Lyell's extreme form of uniformitarianism would have required a perfect balance between heat production and heat loss.Kelvin argued that this was physically impossible (the concept is akin to a perpetual motion machine).

Carbon-14 has a relatively short half life of 5,730 years. Beyond 60,000 - 80,000 years, there is too little Carbon-14 left in the sample and this technique cannot be used.

U nuclei undergo fission and the nucleus splits to form two smaller but very energetic nuclei that move away from each other.

He calculated the modern rate of salt delivery to the oceans, and suggested that the present salinity of ocean water would take at least 100 million years to develop.

In the 1860's, English physicist Lord Kelvin disagreed with Charles Lyells proposition that the earth behaves in a uniform, unchanging manner.

Different isotopes of an element have similar chemical properties (undergo similar chemical reactions) but have different physical properties (such as evaporation rates).

However, we can predict what fraction of the parent atoms will decay over a certain amount of time because each radioactive isotope has a constant rate of decay (unaffected by temperature, pressure, or chemical state).This argument was popularized by Henry Morris (1974, p.164), who used some calculations done in 1968 by Melvin Cook to get the 10,000-year figure. Whitelaw, using a greater ratio of carbon-14 production to decay, concluded that only 5000 years passed since carbon-14 started forming in the atmosphere!The argument may be compared to filling a barrel which has numerous small holes in its sides.Now, the fuller that barrel gets the more water is going to leak out the thoroughly perforated sides, just as more carbon-14 will decay if you have more of it around.Finally, when the water reaches a certain level in the barrel, the amount of water going into the barrel is equal to the amount leaking out the perforated sides.Strata Thickness- In the late 1800s, a British geologist estimated that 75 million years has lapsed since the beginning of the Cambrian.