Modern humans, Homo sapiens, have been on Earth for approximately 200,000 years. The emergence of Homo sapiens as a distinct species is believed to have occurred in Africa around 200,000 years ago, based on fossil and genetic evidence. Over time, early human populations migrated out of Africa and spread to different parts of the world, leading to the colonization of diverse regions.
It's important to note that the history of humans on Earth is much longer when considering earlier human ancestors and hominin species that preceded Homo sapiens. These earlier hominin species, such as Homo erectus and Homo neanderthalensis, were present on Earth for millions of years before Homo sapiens evolved.
As our understanding of human evolutionary history continues to evolve with new discoveries and research, the timeline and details of human presence on Earth may be subject to further refinement. However, the emergence of Homo sapiens around 200,000 years ago is widely accepted among scientists as the approximate time when modern humans appeared on the planet.