# Monthly Archives: April 2016

## Quick Look at Recent Meteor Events

I filter my news feed for anything related to astronomy, and I have been seeing a number of articles recently about large meteor explosions (called fireballs or bolides) in the atmosphere (example, example). These events are not occurring more frequently than before – we now have the technology to discover these explosions. The recent spate of bolide burst reports has caused me to become curious about how frequently these impacts are occurring. It turns out that NASA has an excellent set of web pages on this topic. There have been quite a few large meteor explosions, with the largest being the Chelyabinsk burst in 2013. As you can see in Figure 1, the cataloged meteor events are fairly even spread across the Earth. Continue reading

Posted in Astronomy | 1 Comment

## Nonlinear Piecewise Function for Stellar Luminosity vs Mass

A reader mentioned to me that the Wikipedia has an good article on stellar luminosity versus stellar mass– the article is a good one. I thought I would compare the empirical relationship shown in the Wikipedia with a couple of different data sets that I found on the web. I was motivated to perform this analysis because: (1) I have been doing some reading on exoplanets, and luminosity is important when it comes to exoplanet temperature; and (2) I am presenting a seminar on Mathcad to our engineering staff, and this application provides me a nice demonstration on how to compute nonlinear piecewise functions. Continue reading

Posted in Astronomy, General Mathematics | 1 Comment

## Ice is Almost Out at My Cabin

I love this time of year in Minnesota. I have setup cameras around my cabin in northern Minnesota so that I can see what is going on up there. I have been watching my lake go through the entire thaw process – it is almost clear of ice (Figure 1). I plan on being up there quite a bit this summer. Continue reading

Posted in Personal | Comments Off on Ice is Almost Out at My Cabin

## Exoplanet Revolution Period About a Dwarf Star

In this post, I look at the habitable zone around stars smaller than our Sun and the orbital radii and periods of potentially habitable exoplanets (i.e. having temperatures near that of Earth). Continue reading

Posted in Astronomy | 3 Comments

## Flattening the Golden Gate Bridge Deck

I recently read a post on Quora about the day that the arc of the Golden Gate Bridge was flattened by the load of a large number of people – some reports stated that as many as 300K people were present at the event. The bridge was opened opened to this huge throng of people as part of its golden anniversary. This was the first time I had heard of this event. Continue reading

Posted in General Mathematics | Comments Off on Flattening the Golden Gate Bridge Deck

## Naked and Afraid Statistics

I do not watch much reality television, but one show I do watch is Naked and Afraid (N&A). I have always been interested in primitive survival skills (e.g. I have blogged about knot tying and rigging), and this show really puts those skills to the test. I like the fact that the participants are presented with survival challenges from around the world (Figure 1). They have been on all the continents but Antarctica – I could not imagine someone surviving naked in Antarctica for any length of time. Continue reading

Posted in Statistics | 71 Comments

## Things Not to Do in an Interview

I have been in management since 1995, and I literally have hired many dozens of people and interviewed hundreds of people in the process. I have heard just about everything you can imagine in an interview. After a recent interview, I thought it might be useful to mention a few things not to do in an interview: Continue reading

Posted in Management | 2 Comments

## Product Design vs Research

I saw an interesting discussion on the Dynamic Ecology web site about publishing research papers. As I read the article, I saw that analogies could be drawn between doing research and developing new products. The Dynamic Ecology post was centered on observations made by William Shockley , 1956 Physics Nobel Prize winner, on what makes a successful researcher. Continue reading

Posted in Management | 2 Comments

## Temperature-Compensated SLA Battery Charging Voltage

Quote of the Day If the tiger ever stands still the elephant will crush him with his mighty tusks. But the tiger does not stand still. He lurks in the jungle by day and emerges by night. He will leap … Continue reading

Posted in Batteries | 3 Comments

## CO2 Tonnage Added To Atmosphere Per Year

My youngest son told me that I needed to watch the new Cosmos series with Neil deGrasse Tyson. I was immediately hooked – it is a masterpiece of scientific exposition for a general audience. I thought the original Cosmos with Carl Sagan was excellent, but the progress in computer graphics during the intervening decades makes the program visually stunning. Continue reading

Posted in General Science | 6 Comments