Explore all 1,000 Chrome Experiments: http://g.co/1000
Explore all 1,000 Chrome Experiments: http://g.co/1000
These apparent waves are due to "Moiré effects". They are caused by visual interference between cyclic or pseudo cyclic patterns (e.g. stacked grids or concentric circles). Usually the frequency of one is slightly different than the other, or there is a tiny rotation between them.
When the logo is smoothly scrolled on the screen, the offset between the stripes of the logo and the discrete matrix of pixels of your monitor changes continuously. The stripes may be precisely aligned in some place and lose progressively synchronization further away, before they synchronize again and cycle.
The overlay creates apparent bigger shapes or fuzzy "waves", that are extremely sensitive to the offsets. As such, when the patterns are moved, it creates patterns with very high frequencies, that are only artefacts: there is no change in the patterns of course. The eye & brains are positively interpreting this as a swift movement, as with some other optical illusions.
Moiré patterns are regularly found in real life, mostly with almost-perfectly aligned grids and metallic meshes in cities. The effect can highlight extremely small defaults or bends in the meshes, that you can see moving in the wind or by slightly pushing on the mesh, even when it is sturdy. In computer graphics it was considered a serious annoyance, especially on low-res screens. Graphics cards even include filtering algorithms to try and reduce the effect. It always happens with radial stripes that gets squashed too much.
It is of course also a curiosity and an art, and this logo is a brilliant illustration.
More to read: http://nrich.maths.org/8194
Or check "moire patterns" in youtube.
2015 is set to be an exciting year in physics...
Sounds mind boggling !
1. the hot, dense, smaller state of the universe that expanded and cooled, giving rise to the matter-dominated universe we now see, and
2. an infinitely dense singularity before which time had no meaning.
While #1 is indisputable, #2 is an idea on the ropes. The chart below shows that universes dominated by radiation and matter both have a singularity at time 0; but over the past 50 years, we've discovered that the very early universe was dominated by vacuum energy, and as the chart below shows in yellow, such a universe tends to an asymptote as we go back in time, not a singularity.
The physics we're sure of only tells us what happened at the point where all three curves meet, around 10⁻³² seconds after the point where the singularity might be. Before that, there are two different ideas about what happened.
In the traditional Big Bang model, from 10⁻³² back to 10⁻³⁶ seconds was the "electroweak epoch", a time when energy was high enough electromagnetism and the weak force unified; from 10⁻³⁶ back to 10⁻⁴³ seconds was the "grand unification" epoch, when the electroweak force and the strong force unified; and before that was the "Planck epoch" when the three other forces unified with gravity.
In the inflationary model, there was no initial singularity; the universe could be infinitely old. The forces would still have been unified, but we'd have to go back a lot farther in time, and the Planck epoch would have been infinitely long instead of a mere 10⁻⁴³ seconds. We can set the point from which we measure time anywhere, and it's reasonable to place it at the time where the singularity would have occurred in the absence of dark energy (or vacuum energy, or the cosmological constant---they're all synonyms) even though in that model, there was no singularity. When people say "The inflationary epoch ended 10⁻³² seconds after the Big Bang," this is what they mean.
While there was definitely a time when the universe was much smaller and in a hot, dense state dominated by radiation, there are other observations that the singularity model doesn't explain but inflation does. Inflation explains why there's the vast structure of stars, galaxies, clusters, and filaments throughout the universe, why space (not spacetime) is so nearly flat, why opposite sides of the universe are exactly the same temperature, the absence of weird stuff like magnetic monopoles and topological defects like cosmic strings, and predicted the particular kinds of fluctuations we should see in the cosmic microwave background before they were measured.
The dancing lights of the aurora provide spectacular views of incoming energy and particles from the sun. Aurora are one effect of these energetic particles, which can speed out from the sun both in a steady stream called the solar wind and due to giant eruptions known as coronal mass ejections or CMEs. After a trip toward Earth that can last two to three days, the solar particles and magnetic fields cause the release of particles already trapped near Earth, which in turn trigger reactions in the upper atmosphere in which oxygen and nitrogen molecules release photons of light. The result: an aurora, and a special sight for the astronauts on board the space station.
Video credit: NASA/Barry Wilmore
"In the case of this jewel-like iceberg, the ice is probably very old. In glaciers, years of compression force out air pockets and gradually make the ice denser, according to the National Snow and Ice Data Center. "When glacier ice becomes extremely dense, the ice absorbs a small amount of red light, leaving a bluish tint in the reflected light, which is what we see.” In addition, minerals and organic matter may have seeped into the underwater part of the iceberg over time, creating its vivid green-blue color."
Extremist censorship holds Hindus in chains | WashingtonExaminer.com
Last week, a Hindu extremist group forced Penguin to purge from India all unsold copies of University of Chicago divinity professor Wendy Do
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