In Bill Watterson’s comic strip Calvin and Hobbes, there is a game known as Calvinball. The basic idea of Calvinball is that rules are added by players as the game progresses. Players can add to the rules as you go along, but once a rule is in place it can’t be undone. The result is a hodge-podge game where the action is incomprehensible by anyone but the participants. Often in popular science quantum theory is portrayed as the physics version of Calvinball, even though that isn’t how quantum theory works. Quantum objects may be strange, but they aren’t making up rules as the universe plays on.
Sword of Damocles
According to legend, when Damocles declared that his king, Dionysius, must have a posh and easy life, Dionysius offered to trade places with Damocles. There was only one catch. Dionysius decreed that a sword be suspended over the throne by a single horse hair, so that Damocles would always know the peril of being king. Since then the Sword of Damocles has come to represent a threat of doom that could strike without warning. While the prospect of living under a hanging sword doesn’t seem pleasant, stories of impending doom are quite popular, particularly within popular science.
Into Darkness
Yesterday I wrote about how interstellar clouds of methyl alcohol can be induced to create microwave laser regions (astrophysical masers). This was due to a stimulated emission of light in excited atoms. As strange as that seems, you can also have the opposite effect, or stimulated absorption.
Gravity Check
Yesterday I wrote about how we test whether unitless constants such as alpha (α) change over the history of the universe. You might also have noticed that I said if such constants did change, then it would mean either fundamental physical constants change or there is some exotic physics going on. We looked at the physical constants yesterday, so today let’s look for exotic physics.
Variables of Nature
Within physics there are certain physical quantities that play a central role. These are things such as the mass of an electron, or the speed of light, or the universal constant of gravity. We aren’t sure why these constants have the values they do, but their values uniquely determine the way our universe works. For example, if the mass of electrons were smaller, atoms would be smaller. If the gravitational constant were larger, you’d need less mass to create a black hole, and neutron stars might not exist.
Red Dawn
If you’ve ever watched a sunrise or sunset, you’ve seen how the Sun appears deep orange, or even red when low in the sky. In the middle of the day the Sun appears merely yellow. So why does it appear different colors at different times of the day? The answer lies in how light interacts with our atmosphere.
The Lithium Experiment
One of the big successes of the big bang model is its prediction of elemental abundances. The first elements were produced in the early moments of the universe through a process known as baryogenesis. This process is very complex, and it is highly dependent upon the temperature and density of the universe at that time. Change the temperature a bit one way or the other, and the initial ratio of primordial elements would be different. Knowing the temperature of the early universe, we can predict the amount of hydrogen vs. helium produced by the big bang, and this agrees fairly well with observation.
The Hologram Cosmos
There has been a flurry of news articles about a new experiment that could prove we live in a two-dimensional hologram. Needless to say, we do not live in a 2-D hologram, and even if successful this new experiment would prove nothing of the sort. Unfortunately the “universe is a hologram” headlines always make great link-bait, and it doesn’t help that the press release for this experiment uses a similar link-bait headline. That said, the experiment is is very real, and if it succeeds it could revolutionize our understanding of the cosmos, so it is worth talking about.
Not So Fast
One of the fundamental principles of modern physics is that nothing can travel faster than light. Of course when this is mentioned, someone usually suggests a way to get around that limit. What about warp drive, for example. Or what about tachyons? These are hypothetical particles that can never go slower than the speed of light. What I like about tachyons is that it’s a good example of how what seems like a simple and obvious solution turns out to be deeply complex when you take it seriously.