I woke up to a snowy day on the 30th of December, here in New Jersey and immediately realized two things! It was colder and darker than at the same time on the shortest day of the year, the 21st of December. I suppose you could blame the colder weather on the polar vortex swinging … Read More “Is the longest day the warmest day?” »

# Category: Cosmology for Pedestrians

Its been difficult to find time to write articles on this blog – what with running a section teaching undergraduates (after 27 years of ), as well as learning about topological quantum field theory – a topic I always fancied but knew little about. However, a trip with my daughter brought up something that sparked … Read More “New kinds of Cash & the connection to the Conservation of Energy And Momentum” »

Why is the night sky dark? Wilhelm Olbers asked this question, certainly not for the first time in history, in the 1800s. That’s a silly question with an obvious answer. Isn’t that so? Let’s see. There certainly is no sun visible, which is the definition of night, after all. The moon might be, but on … Read More “Mr. Olbers and his paradox” »

The most refined Standard Candle there is today is a particular kind of Stellar Collapse, called a Type 1a Supernova. To understand this, you will need to read the previous posts (#1-#5), in particular, the Fermi-Dirac statistics argument in Post #5 in the sequence. While this is the most mathematical of the posts, it might … Read More “Fermi Gases and Stellar Collapse – Cosmology Post #6” »

To explain the next standard candle, I need to digress a little into the math of statistics of lots of particles. The most basic kind is the statistics of distinguishable particles. Consider the following scenario. You’ve organized a birthday party for a lot of different looking kids (no twins, triplets, quadruplets, quintuplets …). Each kid … Read More “A digression on statistics and a party with Ms. Fermi-Dirac and Mr. Bose (Post #5)” »

Having exhausted the measurement capabilities for small angles, to proceed further, scientists really needed to use the one thing galaxies and stars put out in plenty – light. The trouble is, to do so, we either need detailed, correct theories of galaxy and star life-cycles (so we know when they are dim or bright) or … Read More “Cosmology: Cepheid Variables – or why Henrietta couldn’t Leavitt alone …(Post #4)” »

This post describes the cool methods people use to figure out how far away stars and galaxies are. Figuring out how far away your friend lives is easy – you walk or drive at a constant speed in a straight line from your home to their house – then once you know how much time … Read More “Cosmology: Distance Measurements – Parallax (Post #3)” »

Continuing the saga about the cosmological red-shift.

I have received some feedback from people that felt the posts were too technical. I am going to address this by constructing a simpler thread of posts on one topic that will start simpler and stay conceptual rather than become technical. I want to discuss the current state of Cosmology, given that it is possibly … Read More “A course correction – and let’s get started!” »