Yesterday the Nobel Prize in Physics was awarded to three scientists who discovered that the universe is being blown apart.

Well, it was a good run.

The upside is that we still have some time before all the energy is sucked out of the universe. So all the brainstorming at a conference in Florida this past weekend about space travel in the 22nd century was not for naught. The purpose of the 100-Year Starship Symposium was to get a hall full of scientists imagining a trip to another solar system. (And some people say no one thinks big any more.)

Not surprisingly, something so challenging and so beyond our experience opened up all kinds of unusual avenues of discourse. George Hart, an evolutionary paleontologist at Louisiana State University, predicted that other solar systems would be explored by robots with human brains. German philosophy professor Christian Weidemann pondered the significance of intelligent aliens in the universe in a talk titled, “Did Jesus die for Klingons, too?” His answer? No.

And a biologist named Athena Andreadis, from the University of Massachusetts Medical School, emphasized one perhaps under-appreciated challenge of prolonged space travel: Interstellar sex would be really difficult.

Somewhere out there

The symposium was part of a joint project by NASA and the Defense Advanced Research Projects Agency, DARPA, the same Defense Department agency that financed the birth of the Internet. To show they’re serious, next month the agencies will award $500,000 to an organization to get the research rolling.

Of course, whatever outfit is chosen to take this on will have to wrestle with the universe’s daunting duo—time and distance. The nearest star, Alpha Centauri, is more than 25 trillion miles away. To give you some context, over the last 34 years Voyager 1 has traveled farther than any manmade object—a mere 11 billion miles.

Clearly, we need a new plan. Chemical fuel is out of the question—you could never store enough of it. Nuclear power is much more likely, and some scientists believe it could propel a spaceship at 15 percent the speed of light, or about 28,000 miles per second. Even so, it would probably take several generations to get to another solar system. (Which brings us back to that sex problem.) Plus, being exposed to cosmic radiation for years and years and years cannot be a good lifestyle choice.

Other challenges are more prosaic, such as how much would this mission cost? And who would be willing to pay for it? Still, DARPA knows that absurdly difficult projects like this spark amazing innovations. For instance, if you can solve the preposterous problem of shipping food trillions of miles and storing it for decades, imagine how easy it would be to send meals to the other side of our planet.

Meanwhile, back in China

Long-term, the United States might once again become the world leader in space exploration and innovation. But with our space shuttle fleet now retired, the short term lead could very well belong to China. Last week it launched a space module that’s an unmanned prototype for a space station it plans to have operating by 2020. And it’s seriously considering an idea that’s long been a pipe dream—getting solar power from an array of satellites in low Earth orbit. It hopes to have that up and running by the middle of the century.

Bonus: For old time’s sake, take a look at the PopSci slideshow of 10 tech innovations that came out of the space shuttle program, including the artificial heart pump and baby formula. Who knew?

Also, interested in other futuristic predictions? Check out our new Paleofuture blog that chronicles the history of futurism. See what scientists and thinkers from the past got right (and wrong) about modern technology.