Is the fourth dimension tangible?

No dimension is tangible.

It is one of the most frustrating aspects of science, the fact that otherwise eminent academics have allowed the word dimension to be so badly misused. (And, yes, Einstein must take some of the blame – but mostly I blame those who came after him)

Dimension means measurement.

A dimension is a measurement framework that we overlay an aspect of reality to calibrate and reference that aspect of reality.

Example – Temperature is the dimension of heat. Temperature is how we calibrate and index heat. Temperature is abstract, heat is real.

Space and Time are both words with multiple meanings. Both have a context as dimensions.

In the context of dimensions, Space is the dimension of (relative) static position, hence xyz-axis. The dimension of Space is how we measure relative static position, using standard units. It is static relative position because, by definition, it excludes Time.

The dimension of Time is how we measure, calibrate, index change. For instance, changing position (motion) is calibrated in, say, miles per hour. The per hour bit is time calibrating the rate of change.

So merge Time, the dimension of change, and Space, the dimension of relative position, and we get Spacetime, the dimension of relative changing position (motion) (in fact relative constant motion, as dimensions are reference-frame specific).

So, in answer to you question, the fourth dimension, like all dimensions, is NOT tangible.

Is it possible that something can be ‘outside’ of the ‘space time’ continuum?

Obviously Yes; abstract nouns, are outside the space-time continuum. Mathematics, justice, fashion, arts, science, religion…all abstract nouns that only exist in our mind.

But are you sure you know what the Space-time continuum actually is??

Space (in this context) is the dimension of (relative) position (hence xyz-axis)

Time (in this context) is the dimension of change (hence ‘rate’).

Spacetime is hence the merged dimension of changing position aka, motion.

So anything that is a ‘concrete noun’ (as opposed to an abstract noun) i.e. has a tangible reality – like a quark, or a table or a solar system – has a physical ()relative) position, and probably incurs change. And mostly will include change of (relative) position…most things in the universe (maybe all things) are experiencing motion, and all experiences relative motion (dimensions being reference-frame specific).

So anything with a physical presence will always be within the space-time continuum, as you call it.

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.

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.