Punctuated equilibrium is the concept that evolution did not happen at a steady rate. Rather, the historical record shows long periods of relative stability, such as the present time, when few new species evolved. These periods were broken by short periods of rapid change. The earth is about 4.5 billion years old. Humans have been on earth for a miniscule percentage of that interval.
Evolution has no specific goal.
Radiometric and other analyses have been developed which permit the accurate dating of rock samples. A scientific theory is a widely accepted belief, solidly based on evidence. The scientific method is self-correcting. Scientists' understanding of evolution and its processes change as new evidence become available. Evolution plays a central, unifying role in our understanding of nature.