The age of the universe thread

Originally posted by divegeester...
So, if time is variable and relative, how can we say with any certainty that the universe is X years old?

This doesn't answer your question, but although we call time the fourth dimension, actually it is just the measurement of change. The environment changes, we find something cyclical and then we can 'quantify rates of change of quantities in material reality' (wiki).

Originally posted by twhitehead...
1. It is space expanding, not objects moving away from each other, so technically the relative time effect doesn't happen as far as I know. ...

I've always wondered about the part I bolded. It seems to imply that space itself is some sort of substance.

Originally posted by chaney3
Okay twitehead. With much respect and curiousity, leaving out the Christian God and the Bible God.....you would be open to 'something' such as a Creator?

That depends on what you mean by 'open to', and what you mean by 'creator'. Could a conscious entity have created the universe? Yes. Do I think it likely? No.

Originally posted by apathist
I've always wondered about the part I bolded. It seems to imply that space itself is some sort of substance.

Not necessarily. Time dilation in relativity does not imply time is a substance.

There is a fundamental difference between objects moving away from each other in static space and space itself expanding. I would need to study relativity quite a bit more to explain it fully though.

originally posted by twhitehead
Not necessarily. Time dilation in relativity does not imply time is a substance.
Is that a typo? You said "It is space expanding" and I said that implies space is a substance.
Also, I've said that time is just the measurement of change.

There is a fundamental difference between objects moving away from each other in static space and space itself expanding.
I understand for example the balloon analogy. But if its correct, it also implies that space is a substance.

Interestingly, the rubber sheet analogy for einstein’s general relativity model of gravity also implies that space is a substance.

I would need to study relativity quite a bit more to explain it fully though.
I think the explanations would depend on the concept of expanding or strectching space, rather than explaining it. Iow they would beg the question. Just say space is made of an 'expansion field' and be done with it. Fields are so handy!

Originally posted by apathist
time is just the measurement of change.

I don't see how that makes any sense. You could try and measure some change (of something) and for, say, one minute, not observe any change thus indicating zero or near-zero amount of change; so no time passed during that one minute? And then the next minute observe loads of change indicating a much larger amount of change; so more time passed in that minute than the minute before?

the rubber sheet analogy for einstein’s general relativity model of gravity also implies that space is a substance.

I could be wrong but I don't think it does because, regardless of whether it actually is a 'substance', it is an analogy and thus I think it doesn't imply it is a 'substance' any more than that it implies it is made of rubber. But I could be wrong here because it may depend on what you mean by 'substance'.

Originally posted by apathist
Also, I've said that time is just the measurement of change.

Well you are wrong about that. Time is a dimension, just like space.

I understand for example the balloon analogy. But if its correct, it also implies that space is a substance.
No it doesn't. That dimensions can change doesn't imply that they are a substance.

originally posted by humy
You could try and measure some change (of something) and for, say, one minute, not observe any change thus indicating zero or near-zero amount of change; so no time passed during that one minute? And then the next minute observe loads of change indicating a much larger amount of change; so more time passed in that minute than the minute before?
How did we determine that the 'one minute' passed? We used a clock, right? So as I said we find something cyclical and then we can quantify rates of change of quantities in material reality.

We see the sun rise and fall and rise again - we call that one day. We see the solstice come and go and come again - we call that one year. Currently one second is defined by the Standard International as 9,192,631,770 cycles of the radiation produced by the transition between two levels of the cesium 133 atom.

Time is just a measurement of change.

I could be wrong but I don't think it does because, regardless of whether it actually is a 'substance', it is an analogy and thus I think it doesn't imply it is a 'substance' any more than that it implies it is made of rubber. But I could be wrong here because it may depend on what you mean by 'substance'.
I know it is an analogy. I have no problem using the analogy - am comfortable with the idea of a gravity well for example.

If space is something, then what is it such that can be curved? If space is nothing, then there is nothing to be curved! It must be that the math we use happens to be the math that does describe curves.

Actually though, I think there is no such thing as 'empty space'. The greatest vacuum is a sea of energy or at least whatever it is that is a potential for m/e.

originally posted by twhitehead
Well you are wrong about that.

No I'm not.

Time is a dimension, just like space.
Time can be considered a dimension, yes. It is not like a spatial dimension at all.

All m/e and all of space exists. But the past and the future do not exist. That's how we know that time viewed as a dimension is a mathematical construct only. We use the maths to describe reality, but it is always a mistake to confuse the map for the terrain.

Originally posted by apathist
Time can be considered a dimension, yes. It is not like a spatial dimension at all.

It is same same, only different.

All m/e and all of space exists. But the past and the future do not exist.
Well that just has to do with how you define 'exist' and how you define 'past' and 'future'.

When you say 'all of space' exists what point in time are you referring to? Is there a universal 'now' point in time? When you actually try to measure, you will be comparing with points in the past that you claim doesn't exist.

That's how we know that time viewed as a dimension is a mathematical construct only.
The spacial dimensions are mathematical constructs too.

We use the maths to describe reality, but it is always a mistake to confuse the map for the terrain.
Mathematical constructs reflect reality. There has to be a reality for the mathematical construct to describe or the construct is useless. The mathematical constructs of time and space are both useful and thus there is reality described by both constructs.

originally posted by apathist
It is same same, only different.

Do you suppose you're being clear?

Well that just has to do with how you define 'exist' and how you define 'past' and 'future'.
I start with the dictionary. How about you?

When you say 'all of space' exists what point in time are you referring to? Is there a universal 'now' point in time? When you actually try to measure, you will be comparing with points in the past that you claim doesn't exist.
I think it's called the god's eye view.

The light we see was produced in the past, and we see it now. You imply that you think the past exists now. Did you mean to imply that?

The spacial dimensions are mathematical constructs too.
Very good! Math is fond of dimensions.

Mathematical constructs reflect reality. There has to be a reality for the mathematical construct to describe or the construct is useless. The mathematical constructs of time and space are both useful and thus there is reality described by both constructs.
Time in physics math works in either direction. Do you suppose that means we can travel to the past?

You realize that you haven't touched my claim that time is a measurement of physical change, right?

Originally posted by apathist
Do you suppose you're being clear?

Sorry, that was a local meme.
What I mean is that of course time is not identical to space, but there are similarities.

I start with the dictionary. How about you?
My dictionary has multiple entries for most words.

I think it's called the god's eye view.
God doesn't exist, nor does his eye.

The light we see was produced in the past, and we see it now. You imply that you think the past exists now. Did you mean to imply that?
No, I imply that the past exists. Existence isn't time-bound. Existence does have a time stamp. So it exists then.

Time in physics math works in either direction. Do you suppose that means we can travel to the past?
Yes. We did.
What we cannot do, is realise that we have travelled to the past. Its one of the outcomes of entropy.
As you say, the math works both ways.

You realize that you haven't touched my claim that time is a measurement of physical change, right?
You realise that that is kind of a definition of a dimension right?
Space is also a measurement of physical change.

Originally posted by apathist

How did we determine that the 'one minute' passed? We used a clock, right? [/b]

What if there is no clock and we didn't measure anything because nobody observed the rate of change (of something) ? One minute still passed, right?
Now, if the rate of change (of something) in one minute was different from the next, does that mean one minute was different in length from the other?
This is why it makes no sense to say time is the rate of change. Rates of change (of something) can vary with the same time passing.

If space is something

it is.

If space is nothing,

It isn't nothing.

I think there is no such thing as 'empty space'

I believe that for all practical purposes, 'empty space' could be reasonably defined as a volume of space that, excluding i.e. ignoring virtual particles, contains no (or at least 'very few' ) particles.

originally posted by twhitehead
What I mean is that of course time is not identical to space, but there are similarities.
I realize you are treating time as if it were like a spatial dimension and so then you see similarities.

My dictionary has multiple entries for most words.
How do you decide which entry to use?

God doesn't exist, nor does his eye.
The god's eye view is a mainstream concept.

No, I imply that the past exists. Existence isn't time-bound. Existence does have a time stamp. So it exists then.
The middle two sentences are very ambiguous. The first and last are incoherent.

Yes. We did <travel to the past>.
What we cannot do, is realise that we have travelled to the past. Its one of the outcomes of entropy.
As you say, the math works both ways.
We have never traveled to the past.
Even if we did (we didn't) you claim we cannot realize that we did so - after claiming you realize that we did so!

As you say, the math works both ways.
Yes, but reality doesn't. By assuming otherwise you confuse the map for the terrain.

Despite the physics maths, an broken egg will never jump off the floor and reassemble on the table.

Time is type of measurement and so exists only in our minds. What exists in reality is m/e that is constantly in flux, always always changing, everything that exists is full of motion.

You realise that <time is a measurement of physical change> is kind of a definition of a dimension right?
Space is also a measurement of physical change.
Space exists even if we did not exist. M/E would exist even if we did not. Measurement systems however would not.

originally posted by humy
<space> is <something>.
What is space other then the m/e within it?

(Such that it can expand and be curved as if it were a substance.)