The crests (bright) and troughs (dark) of waves spread out after they were produced. The picture applies to both light and sound waves.
Most people are familiar with lasers. But what about a laser made with sound rather than light? A couple of physicists have now created one that they plan to use for measuring imperceivable forces.
The sea is blue because of the way water absorbs light, the way particles in the water scatter light, and also because some of the blue light from the sky is reflected.
Photons stream from the sun and interact with all matter on Earth. Depending on what the light touches, some of the photons will get absorbed or soaked up. And some will bounce back.
A cross section of a fractal pattern, created by a laser in the Wits Structured Light Laboratory.
Nature can produce fractals, computers can, too. Could light be a fractal? The answer is yes.
Lighting causes damage to paintings over time.
Juan Di Nella/Unsplash
Researchers have found a way to reduce light damage to artworks by up to 47% by optimising LEDs to prevent light from being absorbed by the artwork.
Is this it?
Everything you can touch is made of molecules – but feelings, sound and light are something different.
We don’t all see the same.
What colours we see depends not just on how things are in the world around us, but also on what happens in our eyes and our brains.
Hanukkah demands fewer religious rituals than most other Jewish observances.
Golden Pixels LLC
Despite the primacy of Christmas in American culture, the visibility of Hanukkah in pop culture reminds Jews that they have their own holiday in which they can take pride.
Are bulb bans a bright idea?
Encouraging people to buy LED bulbs is not a long-term solution. We need lighting which is kind to the planet and our health.
Cloud Gate, 2004. Stainless steel, 1,006 x 2,012 x 1,280 cm.
Anish Kapoor made “Cloud Gate”, a giant bean-shaped mirror in Chicago. Visitors play with the light in the city and its surroundings, where our future lays.
What could a ‘relativistic camera’ capture on the way to Alpha Centauri?
An astronomer suggests an idea to piggyback on the ambitious Breakthrough Starshot project that aims to send nano spacecraft to Alpha Centauri at a major fraction of the speed of light.
Section of a tumor observed with an optical microscope. The two white forms with brown borders are blood vessels. Inside, gold nanoparticles accumulate against their walls.
Mariana Varna-Pannerec (ESPCI)
Gold can be used to make jewelry, but also to fight cancer. Several clinical trials are currently underway in the United States where patients are being treated with gold nanoparticles.
In 1954, three scientists observed a paradox to which they gave their name: the Fermi-Pasta-Ulam recurrence. Now, fibre optics are on the way to finally providing an explanation.
About a century ago, we didn’t even know that galaxies existed.
Mai Lam/The Conversation NY-BD-CC
Pretty much as soon as we understood what galaxies were, we realised they are all moving away from each other. And the ones that are further away are moving faster. In short, the universe is expanding.
It’s been 70 years of instant photography, thanks to Edwin Land, on the left.
Whether at a family gathering or in a research lab, getting access to images immediately was a game changer. And Land's innovations went far beyond the instant photo.
While some things glow all the time, glow-in-the-dark paint must be ‘told to glow’ - just like a phone needs to be charged or it won’t work.
Mai Lam/The Conversation NY-BD-CC
You can see glow-in-the dark paint, but if you touch it, it is just as cold as the bedroom wall. So the glowing of the paint is different to the glowing of a light bulb.
Timeline of the universe.
From blindingly bright and burning hot to pleasantly 'candle-lit', the first years of the universe would have been spectacular to see.
The Small Magellanic Cloud galaxy here seen in infrared light, but it looks different when viewed at other wavelengths.
The galaxies, stars and planets in our universe can look very different when you view them through equipment that sees beyond the visible light our eyes can see.
Super-black feathers on these guys are like looking into a dark cave.
Male Birds of Paradise have patches of super-black plumage that absorb 99.95 percent of light. New research identified their feathers' microscopic structures that make them look so very dark.
Diatoms - like those seen under a microscope here - can teach us a lot about harvesting light.
Diatoms' tricks may offer new insights that keep solar cell energy running efficiently and robustly throughout their processes.
Example of nonlinear effect which can be observed in an optical fiber. All the colors of the rainbow are generated at the output while only one color is present at the entrance. We’re talking about supercontinuum.
To understand what is happening in an optical fibre, physicists can mimic a rupture of the flow of grains of light – the photons – thanks to a laser device.