swansont

Something falling into a black hole will have the time "stop" as far as a distant observer is concerned, but that's only according to the distant observer. What does "nothing changes dimensionally" mean?

Via what interaction? Pretty sure it is, for fermions that can interact that way. A common method in fermi gas experiments is tuning the scattering length (a measure of the interaction strength) via an external magnetic field.

What does that mean? Change has a direction? That lines up with time? What happens with a system that isn't changing? That's kind of a vague statement. What math? I am aware of only one circumstance where one could argue that time stops, and that's in a reference frame that is not the observer's. We know that time is not always measured the same, and we know that length is not measured the same. We also know that these differences compensate for each other, such that c is always the same.

Perfect sound bite(s), I would say. I don't think the journalists have a the narrative fully in place when they are interviewing. Then they have to decide between what they explain and what the interviewee explains in order to tell their story. Since they don't know what they need, they have to get lots of discussion. It's not like you are working from a script.

So the apparent velocity and absolute velocity are invariant. ...except that it's not. Which is it? Please stop doing this. The rules state that the discussion takes place here, and that you must provide enough information to have the discussion without people clicking on any links.

A politician making science-based claims can be several steps removed from the facts. Someone may have explained something to them (and this could be the Nth step of that happening), with the truth eroding each step of the way. The caveats get dropped, and maybes become certainties. All of this before you worry about the track record of the individual.

Yes, but that's true only in a particular frame of reference. When there is relative motion, it looks like a changing field, so you get both if you are moving relative to e.g. a static B field. What it boils down to is that for any dynamic situation, there is electromagnetics. They are different aspects of one interaction. It's only in the case of statics where you can look at one or the other.

“Push” implies a force, so no. A changing B field is an electric field, for example.

But absent any significant loss mechanisms, it has to directly hit the black hole to be lost to it.

That's a question studiot has put to you. To me, it seems to be an initial condition of the problem: the rod is aligned with the y axis and has a velocity in the x direction. I don't see how anything but linear motion follows from that initial condition. I don't see why it would oscillate under the conditions I have described. There is no force, so motion continues in a straight line, in accordance with Newton's laws. To get any motion in the y direction, it must have an initial velocity component in the ± y direction. Then the existence of the rod will come into play.

I think that's coupled with the fact that we had not yet discovered the details of atomic structure (let alone nuclear). The "whoah! Classical physics explains almost none of this" moment (and by "moment" I mean decade or so) is probably where one could not reasonably keep up with what was going on. There was so much that was new.

That's not what constrain means, in this context. You allow motion in the x direction. Indeed. What is the force that causes the system to reverse the motion? I don't see one. I don't agree it will behave as you claim. This is a bit of a problem with how you have framed the problem. You have stated certain behavior will occur, but that's not a conclusion from some analysis, so it is very suspect. You say there is an angular speed, but you haven't shown there will be any circular motion. It is an unsupported assumption on your part. The mass being at some y point, if it is given (or has) a velocity solely in the x direction, will simply move in the x direction. There is nothing in the problem to change that motion. The massless, frictionless arm will go along for the ride, as if it wasn't there.

I think in physics (and probably chemistry), it was when quantum mechanics was discovered/developed. The new discoveries based on that were so widespread, there would be no way to stay on top of advances in all of the sub-fields.

As Eise notes, what Einstein noticed was that in electrodynamics the speed of light didn't depend on the frame of reference. The relativity paper applies that principle to kinematics. The title is (or translates to) "On the Electrodynamics of Moving Bodies"

Then why would the motion in the x direction reverse itself? There's no force in that direction to change the x component of the momentum.

It depends on the clock. The best ones aren't built to be portable — one must make sacrifices in clock performance in order to do that. The clock in Mordred's link and the kind of clocks I work on wouldn't run if you put them in a vehicle and drove around. So you'd have to drive faster to see the change with a clock with lesser performance. Long-term performance of clocks can get to parts in 10^17 fractional frequency stability. Timing stability would be better than a nanosecond at one month. Some devices can do better in the short term, but they tend not to run for very long. But if we were able to move a really good clock at say ~100 km/hr (27 m/s), gamma would be ~4 x 10^-15. If your clock performed better than that you could resolve the accumulated time difference, but it would have to run long enough to get the statistics. IIRC the NIST clock measuring the height difference ran for about 5 hours to be able to resolve the time dilation, with a stability roughly less than an order of magnitude better than the dilation effect edit: the paper is Chou et al SCIENCE VOL 329 24 SEPTEMBER 2010 p1631 The stability is only slightly better than the shift, so that's why it took several hours to discern the timing difference

Or it could be motionless. If your initial condition is that the rod is aligned with the x-axis, and your initial impulse is in the y direction. I think the resulting motion of the mass is only in the y direction, and the pivot is momentarily stopped when the rod is aligned with the x-axis.

Driving across the US at highway speeds, from one coast to the other and back, you will accumulate around 1 ns of time difference from the kinematic effects of time dilation. As with Mordred's example, seeing the effect is just a matter of having a good enough clock

What is it you wish to discuss?

How is that different from goods manufactured by other methods?

Yes, appealing to emotion can be a very effective tool for persuading people. That doesn't mean that it is valued elsewhere.

If you have a hot reservoir and a cold one in contact, heat will be conducted between the two. Energy is transferred, but no work is being done. Saying there are different forms of energy is a bookkeeping notion, so we can make sure we account for it all. Energy is a property, not a substance. One of the things we learn from thermodynamics is that some energy can't be used to do work.

No, for a trivial reason: the transfer of energy doesn't have to be work. There is an entire field of physics (thermodynamics) because of this. Plus you can often define systems such that no work is being done. You can't have free energy because it can't be created, whether or not work is being done. Yes. As I implied earlier, thermodynamics adds a bunch of different energy items to be accounted for that are not present in mechanics.

OK, then, quarks.

There are only two choices here. Either they are the same, or they are not the same. The electron and proton have opposite charge. Same magnitude, different sign. Thus, they have different charge. And something with no charge has a different charge than something that does.