It is often said that we are made of star stuff. Except for hydrogen, the atoms in our bodies were fused in supernovae, and in the cores of stars. What’s not often talked about is just how complex fusion is, and how difficult it is to do, even in the core of a star. Take, for example, the seemingly simple fusion of hydrogen into helium, which is the primary energy source of our Sun.
Boltzmann’s Brain
Ludwig Boltzmann was a physicist who developed statistical mechanics, which connects Newtonian physics of particles to thermodynamics. Boltzmann’s kinetic theory not only explained how heat, work and energy are connected, it also gave a clear definition of entropy. While this revolutionized our understanding of everything from heat to the universe, it also led Boltzmann to a rather puzzling idea known as a Boltzmann brain.
Hole In One
Recently there’s been news that scientists suspect the black hole in the center of our galaxy may be a wormhole instead. Needless to say, you shouldn’t get your hopes up. The news is actually based on a preprint published on the arxiv that outlines how one might distinguish between a black hole and a hypothetical “white hole”.
Light Me Up
One of the properties of atoms and molecules is that they interact with light in an interesting way. If you heat up atoms or molecules in a gas, they will give off light. But they only give off light at specific wavelengths (colors).
Einstein and Eddington
Newton’s laws of motion and gravity predicted the motions of the planets almost perfectly. Newton’s laws are so accurate that we use them to accurately send robotic probes to Mars and other planets, but Newton’s laws aren’t perfect. The motion of some planets differ very slightly from Newton’s predictions. In the case of Uranus, its small deviation led to the discovery of Neptune. In the case of Mercury, however, its small deviation led to a completely new understanding of gravity.
Across the 8th Dimension
A few years ago a research team measured the force of gravity over very small distances. Their result places very stringent constraints on the space-time structure of our universe. Either the universe consists of only the four dimensions we see around us, or else all dimensions beyond those four must be very small, no more than about 10 microns, roughly one-tenth the width of a human hair. What, you might ask, does proving Newton right (yet again!) have to do with hyperdimensional physics? Quite a lot, it turns out.
Making Waves
George Thomson had some big shoes to fill. His father J. J. Thomson had won the Nobel prize for the discovery of the subatomic particle now known as the electron, and George had become a physicist as well. Fortunately George Thomson did quite well for himself, and was also awarded a Nobel prize. In a way, George won his Nobel prize for proving his father wrong.
Current Events
In the late 1800s there was an interesting physics demonstration that became rather popular. Take a partially evacuated glass tube with wires embedded on either end and run a high voltage across it. When you did this, the tube would glow, somewhat like a neon light. It was clear that an electric current ran from one wire (the cathode) to the other (anode) through the tube, but it was not clear what was causing the glow. By evacuating more air out of the glass tube, it soon became clear that the light was emitting from the cathode, and so they were called cathode rays.
How CERN’s Discovery of Exotic Particles May Affect Astrophysics
You may have heard that CERN announced the discovery (confirmation, actually. See addendum below.) of a strange particle known as Z(4430). A paper summarizing the results has been published on the physics arxiv, which is a repository for preprint (not yet peer reviewed) physics papers. The new particle is about 4 times more massive than a proton, has a negative charge, and appears to be a theoretical particle known as a tetraquark. The results are still young, but if this discovery holds up it could have implications for our understanding of neutron stars.