How old is the earth really?

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How old is the earth really?

Postby Ilikeponies on December 7th, 2014, 6:55 pm 

Different sources say it's different ages,how can we tell which source is the most reliable?
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Re: How old is the earth really?

Postby Braininvat on December 7th, 2014, 7:50 pm 

http://en.m.wikipedia.org/wiki/Age_of_the_Earth

You ask good questions, Philohippus. I often find wiki articles to be spotty and gap-filled, but the one on this subject is clear and to the point. Basically, you want sources that take into account radiometric dating of earth and moon rocks and meteorites, and see how that jibes with astrophysical data about the life cycles of stars like our sun and its possible age. Generally, scientists have landed around the 4.5 billion year mark. If you are coming across a different figure, I am interested in what the source was.
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Re: How old is the earth really?

Postby Ilikeponies on December 7th, 2014, 8:26 pm 

Braininvat » December 7th, 2014, 6:50 pm wrote:http://en.m.wikipedia.org/wiki/Age_of_the_Earth

You ask good questions, Philohippus. I often find wiki articles to be spotty and gap-filled, but the one on this subject is clear and to the point. Basically, you want sources that take into account radiometric dating of earth and moon rocks and meteorites, and see how that jibes with astrophysical data about the life cycles of stars like our sun and its possible age. Generally, scientists have landed around the 4.5 billion year mark. If you are coming across a different figure, I am interested in what the source was.



Well,this article is the one that really makes me wonder: http://www.liveleak.com/view?i=f17_1268172473
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Re: How old is the earth really?

Postby Watson on December 7th, 2014, 10:23 pm 

I think the article is saying the coal is not as old as previously represented. It doesn't say anything about the age of the earth on which the coal is found. I do except the coal and other hydro-carbons are not as old or scarce as the oil industry would have us believe.
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Re: How old is the earth really?

Postby BurtJordaan on December 8th, 2014, 3:49 am 

Ilikeponies » 08 Dec 2014, 02:26 wrote:Well,this article is the one that really makes me wonder: http://www.liveleak.com/view?i=f17_1268172473

This seems to be one of many Young-Earth-Creationist misinformed articles.

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Re: How old is the earth really?

Postby mtbturtle on December 8th, 2014, 8:15 am 

troll
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Re: How old is the earth really?

Postby Braininvat on December 8th, 2014, 2:05 pm 

Well, I hope he/she is as open to scientific evidence as he/she is to ponies.
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Re: How old is the earth really?

Postby Dave_Oblad on December 8th, 2014, 4:48 pm 

Hi all,

My Boss had a bunch of Degrees in Engineering, Math and a PHD in something.. etc. But is still a Young Earth Creationist. He thinks the Universe is about 7,500 years old. In a few debates I've had with him, he refuses to let facts get in the way of his Faith.

Best wishes,
Dave :^)
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Re: How old is the earth really?

Postby Eclogite on December 9th, 2014, 1:16 am 

Ilikeponies » Sun Dec 07, 2014 5:55 pm wrote:Different sources say it's different ages,how can we tell which source is the most reliable?
1.Consider only peer reviewed research articles, or textbooks by acknowledged experts.
2. Look at the more recent estimates.
3. Look for consistency.

First, the only practical way presently to estimate the age of the Earth is through radioactive dating.[1] (Contrary to the deliberately ignorant views of Young Earth Creationists, those factors that can influence the apparent age of a sample are readily accounted for.)

The oldest whole rocks dated on the Earth are currently thought to be part of the Isua Greenstone Belt in Greenland. These are dated at between 3.7 and 3.8 Ga. [2] However, there is active research in other Pre-Cambrian cratons and older candidates may appear. (The Accasta Gneiss, a terrane in Australia, and another Greenland greenstone belt are all possibilities. See here.)

The oldest minerals on the planet are zircons from the Jack Hills in Australia. Zircons are very durable and these have been eroded from an igneous rock, then incorporated in a younger sediment. [3] The oldest of these zircons has been dated at 4.4 Ga.

But these post-date the actual formation of the Earth through accretion from the protoplanetary disc in the young solar system. The age of the solar system is often taken to be the time at which the first solid particles formed. This is around 4.567 to 4.568 Ga. These and the later particles accreted to form the proto-planets and planets in a relatively short time - millions, of years, not many tens of millions. [4]

If we date the formation of the Earth to the time of the giant impact that formed the moon, that would be around 30 million years after solar system formation. This is discussed, for example, by Jacobsen. [5].

The Earth has a radiogenic W-isotopic composition compared to chondrites, demonstrating that it formed while 182Hf (half-life 9 Myr) was extant in Earth and decaying to 182W. This implies that Earth underwent early and rapid accretion and core formation, with most of the accumulation occurring in ∼10 Myr, and concluding approximately 30 Myr after the origin of the Solar System. The Hf-W data for lunar samples can be reconciled with a major Moon-forming impact that terminated the terrestrial accretion process ∼30 Myr after the origin of the Solar System.

Keep in mind that this is an active area of research and that ages will be refined, but we should not expect any significant deviations from these numbers.

References:

1. http://www.geo.cornell.edu/geology/clas ... ture04.pdf
2. Rollinson, H. The metamorphic history of the Isua Greenstone Belt, West Greenland Geological Society, London, Special Publications 2002 v. 199, p. 329-350
3. http://www.geology.wisc.edu/~valley/zir ... Nature.pdf
4. Krot, A.N. et al Origin and chronology of chondritic components: A review Geochimica et Cosmochimica Acta 73 (2009) 4963–4997
5. Jacobsen, S.B. THE Hf-W ISOTOPIC SYSTEM AND THE ORIGIN OF THE EARTH AND MOON
Annual Review of Earth and Planetary Sciences Vol. 33: 531-570 May 2005
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