So it looks like Youtube's auto-matching gone dumping random error and false matching shit.
I don't think YouTube/Google is expected to run such an automation by any law, so I really wonder why they are doing it. The only thing they achieve with that is scaring people for nothing.
There's still a notice in my account that one of my videos might be copyrighted by someone else. I'm singing a song that became public domain something like 50 years ago.
I'm assuming that it's not supposed to show just a black screen with some garbled white... I assume text... scrolling from right to left, for 24 minutes. What does it require to actually show some video footage?
I'm assuming this game uses the touchscreen? Perhaps a minor (very minor) problem with this is that the viewer doesn't see what the player is doing, and hence the movie consists of the jewels just disappearing at a rapid pace. It's hard to see what's going on.
Likewise, the earth does not actaully "move" through time. It's a 4-cylinder that has a beginning and an end.
If we don't move along the time axis, why do inertial objects change position due to a curved spacetime? If they change position, that implies that they are moving along a geodesic.
In another forum I got the answer that if the premise is that the universe expands at such a rate that the distance between planet A and planet B increases at a constant rate (that's slightly faster than c), and if A sends a probe towards B, the probe will eventually reach B, regardless of how unintuitive that might sound.
The most intuitive explanation for this was the "snail on a stretching rubberband" analogy.
However, there's a limit to the rate of the metric expansion before sending the probe becomes impossible (in the exact same way as with the snail-on-a-rubber-band analogy). From some rate of expansion up the distance between A and B accelerates so much that the probe will never reach the latter. (I'm not sure what this limit is, but I think that a constant metric expansion of the universe is enough for this.)
I'm assuming that in the former case (where the probe does reach B), from A's perspective it will look as if the probe accelerates until it surpasses c and hence exits A's observable universe. (B will see the opposite, ie. the probe appearing inside its observable universe and decelerating.)
Now you're asking what happens if they move faster than c.
They do not move faster than c. The distance between them grows faster than c. There's a crucial difference.
The answer is: they don't. Not within relativity.
What do you mean by "relativity"? General Relativity allows (and predicts) the distance between two objects increasing faster than c, for example because of the metric expansion of the universe, and this is accepted to be happening to our universe right now (it's estimated that the majority of the universe is so far from us that it's receding from us faster than c).
This was a question about General Relativity.
Assume that we have two planets A and B, and that the universe is expanding at such a rate that A and B are always receding from each other slightly faster than c. Also assume that there's a star between them that both can observe.
You're now including cosmic expansion
My original question was about the expanding universe and overlapping observable universes. I haven't added anything. I just couldn't understand the original answers given to the question, and I would really like to understand.
you're trying to answer a question that cannot be answered strictly within relativity.
Starred movies are a small selection of movies that a first-time viewer could watch to get an overall idea of what TASing is about. They usually ought to have high standards of quality, but that's not the main point: The main point is to introduce the newcomer to the joys of TASing.
I have to agree with you that this one is quite starworthy material. There's a sticky thread in the 'General' group where you can nominate movies for stars.
The gaming event was broadcast freely on a livestream website.
Note that distributing something for free does not remove copyright, or diminish the rights of the author in any way. If the author / copyright owner does not specify any usage license, the default (in the vast majority of jurisdictions and the international copyright) is that you can't use the work for anything (not even redistribution), rather than the opposite (as many people seem to think).
Now, as for this particular type of content, I don't know the answer. Copyright gets fuzzy when it becomes a question of whether the material contains some actual original work or not. In these unclear cases it's probably up to a judge to decide.
Edit: Oh, and a big IANAL!
A point in the observable universe is a point in space-time, not simply a point in space. Since as marzojr said, the observable universe of A is defined as being every point which could have affected A's current state, then a point in A's universe is a point in A's past. As a result, A cannot transmit something to the star in A's observable universe, because this would involve sending the signal backwards in time!
A' B'
\uAB /
\ /
uA \/ uB
/\
/ \
/ u \
A B
In the diagram above, A is A at some point in the past. B is B at some point in the past. A' is A some time later; B' is B some time later. uA is the universe that A can affect. uB is the universe that B can affect. uAB is the overlap. u is the universe that neither can affect.
A can affect B' but not B.
The same diagram can demonstrate observable universes: uA and u are the observable universe of A'; uB and u are the observable universe of B'.
Sorry to return to this (and sorry for the long quote, but I wanted the whole context here), but I really want to understand this. Please help me understand the answers to these questions:
Assume that we have two planets A and B, and that the universe is expanding at such a rate that A and B are always receding from each other slightly faster than c. Also assume that there's a star between them that both can observe.
1) Can A send a probe to the star? If the answer is no, then why not?
2) If the answer is yes, then can the probe then proceed to B? Why?
Again, movement as we know it requires both space and time. If our universe is to "move" across the metaverse, then the metaverse needs a time dimension.
So how would you then explain the time dimension in the metaverse? Moving through a meta-metaverse? How many turtles down, exactly?
is in contradiction with this:
Warp wrote:
[...] we could think of the Earth as a big circle traversing along the time axis [...]
marzojr wrote:
The visualization is correct, with the caveat that it is space-time, not space, that curves.
Either one of these statements must be incorrect (or at the very least lacking). Which one?
If movement along an axis implies a separate time axis, how can be move along the time axis?
In relativity, massive particles are assumed to move in timelike geodesics, while light moves in lightlike geodesics. This assigns a nonzero timelike speed vector to all massive particles, which forces them to move in time.
I'm not completely sure I fully understood the explanation (since the math involved in GR goes well beyond my understanding), but it made me wonder if this is just a (mathematical) description of how it works, rather than an explanation of why it works like that.
As for the former (ie. the description of how it works), could the movement in time be a consequence of something else, perhaps the constness of c for all observers? (I'm just throwing ideas here to try to better understand the mathematical description in more intuitive ways, without needing to dive deep into the GR equations and tensor metrics, which are very difficult to grasp...)
It's not a question of laws of physics; it's a question of definitions of words.
If I have learned anything from quantum mechanics it's that the whole concept of time is... complicated.
The so-called delayed choice quantum eraser experiment is a perfect example of this.
In the double-slit experiment, measuring which slit the particle went through removes the interference pattern. Canceling that measurement after the particle passes the slits restores the interference pattern. Thus you can affect whether the interference pattern appears or not by choosing whether to measure or cancel the measurement.
More oddly, this is so even if the choice whether to measure it or not is made well after the particle hits the detector. It's as if the choice affects the behavior of the particle in the past. Even though, classically speaking, at the moment the particle hits the detector the choice has not yet been made, it still makes or doesn't make the interference pattern depending on the choice made in the future.
It's as if the particle were at all points of its path at the same time, because even a measurement choice made later in the path affects its behavior earlier in the path. Regardless, you can still measure the time that the particle takes from the emitter to the detector, and this is a finite time that depends on the speed of the particle.
It gets really weird.
Again, movement as we know it requires both space and time. If our universe is to "move" across the metaverse, then the metaverse needs a time dimension.
So how would you then explain the time dimension in the metaverse?
The metaverse doesn't need to necessarily obey the same laws of physics as our universe. I'm not versed enough in physics to give a possible physical description of this hypothetical phenomenon.
Like any person with a vivid imagination, I sometimes like to come up with wild hypotheses to explain things. Since I'm not a physicist and I only have a very cursory knowledge of general relativity and QM, this wild hypothesis may very well be waaay of the mark, completely nonsensical from a physical point of view, and basically ridiculous, but nevertheless, it entices my imagination.
It could be that our universe resides inside some kind of "metaverse", which properties are quite different (or possibly not even so much different) than the properties inside this "bubble" that's our universe. It could also be that what we perceive as movement in time is actually our universe moving inside this metaverse. The "time axis" is in actuality the movement axis that our universe traverses along in the metaverse.
Masses "drag behind" in this time axis, bending it. They don't drag in the spatial axes, only in the "time axis" of the metaverse. This is the reason why time passes at a different speed close to massive objects. (Singularities are, in theory, infinitely dense, which means that they have "infinite drag" and thus they don't move at all in the time axis of the metaverse, which is why time is completely still at a singularity.)
This would be what makes the time axis different from the spatial axes, and why everything moves on the time axis (because our universe is moving in the "metaverse").
we could think of the Earth as a big circle traversing along the time axis.
Btw, this is another thing that puzzles me. What causes everything to traverse on the time axis, and why cannot we move freely on the time axis in the same way as we can on the other spatial axes (ie. why can't be freely move faster or slower in time, or even backwards)?
