Speed of Light and the Age of the Universe

Polymath257 · Aug 4, 2019

shmogie said:
I have no problem with dating the universe at 14 billion years.

My point was simply the the ever increasing speed of expansion stretches time as well as space.

I'm curious what you think that means and what effect you think that would have on actual timings we measure. If you could supply the mathematical description, that would be helpful also.

For me, the expansion of the universe is described by the metric tensor

ds^2 = -dt^2 + a^2(t) [ dx^2 +dy^2 +dz^2 ]

Where a(t) satisfies some equations connecting it to energy and pressure density.

Now, the fact that a^2(t) is in front of the dx^2+dy^2+dz^2 says that space is expanding with a(t) representing the expansion factor. The fact that it is NOT in front of the dt^2 shows that there is not a corresponding time dilation. It also means that t represents the proper time of a co-moving observer, which is the appropriate time coordinate for universal expansion.

Do you want to go deeper?

Subduction Zone · Aug 4, 2019

Polymath257 said:
I'm curious what you think that means and what effect you think that would have on actual timings we measure. If you could supply the mathematical description, that would be helpful also.

For me, the expansion of the universe is described by the metric tensor

ds^2 = -dt^2 + a^2(t) [ dx^2 +dy^2 +dz^2 ]

Where a(t) satisfies some equations connecting it to energy and pressure density.

Now, the fact that a^2(t) is in front of the dx^2+dy^2+dz^2 says that space is expanding. The fact that it is NOT in front of the dt^2 shows that htere is not a corresponding time dilation. It also means that t represents the proper time of a co-moving observer, which is the appropriate time coordinate for universal expansion.

Do you want to go deeper?

I do not think that someone that does not understand relativity will be familiar with term of "proper time". I know that I was not familiar with the concept.

Polymath257 · Aug 4, 2019

Subduction Zone said:
I do not think that someone that does not understand relativity will be familiar with term of "proper time". I know that I was not familiar with the concept.

Yep. it is a basic concept, but one that most people with only a popular understanding of relativity never figure out. And yet, it is actually central to all of relativity.

ecco · Aug 4, 2019

Polymath257 said:
Of course. But it is still a silly position to take.

Please explain why...

The Universe, and everything in it, was created last Thursday, along with our memories of everything that happened prior to that.

it is any sillier than...

In the beginning, there was only the sky above, water and marshland below.

The chief god Olorun ruled the sky, and the goddess Olokun ruled what was below.

Obatala, another god, reflected upon this situation, then went to Olorun for permission to create dry land for all kinds of living creatures to inhabit.

He was given permission, so he sought advice from Orunmila, oldest son of Olorun and the god of prophecy.

<snip>

When Orunmila heard the news he climbed down the golden chain to the earth, and cast many spells which caused the flood waters to retreat and the dry African land reappear.

So ended the great flood.

-OR-

1In the beginning God created the heavens and the earth. 2Now the earth was formless and empty, darkness was over the surface of the deep, and the Spirit of God was hovering over the waters.

3And God said, “Let there be light,” and there was light. 4God saw that the light was good, and he separated the light from the darkness. 5God called the light “day,” and the darkness he called “night.” And there was evening, and there was morning—the first day.

<snip>

13By the first day of the first month of Noah’s six hundred and first year, the water had dried up from the earth. Noah then removed the covering from the ark and saw that the surface of the ground was dry. 14By the twenty-seventh day of the second month the earth was completely dry.

ecco · Aug 4, 2019

ecco said:
You use to word "lying". However, when you use the Capital G God, you are referring to a god that most believers feel is Omni-All. You cannot know the mind of such a god. What you refer to as "lying" may just be His way of testing us or some other concept we cannot even begin to imagine.

Subduction Zone said:
Even if it is a test it would still be lying. Which brings that same problem back again for believers in Last Thursdayism. It could be such a test, but how would we know? How could we trust such a god rationally?

No. Testing is not lying. But if you want to take that approach, then please explain why any religion's beliefs would lead to being able to Trust God. All of them are based on what you call "lies".

We know Genesis is false because we know there was no Great Flood. (Genesis 1 NIV)

We know because it did not take many spells to cause "the flood waters to retreat and the dry African land reappear". (Yoruba Creation Myth | African Stories and Myths)

Last Thursdayism gives a more logical and rational view than any other Creation Story.

ecco · Aug 4, 2019

ecco said:
In exactly the same way that the Judeo/Christianity Genesis does.
In exactly the same way that the Cherokee Creation Story does.
In exactly the same way that any of thousands of Creation Storys do.

shunyadragon said:
I disagree they are the 'same,' yes there are similarities, but beyond that it is highly interpretive.

So you assert. But you do not show why.

shunyadragon · Aug 4, 2019

ecco said:
So you assert. But you do not show why.

Why? No one, so to speak 'knows.' The obvious is the nature of being human that makes all cultures in history similar.

Subduction Zone · Aug 4, 2019

ecco said:
No. Testing is not lying. But if you want to take that approach, then please explain why any religion's beliefs would lead to being able to Trust God. All of them are based on what you call "lies".

We know Genesis is false because we know there was no Great Flood. (Genesis 1 NIV)

We know because it did not take many spells to cause "the flood waters to retreat and the dry African land reappear". (Yoruba Creation Myth | African Stories and Myths)

Last Thursdayism gives a more logical and rational view than any other Creation Story.

This is why creationists have to deny reality. They can see that their God would have to be dishonest in their opinion if the Bible was not literally true.

dad · Aug 5, 2019

Polymath257 said:
Tests for what? The light? Sure! The neutrinos? Sure! Gravitational waves? Sure!

Time. What is time like compared to here, way out in deep space?

dad · Aug 5, 2019

ecco said:
I was stating that, if one wanted to play make-believe with an "already existing universe that was expanding" then one had to accept that Last Thursdayism is just as valid as Genesis

If it was created then, you have no clue where to stop or start. Any possibility that is was is ruled out and labelled last thursdayism. Got it.

I was stating that, if one wanted to play make-believe with seeing and visiting a singularity then one must also consider:

So you can't produce one but one created the universe. We get your belief.

dad · Aug 5, 2019

ecco said:
Any tests that you can apply to Genesis can be equally applied to Last Thursdayism, with the exact same results.

Any tests you dream of do not matter. What matters is you can't test your way out of a paper bag.

dad · Aug 5, 2019

ecco said:
You are aware that when you use the phrase "this poster" you are referring to yourself.

No, I was referring to the spammer that pretends he could say something but never does. Occasionally he will utter a phrase as if he settled the debate, but it is inevitably off target, irrelevant and he could not defend it anyhow apparently as he never follows up.

Try to keep up.

Subduction Zone · Aug 5, 2019

dad said:
Time. What is time like compared to here, way out in deep space?

Time has been shown to be the same in space. You are the one that wants to claim that time is different. The burden of proof is upon you.

Subduction Zone · Aug 5, 2019

dad said:
Any tests you dream of do not matter. What matters is you can't test your way out of a paper bag.

No, no, no. You can't test your way out of a paper bag and you make the error of assuming that others are as ignorant as you are.

This is a good time to remind you that you do not understand the concept of evidence. Would you like to discuss it or do you still have your running shoes on?

shunyadragon · Aug 5, 2019

dad said:
Time. What is time like compared to here, way out in deep space?

By the evidence the universe is expanding at a predictable rate, the time/space nature of our universe is predictably uniform. When we look out in deep space we uniformly look back in time based on Einstein's Theory of Relativity.

ecco · Aug 5, 2019

ecco said:
Any tests that you can apply to Genesis can be equally applied to Last Thursdayism, with the exact same results.

dad said:
Any tests you dream of do not matter. What matters is you can't test your way out of a paper bag.

So you, a Christian, are admitting that Genesis is just a bunch of pretend stories. Got it.

shunyadragon · Aug 5, 2019

ecco said:
So you, a Christian, are admitting that Genesis is just a bunch of pretend stories. Got it.

Your negating the fact that many Christians, and Baha'is DO NOT consider Genesis nor Exodus literal history.

ecco · Aug 5, 2019

dad said:
No, I was referring to the spammer that pretends he could say something but never does. Occasionally he will utter a phrase as if he settled the debate, but it is inevitably off target, irrelevant and he could not defend it anyhow apparently as he never follows up.

Try to keep up.

I was keeping up. That's why I felt I needed to explain to you what "This Poster" means.

ecco · Aug 5, 2019

shunyadragon said:
Your negating the fact that many Christians, and Baha'is DO NOT consider Genesis nor Exodus literal history.

That's correct. However, I was inquiring about the specific beliefs of a specific poster. So, let's let him answer, OK?

Polymath257 · Aug 5, 2019

dad said:
Time. What is time like compared to here, way out in deep space?

Well, that depends where you are. Close to a compact object like a neutron star or black hole, it shows dilation as predicted by relativity.

The problem is that there are two types of time: coordinate time and proper time. Coordinate time is arbitrary and can have any parametrization we want. Proper time is what someone/something actually experiences.

Remember that time duration is *defined* via physical processes. We measure time by counting off periodic phenomena. If we see a certain number of wavelengths of some light, that *is* a second.

So, when you ask what is time like 'out there in space', all we need to do is compare the vibrations of light there to those here. And the cool thing is that the light can travel from there to here. That allows us to correlate what happened there and what happens here.

And what we find is that time there is very much like time here, at least for the last 13 billion years.

Speed of Light and the Age of the Universe

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