Moynihan, however, points out that the "go to space, save humanity" argument isn"t as strong as the billionaires present it, especially at this particular moment in time. This century, we face myriad existential threats that are not localised and could easily spread, from bioengineered pandemics to misaligned artificial intelligence. It"s possible such threats could reach beyond Earth. "Rushing to become multi-planetary might not provide a failsafe against every worst-case risk, says Moynihan. "In the immediate term, sparking a worldwide conversation on the issue of extreme risks may be more cost-effective than sprinting to Mars."