cosmos a spacetime odyssey the clean room

Tyson ends by noting that similar work by scientists continues to be used to help alert Patterson would continue to campaign against the use of lead, ultimately resulting in government-mandated restrictions on the use of lead. Kehoe and others that this chemical was safe. He would discover that the higher levels of lead were from the use of tetraethyllead in leaded gasoline, despite long-established claims by Robert A. Patterson examined the levels of lead in the common environment and in deeper parts of the oceans and Antarctic ice, showing that lead had only beenīrought to the surface in recent times. Humans (including the Roman Empire), and that lead is poisonous to humans. Tyson notes how lead does not naturally occur at Earth's surface but has been readily mined by Tyson goes on to explain that Patterson's work in performing lead-free experiments directed him to investigate the sources for lead. With these clean results, Patterson was able toĮstimate the age of the Earth to 4.5 billion years. Lead from the ambient environment, compared to Tilton's results, and required the construction of the first ultra-high cleanroom to remove all traces of environmental lead.

Patterson found that his results were contaminated by George Tilton on uranium counts with the established half-life of uranium's radioactive decay to lead, this would be used to estimate the age of the Earth. Tyson then outlines the work Patterson did as a graduate under his adviser Harrison Brown to provide an accurate count of lead in zircon particles from Meteor Crater, and to work with similar results being collected by Instead, scientists have used the debris from meteor impacts, such as the Meteor Crater in Arizona, knowing that the materialįrom such meteors coming from the asteroid belt would have been made at the same time as the Earth. Some geological events, these can only trace back millions of years. Tyson first describes how the Earth was formed from the coalescence of matter some millions of years after the formation of the Sun, and while scientists can examine the formations in rock stratum to date This episode is centered around how science, in particular the work of Clair Patterson in the middle of the 20th century, was able to determine the age of the Earth.

Cosmos a spacetime odyssey the clean room