Here’s how it works. The Milky Way is home to millions of potentially habitable planets — and approximately four of them may harbor evil alien civilizations that would invade Earth if they ...

Basically, where are the aliens? Perhaps we haven't encountered alien civilizations because there's a "universal limit to technological development" (ULTD) for every intelligent species in the ...

THE KARDASHEV SCALE. We have no idea what an alien civilization would look like. Humans are evolved primates. What if an alien species is reptilian? Or more like an insect? Or a hybrid of these?

For 75 years, scientists have consistently pondered the Fermi Paradox, which asks why we don’t hear from other civilizations ...

"It's like winning the lottery." When other factors are considered — such as the fraction of hospitable planets that host any life at all and how long a signal-emitting civilization might last ...

Don’t bother wondering if alien civilizations can hear our radio broadcasts or not. According to a new study, sufficiently advanced aliens can already see us. The research, set to be published ...

According to the Drake Equation, which calculates the probability of an existing, communicating civilization, there are currently an estimated 12,500 such intelligent alien societies in the Milky ...

In the 1960s, physicist Freeman Dyson proposed that advanced alien civilizations could be building out enormous megastructures around a star to harness much of its energy. These shells, dubbed Dyson ...

He suggests there's a chance that water or other liquid-dwelling aliens, as well as civilizations on super-Earths, may actually be trapped on their planets due to "physical limitations," even if ...

It summarized the results of a NASA workshop on how to detect alien civilizations. What was needed, the assembled group of astronomers, engineers and biologists concluded, was Cyclops, a vast ...