MigL

The internet can be used irresponsibly as well; by people who post crap.

Money is a tool, and monetary systems are institutions. Tools can be used irresponsibly, and institutions can be used by unscrupulous people to take advantage of others. So, is the problem with money and its institutions, or with unscrupulous people ? Good to read your opinions again Ten oz. Welcome back buddy.

He certainly can't place the mirror... But if he were to look at a pre-existing mirror 20 light years away, he could ( with suitable technology ), see himself graduating 40 years ago. Hope I'm not being offensive at estimating your age to be in the 60s, joigus.

Interesting how we all perceive space-time differently. Studiot in terms of intervals between events. Markus in terms of metrics and tensors I'm old fashioned. I see space-time diagrams in my head; and now I'm told that there is no actual need for my imaginary co-ordinate systems. I'm crushed !

I guess it's a good thing you didn't waste your time typing out all 23 pages of this garbage.

Who would have thought these advanced beings have the same difficulties defining time as we do. But seriously, and metric signatures aside, you can't change the rules and imagine the three time dimension (0+3) universe having time behave differently than it behaves in our universe. It still needs to be one way only, and allow interaction with only the local now, as opposed to our spatial dimensions, which allow more degrees of freedom and interaction at a distance. If we consider no spatial dimensions and one of time, the space-time diagram would consist of one axis, the event would be a point on that axis. and its world line would describe a line segment along that axis. Similarly, no spatial and three time dimensions would allow that event, still just a point as it has no spatial extent, to move along three separate time axis, and so describe a curved, or three dimensional, line segment. Still moving only forward ( one way ) along each axis, but the requirement for interaction at a distance is gone as there are no interactions ( or distance ). I really don't know what a curved timeline as opposed to a straight timeline implies in those particular universes

I've often thought of putting a person or two on my ignore list. As I'm sure others have thought about ( or have ) put me on their ignore list. ( I like to argue 'contrary' points of view, especially in the Politics section ) And then, sometimes, those users that I almost ignored, post some real gems.

The last time you introduced this idea, you were told "Do not start another thread on this unless you can provide the required mathematical rigour in place of the waffle." and the thread was closed. What makes you think you can re-introduce it by hijacking this thread ?

Your original question was ... I propose that if we didn't inhabit a spatial+temporal universe, neither I, nor you, would be able to say that it 'changes', so I claim that change is a property applicable to our universe, where we are making the observation from. Your button may have different top and bottom halves, but it doesn't 'change' in the two dimensional universe of my screen. Claiming that you can see 'change' in a two dimensional universe from our spatial+temporal vantage point doesn't amount to much. You cannot claim that 'change' exists in two dimensional space when there is no experiment you can perform, intrinsic to that two dimensional space, that will detect that 'change'. That is the problem with the definition of change.

From Wiki "Ammonium nitrate is not an explosive in the form it is commonly sold.[10] However it readily forms explosive mixtures with varying properties when combined with primary explosives such as azides or with fuels such as aluminium powder or fuel oil." https://en.wikipedia.org/wiki/Ammonium_nitrate As to the violent decomposition when quickly heated, I can also make a balloon full of air explode, by heating it. And just to be clear, once you add heat to decompose it to anhydrous ammonia and nitric acid ( which are not the decomposition products, by the way ), it is the combination of ammonia ( strong reducer ) and nitric acid ( strong oxidizer ) that is explosive, not the original ammonium nitrate.

Never thought I'd see the day that third world countries, banana republics and military dictatorships have to send observers to the USA to verify that the current President doesn't try to pull a fast one in the upcoming election. And the way he's mis-handling the Coronavirus pandemic, waiting until it is safe to have an American election, would effectively make him President for life.

No, that is not my viewpoint; change does not need to involve a process. But we are looking at change, even 2dimensional change such as on a computer screen, from a spatial+temporal perspective. Such as this ... you only note the change because our universe has a time dimension. If there was no time, you would not be able to 'see' the change from top to bottom of the circular button. Our definition of 'change' does not depend on time, but nevertheless, it takes time into consideration. I'm not saying change needs to have an observer ( or interaction ), but it IS defined by the observer ( who happens to be spatial+temporal ). I find that interesting .Could you elaborate ? But I would have thought three (0+3) time dimensions unworkable. Three (3+0) spatial dimensions, or a static ( don't want to use unchanging and cause more arguments ) volume, would be different from a singular (0+1) time dimension, or a 'progressing' point ( along a straight line ). So if the three (0+3) time dimension universe obeys the same temporal rules as our time dimension, it would still result in a single point which can progress along any of three time axis ( along a curved line ). A graph of the system might 'look' the same, but the implications of the motion, or progression, would be entirely different.

The concept of 'change' only makes sense in a universe with time. That is why we can observe a universe without time, such as the teacup universe, or the electrostatic universe, and notice change. we are 'outside' those peculiar universes. That is because the concept of 'change', ( in effect, for change to be observed ) has to involve the paradigm of time passing. So we, in this universe notice change even in the teacup/electrostatic universes, but those universes would never have developed the concept of 'change'. How could they ? ( by the way, that's a lot of nos. Was it for emphasis, or three nos for particular points ? )

Wish I could give you two up-votes Eise. I think, Studiot, that our definition of 'change' references the observer, not the universe being 'observed'. ( WE need to note a difference in order to call it 'change' ) And that is simply because the concept of 'change' has arisen in a universe with time.

As the last glaciation epoch lasted from about 115 000 to 12 000 years ago, and the maximum ice extent was about 22 000 years ago, I can readily see people crossing over the ice/land bridge between Siberia and Alaska 30 000 years ago. Homo Sapiens was already in Northern Europe 45 000 years ago. I guess we got around.

I believe Area54 politely asked you three times to clarify your position. It would have been common curtesy to comply, instead of bragging about your stock portfolio.

And what I'm failing miserably to explain, is that this is not true because you and I are intrinsic to this universe, which has three spatial dimensions and one of time. But it certainly would be true if we were intrinsic to a universe with only three spatial dimensions. You could NOT get hit by a bus, or a giant jack, and I'm not sure an orbital even makes sense in such a time devoid universe. Our definition of 'change' applies to a universe which includes a time dimension, OR, we are extrinsic to a universe which has no time. IOW, I can look at a 2D sheet of graph paper with a teacup drawn on it, and notice 'change' because I'm extrinsic to that 2d graph. But if I was a flat-lander intrinsic to that 2D graph sans time, I could not possibly note any change.

Markus and Studiot So in this 'dead' 3D universe without time, there can be change, but it is only apparent to an extrinsic observer ( outside that universe ) ? That universe itself cannot have an intrinsic observer to detect that change. That seems to me, to be a problem with our common definition of change; it HAS to be observed. And therefore time is required. ( sorry Studiot, I'll get to your orbital/jacks question when I have more time to review the questions )

You remind me of another member we had a few years back, who continuously bragged about his stock portfolio. He crashed and burned very quickly. Are you really participating/contributing in the discussion if you post cryptic comments, then refuse to clarify when politely asked ?

No,no, Studiot, I have one for you... If you inhabited a 'space' with just the three orthogonal dimensions and NO time parameter, how exactly would you 'see' the teacup ? Could you interact with one aspect of it, say the spout, and then another ? Remember the teacup doesn't change with time as it has no time parameter, but you are also intrinsic to that particular space, and there is no time parameter for you either.

It's a good thing most of us ignore your 'generally disagreeable' position, because it's as clear as mud.

While I can easily imagine functions ( or teacups ) changing according to parameters other than time, I suspect the problem is with our common definition of the concept of change; it necessarily involves time. Even though it is not a variable of the system under observation, it is necessary for the observer to detect 'change'. Sure, the teacup 'changes' with respect to location ( from spout to bowl ), but for us to observe both aspects of the teacup, time must necessarily be involved ( first you observe the spout, then, the bowl ).

I understood the OP to be asking whether GR can be expressed in terms of changing scales of the 4 constituent dimensions, NOT whether GR can be expressed as a scalar field. I think we all agree it cannot be expressed as a scalar field, but neither can changing scales in 4 dimensions. I believe I've read some of K thorne's work where he claims aspects of GR can be expressed as either 'changing lengths/intervals' at constant scales, or 'changing scales' at constant lengths/intervals. I'll have to look into the standard model Lagrangian problem with changing scales.

There is a certain simplistic truth to that statement. ( I did not downvote ) We all make choices based on our own priorities, and should be responsible for those choices. The OP seems to believe a 'chemical imbalance' absolves the perpetrator of a crime from responsibility. As an example, drunkenness is a temporary 'chemical imbalance' which affects judgement; are we going to absolve drunk drivers who kill others of responsibility ? I don't think anyone here would support that. Even if you propose that the driver had previously made the choice to drink and drive, the counterargument is that alcoholism is a recognised disease, so he/she is still not responsible for their actions. So where do you draw the line of accountability ? Society has no choice but to consider most to have free will and to be responsible for their actions. So, if you choose to steal ( and possibly hurt others in the process ), instead of making do with what you have, asking for government assistance, or even begging, because you are hungry ( or greedy ), you have made your choice, and are held accountable by society.

Oh, I thought you were going to say "If you're puzzled by women, you're in good company" ( nothing better than a complicated woman )