What is the relationship between time and space? I recently read a book which was based on spirituality wherein an author says time and space are not different as they are interdependent (when it’s spring in Europe, it’s winter in Australia.)

The relationship is that both are dimensions.

Dimensions is a very misused word. A dimension is a mathematical model that calibrates, measures and indexes an aspect of reality using standard units. Dimensions are abstract overlays that quantity underlying reality for us.

So, in the context of Space and Time, Space is the dimension of position and relative position. The xyx-axis allows us to define a position (in space), and relative positions distance. But its a static dimension until we introduce Time, the dimension of change.

So space, measured in say miles, gives us the quantification of the change of relative position. And Time, in say units of hours, gives us the rate of change (hence time is the dimension of change).

Ergo MPH – Miles (space) Per Hour (time)

So merge the dimension of [relative] position (Space) with the dimension of change (Time) and you get Spacetime, the dimension of changing position…aka motion.

So Time and Space are not interdependent. But Space is static without Time.

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Is time thought of as a literal physical dimension (90 degrees perpendicular to our own) or is it something else entirely?

Something else entirely. The ‘fourth dimension’ right-angle thing is a hopeless attempt to interpret spacetime.

Dimensions are (abstract) measurement frameworks. Space (in the context of dimension) measures relative position, for convenience, in 3 right-angles vectors (height, depth, width or xyz-axis).

Time is the dimension of change, i.e. it’s how we measure change rate. For example we measure change in position (aka Motion) in miles PER HOUR. The per hour bit is time calibrating change.

The problem arises because too many physicists don’t seem to understand what ‘dimensions’ are, and don’t understand what Space and Time are within the context of dimension. Hence they really don’t understand what Spacetime is…the dimension changing position i.e. motion.

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Why is time regarded as an extra dimension if it is just an effect (or property/attribute) of 3-dimensional space?

Time isn’t an effect, property or attribute of ‘3-dimensional space’. They are 2 distinct, separate dimensions.

Time is the dimension of change (hence ‘rate’…eg miles per hour…the per hour bit is time calibrating change.)

Space (in this context) is the dimension of (relative) position (hence xyz-axis). In fact, Space is the dimension of static position (because, by definition, it excludes Time).

Merge the dimension of static relative position (Space) with the dimension of change, and hey presto you get Spacetime, the dimension of changing position…aka Motion.

That makes Time a pretty important dimension in its own right. Change is what drives the universe, after all.

I am going to link below to an answer I just posted to a similar question.

I hope this helps…

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If space is absolute no matter the frame of reference but time is relative based on the frame of reference of the observer, should quantum superposition be interpreted as a particle in 2 or more places/states in time simultaneously instead of space?

Is space absolute?

Space, the word, has different meanings depending on context.

When you talk about Space and Time together you are talking in the context of dimensions.

Dimensions are abstract frameworks / models, formulated in standard units, that we overlay an aspect of reality in order to calibrate and index that particular reality.

[There are many many dimensions, many aspects of reality, that are calibrated in standard units. Dimensions of weight, mass, density, radioactivity, heat, colour, brightness, sound volume, tone, pitch etc etc.]

All dimensions are relative. And all dimensions are abstract ( eg the dimension of temperature is abstract, heat the underlying reality). And all dimensions must be, obviously, reference-frame specific.

Space (in the context of dimensions) is the dimension of relative position. The XYZ axis, the three sub-dimensions (vectors) of height, breadth and depth, simply determine relative position. And we calibrate in units of, say, miles, or centimetres etc.

And Time is the dimension of change. We calibrate change (rate) in units if time, as in xxxx PER HOUR. The ‘per hour’ or ‘per second’ etc is the calibration of change.

So Time is always used in conjuncture with another dimension to give that other dimension a ‘rate’ of change.

So, Space is the dimension of (relative) position. Time is the dimension of change. Merge the two and you get SpaceTime the dimension of changing position aka Motion.

Spacetime is the dimension of (constant) motion. [‘Constant’ motion (eg miles per hour) because dimensions are reference frame specific…for changing motion (acceleration) we need spacetime-time (miles per hour per hour) and for increasing acceleration its spacetime-time-time (eg miles per hour per hour per hour) etc]

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Time and space: are they material realities or product of human consciousness?

The words Time and Space both have multiple meanings – not that you would guess that by listening to most scientists on the topic. Both meanings of Time are abstracts, one meaning of Space is. So the answer to your question is they can both be products of human consciousness. Let me explain:-

‘Space’ has several (related) meanings. A space could be a gap e.g. in a car park, for example. Space also refers to the dimension of position, i.e. the three vectors of xys axis. Or Space might mean ‘everything not on earth’ as in ‘outer space’.

And sometimes Space refers to the entire known universe.

But science is so often not specific when it uses the words. It liberally, lazily conflates these different meaning of these words.

In the context of dimension, space is the dimension of position. That is the three sub-dimension of length, breadth and height (xyz-axis), calibrated in standard units, allow us to overlay an abstract framework that calibrates and indexes position, and relative position.

‘Time’ has two core meanings…to expand on this:-

The ONLY empirical evidence of Time is change / change events (look around you – earth spinning, you breathing, quarks decaying – all change event series). Change can be quantum or compound, depending on your reference-frame. Time represents TWO distinct contexts of change:

1.The calibration of change (i.e. the dimension of change – hence ‘rate’ e.g. miles PER HOUR – the calibration of change of position aka motion) i.e. Time is to change what temperature is to heat, a dimension/calibration set. Temperature is abstract, heat is real, Time is abstract, change is real; and

2. Time is the collective ‘flow’ of change. Time is to change-events what ‘River’ is to water molecules – a collective term. Is a river real? Well yes, on one level; but, fundamentally the word River is an abstract collective, water molecules are real. So too Time is a collective abstract, change-events are real – Time, the ‘flow’ of change.

Time, one word, two distinct meaning, both reference change.

So, both words Time and Space have a context / definition as dimension, i.e. are abstract, or , as you say are products of human consciousness

Hence Space (in this context) is the (abstract) dimension of position, and Time (in this context) is the (abstract) dimension of change. So merge the two and space-time is the (abstract) dimension of changing position aka Motion.

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