J.C.MacSwell

If, simultaneously in a vacuum, you dropped 1000 empty egg shells and one egg would they not all hit at the same time? If you glued all 1000 egg shells together, giving them more mass than one egg, would they then fall faster?

You can reorientate yourself in space, but without pushing against something external or jettisoning something internal you can't change your angular momentum. So if you start with none in an isolated system that system will never have any.

We need to photoshop a horse into the passenger seat of Elon Musk's car...

Hi Koti Sorry. I meant to type angular momentum where I typed angular motion. You can't change the angular momentum of an isolated system. What I meant by the appearance of spinning is, for instance, you could spin the surface of a ball one way with the inside spinning the opposite, giving the appearance that the ball itself is spinning with the ball/system having no net spin.

If say a very large mass (ideally infinite) was used outside the system to provide the angular momentum, the energy could come from within the system. This would provide the angular momentum without the energy coming from outside. The mass and gravitational potential would therefore not change. Unfortunately you cannot get the system/ball to actually spin if you mean this to come from within the system/ball . You could get the appearance of spinning but no change in angular motion from within. This is different from what I had suggested earlier with the energy coming from within, but by necessity the system/ball has to be open to external forces for the reason Swansont mentioned Have to be a little careful describing what is within a system vs what is within a frame, and the context implied or assumed

Also of course, if the energy comes from inside the ball/system there will be no net change of energy and no increase in gravitational potential or inertia.

Unless the energy leaves the system, or gets repositioned within the system, there should be no change. (Or is that your point?)

The gravitational potential will increase due to the spin, as will the rest mass of the ball/system. The rest mass and relativistic mass will increase due to the sum of the increased relativistic masses of it's parts. In it's rest frame the rest mass and relativistic mass is the same thing though.

Yeah. Go Physics! An early sting or bite should surely keep them from too much focus on Biology...

Thanks. Is this true just classically, or true in any idealized case? (I pictured the last quantum step getting to the goal line)

Why not? In this hypothetical scenario empty space would effectively be at a temperature of 0 K. Your blackbody would tend to that.and have no reason to radiate further as it reached it. The reason you can't get anything to 0 K is that there is no 0 K space around to be utilized to allow it...your hypothetical does not exist.

Not an expert on evolution or even a biologist but I think I have assumed this (speciation reversal as a potential and likely process) as obvious once I realized that the definition of species is less rigid than I was originally taught back in grade school. I guess the devil is in the details.

Yeah. I think it stands as part of the equation, but there are a lot of interdependencies involved. Best to jog a couple miles before relieving the kidneys...just to get that core temperature up!

A food calorie is actually a kilocalorie of energy. Otherwise I would simply have a nice cold beer and lose weight. (after it goes through my system) So a litre of water at 38 C would net me 1 food calorie equivalent (1 degree above my body temperature) A litre of water at 0 C would save me 37 calories worth of dieting But it has no actual food calories as mentioned above.

So...is taking oil out of the ground without paying the current and future damages it causes effectively, if not literally, a subsidy?

What if we could still negative a post, but it would not count against the poster unless they are currently positive? That way for new posters you can attack the post, but not the poster. It would give them some level of amnesty. They would still be subject to following the rules, subject to suspensions etc, which I think is generally pretty fairly regulated, but a little more forgiven otherwise.

Over time it might. Let's say a new member who wants to learn has -10 the first month, but after 6 months is a -15. They have actually improved but the reputation system says otherwise. If you want them to care about rep they would be better off opening a new account. If I see a good question but know the science is incorrect I never down vote it but some do, especially if the poster has asked a similar question before. I tend to not want to up vote it if the science is incorrect. If someone is poor mannered they are more likely to get away with it if their science is correct, so a double standard with regard to that seems to be in place. So yes, ideally they gain it back over time, but I really don't think it happens readily for those just learning. So they can carry negative rep for some time.

I had made a suggestion a while back but IIRC it wasn't feasible because of a software change requirement or something. Basically it would add points over time to anyone with negative rep, since it seemed new members would tend to get it and not have time to adjust, understand the rules (such as speculating in good faith but in the wrong forum type of thing) They could be potentially solid members but would carry that negative rep for some time. Maybe if a mod would simply clear it after 30 days they could have a fresh start. It is after all a system where we want members to actually care about to some degree about their score, especially if negative and it is much easier to get negative (just start insulting) than positive (well thought out or helpful) rep.

Agree essentially but still perhaps not absolutely. We do not know what is beyond our fixed stars (observable universe), so cannot say definitively that it is not rotating wrt something greater or other, if given that inertial frames can be produced that rotate wrt it as the Wiki article suggests. This was what I meant when I posted previously:

I would certainly agree with that part. Did not know there was an absolute reference frame in GR. Do you have a link for this?

In there simplest and most straight forward form? Because it is not an inertial frame.

One where Newtonian physics, to a close approximation, does not apply. If you mean more precisely than that, LOL, I would not! You mentioned this earlier, can you elaborate on the point you are trying to make and how it relates to absolute rotation?

I think the concept is there. The fact that they have limited realm should support, not detract, from my line of reasoning, should it not?

Again this is clearly true in Newtonian physics and SR/Minkowski space but as I asked earlier is it necessarily true in GR? The Wiki link seems to indicate no, it is not necessarily true in every case. It is very brief, did you read it?

Is there a spinning black hole in the vicinity? If not, or something similar, how is this pertinent? You have a non inertial frame with the roundabout and want to compare it to the playground (essentially inertial). The question I put forward yesterday was whether two inertial frames could rotate wrt one another and the answer according to the link I found seems to indicate that yes, it is possible (albeit extreme circumstances) This does not prove absolute rotation cannot exist but it does (for me at least) raise the possibility and I have heard no arguments against it, Swansonts proclamations notwithstanding.