Monthly Archives: June 2015

Greenland Ice Sheet Trivia

I was reading an article today that says that geophysicists have figured out why the Greenland has been experiencing a flurry of magnitude 5 earthquakes. The scientists claim that the earthquakes are being caused by massive icebergs calving off the Greenland ice sheet in a manner that momentarily jams the movement of the ice sheet. The ice sheet and the calved iceberg are so massive that their interaction cause an earthquake.

While the earthquake information was interesting, there was a side discussion on the amount of ice required to raise sea level by 1 mm and seal level impact potential of a melting Greenland ice sheet. Continue reading

 
Posted in Geology | Leave a comment

Owl Camouflage

I saw these two pictures today and I was stunned by the effectiveness of an owl's camouflage. I occasionally see owls – there is a great horned owl that lives near my house and it is amazing watching it fly at dusk. It has a very large wingspan. Continue reading

 
Posted in General Science | Leave a comment

Lignum Vitae is a Remarkable Wood

I enjoy woodworking very much and I am now in the process of making a solid walnut countertop by gluing small walnut pieces together. While choosing the wood species for my countertop, I did consider a number of tropical species like teak and ipe. During this search, I heard a person mention that Lignum Vitae was the world's densest wood and is known for being so oily as to be considered self-lubricating. It is also a rare and potentially endangered species. Continue reading

 
Posted in Construction | 1 Comment

Barycenter of Pluto and Charon

I am excited about the New Horizon's flyby of the Pluto system (Figure 1) occurring on July 14, and I will be glued to my computer as the data is returning. Fortunately, there is already some data coming back on Pluto and its moons. One interesting aspect of the Pluto system is the fact that the mass ratio of Charon to Pluto is large enough that the barycenter of their orbit is outside the bodies of both Charon and Pluto. Continue reading

 
Posted in Astronomy | 7 Comments

Volt-Ampere Measurement Circuit

This is a circuit designed by Stephen Woodward that I saw years ago in EDN. I originally was interested in the right-hand side of the circuit, which measures the real power usage of the load. I now have an interest in the left-hand side of the circuit, which measures the Volt-Ampere (VA) usage of the load. I will present an abbreviated analysis of the circuit Continue reading

 
Posted in Electronics | Leave a comment

Sun's Galactic Orbital Speed

I was reading Quora this week and I saw the following statement that mentioned the orbital speed of the Sun as it revolves about center of the Milky Way. Continue reading

 
Posted in Astronomy | Leave a comment

Schmitt Trigger Circuit For a Push-Pull Output

I previously wrote a blog post about how to select components for a Schmitt trigger circuit using a comparator with an open-collector output. An engineer stopped by my cube yesterday and asked if I could write-up the same analysis for a Schmitt trigger circuit using a comparator with a push-pull output. This post will provide that analysis. The only thing unusual about the circuit is the use of a Zener diode as a voltage reference instead of the more commonly seen resistor divider network. Continue reading

 
Posted in Electronics | 2 Comments

Number of Photons Per Second from a One-Watt Bulb

An article on Stumbleupon and called "8 shocking things we learned from Stephen Hawking's book" considered the following statement from The Grand Design shocking.

A 1-watt night-light emits a billion billion photons each second. Continue reading

 
Posted in General Science | Leave a comment

Compensating GPS Clocks for the Effects of Relativity

I occasionally read articles on Stumbleupon and I came across an interesting article called "8 shocking things we learned from Stephen Hawking's book" – the book they are referring to is called "The Grand Design". I personally would not call the statements in the article shocking, but that is just my opinion. Continue reading

 
Posted in Navigation | 2 Comments