From what I gather, the article was inspired by a debate taking place about how the universe will evolve over time. In physics, there’s something called entropy, which is basically a measure of randomness. A major guiding principle in physics, known as the second law of thermodynamics, states that the entropy of an isolated system tends to increase over time. In other words, it takes energy to keep things organized. If you don’t keep adding energy, then over time, there’s a really high probability you’ll just get a bunch of disorganized atoms.

Knowing this, one might ask why our universe doesn’t appear random at all. Instead, it’s filled with all kinds sorts of fancily arranged items, like my computer, and Providence, RI, and our solar system. One explanation is that, given enough time, random pockets of organization can appear by chance. For example, you might randomly end up with a brain floating through space, the inspiration for the article’s title. Another, better explanation is that the universe isn’t that old, and also happened to begin in some very special initial configuration called the big bang. This explanation suggests that the universe simply hasn’t had enough time to degenerate into a random cloud of particles.

Astronomers agree that the idea of a big bang clears a lot of things up. Unfortunately, they do not have a good understanding of where our universe is headed. What the they do seem to have is a bunch of theories, and along with each theory, some whacky example of what the theory might imply. These bizarre scenarios that astronomers are describe simply indicate that there’s a lot about the universe we can’t yet explain. Sadly, this point is completely lost in an article that delights in presenting a laundry list of crazy sounding what-if statements.

It bothers me when physics articles present ill-formed theories in a way designed to make the physics involved appear as stupefying as possible. When physics gets things right, it makes sense, and can be presented clearly. When physics doesn’t have something figured out, it doesn’t yet make sense, and the world doesn’t need to know about it. At the very least, don’t don’t tell me about it in the New York Times while at the same time giving computer science extremely little press coverage.

Sound moves through air at 340 meters per second (m/s). That means that if I yell “Go!” then you move away from me at 400 m/s, you can catch to the sound I’ve made. As you catch up to the sound, however, you’ll hear it backwards. First you’ll catch up to the “o!”, than the “G”. The same logic applies to light. If you could travel faster than the speed of light, you’d see things happening backwards. But so what? What’s so special about seeing this happen backwards? If your a fast moving blind person, and you hear things backwards, we don’t say that you’re traveling back in time. Is light special?

Well according to special relativity, yes, light is indeed special. Sound travels through air at 340 m/s, but if you’re moving relative to the air, sounds speed relative to you changes. Also, if you get rid of the air (as in space) there’s no more sound. In the end of the 19th century scientists desperately wanted to find the stuff light used to travel though space. They called this stuff ether, but since if didn’t actually exist, they had a heck of a time trying to find it.

If light were traveling through the ether of space, then as we moved through space in different directions at different speeds, we’d measure the speed of light differently. Special relativity states that this doesn’t happen. Anyone moving at a constant velocity will measure light as traveling at 299,792,458 m/s. As a result, if you and I are floating towards each other in space at a constant speed, and we each a have a flashlight, and we each measure the speed of light reaching us from the other person’s flashlight, we will each be equally justified in claiming that we are stationary, while the other person is moving. In fact, special relativity says that the laws of physics (including the speed of light) will be exactly the same for each of us.

At first glance, this all seems very confusing. If I am moving towards you, and you toss a few photons in my direction, how can you and I possibly both see those photons as moving at the same speed? In particular, suppose I’m holding a measuring stick, and you and I both record the time at which the photons are at each end of the stick. If we agree on the times and the length of the stick, you will conclude that the photons are moving slower than I do. I will have seen them move one stick-length in one time-unit, but you will see them travel less than one-stick length (since the stick is moving toward you) in the same time-unit. The conclusion: for special relativity to hold true, people moving at different speeds must perceive lengths and times differently. In particular, if I am moving towards you, the only way we can measure the same speed of light is if we measures times and lengths differently.

It turns out that as we travel towards each other, we observe a time dilation (as well as a length contraction). If you are holding a watch, I will see it running slow. If I am growing a beard, you will see it growing slow. No matter what each of us does, the other will perceive it as happening more slowly than if we were both standing still next to each other. It’s pretty wild stuff I know, but trust me, it’s been tested many times. It also means that in theory a person can travel many light years on a spaceship traveling near the speed of light, but only age a few days along the way. If the spaceship goes faster than the speed of light however, all bets are off (and as a result, special relativity states that it takes an infinite amount of energy for a spaceship to reach the speed of light).

This brings us back to time travel. Since observers moving at different speeds always agree about the speed of light, but disagree about things like durations of time and the lengths of objects, they also disagree about when events take place simultaneously. In particular, if two stars explode, two people moving towards each other can disagree about which exploded first, and neither can be accurately viewed as incorrect.

Now suppose that in edition to the photons leaving the exploding stars, a message was sent at super light speed to a nearby space station. Upon receiving that message, the station sounds its “exploding star” alarm. An observer moving at a certain speed could accurately perceive the alarm as sounding before the stars exploded. In this way, super light speed travel allows information to travel backwards in time. This poses a problem for the laws of physics, and special relativity forbids it.

Ok, enough of this confusion. In my defense, I’m a computer scientist and haven’t taken a physics class since I got a “C” in thermodynamics my junior year.