Climate change may prevent contact with alien civilisations

Enrico Fermi, when asked about intelligent life on other planets, famously replied, "Where are they?" Any civilisation advanced enough to undertake interstellar travel would, he argued, in a brief period of cosmic time, populate ...

Silence in the sky—but why?

(Phys.org) —Scientists as eminent as Stephen Hawking and Carl Sagan have long believed that humans will one day colonise the universe. But how easy would it be, why would we want to, and why haven't we seen any evidence ...

Nonterrestrial artifacts hard to pin down

(PhysOrg.com) -- Two Pioneer probes left our solar system carrying plaques about humankind, and two Voyager probes will soon join them to gather information about places far out in our galaxy. We can and will send more autonomous ...

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