General Relativity (thesis series)

To start with some bonus material, the featured image of the post is from Einstein’s notebook during the period during which he was developing general relativity. This post is a continuation series of posts goes through the elements of the concordance cosmology: general relativity, inflation, the Big Bang and the expansion of the universe, cold dark matter (CDM) and a Read More …

Concordance Cosmology (thesis series)

This series of posts goes through the elements of the concordance cosmology: general relativity, inflation, the Big Bang and the expansion of the universe, cold dark matter (CDM) and a positive cosmological constant. I will start with a review of the historical, theoretical, and observational advances that led to each model’s widespread acceptance. The posts are excerpts from my Ph.D. thesis, lightly modified for blog format. No mathematical equations are written, with the intent of making the introductory material accessible to the non-specialist. A full bibliography of references in posts in this series is available. Read More …

Finding earth like planets from the comfort of our own planet

Gravitational lensing results from the fact that General Relativity describes our universe: mass bends light and can function in effect like a lens, bending light in ways that can be used to infer the mass distribution itself. Gravitational microlensing is due to this same effect, but refers to the detection of objects which are of Read More …

The Game of Life-simple rules, complex behavior

Here’s a video introduction to the Game of Life Historically, one of the pioneers of computer science John von Neumann was interested in finding machines which could reproduce themselves. He developed an abstraction allowing him to mathematically model his work on a computational grid. A mathematician John Conway took up and simplified his work publishing Read More …

Cold dark matter heats up – a review of a review

This is a review of the recent paper, to be published in Nature, by Andrew Potzen and Fabio Governato Cold dark matter heats up. The paper is itself a review, containing information published in previous studies. I gave a presentation about it at our weekly Astrophysics journal club. The figure in the header is M82, Read More …

Axolotl Protocol for Cryptographically Secure Messaging: An Illustrated Primer

Whisper At Open WhisperSystems Winter Break of Code, I had the privilege to announce our integrated RedPhone/TextSecure roadmap for iOS and Android.  Code named Whisper, it offers a cross platform one stop solution for secure messaging and phone calls. This is a big deal! Close to a billion people are using data channel messaging and phone Read More …

Hacking Philips Hue, wireless controlled multicolored LED lightbulbs

Philips makes a series of wireless controlled, multicolored light bulbs which I purchased. In the month or two I’ve had the bulbs I’ve fallen in love with them! Best of all, they have a great API integrated. After plugging in the bridge, connecting it to my wireless router, and plugging in the bulbs I can control them fully with Philips’ native iOS client from my iPhone or iPad, where I renamed the bulbs. The app works via a REST API, and there’s an iOS SDK you can use to interact with this easily via Objective C. The future of really is made of JSON! They also have an easy way to get started learning the API and controlling your bulbs from web browser. Read More …