From Physics Research Archive - Page 3
How does GPS work? - Sep 1, 2011
The photo shows a Global Positioning System satellite. To find out how the system works, visit How does GPS work?, and be sure to see the video to understand how three or four different GPS satellites specify your position on Earth. For more, check out this Beyond Discovery page from the National Academy of Sciences.
Benoît Mandelbrot, Novel Mathematician, Dies at 85 - Aug 2, 2011
This famous fractal is the Mandelbrot set. Click to make the image larger, and look at the boundary between the black and blue--it is made up of the larger image, at smaller and smaller scales. Check out this Fractal Geometry page from IBM, especially the video (scroll down) that zooms in on the Mandelbrot set.
Smaller image credit: NASA; smaller image source; larger image credit: STS-41B, NASA; larger image source
Footloose - Jul 1, 2011
In 1984, astronaut Bruce McCandless made this untethered spacewalk--the first ever, and one of only a few. He maneuvered with a "jet pack" strapped to his body as he orbited Earth at about 18,000 miles an hour. Click on the image to see McCandless at his maximum distance from the shuttle.
Chaos Theory: A Brief Introduction - Jun 8, 2011
This image shows the "Lorentz attractor," a graph that represents the behavior of a simple model of Earth's weather. Weather is just one example of a chaotic system, in which seemingly irregular behavior does follow certain patterns.
Mechanics of a Meltdown Explained - May 12, 2011
The long red tubes are zirconium-alloy-clad fuel rods being fastened together into large bundles that will form the core of a nuclear reactor. Inside the zirconium cylinders are stacked pellets of uranium oxide, the reactor fuel.
image credit: NASA; larger image
Not Just Another Old Flame - Apr 12, 2011
The photo shows two flames, one on Earth and one in space, with both flames on identical candles.
This X-ray image of 3C273 shows a jet of energy shooting out of the quasar's bright center, thought to be home to a supermassive black hole. If you look closely you can see a small thread connecting the center to the bright spots of the jet. Scientists have observed that matter from that small thread moves very fast, then appears to slow down in the luminous part of the jet, akin to a "cosmic traffic pile-up" of matter. For more details, see Chandra Observes Cosmic Traffic Pile-Up In Energetic Quasar Jet.
The Doppler Effect and Sonic Booms - Dec 1, 2010
This image of the shockwave made by a speeding bullet is a shadowgraph--simply a photograph of the shadow of the bullet and the shockwave. Variations in the density of air refract the light used to make the shadow and produce bright and dark regions.
Quantum Cascade Lasers - Nov 1, 2010
The image above shows a quantum cascade laser captured by a camera that images infrared light. The laser light is the small dot in the middle of the round window. The laser itself--behind the window--is kept at a temperature of -193° C, just above the temperature of liquid nitrogen.
Do We Know What Killed the Dinosaurs? - Oct 16, 2010
In the image above you can see two concentric circles. These mark the location of the Chicxulub crater, and the white line shows the coast of the Gulf of Mexico. See this Canadian site (scroll down to the third image) for a fuller explanation of how the image was made and for related images.