Are we alone in the universe? Are there advanced civilisations out there that we could make contact with?
In 1999, researchers at the University of California released a citizen-science program called SETI@Home.
Anyone could sign up and allow SETI [Search for Extra Terrestrial Intelligence] to use their home internet connection when they weren't using their computer. That is, when their screensavers were on.
A million people signed up. Among them were Kurri's Col Maybury, of the Astronomical Society of the Hunter.
The network of computers was used to help astronomers analyse data for suspicious signals. Essentially, they were looking for a hello from aliens. Anyone with a modem could become the person to make history by discovering another civilisation.
Col said the SETI program was essentially a "massive worldwide analytical computer".
That effort came to nought, but the search for extraterrestrial intelligence continues.
Col has been following a mysterious object in a galaxy 500 million light years away.
Scientists are baffled by the object, which transmits signals that reach Earth in a repeating, 16-day pattern.
The signals are known as fast radio bursts [FRBs]. The object sends out bursts for four days before stopping for 12 days and then repeating.
Scientists recently pinpointed the signals to a spiral galaxy. Researchers hope that tracing the origin of the signal will help determine what caused it.
Col said it could be "tidal interruptions from a black hole".
Or, it could be aliens.
"It is hard to imagine an alien-built transmitter capable of transmitting over such a distance," Col said.
"Anyway, how can we respond to such an enigmatic signal? We humans have been transmitting for only 120 years, so our signals are at best 120 light years away, radiating from our lonely blue planet.
"All our signals are out there - from the radio declaration of world wars I and II, to episodes of Mickey Mouse to Armstrong stepping onto the moon and, more recently, broadcasts about the Covid 19 [coronavirus] epidemic. They're all radiating outwards, diminishing in signal strength as they go."
So, are we alone? Well, with trillions of stars in the universe and 250 billion stars in our Milky Way galaxy alone, Col reckons there's a pretty good chance we're not alone.
But should we be trying to contact aliens? The late Stephen Hawking, in his book A Brief History of Time, said that alerting aliens to our existence was risky. He reckons we should lay low.
Astronomer Jill Tarter, though, argued that any aliens who have survived long enough to communicate and travel across interstellar distances would have evolved a co-operative and non-violent intelligence.
Sticking with Col Maybury's musings, he tells us he's been listening to podcasts of Yuval Noah Harari, the historian, futurist and author of Sapiens.
Col: "It's brilliant the way he can analyse trends, knowledge and the future. But of course, the future will be stranger than we can possibly imagine."
Topics: "We came across a saying the other day that there's no use worrying about the future because life has more imagination than humans."
Col: "Harari says we're all becoming algorithms."
Topics: "OK, now we're worried."