where are the two places that life is hypothesized to have started
Abiogenesis Nonetheless, Earth remains the only place in the Universe known to harbour life,[29][30] and fossil evidence from the Earth informs most studies of abiogenesis. More than 99% of all species of life forms, amounting to over five billion species,[31] that ever lived on Earth are estimated to be extinct.[32][33] The age of the Earth is about 4.54 billion years;[34][35][36] the earliest undisputed evidence of life on Earth dates from at least 3.5 billion years ago,[37][38][39] and possibly as early as the Eoarchean Era (between 3.6 and 4.0 billion years ago), after geological crust started to solidify following the molten Hadean Eon. In May 2017, evidence of the earliest known life on land may have been found in 3.48-billion-year-old geyserite and other related mineral deposits (often found around hot springs and geysers) uncovered in the Pilbara Craton of Western Australia.[40][41][42][43] However, there have been a number of discoveries that suggested the earliest appearance of life on Earth was even earlier. Currently, microfossils within hydrothermal vent precipitates dated from 3.77 to 4.28 billion years old found in Quebec, Canada may be the oldest record of life on Earth, suggesting life started soon after ocean formation 4.4 billion years ago.[1][2][44][45][46] According to biologist Stephen Blair Hedges, "If life arose relatively quickly on Earth â€¦ then it could be common in the universe."[47][48]