image credit: NASA; image source; larger image

NASA-Apollo Missions ` - Sep 1, 2013

This historic photograph shows Earth, the moon, and NASA's Apollo 11 lunar module. The photo was taken from the command service module, which remained in orbit around the moon while the lunar module landed and then spent 21 hours on the moon's surface. During the Apollo 11 mission, astronauts set foot on the moon for the first time.

For more Apollo 11 information and photos, visit this NASA Apollo 11 page and also this Lunar Planetary Institute site.

image credit: Fir0002/Flagstaffotos; image source; larger image

Wikipedia: Laser Lighting Display ` - Aug 1, 2013

To learn the basics of laser light shows, visit Wikipedia: Laser Lighting Display. If you do any activity with a laser pointer, first read laser pointer safety.

image credit: National Library of Medicine (NLM); image source; larger image

Roentgen's Discovery of the x-ray ` - Jul 1, 2013

This photo is one of the first x-ray images, made by Wilhelm Roentgen in 1895. It shows the bones in his wife's hand. The calcium in her bones absorbed much of the energy from the x-ray beam and cast a shadow. Notice the shadow of her ring.

To learn about the early history of x-rays, see Roentgen's Discovery of the x-ray and, to learn more, check out this illustrated article from Stanford University.

Compare the amount of detail in this image with what you can see just to the right in From Physics Research.

image credit: R. Svoboda, UC Davis, Super-Kamiokande Collaboration; image source; larger image

Astronomy Picture of the Day: Neutrinos in the Sun ` - Jun 1, 2013

This image of the sun was made with neutrinos, which are tiny, almost-massless particles that move at nearly the speed of light. Neutrinos are created in nuclear reactions, and were first detected near a nuclear reactor.

The nuclear reactions that power the sun produce lots of neutrinos. In fact, billions of them per second are passing through your hand right now.

For more about the image, see Astronomy Picture of the Day: Neutrinos in the Sun. To learn how the measurement of solar neutrinos led to a change in fundamental physics, check out this PBS webpage.

image credit: NASA/Goddard Scientific Visualization Studio; image source; larger image

NASA Finds Thickest Parts of Arctic Ice Cap Melting Faster ` - May 1, 2013

The bright white region near the center of the image shows the year-round Arctic ice in 2012. To see the startling decrease since 1980, visit NASA Finds Thickest Parts of Arctic Ice Cap Melting Faster and slide the white line in the middle of the image to the right.

image credit: Solar Dynamics Observatory/NASA; image source; larger image

Sun ` - Apr 1, 2013

You are looking at the sun, imaged in extreme ultraviolet light (invisible to us) and shown in false color. To learn more about the sun, visit this this National Geographic article, and also this Hyperphysics page.

Notice how irregular the edge of the sun looks. Hot matter streams from the surface and returns, or occasionally some breaks off and heads out into the solar system. See From Physics Research for more information on this matter and how it moves.

This image was captured by NASA's Solar Dynamics Observatory on March 26, 2013.

(This feature was updated on April 9, 2013.)

credit: Corrie White & Igor Kliakhandler; image source; larger image

Liquid Drop Art ` - Feb 1, 2013

This image was created by photographer Corrie White in her basement workshop. She uses a device a device that releases several drops from the same location in rapid succession, at predetermined time intervals. For more of her work, see Liquid Drop Art.

To learn about the image, see this commentary by a physicist.

To see how Corrie does it, check out her illustrated Drop Photography Guide on Flickr.

image credit: NASA; image source; larger image

Atmospheric Optics: Aurora, Northern Lights ` - Jan 1, 2013

This image shows a view of the Aurora Borealis captured from the International Space Station as it flew over Nebraska. For more information, see NASA Image of the Day Gallery.

To find out more about auroras, visit this Atmospheric Optics page and also the Exploratorium's Auroras: Paintings in the Sky.

image credit: STS-41B, NASA; image source; larger image

Astronomy Picture of the Day: To Fly Free in Space ` - Dec 1, 2012

This is astronaut Bruce McCandless, orbiting along with the Space Shuttle in 1984 as he tests his rocket pack. When he stepped outside to begin his spacewalk, why didn't he fall back to Earth? He stayed in orbit because before and after he stepped outside, McCandless and the Shuttle had the same velocity. The force of Earth's gravity bent his path into the same orbit as the shuttle; that's because the acceleration of gravity does not depend on the mass of the object being accelerated. To learn more about McCandless' spacewalk, see Astronomy Picture of the Day: To Fly Free in Space and Footloose.

Now look at the image at the top right of Felix Baumgartner beginning his supersonic skydive. When he stepped out, his balloon had been lifting him slowly in the thin stratospheric air, so his initial velocity was quite small. Gravity then pulled him back to Earth.

To learn more about gravitational orbits, visit Satellite Motion.

image credit: Ravedave; image source; larger image

How does an LCD display work? ` - Nov 1, 2012

Take a look at this video to see how a liquid crystal display (LCD) TV screen works. For more information, see this Case Western Reserve page.

The molecules of a liquid crystal have a tendency to line up, rather than point in random directions. For more, see these pages from Kent State University and from Simon Fraser University.