#inertial reference frames

[couchnapping]

Monster mass times the speed of light squared

[rabbiteclair]

i think if two people named Alice and Bob meet face-to-face there should be a law that they have to immediately perform some kind of wild scientific thought experiment

like oh hey guys. thanks for coming to my party. forgot about the name thing though, haha. so like, yeah, now I need to fire you both into space at the speed of light. in different directions. don't worry you'll have walkie-talkies. there's this guy who wants to listen to your messages from a different inertial reference frame. yeah it's some relativity shit, I've never been good at explaining it. anyway, get in the cannons. yeah sure you can grab a Sprite first I guess

[sexhaver]

oh so just now since trump is president suddenly non-inertial reference frames aren’t “real??” smh i thought you were woke for real

centrifugal force literally isn't a real sexual orientation

[vagabond-umlaut]

fictitious force

▸ each fic in this series is connected, but can be read as a stand-alone too! :)) ▸ please don't spam like and reblog! enjoy reading! <3 ▸ masterlist

summary:

fictitious force:  a force that appears to act on a mass whose motion is described using a non-inertial frame of reference, such as a linearly accelerating or rotating reference frame; invoked to maintain the validity and thus use of newton's second law of motion, in frames of reference which are not inertial.

a non-linear collection of oneshots depicting the 'relationship' between the world's strongest sorcerer and his somewhat strange, mostly ordinary, darling kouhai— the story starting in the days of their youth and continuing well into their adulthood.

tags: gojo satoru x fem!reader; one-sided enemies to lovers; both canon-compliant & not, simultaneously; fluff & angst; humor; hurt/comfort; manga spoilers!!; gojo satoru is his own warning; whipped!gojo; pining!gojo; you too deserve your own warning out here... but i really love this fic's reader so i won't give you one; developing relationship; it's funny how you're the strongest inhibitor to the former!!; winner x loser dynamics... but no one knows who is which. not even you or gojo; non-linear narrative; time skips

⁕ a battle well begun is the war half won gojo notices you. you notice gojo. [the boy wants your eyes on him at all times.]

⁕ tempest in a teapot gojo finds nothing more delightful than seeing your annoyed frown in the middle of a storm— why should he need the sun to break through the gloomy clouds, when you're right there in front of him, huh?

⁕ chitter-chatter [TEXTS SMAU]

⁕ for love is flesh, it is a flower flooded with blood you're ravishing while gojo is ravenous— rabidly so.

⁕ chitter-chatter (ii) [TEXTS SMAU]

⁕ chitter-chatter (iii) [TEXTS SMAU]

[lets-steal-an-archive]

John: Hey, Bush is now at 37% approval. I feel much less like Kevin McCarthy screaming in traffic. But I wonder what his base is --

Tyrone: 27%.

John: ... you said that immediately, and with some authority.

Tyrone: Obama vs. Alan Keyes. Keyes was from out of state, so you can eliminate any established political base; both candidates were black, so you can factor out racism; and Keyes was plainly, obviously, completely crazy. Batshit crazy. Head-trauma crazy. But 27% of the population of Illinois voted for him. They put party identification, personal prejudice, whatever ahead of rational judgement. Hell, even like 5% of Democrats voted for him. That's crazy behaviour. I think you have to assume a 27% Crazification Factor in any population.

John: Objectively crazy or crazy vis-a-vis my own inertial reference frame for rational behaviour? I mean, are you creating the Theory of Special Crazification or General Crazification?

Tyrone: Hadn't thought about it. Let's split the difference. Half just have worldviews which lead them to disagree with what you consider rationality even though they arrive at their positions through rational means, and the other half are the core of the Crazification -- either genuinely crazy; or so woefully misinformed about how the world works, the bases for their decision making is so flawed they may as well be crazy.

John: You realize this leads to there being over 30 million crazy people in the US?

Tyrone: Does that seem wrong?

John: ... a bit low, actually.

Lunch Discussions #145: The Crazification Factor (October 07, 2005)

[whirligig-girl]

just had a really cool KSP experience. My friend was playtesting my WIP KSP mod and doing a mission to Rival, a moon of the coorbital gas giant Omen. And they hadn't played KSP in a while (even though they've been modding it for as long as I have been), and they'd never played with the Principia n-body mod, so it turned into a kind of Mission Control dynamic with me and the other members in the voice call helping them through the mission.

And I felt so much satisfaction when that little rover successfully touched down on the surface of Rival, like more than I think I could have if i had been piloting the mission directly.

There were so many cool moments, like using the unstable edge of Omen's gravity well in Principia to bounce off of to reverse a retrograde orbit, and trying to think about the same trajectory in multiple different reference frames. In particular, the reference frames used comprised Gymnome Centric Rotating, Gymnome Centric Inertial, Omen-ZwoNmu-Orbit, Omen Centric Inertial, Rival-Omen-Orbit, and Rival Centric Rotating.

[max1461]

Why don't we feel the acceleration of the Earth around the sun though? Or our acceleration around the center of the Earth? Like how come it looks like we're in an inertial reference frame for Earth-based experiments if we aren't?

[bad-time-analogies]

The widely cited factoid that the speed of light is constant regardless of velocity is true, but only in a vacuum. In other cleaning implements, the story is more complicated. In a broom, the speed of light varies from 0.996c at the handle to 1.545c at the bristles. Mops are identical to brooms in this regard, but the bucket can have light speeds as slow as 0.771c.

This has strong implications for the speed of time: if the speed of light differs from one location to another, waveforms of light would distort around brooms, mops, and other cleaning devices. But this is not what has been observed, for light appears to travel in straight lines around all but the most massive of brooms. Therefore, the speed of time must accelerate to accommodate the speed of light. This is why cleaning appears to take forever from an inertial reference frame.

[yesterdays-xkcd]

You spin me right round baby, right round, in a manner depriving me of an inertial reference frame. Baby.

Centrifugal Force [Explained]

Transcript Under the Cut

[James Bond, drawn as Cueball, is strapped to a giant wheel suspended from the ceiling. Black Hat is standing next to two levers.] Black hat: How do you like my centrifuge, Mister Bond? When I throw this lever, you will feel centrifugal force crush every bone in your body.

[Same scene, but a closer shot.] Bond: You mean centripetal force. There's no such thing as centrifugal force. Black hat: A laughable claim, Mister Bond, perpetuated by overzealous teachers of science. Simply construct Newton's laws in a rotating system and you will see a centrifugal force term appear as plain as day.

[Closer shot, only Bond's head is visible.] Bond: Come now, do you really expect me to do coordinate substitution in my head while strapped to a centrifuge? Black hat: No, Mister Bond. I expect you to die.

[avonne-writes]

WIP ask game!!!

RULES: make a new post with the names of all the files in your WIP folder, regardless of how non-descriptive or ridiculous. let people send you an ask with the title that most intrigues them, and then post a little snippet or tell them something about it! then tag as many people as you have WIPs.

I was tagged by @nicijones and @bucking-mustangs-with-wings 💕 I'm not sure how interesting these WIP titles are, and I actually have more ideas than documents already started, but feel free to send me an ask if you're interested in any of these!

Current WIPs in my folder:

HS AU 5+1 (in progress on AO3)

HS AU Georgia's POV

Inertial frame of reference

TA AU

Clubbing AU

Subspace fic 2

I won't tag anyone this time, but please feel free to play! 🩷

[wordsandrobots]

IBO reference notes on . . . the aesthetics of the mobile frame

I'm having a rough time writing this week (I just need to torture Gaelio some more, why is this so haaaard?!) so here's something to keep my hand in regardless. I had a couple of posts planned on the mobile suits of the Post Disaster setting, one about the meanings applied to Gundams – which I shall complete at some point because it's interesting – and one ranking the various 'suits using criteria such as 'excellent round boy, no notes' – which I'm likely to ditch because it's quite boring. But thinking about that got me considering the reasons I clicked hard with IBO's art direction in the first place. So let's look into why it causes my brain to make so many pleasing whirring noises.

A distinction that makes a difference

To start with, this is in contrast to other Gundam series' aesthetics. While I have a certain fondness for the Gundam Wing designs and I enjoy the way the Dauntless, Valiant, etc. reimagine the Universal Century stalwarts for Gundam X, most iterations' mobile suits are firmly 'OK' for me. Neither very interesting, nor something I find anything in to especially dislike.

Iron-Blooded Orphans, however, introduces a concept that sets it apart: the mobile frame. That is, each mecha is built around a base skeleton that is the 'true' machine; everything else is modular and interchangeable. As far as I can tell, this is the only series in the franchise to do this. Other Gundam shows expose inner workings from time to time, but these are usually unique to a particular model of 'suit. Whereas in IBO, multiple different types of 'suit can share the same kind of frame.

Moreover, the fact they are built around an inner frame is made explicit in the art, so the 'suits look – slightly daft as it may sound – much more mechanical than, say, your average UC mecha. These are things approximating the human form, not something you can replicate with a guy in a costume, and that makes them appear somewhat less fanciful and slightly more like actual military hardware.

Which is a cheat, obviously. It's tweaking a genre convention to fit a particular tone: this is not a show in which 'suits are going to start magically bending time and space; it's the one in which they beat seven shades of brick-dust out of each other with giant lumps of metal. Fundamentally, these are no less silly than the more 'filled in' designs that came before. It just appeals to me to see the illusion being given extra depth.

But there's more to it than that.

Atoms of design

Several different types of mobile frame appear in IBO – eight, to be exact: Rodi, Hexa, Gundam, Valkyrja, Geirail, Graze, Teiwaz/Io, and Reginlaze (I count the Teiwaz and Io frames as one since they are functionally identical). These are all visually distinct and easy to distinguish when placed in the finished mobile suits. Yet they also share a common root element: the Ahab reactor.

Most Gundam shows have some sort of wibble-physics black-box to explain why giant humanoid robots are a sensible means of warfare. In the P.D. timeline, this takes the form of 'Ahab particles' that are generated by some form of quantum nonsense inside a drum-shaped reactor. The particles create pseudo-gravity and EM waves that interfere with communications and tracking, and the reactors are effectively infinite batteries, so we get artificial gravity and inertial control, comms black-outs and stealth in space, and the necessary wattage to power a mecha, all for the price of one.

That's the technobabble, anyway. Practically speaking, the Ahab reactor is a design element that must be integrated into each of the mobile frames. And I love this. I love setting arbitrary little rules and using them to create a coherent aesthetic. Because now each frame needs to have a big drum shape in it somewhere (or two, to create the Gundam frame's unique silhouette). A unifying commonality that still permits wide variation.

It's not always necessary to have designs reflect a concept of shared technology. That depends on what the story is doing. Witch From Mercury, for example, explicitly has multiple branches of mobile suit design on display at once, to delineate between 'suits produced by different companies. However, I enjoy the way IBO emphasises that the various mecha are all applications of the same base technology, especially as it gets at something easy to overlook about how the world is set up.

You see, while the Gundams get the reputation as these massively powerful weapons from a lost past, that is true of the majority of non-Gjallarhorn mobile suits. Rodis and Hexas are the most common frames and both predate the Gundam frame's development. Everyone who isn't Gjallarhorn or Teiwaz is using machinery at least 300 years old, never mind that it might be covered in brand new armour.

Those space pirates raiding ships in the Jupiter-sphere? The colonists trying to seize control of their living conditions? That country hurriedly upgrading its military for a modern challenge? They're all recycling the same frames that fought the war out of which the systems they're currently struggling to live with extend. It's incredibly thematically resonant, not to mention pretty close to the truth of the things IBO is assaying in its fiction.

Visceral shorthand

However, I think the most clever thing about the mobile frame model is the way it lends itself to in-the-moment storytelling. Having established the skeletons underlying each mecha, the show can freely expose them as required to demonstrate exactly how badly a fight is going.

IBO abandons the lightsabers and laser-guns of its predecessor shows in favour of a more grounded and brutal approach to combat. That is to say: thanks to additional technobabble, breaking through the armour of a mobile suit requires either something very sharp, going very fast, or something very heavy, also going very fast. Swords, clubs, maces, and heavy-gauge bullets are the order of the day, leading to a lot of crumpling and crushing, and more specifically, bits of armour being ripped off the frame.

It's a great shorthand for 'oh that was a hit', applied generously to all sides, to emphasise the damage being done while also making it clear the machines can technically still function in such a state. Barbatos actively starts out extra-skeletal, while 'suits like the Reginlaze Julia keep going when stripped of their surface layer. Even the unfortunate Graze Ritter on the back of which Mikazuki surf-boards down from orbit is visibly coming apart around its frame, underlining how tough the cores of these things are.

Furthermore, it increases the sense that the human component of a mobile suit is extremely frail by comparison. When you a have weapons structured around extremely durable inner workings, it draws attention to the vulnerability of the cockpit. Because in most of the frames, that's part of what goes on top. Rodi and Io frames have integrated control cabins, but the rest do not. On most of them, the pilot sits at what is nominally the most heavily protected section (the chest), but in fact, they are a little way in front of the piece that can be actively relied on not to break (the reactor).

Or to put it another way: a mobile suit pilot is visibly more likely to die in battle before the war machine they are strapped to does. Skewering the cockpit with something pointy is a deeply feasible strategy, and that vulnerability stems from design limitations imposed by the chosen structure of the mecha. The reactor has to go somewhere central. The mobile suit is built around a set frame. The armour will detach before the limbs break. So on and so forth, ad drill-knees, underscoring how cheap life is next to the hardware of war.

Making it about bones

To sum up, it's a neat concept, well executed. Mobile frames allow for visual coherence while permitting design variation and customisation. They are used to underscore the brutality of the combat, adding weight to blow-by-blow animation and to the general sense of danger for the cast. And they make IBO's mecha stand out from the pack, which to me is a big mark in their favour.

There's another point that delights me too, one I can best illustrate with some images. If you look at the at the Calamity War era frames, you'll see that the Rodi (left) and Hexa (centre) are both heavily robotic in outline. They have complex hands but are otherwise quite blocky, with very inhuman heads. The Gundam frame (right), however, has a more organic design, its points of movement more closely corresponding to the human body, and (uniquely) two eyes placed about where you'd expect.

Now clearly the Gundam is inheriting franchise design considerations (the 'man in a suit' look of the '79 cartoon) but within the fiction, it works brilliantly with the conceit of Gundams perfecting the man/machine interface. Of course it looks closer to a person; it's meant to be a more natural extension of the pilot than the frames that came earlier, to enable the split-second timing and instinctive movement required to beat the mobile armours.

We also see this running in the opposite direction. The Valkyrja (far left) is actually closer to the Gundam's sensibilities than its other contemporaries (it was developed at the same time), but its successors, the Geirail and then Graze, are even more robotic than the Rodi and Hexa, with considerably simplified structures. Even the hands are much more chunky and functional.

The narrative is both of a technological decline and of the requirements of mass-production. In the post-War society, mobile suit combat is less of an issue, so the 'suits don't need to be as complex. It's only when Gjallarhorn's position as top-dog in the solar system is threatened that they invest in something closer to the Valkyrja, with the Reginlaze (far right) being designed to allow a non-augmented pilot to compete with things like Gundam Barbatos.

I really like that degree of thought and detail in something that isn't especially relevant to the story, but adds to it once you know about it.

Other reference posts include:

IBO reference notes on … Gjallarhorn (Part 1)

IBO reference notes on … Gjallarhorn (Part 2)

IBO reference notes on … Gjallarhorn (corrigendum) [mainly covering my inability to recognise mythical wolves]

IBO reference notes on … three key Yamagi scenes

IBO reference notes on … three key Shino scenes

IBO reference notes on … three key Eugene scenes

IBO reference notes on … three key Ride scenes

IBO reference notes on … the tone of the setting

IBO reference notes on … character parallels and counterpoints

IBO reference notes on … a perfect villain

IBO reference notes on … Iron-Blooded Orphans: Gekko

IBO reference notes on … an act of unspeakable cruelty

IBO reference notes on … original(ish) characters [this one is mainly fanfic]

IBO reference notes on … Kudelia’s decisions

IBO reference notes on … assorted head-canons

IBO reference notes on … actual, proper original characters [explicit fanfic -- as in, actually fanfic. None of them have turned up in the smut yet]

[graceofgosh]

human body cannot physically function at 70mph. ludicrous speed. die instantly on impact must likely. so fragile. yet the mind adapts. inertial frame of reference 70mph. so fast. yet so serene. how? why? proof of the soul? the flesh is weak yet its fragile jelly can pilot steel at impossible speeds? hmm

[factsandstuffbyd]

Time dilation is a fascinating and counterintuitive phenomenon predicted by Albert Einstein's theory of special relativity. It reveals that time is not absolute but is relative to the motion of an observer. When objects move at significant fractions of the speed of light or experience strong gravitational fields, time appears to pass differently for them compared to observers in a different frame of reference. This means that time "dilates" or stretches out, causing different rates of time passage for different observers. To understand how time dilation works in space, we must delve into the core principles of special relativity and explore its implications for our understanding of the universe.

In the early 20th century, Einstein revolutionized physics with his theory of special relativity, which introduced the concept of the speed of light being constant in all inertial reference frames. According to this theory, the laws of physics are the same for all non-accelerating observers, regardless of their relative motion. One of the profound consequences of this theory is the time dilation effect.

Time dilation occurs when objects travel at relativistic speeds, i.e., speeds approaching the speed of light (approximately 299,792,458 meters per second in a vacuum). The theory posits that the faster an object moves, the more time appears to slow down for it compared to a stationary observer. To the moving object, time seems to pass at a normal pace, but to an observer at rest, the moving object's time appears to pass more slowly. This relative difference in the passage of time is known as time dilation.

The formula that describes time dilation is derived from the Lorentz transformation, and it states that the time experienced by the moving object (Δt) is equal to the time experienced by the stationary observer (Δt_0) divided by the Lorentz factor (γ), which is dependent on the object's velocity (v) relative to the speed of light (c):

Δt = Δt_0 / γ

where γ = 1 / √(1 - (v^2 / c^2))

As an object's velocity approaches the speed of light (v → c), the Lorentz factor approaches infinity, causing time dilation to become increasingly significant. This effect has been confirmed through various experiments, such as the observation of cosmic ray particles that constantly bombard the Earth. These particles, which are moving at relativistic speeds, have a longer lifetime than predicted by their half-life when at rest, providing empirical evidence of time dilation.

Apart from relative motion, time dilation also occurs in the presence of strong gravitational fields. According to Einstein's general theory of relativity, gravity is not just a force but a curvature of spacetime caused by massive objects. In regions with intense gravity, such as around massive stars or black holes, spacetime is curved, and clocks closer to the gravitational source experience time at a slower rate than clocks further away. This phenomenon, known as gravitational time dilation, has been verified through precise experiments and measurements.

In summary, time dilation is a remarkable consequence of Einstein's theory of special relativity and general relativity. It reveals that time is not an absolute quantity but is affected by an object's motion or the presence of strong gravitational fields. As objects approach the speed of light or encounter intense gravity, time appears to slow down relative to observers in different reference frames. Time dilation has profound implications for our understanding of the universe, impacting everything from satellite navigation systems to the behavior of massive celestial bodies. Its exploration continues to shape our understanding of the fabric of spacetime and the fundamental nature of reality.

[geopolicraticus]

TODAY IN PHILOSOPHY OF HISTORY

Further Elaborations on the Coming Coeval Age 

An essay of mine, “The Coming Coeval Age,” has just appeared in Isonomia Quarterly for summer 2024. This essay isn’t specifically about philosophy of history, but it does touch on some philosophical problems, so I will consider some of these problems in the context of philosophy of history. In particular, I will discuss the relative complexity of terrestrial history, which is the simplest history possible in a relativistic universe. When we have access to different inertial frames of reference, and the ability to travel between then, history will be dramatically complexified.  

Nielsen, J. N. (2024). The Coming Coeval Age. Isonomia Quarterly. Volume 2, Issue 2.

Essay:              https://isonomiaquarterly.com/archive/volume-2-issue-2/the-coming-coeval-age/

Quora:              https://philosophyofhistory.quora.com/  

Discord:           https://discord.gg/r3dudQvGxD

Links:              https://jnnielsen.carrd.co/

Newsletter:     http://eepurl.com/dMh0_-/

Video:              https://youtu.be/fvmCoRrBiEs   

Podcast:          https://spotifyanchor-web.app.link/e/xkVzIKAcIJb        

Text post:        https://geopolicraticus.substack.com/p/the-coming-coeval-age  

[justaboutsnapped]

sweating bullets it's the way i'm getting tested on math and physics theories in *checks phone* 2 hours broooo this is an art school and i'm here reviewing inertial frames of reference and bosons and aristotelian syllogisms

[sklogw]

this is actually a physics meme as this person is referencing the phenomenon of time dilation that occurs when observers attempt to ascertain the simultaneity of two events in different inertial frames of reference