How big are the stars?

Of course I'm sure the experiments are done. I quoted the damn things. I cited several major experiments performed years ago when it first became possible to do direct measurements of the issue. I alluded to the first measurements of the effect in distant stars in 1928. I know of a number of other cases we haven't discussed; and I'd have no trouble finding plenty more.I can't force anyone to learn, but since other people here are taking an interest it is still worth explaining these things so here we go again.The experiments with Pioneer 10 are something I spent a lot of time on about two years ago, I had a couple of exchanges with several of the major researchers involved in the matter; including the primary author of the report I cited, another astrophysicist who has since published a second report confirming the effect, and scientists who maintain the raw data (because I was doing a bit of direct analysis of my own on the data, in a limited way). In all cases I was asking questions and learning from the answers; by checking them for myself.These experiments find a tiny discrepancy, which is so small that it could be accounted for simply by having a sufficiently asymmetric pattern of radiation of waste heat from the probe's power plant. Waste heat is radiation, and radiation exerts pressure, and the pressure would be enough to give the tiny effect detected!That is in fact one of the most widely considered likely solutions. The problem is that it seems really unlikely that heat would be dumped with the degree of asymmetry required. A huge range of other explanations were considered; some of which involve alterations of the laws of gravity. That also is really unlikely, because we don't see corresponding effects in the planets. Really, it all comes down to just not knowing what causes the apparent anomalous acceleration.But the measured effect is tiny... smaller by several orders of magnitude than the effects of gravitational time dilation. What that means is that the experiment EASILY detects and confirms the effects of gravitational time dilation in the Sun's gravitational field to within a fraction of a percent.Gravitational time dilation is rock solid basic physics. It is not in any doubt whatsoever. It directly observed and measured in many contexts, over nearly a century of active research.Sure, we don't know everything. It is possible that new theories of physics could arise... much like Einstein's relativistic physics replaced that of Newton. But when such developments occur, it does not invalidate all the prior observations. Planets still orbit under gravity; we just calculate it a little more precisely with relativity.Likewise, if some new physics is discovered which has an effect on time dilation; it would still need to account for all the massive body of accumulated evidence that shows the plain facts of gravitational time dilation. A new theory might give more detail, or show slight differences in how to calculate the dilation, with better accuracy. It might even account for the Pioneer 10 anomaly; though there are good reasons for confidence that this effect has some other cause. The time effect is already taken into account, and has several orders of magnitude more effect than the anomaly itself. The anomaly could at a stretch be due to some inaccuracy in the way we calculate time dilations. This is a red herring, however. They were only able to detect this tiny effect by applying very accurate models which took gravitational time dilation into effect; hence the results prove time dilation calculation to be correct within a fraction of a percent.Snip more on Pioneer 10. arkathon is just being stupid in the questions I snipped. The short answer is that no, this effect does not bring gravitational time dilation into question. Even being able to detect the effect was a confirmation of time dilation. Once again... science is not about conclusive proof. I can't even prove that the Sun will shine tomorrow.But in so far as science can show anything it all, we have discovered, beyond any possible shred of reasonable doubt, that clocks move more slowly inside a gravitational well. As you move out of the well, clocks move more quickly. It is not a special feature of the Earth; it works for any gravitational source.By the time you get a couple of million kilometres from Earth, the time dilation effects of gravity due to further movement become too small to be detected by any current technology.What we see in light from distant stars is a very slight redshift due to gravity of the star. (Not to be confused with the much greater redshift in distant galaxies due to the expansion of space.) Photons emitted from excited atoms at the surface of a star must climb out of that star's gravitational well. In doing so, they get a slightly lower frequency, corresponding to time running a bit more quickly than at their source. We measure that shift. This isn't some weird speculation; it is very basic physics, thoroughly tested and amply confirmed by many observations. And yes, I do know for a fact that it is confirmed by many observations, just to nip another stupid question in the bud. Apparently you can't even tell the difference between frank acknowledgment of the enormous amount we don't know, and a claim that we know nothing at all.It is funny, in a nauseous kind of way, to watch arkathon make confident assertions about physics or cosmology that are flat out wrong, and then try to avoid learning better on the matter by implying that nobody knows anything. Blech. You're welcome.Anyone who wants to be able to make statements that others might be inclined to agree with, will need to go through the difficult process of actually learning something about the subjects they pontificate upon.This post is dedicated with thanks to folks who have said they did learn things from some of my previous efforts in this thread.I've left arkathon's title in place. It's a lovely demonstration of the limitations imposed on God by creationism. Think about it.Cheers -- Sylas

Yes indeed; good point. Thanks. Arkathon has a basically mediavel perspective, placing Earth at the center and making Earth the focus of his bizzare physical speculations.But in fact, Earth is remarkably insignificant on cosmic scales; and time dilations at places other than Earth's tiny immediate neighbourhood will have no detectable association with distance from Earth at all. Time dilation is associated with distance from whatever is around as the nearest massive objects.Cheers -- Sylas

The idea of "random" gchanges fails to take into account the lack of scholarship which this chance notion would recall in the history of science as to the idea that gravity can not be inmitted or remitted wile todays em might. The seperation of logic and nodes of simple programs was not made by your support of the point. Cheers. Brad. There is an "attitude" transference problem here.

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Of course I'm sure the experiments are done. I quoted the damn things.

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I guess I missed it while looking at them. I saw the clock one, and the plane one, and the 10, 000 km rocket one, but I didn't catch where distance from earth was ruled out. Now if these experiments were done, not focusing on gravitation, but on distance from earth, I have a question. The furthest manmade objects, I thought were the probes. So who did the experiment further out? I was talking about our known clock experiments.

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These experiments find a tiny discrepancy, which is so small that it could be accounted for...

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Yes it could be, on different sides of our solar system. But then again, I thought we didn't know? I'll have to have another look at your links, to see if I can figure out where the distance/time from earth is ruled out.

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Waste heat is radiation, and radiation exerts pressure, and the pressure would be enough to give the tiny effect detected! That is in fact one of the most widely considered likely solutions

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Indeed it may be the answer. Then again, I suppose, it may not.

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A huge range of other explanations were considered; some of which involve alterations of the laws of gravity.

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Of course if there were a distance to earth time effect, the gravity stuff would have no real bearing anyhow.

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Really, it all comes down to just not knowing what causes the apparent anomalous acceleration.

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Yes it comes down to that.

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But the measured effect is tiny... smaller by several orders of magnitude than the effects of gravitational time dilation.

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So then, if there were any distance time dilation, it would be, at the distance they are now, several orders of magnitude smaller than the effects of gravitational time dilation. Now if you went out a billion, trillion miles, who knows, if there were such an effect, it might be huge.

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Gravitational time dilation is rock solid basic physics. It is not in any doubt whatsoever.

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OK, I think we got that part quite a while ago.

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But when such developments occur, it does not invalidate all the prior observations. Planets still orbit under gravity; we just calculate it a little more precisely with relativity.

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The developments I look for, would only affect the time in deep space, in relation to earth. (not our solar system-except perhaps in some tiny little way of no great consequence to our system)

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Likewise, if some new physics is discovered which has an effect on time dilation; it would still need to account for all the massive body of accumulated evidence that shows the plain facts of gravitational time dilation.

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Yes, unless it was something in addition, that didn't much affect locally what we already know.

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The anomaly could at a stretch be due to some inaccuracy in the way we calculate time dilations.

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Funny you should say this.

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They were only able to detect this tiny effect by applying very accurate models which took gravitational time dilation into effect;

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Yes, of course I pointed out here, the grav thing isn't the concern.

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Even being able to detect the effect was a confirmation of time dilation.

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Sounds like time is involved in there somewhere, according to you.

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By the time you get a couple of million kilometres from Earth, the time dilation effects of gravity due to further movement become too small to be detected by any current technology.

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Well, well, well! Going millions of trillions of miles out then, is all very unknown to our technology, time dilation-wise! So I guess it can certainly not be proved one way or the other.

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What we see in light from distant stars is a very slight redshift due to gravity of the star. (Not to be confused with the much greater redshift in distant galaxies due to the expansion of space.)

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I have read creation science material calling redshift as it is understood into some question. After all as solid as eart's spectronomy is, when tou get way out beyond where our technology, as you said, can measure certain things, there is danger it could turn more into "speck-tronomy"!

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It is funny, in a nauseous kind of way, to watch arkathon make confident assertions about physics or cosmology that are flat out wrong,

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You seem to be refering to earth as the center of the universe, I mentioned? Center, in the true sense of the word, I think does not mean the geogaphical pinpoint of our physical surroundings. If you could ackknowledge a spiritual universe, that we can not see, you might have a clearer picture. If you assume there is only the physical, it becomes foolishness. The bible says we will see the heavens depart as a scroll, and a whole new heaven present it's lovely self. Then, you will clearly see earth is the center. This happens also to be when time shall be no more! The physics we know of the real whole universe is, you see, more limited than you now realize.

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Anyone who wants to be able to make statements that others might be inclined to agree with, will need to go through the difficult process of actually learning something about the subjects they pontificate upon.

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Yes, I know it is difficult, but I have tried to help you on the speck thing. Thanks again.
This post is dedicated to all the people who have been told we blew out of a speck, in hopes they will be free of that hopeless end of reason.

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I have yet to come across a mineral or petroleum exploration company which bases its exploration methodology on YEC geology or biblical interpretations. Why is this ?

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I have heard Uri Geller got out of bending spoons, and did some work finding oil. I think Edgar Cayce used to devine a little up as well. Up till recently there was no real creation science. What there is is not super funded, or even all coming from the same page. Add to this the Christian concern has been largely to protect their kids from being assaulted in faith at school. But, you know, they do call it 'fossil fuel'. Apparently there was a hec of a lot of plants, fish, animals, and things that got buried in water, and decided to turn to oil. Maybe Mother Teresa should've dropped her India thing and seen if she could have given Uri a run for the money!

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No experiment indicates any relationship between distance from Earth and the rate of passage of time.

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(JonF)
They did experiments lokking for that? (not gravitational dilation)

AFAIK nobody has done experiments looking especially for that, but there have been literally thousands of experiments involving time and distance from the Earth (a few of which have been discussed in this thread), and if there was an effect of distance from the Earth it would have been noticed. E.g. in SN1987A.You can often answer a scientific question without doing experiments specifically designed to answer that question, byt analyzing existing data form other experiments. In this case, an effect of distance form the Earth would have leaped out at us without any need for formal analysis.If you want to explore the hypothesis that time runs differently with distance from the Earth, start with explaining the decay of radioactive cobalt in SN1987A. Links in message 20 of this thread.

Reference please? Did he use creationist "geology"? Did he find any oil? Reference please? Did he use creationist "geology"? Did he find any oil? Well, it didn't happen underwater, and the amount of plants, fish, animals, and things that turned into oil is far, far, far more than could physically fit on the Earth at one time.

I'm afraid this is starting to drift along way from Stars and all the way out of Big Bang and Cosmology. Could you take it to another forum (Geology and the Great Flood perhaps)?

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nobody has done experiments looking especially for that, but there have been literally thousands of experiments involving time and distance from the Earth (a few of which have been discussed in this thread), and if there was an effect of distance from the Earth it would have been noticed

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Since you say no one did the experiments, and dilation would be tiny, I was just covering bases, as to be sure it could not have been missed. As far as the 1987 rings ot the supernova, are we sure our measurements are so precise, that if the rings, actually took a few a few more hours than you thought, we would notice? If a clock was in the rings, and we could see it in real time compared with one clock here, do we know that there is no relation to distance from earth? If not a few hours, how about a few days, or weeks, or minutes, or months difference? Since there is almost certainly a clock difference, do we know none of it is because of distance to earth? I thought Sylas said something about us not having technology to really go to far on this?

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In this case, an effect of distance form the Earth would have leaped out at us without any need for formal analysis.

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With distance from the earth (aside from gravitational) possible time dilation being miniscule close by in our solar system maybe it would not 'leap' at us as much as we think? After all, we have a little probe quirk of somewhere around 1/10 of a second every 4 or 8 years, we do not even know anything about.
You could be right, but it sounds like the speed of light is your main concern..

Arkathon's posts in these threads are pretty much impossible to work into any coherent position at all.JonF is making a valiant attempt to give a substantive response.I have a minor quibble with JonF. There are experiments that explicitly sought and found a relationship between distance from Earth and the rate of passage of time, both at small scales and at very large scales. The small scale experiment is the scout rocket mentioned previously. It found that clocks which moved away from the Earth over local distances of several thousand kilometers ran more quickly, as predicted by general relativity. The large scale experiment is the measurement of light curves in distant supernova, over distances up to several billion light years. It found that clocks at enormous cosmological distances appear to run more slowly, as predicted by cosmological expansion of space. The gravitational effect is an intrinsic effect; time itself really does pass more quickly as you move out of the gravitational well, and more slowly as you move into the well. The cosmological expansion effect is an observer effect. The slow down is a consequence of how the clock is observed; not a change in the rate at which time passes.Arkathon's notion of a fundamental relationship between time dilation and distance from the Earth is wrong. In Earth's immediate neighbourhood, there is a relationship between distance from Earth and the rate of passage of time; but out in the solar system or in the universe the passage of time bears no relation to the distance from Earth at all.In the thread, we've considered experiments over scales as small as 22.6 vertical meters. I believe present day atomic clocks could pick up dilations caused by being lifted as little as a meter. We've also referred to tests of gravitational time dilation measured in deep space probes and in distant stars.Arkathon's ideas are not from the bible, and not based on any empirical evidence, and are inconsistent with all available data; but they do have some vague similarity to the ideas of creationist physicist and mega-nutcase Russell Humphreys, who proposes similar notions in the book "Starlight and Time".Arkathon has been suggesting that perhaps there are other effects at greater distances. But that has been tested also. JonF here refers to some of those tests. The reason such tests are important is that cosmological redshift is generally attributed to the effects of the expansion of space. Another proposed cause for cosmological redshift is the "tired light" model, in which light somehow gradually loses energy over time. One way to distinguish these models is to look for changes in clocks at distances of billions of light years.The case of SN1987A to which JonF refers is actually only at a distance of 167,000 light years; practically next door on cosmological scales. This is far too close for cosmological redshift to play any role. SN1987A is studied in considerable detail because it has been able to shed light on many aspects of supernovae. It has also allowed a good calibration of distance measures and confirmed constancy of the speed of light; but these are minor matters for scientists. Scientists are much more interested in what SN1987A reveals about the development of stars and supernovae, and the composition and causes of clouds and rings of gas in its immediate neighbourhood.Still, it is a useful object lesson for debates with people who are proposing various way out ideas from crank physicists, because it is a readily comprehensible confirmation of a number of fundamental scientific models: the ways of measuring distance in deep space, constancy of the speed of light, constancy of radioactive decay rates, invariance of participle physics with distance, and so on. Arkathon's ludicrous fantasies about variations of time with distance from Earth are falsified by this example also. You just can't make up nonsense like this and hope for it to be consistent with the detailed observations on which modern astronomy is based.The other famous experiment I mentioned above it measurement of light curves in distant supernova. This is discussed in Errors in Tired Light Cosmology, by Professor Ned Wright at UCLA. Basically, the experiment sought and found a time dilation in light curves of distant supernova; but in exactly the opposite sign from that which creationists would require.The original study (since repeated by others) used 60 supernovae with z factors up to 0.8, which corresponds to a distance of several billion light years. At such distances, even the term "distance" becomes ambiguous, for a number of reasons which I won't go into here.The essential proposal of Russell Humphreys is that Earth is roughly at the centre of the universe and in a deep gravitational well, so that clocks on Earth run more slowly than clocks in the distant stars. 6000 years can pass on Earth while billions years pass out in the far reaches of the universe.We do observe, close to Earth, that as you move further away clocks will run more quickly. The effect is tiny, but it is measured. In the solar system Earth's gravity has no appreciable effect, and distance from Earth is observed to be completely irrelevant; but we do measure the same effect as you move away from the Sun. In the galaxy the Sun's gravity has no appreciable effect; and the effect of galactic gravitation is too small to make any detectable effect on objects in deep space. Observation of gravitational time dilation in distant stars is due to local gravitational effects of those stars. For example, the case of Sirius B to which I alluded earlier could only be detected because it is a binary star. We can compare the light from one star with light from the other, and use the difference in time dilation effects to check relativistic models. The light from the smaller and much denser dwarf star is shifted in relation to the other. This, by the way, also confirms that the effect has nothing to do with distance from the Earth... both stars are equally distant from the Earth.I digress... back to the cosmological shifts. When we look into really deep space, we see a time dilation, but it is not due to gravity. It is due to expansion, and this means we see the distant clocks as running more slowly; not more quickly as creationists would require. This effect (unlike gravitational shifts) is a matter of perception rather than an intrinsic difference in the rate at which time passes. The clocks are actually running at the same speed, but appear to run more slowly due to space expansion. This is analogous to (but not quite the same as) Doppler effects. When you hear a train blow its whistle, you hear a high pitch as it approaches but a lower pitch as it recedes. The effect depends on your relative velocity, not on an intrinsically different oscillation of the whistle.Cheers -- Sylas

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Arkathon's ludicrous fantasies about variations of time with distance from Earth are falsified by this example also.

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Arkathon's questions, not fantasies. If anyone could answer questions clearly the first time, maybe you absent minded professor types wouldn't get so consternated.

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You just can't make up nonsense like this and hope for it to be consistent with the detailed observations on which modern astronomy is based

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Questions like this you mean, and I don't much care what the result is, actually. For someone who can't even tell what's going on in the probes, you should not get too indignant if someone doublechecks your statements.

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Arkathon's ideas are not from the bible, and not based on any empirical evidence, and are inconsistent with all available data;

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You are of course refering to questions I posed on a possible relationship of time to distance. If you want to get righteous about it, forget it.

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The essential proposal of Russell Humphreys is that Earth is roughly at the centre of the universe and in a deep gravitational well, so that clocks on Earth run more slowly than clocks in the distant stars. 6000 years can pass on Earth while billions years pass out in the far reaches of the universe.

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Ahh, so that's what he says. I had heard something about time going faster away from the center of the universe, but didn't realize that it was supposed to have something to do with gravity. This was one reason I was double checking if there was a possible distance time dilation, independant of gravitational forces. It was also why I checked your notes on the probes, and was trying to see if aside from gravity, there could be an effect.
I am trying to wind now, the clock back in my mind some 6200 years ago, and imagine how much space would contract, roughly. If space is expanding, that holds all the stars etc. I wonder if it expands at a constant rate, and conversely, if it would contract at the same rate. In other words, I'm now moving to space itself, the container of the galaxies, and asking (not fantasizing) if we were possibly able to reduce the space between us, and the far out cosmos, so as that it would be a lot closer 6200 years ago. We probably have only been measuring it, I would guess, say 150 years? Has the expansion rate always been absolute, and measureable? Is it possible that there could have been a phase, like blowing up a baloon, where it was a lot different some thousands of years ago? If not, why not? Looks like you answered the time stuff pretty good already.
(contrary to public opinion, I can learn things, such as what to use, and not use in more effectively targeting evo cosmology)

Regarding earlier expansion; we can watch distant stars (which means we see them in the past) and the redshift we see can be directly related to their distance. That is, if it's twice as far away, it 'moves' twice as fast due to expansion. Which means that (for as long back as we can directly measure) the expansion was measurably consistant over time.

Approximately zero.Second approximation: 6.2*10³/1.4*10¹⁰ = 0.000043% It appears not to. Huh? If you are imagining running it backwards in order to see where it was 6,000 years ago, of course it would.

You're a tad out of date; more recent data indicates an accelerated expansion over time. Confirmation of the accelerated expansion of the Universe.