What geological process is used to explain how nearly identical animals that cannot swim, are found on continents separated by large oceans?
What is the half-life of Uranium 238 and what did we use that radioisotope to date as the oldest item on Earth?
The geological process that helps explain the presence of similar animals on continents separated by large oceans is known as continental drift or plate tectonics. This theory suggests that the Earth's continents were once joined together in a single landmass called Pangaea, which gradually broke apart and drifted to their current positions.
To answer your second question, the half-life of Uranium-238 (U-238) is approximately 4.5 billion years. This means that it takes 4.5 billion years for half of the U-238 sample to decay into its daughter isotopes. However, it's important to note that U-238 decays into a series of different isotopes before eventually reaching a stable isotope of lead (Pb-206).
Uranium-lead dating is a common method used to determine the age of rocks and minerals on Earth. By measuring the relative amounts of U-238 and its daughter isotopes (such as Pb-206) in a geological sample, scientists can calculate the time it took for the radioactive decay to occur. This technique has been used to date the oldest rocks on Earth, including samples from the Jack Hills in Western Australia, which were found to be approximately 4.4 billion years old.