Start Using radiometric dating how old is the earth

Using radiometric dating how old is the earth

It was not until 1926, when (under the influence of Arthur Holmes, whose name recurs throughout this story) the National Academy of Sciences adopted the radiometric timescale, that we can regard the controversy as finally resolved.

Thus, when in 1919 Shapley stated that for him the radiometric timescale was fully established, he acknowledged that there was as yet no explanation for the sun’s energy. In 1920 Sir Arthur Eddington came up with the answer: the fusion of hydrogen into helium.) In reply to Lord Kelvin’s attacks, the geologists used two principal lines of reasoning.

Roman poet Lucretius, intellectual heir to the Greek atomists, believed its formation must have been relatively recent, given that there were no records going back beyond the Trojan War.

The Talmudic rabbis, Martin Luther and others used the biblical account to extrapolate back from known history and came up with rather similar estimates for when the earth came into being.

The third act sees the entry of a newly discovered set of physical laws—those governing radioactivity.

Radioactivity offered not only a resolution to the puzzle of the earth’s energy supply but also a chronology independent of questionable geologic assumptions and a depth of time more than adequate for the processes of evolution.

This position came to be known as uniformitarianism, but within it we must distinguish between uniformity of natural law (which nearly all of us would accept) and the increasingly questionable assumptions of uniformity of process, uniformity of rate and uniformity of outcome.

That is the background to the intellectual drama being played out in this series of papers.

They assumed that current rates—of sediment deposition and of salt transport by rivers—were the same as historical rates, despite the evidence they had that our own age is one of atypically high geologic activity. The rock cycle, as we now know, is driven by plate tectonics, with sedimentary material vanishing into subduction zones.

Dzisiaj jest:
18-Jan-2020 08:19