Discussion Topic |
|
This thread has been locked |
Ed Hartouni
Trad climber
Livermore, CA
|
|
|
Jul 14, 2008 - 11:46pm PT
|
the contaminants don't affect the isotope lifetimes... as I said, that is a physical constant....
it is the ratio of isotopes that measures the relative lifetime of the rock... so you may have to make some assumptions about the initial isotopic composition of the rock.
Depending on the age of the rock, the isotopic abundance might be processed by supernova... cosmic rays, stuff like that.
All of these may seem like "problems" but different elements are processed differently, and so reconciling all of these "chronometers" actually teaches you about where the stuff has been and what has happened to it.
As I said, this is pretty solid stuff. In general, the error bar attributed to the time determination tells you the uncertainty in the assumptions of the initial conditions.
When you think about it, it's pretty sweet, you get an answer, and you get an estimate as to just how good the answer is...
|
|
Jennie
Trad climber
Idaho Falls
|
|
|
Jul 15, 2008 - 12:13am PT
|
"Many if not most people are unaware that the Bible teaches the earth is flat. All standard Bible references, all standard mainstream non- fundamentalist Bible scholarship acknowledges this. Like on so many other topics, the Bible simply reflects the primitive and mistaken cosmology of the day"
The Bible does NOT teach the earth is flat and contrary to prevailing modern opinion, the Roman Catholic Church did not create, extol or exalt the flat earth model.
And some have posted claiming “the church” promoted the flat earth theory. Not being a member of the Roman church or an adherent to “catholic” doctrine, I chose not to post counter argument to that declaration. But the common acceptance of this falsehood SHOULD be addressed, whether from within or outside the capacity of Roman Catholicism.
Jeffrey Russell, a professor of history at the University of California in Santa Barbara, wrote an interesting book Inventing the Flat Earth stating ”(that) through antiquity and up to the time of Columbus, “nearly unanimous scholarly opinion pronounced the earth spherical.”
The concept that the Roman church leadership advanced and held fast to the flat earth concept is a popular myth forwarded, nourished and cherished by individuals with antagonism and hostility to religion. But historical sculpture, art, coinage and documents tell a whole different story.
The Catholic Church held to the geocentric model of the universe rather than the heliocentric hypothesis conceived by Copernicus, himself a PRIEST. Copernicus received little opposition to his hypothesis from the church, but his sun centered model was the central issue in the trial and censure of Galileo a few decades later, possibly because of Galileo’s acerbic and argumentative nature. But Roman Catholicism never decreed a FLAT earth doctrine. Again, the earth was known to be spherical by the educated throughout Europe, and that knowledge was accepted by most all members of the educated clergy.
Numerous evidences of Greek and Roman knowledge of a spherical earth dogma came down (strongly) through history, before and during the Christian era. Writings, numerous statues of Atlas bearing a spherical Earth, statues of Caesars holding a globe (of the world) in their hand as testament of their universal dominion, coins bearing globes symbolizing the earth appeared before and long after the reign of Constantine.
The Bible, in my opinion, does not teach either flat earth or round earth cosmology. Christians often use scriptural quotations, including Isaiah chapter 40 and Luke chapter 17 as evidence of the Bible instructing readers of a spherical earth. Opponents quote passages from Genesis’ creation story as well as Christ’s being lifted up to see all the kingdoms of the Earth as evidential of the Bible advancing the flat earth notion.
These biblical verses are symbolic and highly metaphorical and can’t logically be used as tangible or literal grounding of Christianity or Judaism in either the flat earth or round earth view.
Although many moderns continue to believe the myth that medieval Europe’s intelligentsia followed the flat Earth concept, the Earth was, in fact, KNOWN to be spherical, by the educated and enlightened, from Greek and early Roman times through the Middle Ages. History or pseudo scholarship CAN NOT support or prove the claim that Roman church officials believed or taught that the earth was flat. But some modern writers, who considered themselves “enlightened”, and needing to cast Christianity as the afflicting angel of ignorance, superstition and irrationality promoted that myth. Thus these intellectual lighthouses attempted to dye and re-weave history to fit that theme.
The myth of Roman Catholic flat earth doctrine is, to large degree, a product of the prejudices and imagination of American writer Washington Irving. His book The Life and Voyages of Christopher Columbus portrays Columbus as a solitary believer of a radical, spherical earth hypothesis contending against consolidated ranks of ignorant, hostile and highly partial professors and clergy and (himself) barely escaping with his life at the Council of Salamanca.
In reality, most attending the Council believed the spherical earth model. The council was assembled to discuss the size of the Earth and the distances between islands and continents, NOT debate the shape of the Earth.
From John Noble Wilford, in his The Mysterious History of Christopher Columbus:
“However, it was not the facts of history that were important to myth-builders like Irving; it was the symbolism. Columbus, the little guy with the big idea, coming face to face with ignorance and indifference at the top, was a favorite American trope and became an important factor in the Columbus myth.”
Irving’s fanciful “biography” of Columbus has been widely quoted, even today, without investigating the historical facts.
The nineteenth century was the prime era of great perceived antagonism between science and religion and subsequent to the Darwinian revolution many scientist’s popularized the perception of religion as the hostile aggressor toward new scientific ideas. Antoine-Jean Letronne in his On the Cosmographical Ideas of the Church Fathers, 1834, misrepresented the church fathers and their medieval successors as believing in a flat earth.
Letronne falsely claimed that most of the prominent Church Fathers, including Augustine, Ambrose and Basil, held to a flat Earth.
But Augustine definitely believed in a spherical earth. Just one evidence in his writing: ” But they do not remark that, although it be supposed or scientifically demonstrated that the world is of a round and spherical form, yet it does not follow that the other side of the earth is bare of water; nor even, though it be bare, does it immediately follow that it is peopled.”
Other influential theologians including Boethius, Bishop Isidore of Seville, the 9th century bishop Rabanus Maurus, he monk Bede, Bishop Vergilius of Salzburg wrote treatises on the spherical Earth.
Yet, the modern belief that medieval Christianity believed in a flat earth has prevailed among the general public. In 1945, it was listed by the Historical Association (of Britain) as the second of 20 in a pamphlet on common errors in history. ”But, in fact, very few educated people in the history of Western Civilization from the third century B.C. on believed that the earth was flat and that the prevailing view was of a spherical earth.”
|
|
WBraun
climber
|
|
|
Jul 15, 2008 - 12:25am PT
|
"Hmmm... a rejection of education, a purposeful turning away from science, superstition in place of reason: where have we heard THIS recently?????"
That's definitely modern science's problem.
They mislead everyone .......
|
|
Jaybro
Social climber
wuz real!
|
|
|
Jul 15, 2008 - 12:27am PT
|
link fixed
|
|
Ed Hartouni
Trad climber
Livermore, CA
|
|
|
Jul 15, 2008 - 12:46am PT
|
and heliocentricity?
|
|
monolith
Trad climber
Berkeley
|
|
|
Jul 15, 2008 - 01:02am PT
|
And how would an error of a few millions of years in a billion year old estimate matter to a creationist who thinks the world is only 6000 years old?
|
|
graniteclimber
Trad climber
Nowhere
|
|
|
Jul 15, 2008 - 01:04am PT
|
"These biblical verses are symbolic and highly metaphorical and can’t logically be used as tangible or literal grounding of Christianity or Judaism in either the flat earth or round earth view."
Jennie, but then might not the biblical verses in Genesis on the creation of the earth also be symbolic and metaphorical can't logically be interpreted literally?
Although the Bible is a collection of books written over thousands of years by different people of different times and backgrounds (some Jewish, some Greek and some Roman), some people today consider the Bible to be a single infallible document, of which every word is literally true. That is what I am questioning.
A couple hundred years before Christ, the Greeks had already determined the approximate diameter of the earth However some of the books of the Old Testament are much older then this. (Also, the Old Testament isn't Greek.)
http://en.wikipedia.org/wiki/Flat_Earth
Antiquity
Belief in a flat Earth is found in mankind's oldest writings. In early Mesopotamian thought, the world was portrayed as a flat disk floating in the ocean, and this forms the premise for early Greek maps such as those of Anaximander and Hecataeus of Miletus.
Some theologians and biblical researchers maintain that at least some of the writers of the Old Testament books of the Bible had a Babylonian world view, according to which Earth is flat[5] and stands on pillars, and is covered by a solid sky-dome[6][7] (the Firmament). The firmament was the heaven in which God set the sun (Psalm 19:5) and the stars (Gen 1:14).[8] The flat earth concept appears to be mentioned in (Isaiah 40:22) where it speaks of God "dwelling above the circle of earth" which means a literal circle, from the Hebrew word "chuwg". However in Isaiah 22:18, the word "duwr" is used to describe a ball. This would appear to be in conflict with the Babylonian world view. Job 26:7 states that God was "hanging the earth upon nothing" and the same verse also described the north (of the Earth) as hanging over nothing too. The non-canonical Book of Enoch presents a concept In which the Sun and Moon move in and out of the Firmament dome through a series of openings (reflecting the apparent movement of their rising and setting points throughout the year). This is explained in considerable detail in the following excerpt:[citation needed]
"This is the first commandment of the luminaries: The sun is a luminary whose egress is an opening of heaven, which is (located) in the direction of the east, and whose ingress is (another) opening of heaven, (located) in the west. I saw six openings through which the sun rises and six openings through which it sets. The moon also rises and sets through the same openings, and they are guided by the stars; together with those whom they lead, they are six in the east and six in the west heaven. All of them (are arranged) one after another in a constant order. There are many windows (both) to the right and the left of these openings. First there goes out the great light whose name is the sun; its roundness is like the roundness of the sky; and it is totally filled with light and heat. The chariot in which it ascends is (driven by) the blowing wind. The sun sets in the sky (in the west) and returns by the northeast in order to go to the east; it is guided so that it shall reach the eastern gate and shine in the face of the sky" (1 Enoch 72:2-5).
[edit] Classical Antiquity
By classical times the idea that Earth was spherical began to take hold in Ancient Greece. Pythagoras in the 6th century BC, apparently on aesthetic grounds, held that all the celestial bodies were spherical. However, most Presocratic Pythagoreans considered the world to be flat.[9] According to Aristotle, pre-Socratic philosophers, including Leucippus (c. 440 BC) and Democritus (c. 460-370 BC) believed in a flat earth.[10] Anaximander believed the Earth to be a short cylinder with a flat, circular top which remained stable because it is the same distance from all things.[11] It has been suggested that seafarers probably provided the first observational evidence that the Earth was not flat.[12]
Around 330 BC, Aristotle provided observational evidence for the spherical Earth,[13] noting that travelers going south see southern constellations rise higher above the horizon. He argued that this was only possible if their horizon was at an angle to northerners' horizon and thus the Earth's surface could not be flat.[14] He also noted that the border of the shadow of Earth on the Moon during the partial phase of a lunar eclipse is always circular, no matter how high the Moon is over the horizon. Only a sphere casts a circular shadow in every direction, whereas a circular disk casts an elliptical shadow in all directions apart from directly above and directly below.[15] Writing around 10 BC, the Greek geographer Strabo cited various phenomena observed at sea as suggesting that the Earth was spherical. He observed that elevated lights or areas of land were visible to sailors at greater distances than those which were less elevated, and stated that the curvature of the sea was obviously responsible for this.[16] He also remarked that observers can see further when their eyes are elevated, and cited a line from the Odyssey[17] as indicating that the poet Homer was already aware of this as early as the 7th or 8th century BC.
The Earth's circumference was first determined around 240 BC by Eratosthenes. Eratosthenes knew that in Syene, in Egypt, the Sun was directly overhead at the summer solstice, while he estimated that a shadow cast by the Sun at Alexandria was 1/50th of a circle. He estimated the distance from Syene to Alexandria as 5,000 stades, and estimated the Earth's circumference was 250,000 stades and a degree was 700 stades (implying a circumference of 252,000 stades).[18] Eratosthenes used rough estimates and round numbers, but depending on the length of the stadion, his result is within a margin of between 2% and 20% of the actual circumference, 40,008 kilometres. Note that Eratosthenes could only measure the circumference of the Earth by assuming that the distance to the Sun is so great that the rays of sunlight are essentially parallel. A similar measurement, reported in a Chinese mathematical treatise, the Zhoubi suanjing (1st c. BC), was used to measure the distance to the Sun– albeit by assuming that the Earth was flat.[19]
Lucretius (1st. c. BC) opposed the concept of a spherical Earth, because he considered the idea of antipodes absurd. But by the 1st century AD, Pliny the Elder was in a position to claim that everyone agrees on the spherical shape of Earth,[20] although there continued to be disputes regarding the nature of the antipodes, and how it is possible to keep the ocean in a curved shape. Pliny also considers the possibility of an imperfect sphere, "shaped like a pinecone".[20]
In the Second century the Alexandrian astronomer Ptolemy advanced many arguments for the sphericity of the Earth. Among them was the observation that when sailing towards mountains, they seem to rise from the sea, indicating that they were hidden by the curved surface of the sea. He also gives separate arguments that the Earth is curved north-south and that it is curved east-west.[21] Ptolemy derived his maps from a curved globe and developed the system of latitude, longitude, and climes. His writings remained the basis of European astronomy throughout the Middle Ages, although Late Antiquity and the Early Middle Ages (ca. 3rd to 7th centuries) saw occasional arguments in favor of a flat Earth.
In late antiquity such widely read encyclopedists as Macrobius (4th c.) and Martianus Capella (5th c.) discussed the circumference of the sphere of the Earth, its central position in the universe, the difference of the seasons in northern and southern hemispheres, and many other geographical details.[22] In his commentary on Cicero's Dream of Scipio, Macrobius described the Earth as a globe of insignificant size in comparison to the remainder of the cosmos.[22]
|
|
graniteclimber
Trad climber
Nowhere
|
|
|
Jul 15, 2008 - 01:06am PT
|
Okay, Jody, how old to you think the Earth is?
|
|
monolith
Trad climber
Berkeley
|
|
|
Jul 15, 2008 - 01:06am PT
|
Then please explain why an error of a few million years in a billion year old rock estimate would matter to you Jody?
|
|
DJS
Trad climber
wherever my mind exists
|
|
|
Jul 15, 2008 - 01:09am PT
|
The myths slipped through in the "history books"...not the Bible. Now, if by "Church" you mean the Catholic Church...you have a point. But if by "Church" you mean the community of christian believers, then, no.
History is a verbal or written documentation of the past. The Bible was a verbal and then became a written documentation of the past. The Bible is a "history book".
Therefore if myths slipped through "history books", then myths slipped in to the Bible.
|
|
Ed Hartouni
Trad climber
Livermore, CA
|
|
|
Jul 15, 2008 - 01:16am PT
|
the accuracy of the dating depends on many things: the lifetime of the isotope, the processing of the element in the material, the initial isotopic ratio.
Do you know what an isotope is? Nuclei determine which element the atom will be by the number of protons. There are an equal number of protons and electrons in an atom, and the electrons determine the chemistry of the element.
Naturally occurring elements will often have a set of nuclei with the same number of protons, but different numbers of neutrons. The atomic mass changes (the chemistry might change a tiny bit due to the isotopic shift, but not usually much). Depending on the nucleus, adding neutrons might make the nucleus unstable.
Nuclear decay, radioactive decay is a random process, the probability distribution is an exponential decay curve and the half-life of the decay is the time that half of the original nuclei would have decayed.
The half-life depends on the nuclear force and the numbers of protons and neutrons. It is not changed by the environment the nucleus is in. It is a constant for that particular isotope.
If you have a lot of atoms of a particular isotope, and their nuclei are unstable, then you can measure the number of that isotope remaining, and the number of "decay daughter" isotopes. This ratio will give you a measure of the time that has passed.
Usually you'd pick a couple of isotopes to start, now you're measuring four things. If you pick your isotopes correctly, you can determine the starting concentration and the time since the initial conditions, knowing the half-lives of the isotopes you've picked.
The uncertainty in the determination of that time is quantifiable, and usually is quoted as an "error" on the determination of that time. So the measurement has finite precision and accuracy.
Interpreting the chemistry of the samples is important, and often leads to ambiguous results for well know reasons. Additional information can help resolve the ambiguous results. The "clocks" are not perfect, but provide constraints on the age of the samples being measured.
|
|
Lynne Leichtfuss
Social climber
valley center, ca
|
|
|
Jul 15, 2008 - 01:18am PT
|
Just would like to insert here that I think the main point of the bible and god is sometimes being missed here. The Old Testament Books bascially prepared the path and gave information about when Jesus would come and why.
The New Testament is about Jesus. Jesus came to help people. He helped and continues to help me and anyone else who wants help.
That about sums it up IMHO...trying to keep it simple...like me.
Lynne
Sorry, off topic somewhat...please forgive...oops to do that go to forgiveness thread by Karl B. hehehe Need to keep a few chuckles in life right?
|
|
monolith
Trad climber
Berkeley
|
|
|
Jul 15, 2008 - 01:31am PT
|
So how large an error bar would make a billion year old estimate wrong Jody?
A day, a week, a year, 1000 years, 100000 years....
How accurate would it take for you to accept it?
And if the estimate is wrong in the first place, why would you care about the accuracy anyway?
|
|
Jaybro
Social climber
wuz real!
|
|
|
Jul 15, 2008 - 01:37am PT
|
But with the 'scientific'view there are facts and a logical paradigm. Respectfully, Jody, is there any part of the explanation that works for you that isn't "assumptions and estimations" plus of course, faith? any facts at all?
|
|
monolith
Trad climber
Berkeley
|
|
|
Jul 15, 2008 - 01:38am PT
|
Then why did you care about the accuracy Jody?
Remember you said:
So you are admitting it might not be completely accurate?
Give us some idea of what you mean by 'completely'.
|
|
graniteclimber
Trad climber
Nowhere
|
|
|
Jul 15, 2008 - 01:41am PT
|
So how old is the earth Jody? We're still waiting.
|
|
Ed Hartouni
Trad climber
Livermore, CA
|
|
|
Jul 15, 2008 - 01:44am PT
|
the "if" meant that you pick isotopes appropriate for the dates you are determining... so that is just getting the right half-lives....
...the initial conditions has to do with processing, chemical and cosmogenic. Depending on what you are measuring you may have a really good idea of what he conditions are, initially. However, you depend on many other constraints to get an accurate determination of the time.
Really you perform a statistical analysis with all the constraining measurements.
The earth was formed well after the universe was... currently we put the age of the universe at something close to 14 billion years. The earth is only like 4.6 billion year old. So the material the earth was formed out of was processed through supernova, and other nucleosynthesis pathways we think we understand, but have yet to identify a site. Probably because there is no single site for these processes.
Once again, this information is a part of the puzzle, not the absolute truth that you seek. You will not find that here. Understanding this you begin to understand a lot more about the world around you.
|
|
UncleDoug
Social climber
N. lake Tahoe
|
|
|
Jul 15, 2008 - 01:45am PT
|
Good question Granite.
|
|
monolith
Trad climber
Berkeley
|
|
|
Jul 15, 2008 - 01:47am PT
|
Still don't know what you mean by 'completely' Jody.
If it's not 'completely' accurate then you get to throw the whole thing out?
|
|
|
SuperTopo on the Web
|
Let us know!