As a philosophy minor in college, I was subjected to metaphysics – one of the most interesting and challenging experiences I’ve ever had (if I even had it).
One of the questions that metaphysics examines is the nature of time. Wired Magazine currently has an interview with Sean Carroll, a theoretical physicist at CalTech who has attempted to understand the physics of time.
But the particular aspect of time that I’m interested in is the arrow of time: the fact that the past is different from the future. We remember the past but we don’t remember the future. There are irreversible processes. There are things that happen, like you turn an egg into an omelet, but you can’t turn an omelet into an egg.
And we sort of understand that half way. The arrow of time is based on ideas that go back to Ludwig Boltzmann, an Austrian physicist in the 1870s. He figured out this thing called entropy. Entropy is just a measure of how disorderly things are. And it tends to grow. That’s the second law of thermodynamics: Entropy goes up with time, things become more disorderly. So, if you neatly stack papers on your desk, and you walk away, you’re not surprised they turn into a mess. You’d be very surprised if a mess turned into neatly stacked papers. That’s entropy and the arrow of time. Entropy goes up as it becomes messier.
So, Boltzmann understood that and he explained how entropy is related to the arrow of time. But there’s a missing piece to his explanation, which is, why was the entropy ever low to begin with? Why were the papers neatly stacked in the universe? Basically, our observable universe begins around 13.7 billion years ago in a state of exquisite order, exquisitely low entropy. It’s like the universe is a wind-up toy that has been sort of puttering along for the last 13.7 billion years and will eventually wind down to nothing. But why was it ever wound up in the first place? Why was it in such a weird low entropy unusual state?
This is one of the best overviews of the topic that I’ve seen, especially for the non-philosophers sane people of the world.
Worth a read if you want your brain to get a workout/squeezing.
BONUS! – many blog posts have discussed the anthropological wonder that is Google’s suggest. Whenever you start typing in a search, you can see all kinds of funny suggestions (here is a whole website devoted to the best ones).
While putting together this post, I saw the following. It looks like at number 7, the average Googler goes from intrepid scientist to hopeless romantic.
