But let there be spaces in your togetherness and let the winds of the heavens dance between you. Love one another but make not a bond of love: let it rather be a moving sea between the shores of your souls. ~Kahlil Gibran Two weeks ago now, I flew to Conway, Arkansas to attend the wedding of my very good friends Vincent and Mary. This and an academic conference got in the way of blogging for a little while but I’m back. As such I decided to a post in their honor about bonding. Not human bonding, mind you,
Physics
explanatory articles on physics
cosmology / Discrete Math / Geometry / etc.
Quantum Geometry: Causal Dynamical Triangulations
A “quantum gravity expert” is presumably someone well acquainted with the details of our immense ignorance of the subject. I suppose I count. ~John Baez I long ago promised that I would discuss some of my own research. Here’s the first post that makes good on that promise. Today I’ll discuss a theory of quantum gravity. Why Quantum Gravity? Without a doubt, the two greatest advances in physics in the last 120 years were the advent of general relativity and quantum mechanics. These two amazing theories have totally changed the way we see the world. Quantum mechanics describes the
Analysis / Mathematics / Physics / etc.
Between Being and Non-Being: Imaginary Numbers
Imaginary numbers are a fine and wonderful refuge of the divine spirit almost an amphibian between being and non-being ~Gottfried Wilhelm Liebnitz One of the first things we learn how to do is multiply numbers. . That sort of thing. But what if we multiply a number by itself? This is the familiar operation, which we call squaring a number. and . That sort of thing. You can take a number to a power by multiplying it by itself some number of times equal to the power. So if you square a number, you’ve taken it to the second power.
Physics / Quantum Mechanics / Science And Math
Reality Is—The Feynman Path Integral
Will you understand what I’m going to tell you? …No, you’re not going to be able to understand it. … I don’t understand it. Nobody does. ~Richard Feynman on the Path Integral The “paradox” is only a conflict between reality and your feeling of what reality “ought to be.” ~Richard Feynman, in his lectures on physics Quantum mechanics is a very strange beast. Things tunnel and ooze. You can’t know both position and momentum at the same time. These strange properties come from the amazing realization that particles are waves. Not only that, but the amplitude of the wave
cosmology / Physics / Relativity / etc.
Fixing the Early Universe: Cosmic Inflation
Expansion means complexity and complexity decay. ~Cyril Northcote Parkinson This is part three of a series on the early universe. In the first article, I described the history of the Big Bang theory and why we believe the universe started in a colossal explosion. In the second article, I described some inconsistencies in the Big Bang theory that need correcting. Now I’ll explain how the theory of cosmic inflation addresses these inconsistencies and why we might believe it in inflation. This explanation will use ideas from quantum mechanics and general relativity; you can find my articles on these subjects
Education / Physics / Science And Math
How I Got Interested in Physics and in STEM
The Google+ community, +STEM on Google+ Community, is asking people to share how they got interested in STEM. The format is a video. I decided that for this week, I’d record such a video and share it with you all. This is the first time I’ve ever done any kind of video recording, so this was a new experience for me. Hope you like it!
cosmology / Geometry / Mathematics / etc.
A Mess of Cosmic Coincidences: Problems With the Big Bang Theory
The furthest bodies To which man sends his Speculation, Beyond which God is; The cosmic motes Of yawning lenses. ~Robert Frost, I Will Sing You One-0 I apologize for the long time of silence! I graduated from the University of Colorado about a month ago and was immediately assaulted by a huge amount of family affairs… and then caught up in moving. Sorry about this, everyone! My regular Sunday update schedule should resume next week. Last time, I described the theory of the Big Bang. I gave some history of the theory, and some reasons for why we believe
cosmology / Physics / Relativity / etc.
Always Walk Away From An Explosion—The Story of the Big Bang
We were fortunate to be there a day or two before ‘the big bang’ and then we got the heck out of town. ~Scotty Moore A few weeks ago, +Matthew Villaneuva asked the following question on Google+: Does anybody else find the Big Bang (the scientific explanation on how the universe got created) weird? Actually, yes! Just a century ago, everyone believed that the universe was static—i.e., that it had always existed and that it would always continue to exist. Even Albert Einstein held this view. I previously explained why we know the universe is expanding, so I’m going
Geometry / Mathematics / Physics / etc.
An Update On Kaluza-Klein Theory
I recently posted an article on Kaluza-Klein theory. This was partly because I was working a paper on it as a final project in my second semester of general relativity. The paper is finished, and I thought I’d upload it for the more mathematically inclined of my readers. If you’re interested, you can find it here.
Physics / Science And Math
Faster than a Speeding Pony: Why We Do Back-of-the-Envelope Calculations
This post will be rather short because I’m in the middle of finals. Of course, if you follow me regularly, you also know that I’ve posted rather a lot this week. When I’m exhausted from studying, it’s much easier to write in short bursts, which might explain all the short posts recently. While reading this article, I recently found the following video, in which a fan of My Little Pony: Friendship Is Magic demonstrates the physics impossibilities in a few scenes of his favorite show. Let’s watch it, and then I’ll explain why I showed it to you. (A