As discussed in the preceding few entries, the fate of the universe is unknown, and some theories posit the continual creation of universes that “bud” from our own. However, let’s focus on our own universe. One possibility is that our universe will continue to expand forever, and particles will become increasingly sparse. This seems like a sad end, doesn’t it? However, even in this empty universe, quantum mechanics tells us that residual energy fields will have random fluctuations. Particles will spring out of the vacuum as if out of nowhere. Usually, this activity is small, and large fluctuations are rare. But particles do
emerge, and given a long amount of time, something big is bound to appear, for example, a hydrogen atom, or even a small molecule like ethylene, H2C=CH2. This may seem unimpressive, but if our future is infinite, we can wait a long time, and almost anything could pop into existence. Most of the gunk that emerges will be an amorphous mess, but every now and then, a tiny number of ants, planets, people, or Jupiter-sized brains made from gold will emerge. Given an infinite
amount of time, you will
reappear, according to physicist Katherine Freese. Quantum resurrection may await all of us. Be happy.
Today, serious researchers even contemplate the universe being overrun by Boltzmann Brains
—naked, free-floating brains in outer space. Of course, the Boltzmann Brains are highly improbable objects, and there is virtually no chance that one has appeared in the 13.7 billion years our universe has existed. According to one calculation by physicist Tom Banks, the probability of thermal fluctuations producing a brain is e to the power of −1025. However, given an infinitely large space existing for an infinitely long time, these spooky conscious observers spring into existence. Today, there is a growing literature on the implications of Boltzmann Brains, kick-started by a 2002 publication by researchers Lisa Dyson, Matthew Kleban, and Leonard Susskind that seemed to imply that the typical
intelligent observer may arise through thermal fluctuations, rather than cosmology and evolution.