Image used with the consent of Agilent Laboratories; image source; larger image

The Physics Classroom: Total Internal Reflection - Sep 16, 2010

The optical fiber in the photo above doesn't just guide the beam--the fiber produces the beam. Instead of a tube of helium and neon gas, or a piece of ruby, the "active medium" of this laser is added to the glass in the fiber. Since the mirrors are just the polished ends of the fiber, there is nothing to go out of alignment, and maintenance is easy.

- Fiber lasers are using laser cutting.
- To find out how the fiber optic laser promises to fuse the technologies of transistors and fiber optics, see this Penn State page. Also, here's another image of a fiber laser.
- To see how the fiber contains a laser beam, visit The Physics Classroom: Total Internal Reflection.

image credit: Cesar Hidalgo; image source; larger image

Network Theory: A Key to Unraveling How Nature Works - Sep 1, 2010

You are looking at a network diagram that shows the interconnectedness of the world economy. To learn more about this network, visit Mapping the World Economy.

- To find out how networks are related to "Six Degrees of Kevin Bacon," visit Network Theory: A Key to Unraveling How Nature Works.
- To learn about a physicist who studies networks, see Physics Rules Network Dynamics.

Image credit: American Physical Society; Image source; Larger Image

Making a supersonic jet in your kitchen - Aug 16, 2010

What exactly happens when an object makes a splash in water? The disk shown above was pulled into water in a reproducible way to investigate the splash.

- The results were surprising... including a supersonic jet of air!
- To learn more, see Making a supersonic jet in your kitchen, and don't miss the video of the splash.

Image credit: Philippe Lijour; Image source; larger image

The Real Sea Monsters: On the Hunt for Rogue Waves - Aug 1, 2010

This "rogue wave" broke over the deck of an oil tanker, and was much taller than the other waves on the ocean at the time. See Freak Waves, Rogue Waves for graphs of rogue waves building up in the ocean, and for the measurement of one that struck an oil platform in the North Sea.

- To learn more about these waves, see The Real Sea Monsters: On the Hunt for Rogue Waves
- Also, check out this Discovery News article to find out about a cruise ship that was recently damaged by a huge wave.

Image credit: soapbubble.DK; image source; additional image

From Soap Bubbles to Technology - Jul 16, 2010

The soap film you see here, made in between two metal rings, is called a catenoid, and it uses the minimum area to enclose a given volume. Click on the image to see another example of a "minimal surface" soap film.

- Minimizing area can reduce construction costs--see this catenoid-shaped cooling tower, from this Wikipedia page.
- To learn more, visit From Soap Bubbles to Technology.

image credit: MODIS Rapid Response Team; Image source ; Larger image

About Dust - Jul 1, 2010

This satellite image shows a recent dust storm in China that was so large it spread out to neighboring countries. For more on this storm, see this Time magazine article and also About Dust.

- Also, see this photo essay on a dust storm in Sydney, Australia
- And for dust storms around the world, visit Earth Snapshot.

(This feature was updated on 1/24/2013.)

Image credit NASA; Image source; larger image

Shock Diamonds and Mach Disks - Jun 16, 2010

When the speed of the gases in a jet or rocket exhaust exceeds the speed of sound, a dazzling pattern results called "shock diamonds" or "Mach disks," as shown in this photo of the SR-71 Blackbird. The diamonds are created by crisscrossing shock waves in the exhaust.

You can see shock diamonds in a static rocket test in this NASA video. For more information, check out Shock Diamonds and Mach Disks.

image credit: NASA, ESA, H. Bond (STScI), R. Ciardullo (Penn State), and the Hubble Heritage Team (AURA/STScI); image source; larger image

Stellar Evolution - Jun 1, 2010

When the Sun reaches the end of its life, its outer layers will drift into space, an intricate cloud illuminated by its hot, dense core, as in this false-color image of a planetary nebula and white dwarf. For more details, see this page on the death of solar-mass stars.

How a star lives and dies depends upon its mass. For an overview of the lifetime of different types of stars, see The Life and Death of Stars. You should also see the Interactive Guide to Stellar Evolution and, for very thorough explanations, the Stellar Evolution pages from the Chandra website.

image credit: Caroline J. v. Wurden and Glen A. Wurden, Los Alamos; image source; larger image

Perspectives on Plasmas - May 16, 2010

This is a ball of plasma, created by discharging electricity into a solution. See the image source for more on how the image was made.

To learn about plasmas and their many applications, check out Perspectives on Plasmas and Plasmas.com.

image credit: USGS; image source; larger image

Properties of Volcanic Ash - May 1, 2010

Why were so many European airports closed due to the volcano? The image above of one volcanic ash particle begins to tell us why: the extremely small particles, with their many voids, can travel great distances after eruption. Once inside a jet engine, they melt and then re-solidify. Read Properties of Volcanic Ash for more details. You can learn about the specific dangers of flying through volcanic ash here.

Airlines try to avoid flying through ash, but it does happen. Read the account of one pilot at What it's Like to Fly through Volcanic Ash, and see the precautions against ash that Boeing takes here. For more on the hazards of flying through ash, see this Cocktail Party Physics blog post.