Interview: Juan Collar and Detecting Dark Matter

We bring you another fascinating cosmology interview with a genius over at the Kavli Institute for Cosmological Physics. This time we speak to Juan Collar, a name that I am, apparently, incapable of saying. He leads a group at Kavli which is pursuing several experimental approaches to detecting dark matter in the lab.

Interview: Juan Collar and Detecting Dark Matter (MP3, 28.3MB, 41:10, Show Notes)

First Principles 4.0 - Inside Stars

Well, we pulled our heads out of our slacker haze and managed to post a new podcast on the feed! It’s a First Principles® episode about stars.

First Principles 4.0 - Inside Stars (MP3 file, 26.7MB, 28:24)

Black Hole Rays

The BBC is reporting that Science is reporting that scientists are reporting that:

Black holes are the most likely source of the mysterious ultra high-energy cosmic rays that bombard the planet… Observations at the world’s largest cosmic ray detector suggest the particles are emitted by huge black holes in the middle of nearby galaxies. 

Cosmic rays are a pain in the ass for spectroscopy, astrophotography and other CCD-based astronomy. Especially spectroscopy is plagued by cosmic rays. There are 3 kinds of cosmic rays that I’m aware of, electrons, protons and Helium nuclei (or alpha particles). The cosmic rays discussed in this article are high-energy and create a shower of interactions when they slam into the earth’s atmosphere.Pretty cool that we are starting to see results out of the Pierre Auger Observatory.

Energy Part 2

A while back I wrote a post about energy.

Here’s another example of energy that I think is interesting. When you take an automobile which is initially at rest and get it going 55 miles per hour, it gains kinetic energy. KE = (1/2)mv^2. So a car that weighs 2000 lbs. (900 kg) going 55 mpg (25 m/s) would have KE=(1/2)(900)(625)=280 kJ (kilo-joules) of energy. That energy comes at the expense of gasoline — chemical energy — exactly 281 kJ’s worth. Excluding all the messiness of friction and air resistance and such, we used exactly the same amount of chemical energy as we gained in kinetic energy. So it doesn’t matter if you use gasoline, hydrogren, electricity or biodiesel, it takes 281 kJ of energy to get your car going 55 mph.

Continue reading Energy Part 2…

Energy

There was a “Wanted Pages” entry in the Slackerpedia Galactica for the word “energy“. I banged out a quick paragraph, more as a placeholder than anything else, but it got me thinking. Energy can be somewhat hard to describe. Wikipedia has a good statement to the effect of “the potential for causing changes”. I have been thinking of some examples that illustrate that. I’ll probably do a video podcast about it eventually but here goes in blog form…

Continue reading Energy…