The absence of encounters with intelligent alien life could be attributed to the necessity of fossil fuels for technological advancement, according to a reader's perspective published today. To develop advanced technology capable of off-world travel, alien civilisations might need to undergo an equivalent of Earth's Industrial Revolution, which was fuelled by coal, oil, and gas.
It is suggested that many intelligent alien races could exist, but on planets lacking easily accessible fossil fuel equivalents, their development might not progress beyond a 17th-century level. Consequently, these civilisations might remain undetectable from afar, as their planetary signature could be indistinguishable from that of a planet supporting only plant-like life.
Another viewpoint offered in the same correspondence considers humanity's own trajectory, with observers potentially debating whether human civilisation will endure given the presence of atomic weapons, or if it has a habit of rebuilding and living in balance.