, 2025, 11:33pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-2/1004785/2512 "2025-05-26T23:33:38Z")
That would make that an extremely poor design for an accelerometer. ---
**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:** [May 26, 2025, 11:58pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-2/1004785/2513 "2025-05-26T23:58:18Z")
It is pretty confusing, but a geodesic seems to be defined in terms of the old [cone slice](https://storage.googleapis.com/tb-img/production/18/11/cone.PNG) diagram. Whatever your path plane is relative to the gradient, it is a straight line. All of the planets have non-flat orbits (ellipses) which means that, in an outside frame of reference, their speed is observed to change (accelerate inward, decelerate outward) but in the frame of reference of the planet, speed is constant. From my location, I can infer that my speed is changing by triangulating on other reference points, but if there are no reference points, I can only observe my speed to be constant along my geodesic. ---
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [May 27, 2025, 12:17am UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-2/1004785/2514 "2025-05-27T00:17:22Z")
It takes longer for a spacecraft to travel to Mercury than it takes to travel to Saturn. ---
**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:** [May 27, 2025, 12:34am UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-2/1004785/2515 "2025-05-27T00:34:39Z")
Well, depends on how you do it. A Hohmann transfer orbit (the most fuel-efficient orbit that doesn’t depend on interactions with third bodies) from Earth to Saturn takes longer than a Hohmann transfer orbit from Earth to Mercury. But there are other ways that use even less fuel, but do depend on interactions with third bodies. If you’re clever enough (and patient enough-- These orbits can take many cycles around many objects, meaning many years), you can get pretty much anywhere, using only slightly more energy than it takes to get to the Moon. And a Hohmann orbit to Mercury requires more fuel than a Hohmann orbit to Saturn, so there’s more incentive to use one of these clever, slow paths. ---
**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:** [May 27, 2025, 1:06am UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-2/1004785/2516 "2025-05-27T01:06:03Z")
There’s also the [Bi-elliptic transfer](https://en.wikipedia.org/wiki/Bi-elliptic_transfer) which under some circumstances can be more fuel efficient than a straight Hohmann transfer. Also restricting oneself to just the starting body one can use the [Oberth effect](https://en.wikipedia.org/wiki/Oberth_effect) to use delta-v more efficiently; though as you mention at the cost of greater travel time. ---
**Author:** ![Xocomil](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/xocomil/32/14927_2.png) [@Xocomil](https://boards.straightdope.com/u/Xocomil)\ **Post date:** [May 27, 2025, 2:41am UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-2/1004785/2517 "2025-05-27T02:41:49Z")
The Equivalence Principle states that, barring tidal effects, standing on the surface of Earth is equivalent to standing on the floor of a ship accelerating at 9.8 m/s/s and being in free-fall is equivalent to being outside of a gravitational field moving at constant velocity. Yes, astronauts in orbit experience centripetal motion and yet, being in free-fall, they experience no unbalanced force. Their experience is indistinguishable from from astronauts outside a gravitational field moving in a straight line at constant speed. Contrast that with astronauts using their ship’s engine to circle an empty point in space. They experience both centripetal acceleration and an unbalanced force in the direction of the point they’re circling. It would feel to them like the the floor of their ship were accelerating towards them or, conversely, that they were falling towards the floor, away from the point they’re revolving. Gravity’s weird, man. When the only force acting on you is gravity, you feel nothing. We can feel electromagnetism. We can feel the weight on our soles (if not our souls.) Maybe that’s an interesting random fact we stumbled across. Electromagnetism is the only one of the fundamental forces that we can _feel_. ---
**Author:** ![Cheesesteak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cheesesteak/32/3694_2.png) [@Cheesesteak](https://boards.straightdope.com/u/Cheesesteak)\ **Post date:** [May 27, 2025, 11:47am UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-2/1004785/2518 "2025-05-27T11:47:29Z")
We spent the weekend outside gardening and got to watch birds at the bird feeder. We have a few mourning doves in the neighborhood, and were chuckling about how clumsy they seem as fliers, and always make this surprised sounding whistling noise whenever they take off. It’s rather amusing, and you can hear it at the link below. The interesting random fact? The whistle isn’t a vocalization, it’s produced by their wings! [The Mourning Dove Whistle](https://youtu.be/1N9nMkZt1l0?t=101) ---
**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:** [May 27, 2025, 5:50pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-2/1004785/2519 "2025-05-27T17:50:13Z")
> [@Xocomil](#): > > Gravity’s weird, man. When the only force acting on you is gravity, you feel nothing. We can feel electromagnetism. We can feel the weight on our soles (if not our souls.) > > Maybe that’s an interesting random fact we stumbled across. Electromagnetism is the only one of the fundamental forces that we can _feel_. Only because it’s not applied uniformly and simultaneously throughout our body. Hence my multiple references to magnetism. ---
**Author:** ![Bookkeeper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bookkeeper/32/281_2.png) [@Bookkeeper](https://boards.straightdope.com/u/Bookkeeper)\ **Post date:** [May 27, 2025, 9:53pm UTC](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-2/1004785/2520 "2025-05-27T21:53:02Z")
We have mourning doves back again after them being absent for several years (probably due to the large numbers of crows infesting the area). They walk around the porch eating the bird seed that falls from the feeders. I never see them at the feeders, and ground feeding appears to be the norm for most seed-eating pigeon species. It’s nice to hear their cooing in the early morning. Interesting fact - according to the Canadian Museum of Nature, field studies show that Canada has only one exclusively carnivorous species - polar bears, and only one exclusively vegetarian species - groundhogs. Caribou are normally herbivorous, but will eat lemmings when they migrate in large numbers. I have seen chipmunks happily chow down on caterpillars they have found. [Previous page](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-2/1004785.md?page=125) [Next page](https://boards.straightdope.com/t/tell-us-an-interesting-random-fact-you-stumbled-across-part-2/1004785.md?page=127)