ericwdhs

@ericwdhs@discuss.online

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⁨Comment⁩ on ⁨Is this sufficiently advanced technology?⁩ ⁨⁨1⁩ ⁨day⁩ ago⁩:
Ah, judging by the upvotes, that’s the more common interpretation too. I guess I’ve just not been subject to enough obscure bugs to have ever made the association.
⁨Comment⁩ on ⁨What's the thing you're supposed to be doing right now instead of scrolling?⁩ ⁨⁨2⁩ ⁨days⁩ ago⁩:
Work…
⁨Comment⁩ on ⁨Is this sufficiently advanced technology?⁩ ⁨⁨2⁩ ⁨days⁩ ago⁩:
That’s a very… unique interpretation honestly. I’ve never seen anyone associate this meme (including all the “we trapped lightning in a rock and taught it to do taxes” variants) with the fragility of tech, only the idea that microprocessors are such a ridiculous technology that anyone reaching expert level is back in the state of wonderment.
⁨Comment⁩ on ⁨Statistically unlikely⁩ ⁨⁨3⁩ ⁨days⁩ ago⁩:
Genius! Also, did you know “whale” comes from “large sea fish?” Ridiculous. Another one for the list.
⁨Comment⁩ on ⁨Statistically unlikely⁩ ⁨⁨3⁩ ⁨days⁩ ago⁩:
I didn’t miss it. It just doesn’t cleanly fit into this framework (imagine it as a square table instead of a list):

Horror + -ble = horrible (bad) Horror + -ific = horrific (bad) Terror + -ble = terrible (bad) Terror + -ific = terrific (good)
⁨Comment⁩ on ⁨Statistically unlikely⁩ ⁨⁨3⁩ ⁨days⁩ ago⁩:
If we’re putting effort into fixing how society uses words, can we work on flammable versus inflammable first? Then I vote for fixing the odd one out in the terrible, terrific, horrible, horrific quad. Then the split between awful and awe. Then…
⁨Comment⁩ on ⁨Its all about bonding⁩ ⁨⁨3⁩ ⁨days⁩ ago⁩:
I’ll be honest. I did exactly this very recently. In my defense, I’m an okay home cook. I was constrained to a smaller pot than usual and way too desperate to still fit a full box of pasta in it.
⁨Comment⁩ on ⁨Which is it Lemmy?⁩ ⁨⁨4⁩ ⁨days⁩ ago⁩:

Pretty sure the momentum from the perspective of the box stays the same.

How exactly are you defining monentum here? “The box sees the entire universe move at velocity V backwards both before and after passing through the portal.” This is probably at least approximately true, but total momentum of the universe minus the box would have to be exactly zero to make this technically correct. “The box never perceived a change in its own momentum.” This is 100% true.

The game doesn’t explicitly say that momentum for the entire system stays the same

Then why are we still talking about this? Lol. I thought that was one of the main points of your position.

the box never actually experiences a change in momentum

Correct, the box never experiences a change in momentum. The box exists in one inertial reference frame and, in going through the portal, is deposited into a different reference frame. Two inertial reference frames that differ in orientation are equally as distinct as two inertial reference frames that differ in velocity. The same logic applies to both.

Maybe a better way to put it, is that the absolute momentum of the box never changes when it passes through a portal.

You’re describing what I labeled as “inherent,” so I’ll take it.
⁨Comment⁩ on ⁨[deleted]⁩ ⁨⁨4⁩ ⁨days⁩ ago⁩:
Seeing the social consensus can be legitimately useful in many situations outside subjective opinion though. YouTube dislikes are the classic example. They were a very reliable way to know when a tutorial was not worth your time.
⁨Comment⁩ on ⁨Which is it Lemmy?⁩ ⁨⁨4⁩ ⁨days⁩ ago⁩:
Ah, if that’s how you’ve been interpreting the explanation, I can see why we’ve been at an impasse. Portals as shown absolutely do seem to violate conservation of momentum in the more global sense.

You don’t even need a complicated set up to do it. Put a portal in empty space, rotate the plane of the exit 90 degrees, then send a box through at a simple constant speed. Assuming the universe isn’t compensating in other ways*, the total momentum of the universe will be different before and after the box went through, so there’s no environment encompassing the portal interactions that will satisfy the zero condition. Only each object’s local experience will keep the condition.

*I can think of a few options for this bit:
1. The entire universe somehow accelerates the opposite way in response, a fun idea, but it has no meaningful consequences.
2. Portals behave more like wormholes as scientifically defined. They have mass themselves and, if free-floating, move in reaction to mass sent through them in a way that preserves total momentum. This is enough to run with though. The games’ portals always have to be anchored to other mass. This leaves room for the idea that the portals actually do want to move in response to objects passing though them. They just transmit that force into the mass they’re anchored to, and that force propagating out is where the momentum conservation actually resolves.
⁨Comment⁩ on ⁨Which is it Lemmy?⁩ ⁨⁨4⁩ ⁨days⁩ ago⁩:

it looks like you are dropping the argument about relative movement not being real

I’ll chalk that up to me not being as clear as I should have been from the start. Please consider my position to have always been the last point: Motion relative to other objects = convention not directly based on something real but usually useful due to building on things almost always true. Motion relative to local spacetime = the actual real thing on which everything else builds. So…

GLaDOS specifically states “Momentum, a function of mass and velocity, is conserved between portals.”

I’m not disagreeing with this. To break it down further though, mass is just an inherent property of an object, and its velocity is fundamentally expressed in the object’s relation to local spacetime.

Except it’s not moving, it has the appearance of movement, but the actual velocity of the box is 0 m/s.

Declaring an “actual velocity” sounds more like an argument against relativity (again for clarity, the fundamental spacetime geometry based relativity I was never intending to call into dispute). The critical detail you skipped over is that the 1 m/s velocity is seen in the inertial reference frame in which the portal is at rest.

Since this has started retreading the same points, I’ll just go ahead and jump to where I think our understandings actually diverge, how portals relate to spacetime.

Your argument seems to boil down to: The box starts at 0 m/s in its local spacetime, and the portal is a simple hole on top of reality with no power to change this, so the box must end at 0 m/s in the same local spacetime.

My argument boils down to: Portals can momentarily link different inertial reference frames within spacetime together, so the box can seamlessly transition between the two resulting in an apparent momentum change while the actual inherent momentum doesn’t change.

It’s worth adding that static portals already do the same thing. Momentum and velocity have a direction component, not just speed. When an object enters a portal going one direction and comes out in another direction as measured against the wider environment, that’s also an apparent momentum change.
⁨Comment⁩ on ⁨Which is it Lemmy?⁩ ⁨⁨4⁩ ⁨days⁩ ago⁩:
Sorry. Lol. I used some shorthand I didn’t think I’d need to defend based on earlier statements, but for clarity:
1. Movement relative to other objects is in itself not a real thing. 2) Movement relative to local spacetime geometry is always real. 3) Spacetime geometry is usually continuous. 4) The usual continuity of spacetime allows for the convention of defining movement relative to other objects with the underlying connecting spacetime element left unstated. 5) Breaking any underlying assumptions about spacetime continuity also breaks the convention, but the convention is still valid across spaces where the underlying assumptions are not broken.
Expanding out my last statement:
1. The box is initially moving 0 m/s in the inertial reference frame we defined to be at rest.
2. The portion of the box that has not yet crossed the portal boundary is moving 1 m/s in the inertial reference frame the entry portal is currently at rest in (valid due to the continuity in spacetime across the measurement between them).
3. The portion of the box that has already crossed the portal boundary is moving 1 m/s in the inertial reference frame the exit portal is currently at rest in (valid due to the continuity in spacetime across the measurement between them).
There are additional possible declarations to make if the portal boundary is a non-zero volume instead of a plane of instantaneous transition, but the games’ interpretation of portals constrains that to either be zero or close enough to zero to not matter for the end result. Let me know if you want me to expand on that too.
⁨Comment⁩ on ⁨Which is it Lemmy?⁩ ⁨⁨4⁩ ⁨days⁩ ago⁩:
0 m/s relative to the chosen inertial reference frame, 1 m/s relative to the portal entry, and 1 m/s relative to the portal exit.
⁨Comment⁩ on ⁨Which is it Lemmy?⁩ ⁨⁨4⁩ ⁨days⁩ ago⁩:
I think I see exactly where you’re going with this, but let’s just say the cube is defined to be at rest with the portal approaching at 1 m/s.
⁨Comment⁩ on ⁨Which is it Lemmy?⁩ ⁨⁨4⁩ ⁨days⁩ ago⁩:
Yes, it would have velocity, or at least all the mechanical properties of it. That velocity would be undefined from our perspective since all possible ways you could define it (0, 5 m/s to the right, etc.) would be equally valid depending on the coordinates you choose to put at rest, but that’s a measurement problem, not anything intrinsic to reality.

The important bits are: 1) inertia exists as long as you have the minimum ingredients, an object in spacetime, 2) all possible inertial reference frames are still meaningfully distinct from each other and stay as such, 3) any change in velocity of the object would show up in all possible inertial reference frames, and 4) any such change will stay logically consistent regardless of which inertial reference frame you choose to measure the velocity change in.
⁨Comment⁩ on ⁨Which is it Lemmy?⁩ ⁨⁨5⁩ ⁨days⁩ ago⁩:
Lol. Serious /uj question: Are you deliberately misreading me to do the rage bait thing? I’m using “worldline” in the first sense you gave. I’ll avoid it and reword the actual main point as this is good practice for me anyway:

Local spacetime is the ultimate thing all velocity maps onto, so any examination of this problem needs to respect spacetime as the primary driver of behavior. Answer A ignores the spacetime the cube is being moved into on the exit side of the portal as a real thing it must maintain inertia within (the critical detail also overlooked in the “Buster Keaton” answers).
⁨Comment⁩ on ⁨Which is it Lemmy?⁩ ⁨⁨5⁩ ⁨days⁩ ago⁩:
Trick question. Fun answers are not ragebait. Serious answers (correct or incorrect) are ragebait. You get an F.
⁨Comment⁩ on ⁨Which is it Lemmy?⁩ ⁨⁨5⁩ ⁨days⁩ ago⁩:
Maybe I’m misinterpreting your use of the phrase, but it seems you’re arguing from applied Newtonian mechanics where objects define a reference frame. A reference frame in that sense is a useful convention but doesn’t actually signify something in reality, hence my comment. Objects don’t care about their velocity relative to other objects or about reference frames suddenly shifting as measured that way. An object’s motion is encoded as an entirely local property in spacetime itself, AKA its worldline. This distinction between object-based reference frames and local reference frames is usually not worthwhile, because they’re usually entirely consistent with each other. The convention just happens to break in situations where worldlines cease to be continuous and consistently differentiated, as in the case of portals.
⁨Comment⁩ on ⁨Which is it Lemmy?⁩ ⁨⁨5⁩ ⁨days⁩ ago⁩:
Lol. This will be fun. Glados’ explanation is still correct, but momentum being conserved between portals is exactly what gets you answer B.

“A perspective that encompasses all of the objects involved” is not a thing in reality. No point in space cares about another point in space beyond the forces felt from that direction transmitted through spacetime, and the frame of reference following the left portal moving down and the frame of reference following the stationary right portal are both equally valid and moving relative to each other over the timeframe of the cube transitioning through the portal. I don’t agree that the game is pushing a different model, but if it actually is, then that opens up so many holes in physics that we may as well be debating magic.

I actually addressed the portal stopping halfway in another comment here which I won’t bother to copy here, but the summary is that you shouldn’t think of the box as one item but a mass of particles connected by internal forces. Your answer is indeed “obvious” and intuitive, but accelerating portals do funny things with frames of reference that means intuitive isn’t always right.

As the portal comes down across the top half of the cube with constant relative velocity V and the appropriate momentum for said velocity, all those portaled particles will emerge from the other side of the portal with the same relative velocity V and same associated momentum compared to that side of the portal. Whether the particles maintain velocity relative to the portal because of something intrinsic to how space works at the portal boundary or because particles coming in forcibly displace particles going out in equal measure, the result is the same, fast in = fast out.

When the descending portal suddenly stops halfway, the particles already portaled through don’t “know” this. They’ve still got the momentum of being sent through moments earlier reinforced by all the particles around them doing the same thing, so they “desire” to keep moving away from the portal. The particles of the bottom half of the box are similarly “ignorant” of all the shenanigans above and “want” to maintain the zero momentum they’ve had all along as measured by most of the objects in the scene.

This means the top and bottom halves of the box, despite never losing conservation of momentum, suddenly don’t align with each other. The conflict of the top half “wanting” to keep moving away from the portal at velocity V and the bottom half “wanting” to stay where it is will resolve in one of two ways:

If the cube’s internal forces are strong and “springy” enough to accommodate the disagreement, forces will propagate and equalize throughout the whole cube effectively averaging all “desired” motion out and the cube will fly out of the right portal at velocity ~1/2 V.

If the internal forces are not enough, the two halves of the cube will separate from each other, either cleanly at the portal boundary if the momentum disagreement massively overpowers internal forces or more messily and violently if it barely overpowers them. Obviously we don’t have portals in real life to visualize this, but you can kind of get a feel for the effect through planetary bodies breaking up at Roche limits.
⁨Comment⁩ on ⁨Which is it Lemmy?⁩ ⁨⁨5⁩ ⁨days⁩ ago⁩:
Even stationary portals break conservation of energy unless there’s some unseen location changing energy to compensate, but yes, it gets more complicated with relative movement. In lore though, it is established that portals can move relative to each other at least with enough distance when you ::: spoiler spoiler shoot one portal to the moon :::.
⁨Comment⁩ on ⁨Which is it Lemmy?⁩ ⁨⁨5⁩ ⁨days⁩ ago⁩:
This only works if you treat the cube as one object anchored by a small part. In reality, objects are a bunch of particles each with their own momentum held together by forces between each particle usually strong and springy enough to cancel out differences in momentum. This is why all objects tear apart if enough uneven force is applied on them.

If the portal stops partway through the cube, the stationary bottom part on one side of the portal and the top part still carrying the momentum of recently exiting the portal will have very different competing momentums. If the cube’s internal forces win out, the overall momentum will average out, and the cube will fly up with a speed proportional to however much of it got pushed through the portal before it stopped. If the competing momentums win out, the cube will break into both stationary and flying parts.
⁨Comment⁩ on ⁨Which is it Lemmy?⁩ ⁨⁨5⁩ ⁨days⁩ ago⁩:
I think the game treating portals as fuzzy holes in reality is more just a limitation or oversight in the physics engine. It completely ignores relativity and makes the portals no longer logically consistent and pointless to argue about. Velocity and angle conservation relative to the portal is established elsewhere though, so running with that gives you the “fly up” result.
⁨Comment⁩ on ⁨Which is it Lemmy?⁩ ⁨⁨5⁩ ⁨days⁩ ago⁩:
Terminal velocity is only reached because the object (or player) is colliding with the air. Momentum is still being added. It’s just also transferring out into the air. You can kind of think of the object as being a fan blade running on zero power. It’s technically a source of infinite energy, but it might be hard to extract from that exact setup. If we could do this in the real world, we’d tweak it to just be water in a vertical pipe with a turbine extracting the free momentum.
⁨Comment⁩ on ⁨Which is it Lemmy?⁩ ⁨⁨5⁩ ⁨days⁩ ago⁩:
Ragebait successful. College physics here. The only correct answer is B. You can only get A if the box is securely anchored to the pillar.

I love the games, but you can’t trust a game physics engine to properly track what’s going to happen with moving and especially accelerating portals. They (usually) track an entire object from one reference point against one absolute world grid.

Think of a portal as moving a plane of particles from one location to another. An entire object passing through a portal is just a bunch of successive planes being moved. One particle plane entering the portal plane on one side must displace the previous particle plane at the same rate on the exit side. Therefore, an object’s speed through a portal must remain consistent relative to the portal on both sides, and with nothing to magically cancel that inertia, that motion will continue even after the object has completely left the portal.
⁨Comment⁩ on ⁨How do other countries view American super hero movie's always putting the threat in new york or whatever? Instead of their own country and have their own superheroes?⁩ ⁨⁨2⁩ ⁨weeks⁩ ago⁩:
Funnily enough, I find NYC and Tokyo to be the least masturbatory targets for off-world interest.

NYC makes sense as a combined seat of international politics (see the UN building), economic power (largest GDP by city and Wall Street seeing 2/3rds of all public trade), and genetic representation for humanity (Queens being the most ethnically and linguistically diverse urban area on the planet).

Tokyo makes sense as the world’s most populous metropolitan area and highest GDP by metropolitan area.

So, aliens scanning the planet or the Internet or whatever and thinking “we need to go here first” for either location is believable to me in an objective sense.

It also helps that there is often some background lore adding to why a particular location is important, which also includes explanations for Earth itself being important on a cosmic scale.
⁨Comment⁩ on ⁨"it only takes one slow walking person in the grocery store to destroy the illusion that you're a nice person."⁩ ⁨⁨2⁩ ⁨weeks⁩ ago⁩:
Not consciously? I build it into my routine. If I can’t hit the grocery store within an hour or so of them opening, I usually wait until 30 minutes from closing time to visit. Shopping in a mostly empty store is just too nice to do anything else.
⁨Comment⁩ on ⁨GTA 6 Price Finally Confirmed, Features a 'Single-Player Experience' at Launch⁩ ⁨⁨5⁩ ⁨weeks⁩ ago⁩:
I’m just saying the phrase you singled out has the same feeling as this heavily memed phrase.
⁨Comment⁩ on ⁨GTA 6 Price Finally Confirmed, Features a 'Single-Player Experience' at Launch⁩ ⁨⁨5⁩ ⁨weeks⁩ ago⁩:
Huge “I like shorts. They’re comfy and easy to wear.” energy.
⁨Comment⁩ on ⁨GTA 6 Price Finally Confirmed, Features a 'Single-Player Experience' at Launch⁩ ⁨⁨5⁩ ⁨weeks⁩ ago⁩:
Kojima games are famously cutscene heavy. They may not be for everyone, but lazy is the last word I’d use to describe anything about them. I think it’s perfectly fine for a story to lean on its medium or outside context to feel special, interactive movies included.

In fact, I’ll even say it’s perfectly fine for a game’s presentation to force tons of people out of its audience in general, whether that’s via extreme difficulty, reliance on senses not everyone has, not being pausable, or not being enjoyable in anything less than 3 hour chunks.
⁨Comment⁩ on ⁨That's a no⁩ ⁨⁨1⁩ ⁨month⁩ ago⁩:
Agreed on never being the one blocking merges, but for the merging party, “if people don’t prevent merges” is such a huge caveat that I think attempting a zipper merge at a lane ending at any appreciable speed is impractical at best and downright dangerous at worst.

If everyone is traveling slow already, failing to merge quickly at the lane ending isn’t a huge threat to safety and just a slight hit to efficiency. Most merges I’ve experienced are probably in the 40 to 80 mph range though. In that case, you absolutely do want to take the first decent merging opportunity you can, because waiting to do it until the lane ending can have huge safety and/or efficiency consequences if another good merging opportunity doesn’t open up at speed.

Also, I’m pretty sure zipper merging was mentioned zero times in driving lessons and tests where I’m from, so you should basically just assume other drivers don’t even have it as a concept. If you’re from somewhere where more people practice it regularly, then I can see why you are more encouraged to enforce it as a baseline.