I looked through and didn't find any questions that directly addressed this, although maybe I missed something.
My question is: where did the Australian Aboriginal people originate from- how did they get to Australia? According to Wikipedia, there isn't a widely accepted origin, but I'm curious to learn more on the different theories. They are commonly believed to be migrants from Africa, though they likely migrated through Asia but don't have any link to Asian genetics.
I've also heard that there isn't a lot of evidence of the advanced naval capabilities needed to migrate to the Australian continent at that time. Again, this could be wrong as it is just something I've heard.
The problem with this question is that Australian Aboriginals came to the continent long before written records even existed. It pre-dates history, and historians are not the dudes to ask.
I happened to be looking through some old questions and came across this one. Better late than never, right?
The current dominant anthropological theory is that the first Australians were the leading edge of the earliest modern human migration out of Africa. Known as the "(Great) Coastal Migration," this wave of human expansion traveled along the coast of the Indian Ocean and arrived in Sunda - the peninsula has since become the Indochinese Peninsula, Sumatra, Borneo, and Java as sea levels rose - by 75,000 years ago.
As these people expanded, they appear to have pushed the poorly-known Denisovans ahead of them. The Denisovans are another species of humans, a bit more closely related to Neanderthals than they are to us. But all three species are closely related enough to allow for limited interbreeding. Most of that interbreeding seems to have happened once Denisovans were backed into the Sunda corner. Today, Aboriginal Australians and Papuans have the highest percentage of Denisovan genes. Except for a few other populations in Asian, most modern humans don't have Denisovan genes.
Sometime between 60,000 - 70,000 years ago, the first Australians made the crossing to Sahul - the continent back when Australia, New Guinea, and Tasmania all formed one landmass. Even at the height of the Ice Age, Sahul and Sunda were never directly connected. That's why you don't find elephants in Australia or kangaroos in Thailand. Since humans made the crossing, it's hypothesized that they had boats or rafts of some sort back then. They probably weren't suited for long distance travel, but would have done the job to island-hop through Wallacea. Eventually these boats would carry Coastal Migrants to the Bismarks and the Solomons by 35,000 years - after this there's a halt in human expansion into the Pacific islands, indicating that whatever sort of watercraft people had at this time, they didn't trust them once they completely lost sight of land. There were probably two distinct crossings, one that went into northern Sahul and one that went into western Sahul, ultimately becoming Papuans and other Melanesians on one hand and Aboriginal Australians on the other. The division between these two populations is quite old. Their relations that stayed behind in Sunda are the likely ancestors of the Andamanese, Semang, Aeta and others.
Though the Coastal Migration came through southern Asia on its way to Australia, most Aboriginal Australians don't have a notable genetic connection to modern Asian populations because those Asian populations reached Asia after the Coastal Migration had gone through. They're a later wave of immigrants out of Africa. This includes the Austronesian, who expanded out of southern China / Vietnam a few thousand years ago and variously mingled with or displaced many old Coastal Migrant populations in Indochina and Indonesia.
If you can track down a copy, First Footprints is good introduction to the pre-colonial history of Australia. There's an associated documentary too, if you'd prefer to watch something instead of reading. It should be available on iTunes if you're interested.