Stories tagged light
Spiral galaxy M81: The black hole in the center of this galaxy is 70 million times as massive as the Sun, but it behaves exactly the same as much, much smaller black holes.
Courtesy X-ray: NASA/CXC/Wisconsin/D.Pooley & CfA/A.Zezas; Optical: NASA/ESA/CfA/A.Zezas; UV: NASA/JPL-Caltech/CfA/J.Huchra et al.; IR: NASA/JPL-Caltech/CfA
This may fall under the heading of small comfort, but a new study has shown that all black holes, big or small, suck in matter in the same way. Using NASA’s Chandra X-ray observatory, astronomers studied the different types of light (X-ray, radio and visible) emanating from the region around a massive black hole in the center of galaxy M81. They found that this light was the same as light coming from smaller black holes, even though this one is some 10 million times bigger, and is sucking in matter from a different source. This confirms a part of Einstein’s theory of relativity, which predicted that black holes would be fairly simple objects, not subject to a lot of variation. Which doesn’t really help much if you find yourself getting sucked in, but at least you know it’s nothing personal.
You can learn more about Chandra and X-ray astronomy in our Be an Astronomer! web exhibit. And you can ask questions of Megan Donahue, a scientist who work with the Chandra observatory.
Tags : A California company has developed a new type of light bulb, the size of a breath mint, that pumps out as much light as a street lamp. The bulb is twice as efficient as an LED, and 10 times as efficient as an incandescent light. It also produces a full spectrum of light frequencies, illuminating objects in true color.
You'd be blue, too: Compact fluorescent light bulbs save energy, but come with a number of problems.
Courtesy Tiago Daniel
We’ve written before about compact fluorescent light bulbs – a new type of bulb you can buy for your home that uses a lot less electricity than standard bulbs, and thus reduces pollution and greenhouse gas emissions. But are they all they’re cracked up to be?
Some environmental groups warn that the bulbs contain mercury, which can be toxic and difficult to clean up in the event of a broken bulb.
Researchers in England claim the bulbs can trigger migraines, epilepsy and lupus.
And a review panel assembled by the New York Times concluded that most CFL bulbs do not give off attractive light.
Though a step in the right direction, clearly there are still some bugs to work out of the bulbs.
An invisible tank: Right in front of that other tank. (photo courtesy of wikimedia commons)Great Britain has been making some progress in the field of “ways to kill people with out them seeing you do it.” In the past, we had to be satisfied with impersonal methods like booby traps and poisoning, but, with the help of science, before long we should be able to safely view our own nefarious deeds - while hiding in plain sight! Sort of.
The UK’s Ministry of Defense has recently unveiled a prototype “invisible” tank, and predicts that similar models will be ready for service (the service of blowing things up! Yeah!) by 2012.. Unlike a lot of other invisibility research, which often focuses on bending light around an object, the invisi-tank (as I like to call it) relies on “cameras and projectors to beam images of the surrounding landscape onto the tank.” I’m not sure if these cameras and projectors are on the tank itself, or nearby. That’s probably a secret.
A soldier who was present at the trials was quoted as saying, "This technology is incredible. If I hadn't been present I wouldn't have believed it. I looked across the fields and just saw grass and trees - but in reality I was staring down the barrel of a tank gun."
It is also believed that the Ministry of Defense is “testing a military jacket that works on the same principals.”
I recommend that you take a look at the original article. The picture of the scientist in charge of the project is great. He completely redefines the stereotypical image of a scientist. Oh wait, no, I mean he reinforces it.
Nanotechnology sometimes borrows from nature.
Morpho butterfly: Pigments don’t cause these butterflies’ intense colors. Instead, super-small lattice-like structures on the wings reflect only certain wavelengths of light (or color). And the colors shift with your perspective. (Photo courtesy Lionoche, through Flickr)
Super-small, light-reflecting structures—instead of pigments—create a morpho butterfly's intense, iridescent wing color. Scientists are developing nanomaterials with similar properties.
Zoom in on a butterfly's wing
If you used a special microscope to look at these butterfly wings, you’d see tiny scales made up of thin layers of transparent wing material with nanoscale gaps between them. Light waves bouncing off the bottom surfaces interfere with waves reflecting from the tops. Most light waves are cancelled and only certain wavelengths—or colors—bounce back to your eyes. The more light in the environment, the brighter the color.
Wing structures: These complicated structures on butterfly wings manipulate light to control the color that we see.
How do transparent thin films create color?: Scientists haven't yet created materials that work exactly like the butterfly wings. But layers and layers of transparent, super-thin films--each with a different index of refraction--can be tuned so that they only reflect specific wavelengths of light (o
Scientists are developing all sorts of products that, like the butterfly wings, use layers of transparent materials with nanoscale spacing between them to manipulate light and create color. With them, we can create computer and cell phone displays, fabrics and paints that change color, optical devices that improve telecommunications systems, and films that reflect much more light than glass mirrors. Can you imagine other uses?
We've discussed energy-saving compact fluorescent lightbulbs elsewhere on this blog. Now, Popular Science magazine has a round up of the next generation in low-energy lighting technology.
New nano material a black hole for reflections.
Silica nanorods make a super dark surface.: This SEM image shows the silica nanorods mounted at exactly 45 degrees which makes the surface super anti-reflective.
Scientists at Rensselaer Polytechnic Institute have created a material that reflects virtually no light. By depositing layers of silica nanorods at an angle of 45 degrees on top of a thin film of aluminum nitride, a new world record has been set for anti-reflective surfacing.
The technique allows the researchers to strongly reduce or even eliminate reflection at all wavelengths and incoming angles of light, Schubert said. Conventional anti-reflection coatings, although widely used, work only at a single wavelength and when the light source is positioned directly perpendicular to the material. PhysOrg.com
Where will this make a difference?
The new optical coating could find use in just about any application where light travels into or out of a material, such as:
- More efficient solar cells
- Brighter LEDs
- High-reflectance mirrors
- Black body radiation
- Optical interconnects (photonics)
RPI press release here:
Researchers at the University of Rochester have successfully slowed the speed of light by shooting it through a chamber filled with Cesium gas. This may one day lead to computers, telecommunication, and other technology transmitting information as light rather than as electriity -- a far faster and more efficeint method.
Puffy clouds, sudden storms
in Earth and Space Science, Math, The Water Cycle, Weather and Climate, and Forces of Nature
Storm chasers know that puffy cumulus clouds often cause sudden rainstorms, while storms associated with stratus clouds form more slowly. Now physicists at England’s Open University have finally found an explanation.
They propose that neighboring water droplets in a stable stratus cloud don’t crash into each other because they’re all moving at about the same speed. But fast-forming, turbulent cumulous clouds contain water droplets moving at many different speeds. They crash into each other and form larger drops. As the turbulence grows, the drops grow quickly and fall as rain within a few minutes.
Cumulous cloud: These puffy clouds are associated with sudden rainstorms. Scientists are beginning to understand why.
Sun and rain
Ever noticed the bright, moving lines on the bottom of a stream, bathtub, or swimming pool? They’re called caustics, and they’re caused when ripples on the water’s surface focus sunlight. (Caustics form whenever light rays are bent by a curved surface or object and then projected onto another surface. This interactive shows you how.)
Caustics have a characteristic shape. Physicists can graph the phenomenon mathematically, and the graph also describes other phenomena, such as particle motion or the movement of raindrops within a cumulus cloud.
Caustics: What do the rippling patterns on the bottom of a swimming pool and cumulous clouds have in common? (Photo by R. Motti)
Atmosphere to outer space
The researchers say their finding won’t have any impact on weather forecasting. But particle collisions in turbulent gases must have been involved in planet formation. Perhaps the same theory can be applied?
If you're at the museum on Saturday afternoon (11/18), the MakeIt team can help you play with caustics. Does bending mylar in a different direction produce a new pattern? Does using a different color flashlight or a brighter or dimmer light affect the design?
You can also play with caustics at home.
Compact fluorescent lighting: Changing lightbulbs. photo by Art Oglesby
Lets go on a diet.
I am going on an energy diet. Each year I hope to reduce the amount of energy I use. By recording the gallons of gas, the electricity, and the natural gas I pay for each year, I will measure my success.
What will you give up?
“The Energy Diet,” a story in Thursday’s Home & Garden section of the New York Times gave me this idea. Its author, Andrew Postman, asks, "What would you be willing — or not willing — to give up in order to lessen your household’s impact on the environment?" So far, 159 people have answered in their comments.
Tell us what you are doing.
Please use comments to tell me what you are doing to reduce your energy consumption. I will add the most commonly used ones to this list.
- Change incandescent lightbulbs to compact fluorescent bulbs(CFLs)
Dial down the thermostat in the winter.
Dress warmer and exercise to warm up if needed.
Reduce the number of times you run to the store, etc. (make a list and buy lots at a time)
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