Ten Random Ideas

It's been a while since I posted a new blog entry. Since I don't have any specific subject on my mind today, I thought I would just share ten random facts, theories, or ideas that I find fascinating:

1. Dark matter and dark energy – We have no idea what 96% of the universe is made of. Physicists confirm that only about 4% of the universe is composed of the familiar matter that we're accustomed to. Another 24% is made up of dark matter (which only interacts with regular matter via gravity), and 72% is made up of dark energy (which is a repulsive force that causes space itself to expand). But we have no clue what dark energy or dark matter are.

2. Toba Catastrophe Theory - Approximately 70,000 years ago, a supervolcano erupted on Lake Toba, on the island of Sumatra in present-day Indonesia. This eruption was so unimaginably enormous that it blanketed all of South Asia in 15 centimeters of ash, and put enough ash into the atmosphere to cause a volcanic winter, which abruptly changed the entire planet's climate for several decades. At this time, humanity nearly went extinct - the entire human population may have been reduced to just 1,000 breeding pairs, creating a bottleneck in human evolution. We are all descended from the few survivors of this apocalypse.

3. String theory - Why don't the rules of physics that apply to macroscopic objects (i.e. the theory of relativity) seem to apply to particles (i.e. quantum mechanics) and vice versa? Since macroscopic objects are composed of particles, it would stand to reason that they should. String theory attempts to reconcile these two sets of laws by postulating that at an extremely tiny scale (much smaller than subatomic particles), the universe is made up of tiny vibrating strings. Different vibrations produce different kinds of particles. It also calls for the existence of 6 or 7 extra dimensions, which we don't notice in our every day lives because they are so tiny. So far there is zero evidence that string theory is correct, but it has widespread support among physicists due to its mathematical elegance. This is one of the first serious scientific hypotheses to be considered not because the evidence necessarily suggests it is correct (at least not yet), but because physicists believe that the universe “should” be simple. If it proves to be right, it may call for us to reevaluate how scientific theories should be developed.

4. Happiness Economics - For the last 200 years, economists have mostly measured wellbeing in terms of money, such as measurements like GDP. While this is often a good approximation of human wellbeing, it's a crude tool. Consider that Russia and Mexico have approximately the same GDP per capita, yet Mexicans consistently report being much happier than Russians do. Maybe the next big shift in economics is to determine the policies most likely to improve a population's happiness, rather than assuming that more GDP growth will do the trick.

5. Self-driving cars - The transportation industry is about to see its biggest game-changing revolution since the invention of the automobile itself. Self-driving cars are being tested by Google, Stanford University, Carnegie-Mellon, and every major automobile manufacture. They're already on the road being tested, but aren't commercially available yet. They should be by 2017-2020. This will radically change the way we live our lives. It will eliminate most of the 40,000 annual traffic fatalities in the United States, which are mostly caused by human error. It will free us from the stresses of daily commutes, and allow us to do things other than watch the road. And for many people it will eliminate the need for car ownership entirely, as it will be easy to simply summon a car to pick you up whenever you need one.

6. Biology causing mass extinctions - It turns out that we humans are not the first species in the history of the earth to single-handedly wreck the planet's climate. We share that distinction with at least two others: Cyanobacteria and Azolla Ferns. 2.4 billion years ago when life was very primitive and microbial, there wasn't much oxygen in the atmosphere. Therefore, nearly all species were anaerobic - they had evolved in conditions of very little oxygen. Over time, a species of cyanobacteria began to proliferate which excreted oxygen as a waste product. This changed the composition of the earth's atmosphere and poisoned nearly all of the anaerobic species, resulting in the extinction of most types of life on earth. More recently, a mere 49 million years ago the earth had an extremely warm climate, in which ferns were able to grow as far north as the arctic. They began proliferating around the Arctic Ocean, sucking up lots of carbon dioxide in the atmosphere and then sinking to the bottom of the ocean when they died. This sudden reduction in the amount of CO2 in the atmosphere caused global cooling, which eventually turned the entire planet from a greenhouse into an icehouse.

7. Simulation Hypothesis - Is our reality a simulation, like The Matrix? Transhumanist philosopher Nick Bostrom thinks so. Consider the following argument: If we assume that it is possible to create simulated worlds, and that at least one species somewhere in the universe would like to do so, then we are almost certainly living in such a simulation. Why? Because such a civilization would be likely to create multiple simulations (some of which might be running simulations of their own), and so probability would dictate that it's far more likely we are living in one such simulation than in the "original" universe. You can be the judge as to how compelling you find this argument...but I can't find any obvious flaws in the logic.

8. Post-scarcity - Assuming that we don't blow ourselves up and that we don't encounter civilization-wrecking climate change in the next few decades, we will soon enter into an age of abundance where virtually everyone has access to the basic necessities of life. This is due to a convergence of several trends. As genomics improves, we will soon be able to grow meat in laboratories and grow crops hydroponically, eliminating the need for most farms/ranches, ensuring a stable food supply, giving the environment a much-needed breather from the damage we've done, and freeing up freshwater to be used for humans. As solar energy improves (the capacity is growing exponentially), it will soon be able to compete dollar-for-dollar with fossil fuels...and soon thereafter leave fossil fuels in the dust. Education will become much cheaper due to effective online tools that are finally becoming available, and the subsequent end of the 19th/20th century model of education. Health care will become much better due to effective personalized medicine, which will proliferate as it finally becomes affordable to have your genome sequenced.

9. VY Canis Majoris - The scale of some of the objects in our universe is so unimaginably vast that it's difficult for us to comprehend. The largest known star is called VY Canis Majoris, and it's located about 4,000 light-years away from us. It's so big that if it were placed in the middle of our solar system, its surface would extend beyond the orbit of Saturn and it could hold over a billion suns (or 11 quadrillion earths). Wow. That's big.

10. The hidden potential of the human brain - Some people (usually with autism) have a rare mental condition called synesthesia, where the senses get mixed up due to neural connections in the brain getting routed to the wrong place. This may take the form of associating numbers with specific shapes or colors, or associating certain sounds with textures or smells. Synesthetes are often capable of amazing feats, such as memorizing pi to tens of thousands of digits or creating beautiful works of art with little training. It is thought that we all have these astounding abilities somewhere within our brain, but we can't access it because we don't yet understand how our brains work enough to unlock those neural pathways.

Big Bangs and Boltzmann Brains

This past week, I watched a fascinating TED Talk from cosmologist Sean Carroll. The question he poses is one that has puzzled scientists, philosophers, and theologians for millennia: Why does our orderly universe exist at all? The second law of thermodynamics states that entropy (disorder) tends to increase over time. This is intuitive to most of us; it’s easy to break an egg, but difficult to put a broken egg back together, because there are far more arrangements in which the pieces of the egg can be shattered than unbroken. As a result, things tend toward more chaos and disorder. But why was the universe ever orderly to begin with?

Carroll does a great job demolishing the explanation which I’ve always favored, that our universe is just a fluke. Even though individual atoms move in hard-to-predict ways we can nevertheless predict the behavior of macroscopic objects. For example, the molecules in the air and ground are constantly jostling one another, moving in every possible direction. But we don’t expect them to spontaneously arrange themselves into a car, because the probability of the molecules simultaneously moving into the correct position is extremely unlikely. But over a long enough period of time (vastly longer than the age of the universe) it will eventually happen by pure chance.

This same argument could be scaled up to the universe itself. Quantum mechanics indicates that particles are constantly popping in and out of existence at random. If you wait for an unimaginably long time, all of the particles that make up our universe will spontaneously pop into existence out of the nothingness and assemble themselves in an orderly way, in a random quantum fluctuation. Many have speculated that such a fluctuation caused the Big Bang. The length of time we would have to wait for such an event to occur is called the Poincarre Recurrence Time, and is estimated to be on the order of 10^10^10^10^10^1.1 years. I’ve always been fond of this idea, and it seems easy to invoke the Anthropic Principle here: Conscious observers will only be able to marvel over their own existence during those rare periods of time when the universe is in a low-entropy state by pure chance. But as Carroll points out (using an argument originally made by Ludwig Boltzmann over a hundred years ago), that isn’t necessarily the case. It would be far easier for an individual brain to form from a quantum fluctuation, than an entire universe with hundreds of billions of galaxies. If our existence was a fluke of an infinitesimally unlikely quantum fluctuation, we would predict that we should be lonely Boltzmann Brains floating through empty space, rather than inhabitants of an enormously complex universe. Since we do indeed live in a complex universe, Carroll therefore concludes that our universe is not merely a random quantum fluctuation.

But if the Big Bang wasn’t merely a freak random occurrence, what caused it? Unfortunately, neither physicists nor philosophers have a solid answer for this question. Carroll suspects that there must be a multiverse, in which unknown laws of nature occasionally give rise to low-entropy universes such as our own. He cites the work of Lee Smolin, who proposed the idea of the fecund universe, in which a Big Bang occurs at the singularity of a black hole and a new universe is created. This would solve the Boltzmann Brain paradox, because universes would constantly be spawning new universes through the laws of nature, but randomly-occurring Boltzmann Brains would still be unfathomably rare.

Another possibility is that our understanding of entropy is incomplete; perhaps our universe is indeed a random quantum fluctuation, but for reasons we don’t understand it’s easier for entire universes which can eventually produce conscious observers to randomly fluctuate into existence, than it is for Boltzmann Brains to do so. Perhaps the laws that govern the creation of universes tend to give rise to things like our own universe rather than Boltzmann Brains. Perhaps our universe is merely a holographic representation of a two-dimensional universe with different laws of physics than those we observe, and therefore entropy doesn’t apply at all. Perhaps our world is a simulated reality, and the simulators find complex worlds more interesting than lone Boltzmann Brains. Or perhaps we are indeed Boltzmann Brains, and for some reason don’t realize it.

Whatever the reason we live in an orderly universe, our understanding of physics is slowly making it possible to weigh the different theories to see which are the most likely. As our understanding of cosmology continues to improve, perhaps we will one day be able to understand what (if anything) caused the Big Bang. If Carroll’s multiverse theory turns out to be correct, perhaps it will vindicate the Hindu concept of cyclical creation and destruction: Universes are born, die, and are eventually reborn in different forms.

Watch the short version of Sean Carroll’s talk here. If you’re interested in the full hour-long lecture, watch it here.