Final answer:
Modern humans reached Australia around 45,000 years ago, using rafts or watercrafts to cross the sea, as Australia was not connected to Asia by land due to lower sea levels during the Ice Age.
Step-by-step explanation:
The migration of Homo sapiens to Australia is a significant event in human history that showcases the great navigational and seafaring abilities of early humans. It is believed that modern humans reached Australia about 45,000 years ago. During this time, the Earth was in the midst of an Ice Age, which led to lower sea levels and exposed land bridges, such as Beringia connecting Siberia to Alaska. However, Australia was not connected to Asia by land, indicating that early humans must have crossed sea channels using watercraft.
No physical evidence of these crafts has been found, but their existence is inferred from the patterns of human migration and archaeological findings in Australia. These achievements were accomplished well before the development of technology and civilization as we understand it, underscoring the remarkable adaptability and ingenuity of our ancestors.