geordief

Does it matter that we can't say whether the universe is infinite or not? Is infinity(in this context) an approximation,albeit as close an approximation to anything as can be imagined ?

Have we lost Mordred's answer to your post ? He said that Kip Thorne seems to have just got it wrong if I recall right. Edit:it seems to be koti's post I was looking at . Thought it was Mordred's .My mistake.

Is it just my approximate level of understanding or do these fluctuations bear any (extremely loose analogical) comparison with the "god of the gaps" notion? Do they sort of appear because the overall framework is stretched and ,like a night sky these fluctuations peep through like stars (again just an analogy) These fluctuations do have consequences,don't they ?

Am I going (further) off topic to wonder whether quantum fluctuations are embedded in the various fundamental fields or ,as it were separate to them?

Are there any theories as to why the values for permittivity and permeabiity of the vacuum are as they have been measured? Are there any circumstances where they could (have been) be different ? Could they be a function of any other variable ? Have they any role in quantum theory?

If there were no upper limit to the value of c would it be incorrect to define it as "infinite" since ,once measured it is ,by definition finite? Would the speed of any object be dependent on an energetic input? (the size or energy capacity of the universe as a whole) Agree about the flashlight.

Interactions would be instantaneous**. I am not sure what would follow from that but it is not what I would call an interaction ;everything would be undifferentiated,there would only be one global "interaction". **or is it they would approach instantaneity as a limit in the same way as the universal speed limit would only approach infinity ?

If there had been a reflector at the other end ,wouldn't the Swiss end have seen the experiment before it began? That observation couldn't have been made could it? Would that "impossible experiment" disprove the other a priori?

Not contrary to all our observations? Are there any hypothetical observations that could lead one to believe that something had moved faster than c or at an infinite speed? Would they be ,by definition unobservable ?

And since there is (and must be) a universal speed limit ,it follows that the vacuum cannot have an infinite permittivity/permeability*? (separately from the maths which seems to define the universal speed limit (in terms of permittivity/permeability) *if I am right to understand these terms as a measure of resistance to motion.

Is that because it is only found when detected and so does not "travel" between detections?

I think c and the permittivity/permeability are the "same thing";the 3 hang together in one equation. unrelated to any other variable.

Is it bound up with the universal speed limit (of causation)?

Can I understand the vacuum as being a medium whose permittivity limit approaches infinity? I know that it does have a finite number but my natural inclination is to see it this way. Is there a reason why it is finite ? Because the vacuum is never empty perhaps?

Not consciously. Perhaps I am waffling but definitely not deliberately misleading(I can be obtuse)

So we would be physically** and intellectually stunted in comparison to a civilization that was able to travel in space.... As they say, travel broadens the mind and in our case it may be our only way of prolonging any remnants of our civilization after the circular firing squad that may be just around the corner. ** well,maybe not "physically". Culturally?

That was only intended as a reinforcer of the idea that will will always be curious (not quite sure what you are getting at) Normally about things we see far away but even when ,as in a BH or out there where galaxies are regressing at superluminary speeds

People would leave in their imagination and remain curious for ever. We have no idea what lies beyond the observable universe and yet some still find it fascinating and search for testable hypotheses in the remotest possible environments. What else are we going to do once we have filled our bellies ?

Up to the 60s the idea that space travel was impossible would have normal to most people .It was to me. it didn't stop one being curious as to what lay beyond the Earth.

My confusion .I was (double) counting the positive and negative axes separately.

Is it fairly easy to show when two vectors in a space with n degrees of freedom are orthogonal? Suppose the model had 10 dimensions would there be 2^10 orthogonal axes?

So ,if we start with any unit vector there are an infinite number of ways that one can define a new unit vector so that its dot product with the original vector is zero? Is this dot product a more general requirement for a new spatial dimension than the right angle requirement which I would be more used to?

The space that we are used to is 3D and we construct it (the model) by ensuring that the 3 planes (x=0:y=0:z=0) are orthogonal to each other. How do we move on from there if we want to build a model with 4 such planes ,all presumably orthogonal to each other in the same way? To my untrained eye it seems that the new( 4th) plane will have "nowhere to go" ie ,if it is orthogonal to the x=0 plane then it feels like it should be identical to the y=0 or the z=o plane which already occupy those areas("area" is a poor choice of word ,but I hope the meaning is clear) How do we "shoehorn " this extra plane into the model when it feel like there is no space available. PS I am obviously thinking about the spacetime model but the difficulty I have seems to apply to any 4d model with 4 spatial axes (which is what the spacetime model can be viewed as sine "ct" is a spatial distance)

Is assymetry a synonym for net energy? Or a closely related concept?

"a moat if fog" = "a motive for " ? Not a frog in the moat, anyway..... Or maybe Trump is a slimy toad (if that is the write spelling)