[chris (OP)]

Robert says:

The speed of sound was obviously finite before it was measured. Since all measurements are finite a measurement alone proves nothing. It is axiomatic that any visible object is seen as it appears.

What do you think?

[Colin2B]

Until the speed of sound was measured no one knew whether it was constant, or varied under different conditions, or varied by frequency, etc.
Each measurement tells us more about how things behave and allow us to make predictions.


The number of people in a room is finite, but if you are trying to feed them a simple count of people and food can prove whether it is possible.


"It is axiomatic that any visible object is seen as it appears."
I don't think that is true, as shown by numerous optical illusions.

[evan_au]

It is axiomatic that any visible object is seen as it appears.

If this is suggesting that light is instantaneous, then I would paraphrase the OP as follows:

The speed of light was not obviously finite before it was measured.

It was so fast that measurements like waving lanterns on hills is too slow to measure it.

But the speed of light was eventually measured indirectly by Ole Rømer's observations of the moons of Jupiter, and directly by  Fizeau by watching light beams passing through a spinning wheel.

I agree that practical measurements take a finite amount of time, but this is adequate to measure finite things like the speed of light. According to Einstein, nothing should travel faster than light, so we should be able to measure them, too (in principle).

See: https://en.wikipedia.org/wiki/Speed_of_light#First_measurement_attempts

[puppypower]

It is axiomatic that any visible object is seen as it appears.

If this is suggesting that light is instantaneous, then I would paraphrase the OP as follows:

The speed of light was not obviously finite before it was measured.

It was so fast that measurements like waving lanterns on hills is too slow to measure it.

But the speed of light was eventually measured indirectly by Ole Rømer's observations of the moons of Jupiter, and directly by  Fizeau by watching light beams passing through a spinning wheel.

I agree that practical measurements take a finite amount of time, but this is adequate to measure finite things like the speed of light. According to Einstein, nothing should travel faster than light, so we should be able to measure them, too (in principle).

See: https://en.wikipedia.org/wiki/Speed_of_light#First_measurement_attempts

We measure the light coming from objects since light is the fastest method to capture observation before there is change. However, once the light leaves its source, there is no longer any connection between the source and the light. Light leaving the sun, has no sentimental attachment to the sun, and acts independently, thereafter. This detachment of the light from the source can create a dissociated observation, if based only on light and not also, matter.

The problem of simultaneity is based on using light only. There is a detachment of the light from the source, and therefore a time delay, which does not allow us to know what the source is doing in real time.

As an analogy, say a skunk was to release its stink. By the time the stink reaches us, we will know this is due to a skunk. We can even tell the general direction of the source, based on where the smell comes from. However, by the  time the stink reaches us, the skunk may not be in the same location, as the inference, base of the direction of the stink. Once the odor leaves the skunk, it is only attached to its point of origin, but not to the skunk. This is not problem as short distances, but it become a problem as distances increase. If you smell a skunk 1/4 mile away, he could be anywhere by then.

When we look out into space and see light from sources, say 1 billion years ago, this light has been detached from the source for 1 billion years. It can tell nothing of what the object is doing today. It can only tell us what it did 1 billion year ago, when the two were connected. There is a tendency to extrapolate this light to the real time universe.

The idea of an expanding universe is based on light that is not directly connected to the matter of origin. This is the skunk odor from 1/4 mile. All we know is the universe was expanding long ago, with the fastest expansion longest ago. This is based on the premise that this light tells us only about the final connection between the matter and energy. This adds up to a big boom followed by slow down. But relative to the observed light all around us, appearing at once at the telescope, it appears as something different. Expansion from the past; when inferred from all the light coming to us at the same time, adjusted for red shift, is interpreted as real time universe expansion. But it ignore the simultaneity problem of the detached matter.

When we make close observations, like measuring a meter, the distances are small and the speed of light is fast, therefore we begin to approximate the point in time and space, where the energy and matter are attached in real time.  But as distances increase, even the speed of light is way too slow to use this assumption.

[evan_au]

All we know is the universe was expanding long ago, with the fastest expansion longest ago

This was the expectation from general relativity, after Edwin Hubble's discovery of the expansion of the universe.

However, more recent discoveries point to an accelerating expansion of the universe, that suggests that the universe is expanding more rapidly now than it did (say) 5 billion years ago. This mysterious effect is dubbed "dark energy".

See: https://en.wikipedia.org/wiki/Dark_energy
 

[puppypower]

All we know is the universe was expanding long ago, with the fastest expansion longest ago

This was the expectation from general relativity, after Edwin Hubble's discovery of the expansion of the universe.

However, more recent discoveries point to an accelerating expansion of the universe, that suggests that the universe is expanding more rapidly now than it did (say) 5 billion years ago. This mysterious effect is dubbed "dark energy".

See: https://en.wikipedia.org/wiki/Dark_energy
 

This is still based on ignoring simultaneity. We don't know what the current matter source is doing based on old light, since the light will become detached from its source and both will thereafter move, independently.

To slow this down so it is easier to see, picture a tracking a jet by the sound of its engine, with the jet 65,000 feet above us. There is a time delay between what we hear and where the jet is. If it starts to turn, we will not know for many seconds. There is also a time delay between what we see and where the jet is, with this much less but still finite, since there is also a time delay.  If we place the jet a million light years away, the delay becomes very significant and may not reflect what we think we see. It is not real time.

The light we see from a stars way out on space, outputted from matter at one point in time. This is the only point in space and time where the two are one were real time connected observations. After that there is dissociation. That being said, the only way we can paint an accurate picture of space is to associate the light we see, with one point in space-time; past only but not present or future. 

When we look out into space, all forms of light reaches us, at the time, from all directions. However, this did not originate at the same time. We see all this energy at the same time. We can take a photo, which can stop time. It looks like space in real time. However, it actually represents a time line, that all appears to overlap in the photo,  that dates back billion of years, when light was detached from the matter of origin. The farthest observations are earliest on the time line. These have the most red shift. All we know is earliest parts of the time line, had the fastest acceleration.

An apparent accelerated expansion of the detached light, is actually a series of points, following a time line. This tells me a big boom, like an explosion, that was acted upon by a force, maybe gravity, which slows the matter over time. This create what appears to be an accelerated expansion in the detached light, that appears to us all at the same time as seen in a photo.

As an analogy, say we had a circus of planes and jets at an air show. They move at different speeds and distances, while doing passes and acrobatic moves. What we do is make an audio recording, where we can hear and identify 100 planes and jets by the sound. Then we try to locate all the planes by this sound recording. We can't take into consideration all the time delays, since we hear all the sources, simultaneously. We may be able to plot the sound image, but this will not be what was happening when the sound was recorded due to variable time recorded as constant. 

[PmbPhy]

The speed of sound was obviously finite before it was measured. Since all measurements are finite a measurement alone proves nothing.

Robert is quite correct on this point. In fact on my website I have a section on common misconceptions in physics/science. The one regarding this is called. Physics Is About Proving Things. As explained on that site the science of physics is not about "proving" anything. Science has never proved anything is true. The role of science is building a description of nature as Alan Guth explains this in a video he did for me.

http://www.newenglandphysics.org/common_misconceptions/Alan_Guth_04.mp4

It is axiomatic that any visible object is seen as it appears.

I['d say yes since the term "appears" means that its visible and that we are seeing it. So I'd say its correct by definition. That's true if we understand "appears" to refer to being seen by the light it gives off.

[mrsmith2211]

As Einstein said it is all relative, but relative frame of reference has no focal point, ie the final determination is relative

[evan_au]

All we know is earliest parts of the time line, had the fastest acceleration.
... This tells me a big boom, like an explosion, that was acted upon by a force, maybe gravity, which slows the matter over time.

The photo analogy is good, but based on inadequate data.

The current interpretation is that gravitation did decelerate the expansion of the universe when the universe was smaller and denser.

However, when the universe became older, larger and less dense, gravity could no longer overwhelm the Dark Energy, and the expansion of the universe accelerated.

It is today's more powerful telescopes that let us observe a significant population of galaxies before this balance point, and allow us to refine Hubble's ground-breaking discovery. (...or should that be a space-breaking discovery?)

[PmbPhy]

As Einstein said it is all relative, but relative frame of reference has no focal point, ie the final determination is relative

Einstein never actually said that. In fact there are many things which aren't relative within the theory of relativity.