In his excellent book about exoplanets, Five Billion Years of Solitude, Lee Billings speaks with astronomer Frank Drake about the scientist’s attempts at sending messages, via radio signals, to other technological civilizations out there, something he’s been working on since 1960, thinking this sort of contact more likely than an interstellar meet and greet. In one passage, Drake explains why he believes it likely humans will die along with the sun. An excerpt:

“Some techno-prophets spoke worshipfully or fearfully of computers becoming sentient and gaining godlike powers. Others speculated that someday humans would break free of their carbon-based chains by uploading their minds into silicon substrates, where they could, in some manner, live forever. All seemed to agree that if humans themselves weren’t destined to inherit the Earth, they would certainly author whatever ultimately would. A few even conjured up the bygone Space Age dreams of Drake’s youth, envisioning a new golden era of prosperity and exploration in which humans would travel with their intelligent machines throughout the solar system, and perhaps someday to other stars.

‘Yeah, I’ve heard all that stuff,’ Drake replied. ‘It would be nice if we made it to Mars. But I don’t hold with the hypothesis that we’ll all slowly become or be replaced by computers. And of all the things we might someday do, I don’t think we’ll ever colonize other stars.’

I asked why not.

‘I don’t think computers can have fun,’ he said. ‘I think joy is a quality not available to computers. But what do I know?’ He laughed. ‘Interstellar travel, on the other hand, I’ve worked on that quite a bit. Putting a hundred humans around a nearby star costs about a million times as much as putting them in orbit in your own system. You’d have to be pretty rich to pull that off. 

‘Let’s say you have two colonies ten light-years apart–that’s probably the typical distance between habitable planets, I’d guess. The fact is, you can’t really go faster than about a tenth of light-speed. At speeds higher than that, if you hit anything of any substance whatsoever, the amount of energy released approaches that of a nuclear bomb. So you’re limited to about ten percent, a speed we can’t currently come anywhere close to, and that means your looking at journey times of at least a hundred years. The distances, times, and speeds are daunting, but the most daunting thing of all is the cost. Take something the size of a Boeing 737 plane, which is about the smallest that might make a reasonable crewed expedition, and send it at a tenth the speed of light to a nearby star, okay? Now just work out the kinetic energy that’s in it. It turns out to be about equal to two hundred years of the total electric power production in today’s United States. And that’s assuming a one-way trip, where you don’t even slow down and enter orbit on the other end. The inherent difficulty of interstellar travel is one of the big reasons why looking for things like radio signals is so appealing.’

‘So you think we’re stuck in the solar sytem,’ I said, thinking of distant days when the swollen red sun would sterilize Earth. ‘This is it?’

‘Yeah, I think so,’ Drake somberly replied. ‘You have to admit, though, that it’s pretty good while it lasts.'”