Hot answers tagged

14

The age of the solar system is 4.6 billion years. We know that because almost all meteorites are 4.6 billion years old¹. Therefore, that puts a very solid upper boundary to the age of the Earth. According to solar system models, it took between 10 million and 100 million years for the Earth to form in the early Solar System. That result is consistent ...


6

The age of groundwater can vary over a large span. The moment a drop of rain enters the ground it becomes groundwater and when it reaches the groundwater table, the water starts to flow towards a lower hydrostatic level, usually towards the sea, a river or a lake. If you have a well, you'll pump up water to lower the hydrostatic level near the well, so that ...


5

Groundwater ages vary enormously across the globe and with depth: from hours in parts of Florida and areas with Karstic geology, to tens of thousands of years in the American breadbasket, all the way to several billion years as was recently discovered in Canada. Remember that some of this groudwater may be perfectly drinkable, while by far, most of it will ...


4

Radiocarbon dating cannot be used to date rocks or lava, only organisms that absorbed carbon from the atmosphere in the last 50'000 years or so. The older the samples, the more difficult it is to get an accurate age because the amount of 14C remaining becomes close to zero and thus the more likely it is that a few atoms of 14C from sample handling or ...


4

I run an argon lab which does also K-Ar measurements. The sample amount depends on the age because you need enough signal strength to measure the radiogenic argon component precisely. Young rocks have very low 40Ar* and to get enough volts on the detector you need more sample. Having the incorrect amount is akin to trying to measure micrometers with a ...


3

From zircon dating we know that the age of the earth is close to the age of the asteroids in our solar system (i.e. there is not a huge discrepancy between their ages). Without evidence indicating otherwise, scientist are left with no other conclusion but that the asteroids and the earth are of nearly the same age.


3

The chances of this actually being accurate are remote to the extreme, but Earth could in theory be a captured planet older than the solar system, and the resurfacing from the giant impact removed all the evidence. First, captured rogue planets with stable orbits in the inner solar system are virtually impossible. Second, the timing would need to be ...


3

The ages are not the only piece of information that we have. Gerrit covered most of the age issue in his answer. To summarise: We know the age of the solar system (4.5-4.6) and the oldest material we have on earth is 4.4. To add to that, we know that the composition of the Earth is very similar to what we would expect from having formed in the solar system....


2

Claire Patterson et al settled the Age of the Earth in 1956. In this paper, which can be obtained for free from Colorado.edu, we read: "The following assumptions are made concerning meteorites: they were formed at the same time; they existed as isolated and closed systems; they originally contained lead of the same isotopic composition; they contain ...


1

Geochron's answer is correct. For the sake of completeness I will add this: sample from surface of the earth = Sample A You will get some age, if the sample is young enough. sample from 1km deep of the earth = Sample B Low chance of getting any age. sample from 10km deep of the earth = Sample C Carbon-14 below detection limit. sample from 20km ...


Only top voted, non community-wiki answers of a minimum length are eligible