An interesting gamma ray burst during final exam week, GRB 130427A

An interesting gamma ray burst happened during finals week, GRB 130427A

Back in the early 1960s, the United States launched a few satellites, the Vela satellites, to detect secret nuclear weapons testing by the Soviet Union. By treaty between the US and USSR, no one was to test nuclear weapons above ground; underground testing was permitted. To monitor the Russians, US scientists at Los Alamos developed the Vela platform.

Nobody ever saw the Russkies nuking off any above ground tests, but while the detectors were not over Siberia, they could definitely see bursts of high energy gamma rays from sources outside the solar system.

Excellent.

In the 1970s, they began publishing scientific studies of these gamma ray bursters. The image below is an animation of the April 27 burst. Click the image to see the animation.

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There is still a lot of study going on as to why these GRBs happen all over the universe. We do not know for sure, and neither do the Russians. This GRB was so close and so well-imaged, that maybe someone will now crack the puzzle, using F = ma, quantum physics and all the concepts we study in PSC1121.

Diffraction Youtubes

We observed diffraction of laser light off the surface of a set of staples from a Swingline stapler. We also compared that to regular reflection from a small mirror.

But there are many other places where diffraction occurs, many different sources of light that diffracts. I have several YouTubes up that show diffraction in action. Look at my diffraction playlist.

I also like a diffraction YouTube from Saint Mary's Univ. up in Canada, especially from about the 0:25 mark.

Isotope in the news

Radioactive iodine, ¹³¹I, in the news.

Nuke agency reports unusual radiation in Europe Associated Press Vienna, Austria

The International Atomic Energy Agency says the "very low levels of iodine-131 have been measured in the atmosphere over the Czech Republic" and elsewhere on the continent.

Look at Webelements.com and see if you can tell why the last sentence in this article mentions a specific number of days.

Demonstrations tomorrow: pendulum and quantum physics

Tomorrow (Thursday) we will have a demonstration and measurements of the periodic behavior of pendula. Amanda and Rylee will be taking digital video, too, for iTunes U and YouTube.

We will also map out the momentum of the pendulum and build a foundation for the quantum physics on our agenda for the last three weeks of the semester.

YouTube of hydrogen spectrum

Here are the demonstrations of thermal and hydrogen spectra from Tuesday's lecture. All PSC1121 students, both lecture sections, must view this.



One of the interesting things about this quantum spectrum of hydrogen: it displays almost all the physics concepts we will study this semester. So you can think of this demonstration as the goal of our quest, how to understand the quantum world of hydrogen, the most abundant element in the visible universe.

Exam 4 SMA scores are UP.

What a stressful Wednesday.

But all work is now finished.

1. Your scantrons are at test scoring. Good.
2. Your SMA points from today's test are UP in Webcourses. Good.
3. Time to relax now, and get some ZZZZZZZ. Good.

See you all for lecture on Friday, in which we will look right into the quantum world, starting with chapter 23.

Images: discrete spectrum of hydrogen; Claude Elwood Shannon

Brain burners on HW 17, ready to go

OK, go to town on HW 17 and sharpen your wits with the basic questions on the yellow-green photon and with the two brain burners!!!! There is a blurb page to read BEFORE tackling the homework, "Calculation with Planck's constant and the speed of light." which you will find in the Homework folder alongside the actual assignment.

Spoons

I have set up a mini-blurb page on the spoon demonstration in today's lecture. Some cool quantum wave concepts. Look in the Lecture Files.

About pendulum periodicity

Chapter 15 has a nice diagram about the forces on a pendulum mass, Fig. 15-3, I think. We treat a pendulum just as if it were a spring IF its amplitude of oscillation is only a few degrees left and right of vertical.

I just activated a new page, "Why a pendulum behaves periodically, like a spring." It has a bunch of diagrams, for those of you who want some extra depth of knowledge. No trig, no calculus, just proportional right triangles. Look for this in the Lecture Files.

Quantum teleportation and our vocabulary

In Lecture Files, I have set up another blurb sheet that has a really fancy-shmancy diagram about quantum teleportation. We will not have to do any calculations or questions on the exam about quantum teleportation, but have a look at the vocabulary in the caption. There is a TON of PSC1121 concepts in there!!

SWEEEEEEEEET

Quantum physics, photons and ping pong balls

Here is an interesting news article about quantum states and how they work, as an elaboration of my comments in lecture this morning.

Blurb:

Researchers have shown that removing a photon from a laser beam can lead to it containing more photons than it had before... Measuring position and momentum in different orders produces different results. "You are working at the quantum level," explains Marco Bellini from the National Institute of Applied Optics in Florence, Italy. "If you did it with ping-pong balls it wouldn't work this way," he says.
K. Sanderson, News@Nature.com, 27 Sept. 2007

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