"Physicists have dreamed up some bizarre ideas over the years, but a decade or so ago they outdid themselves with the concept of Boltzmann brains – fully formed, conscious entities that form spontaneously in outer space. It may seem impossible for a brain to blink into existence, but the laws of physics don't rule it out entirely. All it requires is a vast amount of time. Eventually, a random chunk of matter and energy will happen to come together in the form of a working mind. It's the same logic that says a million monkeys working on a million typewriters will replicate the complete works of Shakespeare, if you leave them long enough. (...) However, if we can demonstrate that the universe has a finite lifespan, that would deny Boltzmann brains the infinite time they need to outnumber us. String theory might be able to help (...)." - Amira

"According to string theory, there may be a large number of universes. All of these universes are believed to come into existence through a process called eternal inflation, in which at least one universe continually expands at an incredible rate, while others form and grow within it like bubbles. This pool of universes has been dubbed the multiverse. Many of these other universes could be chock-full of conscious creatures early in their histories when, like the universe we see today, the past is distinct from the future. That could help make our point of view the standard one. But if these universes eventually become featureless and continue to linger, they will all accrue Boltzmann brains, tipping the balance away from us again. Zukowski and Bousso's latest work suggests this won't happen. Universes are constantly budding off a parent universe in the multiverse, so the parental characteristics can determine what kinds of "baby" universes form within it – and whether those universes will stick around long enough to be filled with Boltzmann brains or decay first. (...). "This is potentially an added experimental success for string theory and eternal inflation," says Daniel Harlow, a physicist at Princeton University. "We need to understand it better – [but] the fact that it potentially explains something is motivation to understand it better." - Amira