Is there life beyond Earth? The question has turned out to be one of the hardest to answer in science. Despite the seemingly boundless expanse of the universe, which implies there's potential for abundant life, the vast distances between stars render the search akin to locating a needle in a cosmic haystack.

The Search for Extraterrestrial Intelligence (SETI) constitutes a branch of astronomy dedicated to finding extraterrestrial life by searching for unusual signals, dubbed technosignatures. The identification of a technosignature wouldn't just signify the existence of life, but specifically point to the presence of intelligent life using advanced technology.

That said, 60 years of searches have so far come up short. But now my colleagues and I have started investigating a previously unexplored range of frequencies.

SETI makes the assumption that extraterrestrial civilizations might rely on technology in a similar way to people on Earth, such as using cell phones, satellites or radar.

Since a significant portion of such technology generates signals that are prominently detectable in radio frequencies, focusing on these wavelengths serves as a logical starting point in the quest for potential extraterrestrial intelligence.

In 1963, six years after the first satellite was launched, editors from the Encyclopedia Britannica posed a question to five eminent thinkers of the day: "Has man's conquest of space increased or diminished his stature?" The respondents were philosopher Hannah Arendt, writer Aldous Huxley, theologian Paul Tillich, nuclear scientist Harrison Brown and historian Herbert J. Muller.

Sixty years later, as the rush to space accelerates, what can we learn from these 20th-century luminaries writing at the dawn of the space age?

The state of space 60 years on

Much has happened since. Spacecraft have landed on planets, moons, comets, and asteroids across the solar system. The two Voyager deep space probes, launched in 1977, are in interstellar space.

A handful of people are living in two Earth-orbiting space stations. Humans are getting ready to return to the moon after more than 50 years, this time to establish a permanent base and mine the deep ice lakes at the south pole.

There were only 57 satellites in Earth orbit in 1963. Now there are around 10,000, with tens of thousands more planned.