Until the 18th century, this question was principally in the hands of theologians, who based their calculations on biblical chronology.
Bishop James Ussher, a 17th-century Irish cleric, for example, calculated that creation occurred in 4004 B. There were many other such estimates, but they invariably resulted in an Earth only a few thousand years old.
He'd felt suicidal there, he later said, and searching for cosmic awareness in the Maharishi's camp made him feel like the clueless Mr. But to sing it was something else." To re-create the vibe of its early years, Lennon had the band record the basic track of "Yer Blues" elbow-to-elbow in a closet next to the main Abbey Road studio.
Jones from Bob Dylan's "Ballad of a Thin Man." Lennon channeled his misery into one of his most scalding performances, although he told that he had "a self-consciousness about singing blues.
These parent isotopes decay to stable daughter isotopes at rates that can be measured experimentally and are effectively constant over time regardless of physical or chemical conditions.