How big are the stars?

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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.

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Someone not too familiar with the mental concept might have a little trouble visualizing this. Now, what we see out there, (what would be billions of present light years) is, as we've seen it since science started really looking at it, expanding at a certain rate. The space between stars that is. If somehow there was much less space for some reason due to some process we don't know about thousands of years ago- where the expansion rate suddenly mushroomed- would the light from the now far away stars not have taken much less time to get here? Then, what we see now, if we think of as billions of years away, we would presume must be old, because there is now a lot more space between us? I don't know if you can follow this. Why then, can we be absolute in saying even before science got rolling, and could measure much of anything, space itself did not undergo most of the expansion we now measure?

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If space is expanding, that holds all the stars etc. I wonder if it expands at a constant rate "It appears not to."

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Well, then how is it we can know that say 6000 yrs ago, it didn't have a growth spurt (space)? Now, if it did, we could not say it did not, just by using measurements of present time, and space. In other words we could not look out and say in what now would take 6000 yrs to travel, would have taken the same time to travel, if the space was greatly reduced. So then, how far back did we start really measureing?

We know this beyond any shadow of reasonable doubt because when we look at anything beyond the galaxy we are already looking back some several million years. We see structures in place which demonstrate stability of space over millions of years.Bear in mind that the expansion of space is about 71 km/s/MPcJonF showed the implications of this; over the 6000 years, or even over several million years, the expansion of space is such that environments on the scale of galaxies are essentially a very stable flat space.A growth spurt on a scale of 6000 years would have dramatic observational consequences. We can see, with complete confidence, that there has been no such spurt.Cheers -- Sylas

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A growth spurt on a scale of 6000 years would have dramatic observational consequences.

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What would these be. At first glance, it seems just that some empty space would be missing.
Todays headlines, for example, on BBC tantalize us with possibilties of majoe rethinks.
BBC NEWS | Science/Nature | Theory of matter may need rethink

Sorry, I seem to have missphrased that. What I ment was that since we can look at the redshift compared to the distance, we can measure a expansion rate that is consistant, and does not have any massive jump at specific times.Hence, we can measure the way the expansion behave, and it's not possible, given the measurements, that the expansion rate was several magnitudes faster only 6000 years ago.

For one, an overwhelming number of stars would become invisible to you, because the speed of the expansion would be so large that the light emitted by them would go into the invisible part of the light spectrum.

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What I ment was that since we can look at the redshift compared to the distance, we can measure a expansion rate that is consistan

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It seems you depend very very heavily on the color of the star here. Are we saying here that the color of a distant star or galaxy gives us the final proof there was no different expansion rate in the past?

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For one, an overwhelming number of stars would become invisible to you, because the speed of the expansion would be so large that the light emitted by them would go into the invisible part of the light spectrum.

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Interesting statement. What was it supposed to relate to again?

Redshift and color are not the same thing. Redshift is measured by measuring the displacement of characteristic lines in the spectrum. I don't know exactly which lines are used, but each element in each star gives off a characteristic pattern of wavelengths of light; and we know what that pattern looks like when the source is not moving. We see exactly the same patterns in the light from distant stars and galaxies (somewhat smudged in the case of galaxies) and we can easily measure the difference in position in the spectrum, which is the redshift. See THE HUBBLE REDSHIFT-DISTANCE RELATION I'm not; there is no such thing as final proof in science. The correlation between redshift and distance (measured by other means) is very strong evidence that the expansion rate was not significantly different in the last 10 billion years or so. See MEASUREMENT OF GALAXY DISTANCES Results from observing distant supernovae indicate that there is some acceleration in the expansion rate, but nowhere near enough to indicate that the Universe is significantly younger than 14-ish billion years.. See Research News and Supernova Cosmology Project.

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Whereas redshift measurements by different observers rarely exhibit major differences,
redshift-independent distances obtained by different observers can, and generally do, differ systematically for any number of
reasons. In some cases the origin of such differences is different calibrations of the DI. In others, the calibrations are the same
but the input data differ in a subtle way. Finally, the way statistical bias effects are treated (Section 9) often differs among those
involved in galaxy distance measurements. For all these reasons, it is not possible simply to go to the published literature, find all
papers in which galaxy distances are reported, and lump them together in a single database. Instead, individual data sets must
be assembled, their input data and selection criteria characterized, their DI relations recalibrated if necessary, and the final
distances brought to a uniform system. Only then can the resultant catalog be relied upon - and even then, caution is required.

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As the quote from your link indicates, perhaps we should use some caution. I guess this is a bit too high for me, to swear that even billions and trillions upon trillions of miles away, nothing filters or colors the light from the objects on it's long way here.
Since I do know some creation science people call into question the interpretation of redshift, I must assume for now you could be wrong in this.

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The correlation between redshift and distance (measured by other means) is very strong evidence that the expansion rate was not significantly different

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Without links, and in baby english, can you simplify the explanation as to why anything out there we now see would have anything to do with how much space expanded near creation time. If it somehow expanded like crazy 6000 years ago, what would I see in the sky that was different? How could I tell there was a spurt of expansion before we measured things? How does redshift tell us (with it's usual interpretation) that the was not less nothingness of space between us? If a galaxy was 15000 light years away, say, 6000 years ago, then space quickly expanded for a time, to where the galaxy was now 10 billion light years away (because the space between us was greater) how could we tell? By it's present rate of expansion? Assuming it must have been similar for a long time?
The simpler the explanation, the more people might understamd it.

In your scenario, where the universe is 6k years old and the galaxies would expand from say 150,000 light years apart to billions of light years apart, there are several problems. Well, for one, the galaxies would be expanding apart faster than light in your scenario. In fact, they would have to have to be receding several times faster than the speed of light. If space is expanding faster than the speed of light, you wouldn't see any galaxies at all. Additionally, any light would be so dramatically redshifted that it would be unlikely that there would be any visibile light coming from the stars even if it was to reach earth. Of course there are a slew of other problems, but those are just for beginners .[This message has been edited by Darwin Storm, 03-25-2004]

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If space is expanding faster than the speed of light, you wouldn't see any galaxies at all.

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Good point. Now, I suppose no way exists for for the space that was expanding to have expanded the light along with it?

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Additionally, any light would be so dramatically redshifted that it would be unlikely that there would be any visibile light coming from the stars even if it was to reach earth.

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This would assume that redshift was correctly interpreted as it is now understood.

You have humoured this imbecile for nigh on 300 posts.

Thanks for the reminder Eta. This thread is close enough to the magic 300 posts. Closing it down. Any masochists here can start a new thread on the topic.

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AdminAsgara
Queen of the Universe