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If, in the year AD 1600, you had asked an educated European how old the planet Earth was and to recount its history he would have said that it was about 6000 years old and that its ancient history was given by the biblical account in Genesis.
If you asked the same question of an educated European in AD 1900 you would have received a quite different answer.
It is then detected with a GM counter above ground.
Because Gamma rays can kill living cells, they are used to kill cancer cells without having to resort to difficult surgery.
The selections and comments here are not a complete exposition of the works of the authors mentioned; rather they were chosen to illustrate and exemplify changing perspectives over time.
In Europe the issue of the age of the Earth was not a serious one prior to the rise of science; the history of the Earth was assumed to be accounted for in Genesis.
Some cancers are easier to treat with radiotherapy than others - it's not too difficult to aim gamma rays at a breast tumour, but for lung cancer it's much harder to avoid damaging healthy cells.
Also, lungs are more easily damaged by gamma rays, therefore other treatments may be used.
During the early part of this period there was a considerable amount of activity by runs from AD 1850 to the present.Also radioisotopes are used in industry, to detect leaking pipes.To do this, a small amount is injected into the pipe.These cosmogonies were part of the new emphasis of science in seeking rational explanations of the features of the world. This period was marked by a great deal of field geology rather than grand cosmogonies.It became clear that there had been significant changes in the Earth's topography over time and that these changes could neither be accounted for by natural processes operating during the brief nor by the postulated Noachian flood.Animals and plants have a known proportion of Carbon-14 (a radioisotope of Carbon) in their tissues.When they die they stop taking Carbon in, then the amount of Carbon-14 goes down at a known rate (Carbon-14 has a half-life of 5700 years).Notable observations included: ran from about 1780-1850.By the end of the 18'th century it was clear that the Earth had a long and varied history. The major debate was between the catastrophists, e.g., Cuvier, who held that the history of Earth was dominated by major catastrophic revolutions and the uniformitarians, e.g.The age of the ancient organic materials can be found by measuring the amount of Carbon-14 that is left.The most common tracer is called Technetium-99 and is very safe because it only emits gamma rays and doesn't cause much ionisation.