Posted on 04/24/2002 6:30:34 PM PDT by longshadow
What you are seeing is lots of estimation rather than contradiction. As more measurements are made, the results seem to be in better agreement. There should be error indicators with each estimate, if not, it's sloppy reporting.
It is only a contradiction if you ignore the measurement errors in BOTH. We already know the WHite dwarf methodology has an acknowledged error of 0.5 billion years. We don't know the error estimate for the observation in your linked article because it does mention it, but let's use 5% as a round number.
Taking the White dwarf estimate to it's upper most value (13.7 billion + 0.5 billion) yeilds 14.2 billion years. Taking your estimate of 15 billion years and using the minimum value based on a 5% measurement error, yeilds 14 and a quarter billion years.
Both measurements are within their error limits of each other.
In conclusion, there is no contradiction.
I'll have to defer to "Physicist" and ThinkPlease" on details such as those....
and from the other article . . .
Inside a gravastar, space-time would be "totally warped," the researchers say. Further, the inner space would exert an outward force, which would enhance the durability of the bubble
and . . .
Mottola and Mazur have taken their extreme idea to a mentally dizzying new level: The say our entire universe may be the interior of a giant gravastar.
For some reason these two articles together got my brain lobes flapping.
I have to admire the guys who wouldn't stop looking until they'd found the faintest dwarf. I guess they had a comfortable number of dwarves to work with.
Now you're talking!
Maybe it's me, but what I see is lots of potentially out-of-date estimates, and NO scholarly references to back them up.
If I were so inclined, I could put up a website that said the Universe is 13 days old, and it would have as much validity on your list as any other internet website estimate.
Also, you fail to note the error range for each estimate. As I pointed out earlier on this thread, 20 years ago, they thought the Universe was 10-20 billion years old (or 15 +/- 5 billion, if you prefer). Today, they think it is 13.7 +/- 0.5 billion years old. There's no contradiction; the later measurement lies entirely within the earlier estimate.
Exactly; and if there were evidence that these methodologies were erroneous, you'd have posted it by now.
Lacking any evidence that they are erroneous, we conclude this is the best estimate we have, and our confidence in it is much greater than before we had this independent methodology that produces virtually the same answer.
Ahhh, excellent question!
In the press conference Wednesday, they described their methodology as using exposures of such long duration that had their been fainter dwarfs, they would have been detected. In other words, the minimum detectable magnitude was below that of the faintest dwarf they saw, sufficiently lower such that they feel confident that they would have seen them if there were fainter ones.
The new Hubble camera is MUCH more sensitive, and they plan to use it to look for much fainter dwarfs (to verify that what they found WAS the faintest (and thus oldest), and to look at dwarfs in a completely differnt type of cluster, and in cluster much more distant.
I'm not sure about the error in either of these studies. I've never heard of the 5% standard you cite. For this article, they seem to be using .5 billion ly vs. 5%. But you're definitely right about the contradiction thingy; i.e., I should've said discrepancy instead of contradiction because even if the interval estimates do not overlap we wouldn't necessarily have a contradiction in the strict sense of the word.
They apparently are running at the edge of the sensitivity of the old Hubble scope equipment; this is why they selected M4 -- they just didn't have enough sensitivity to see dwarfs that old any farther away that M4 is.
Calling Robert Reich!
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