Showing posts with label physics. Show all posts
Showing posts with label physics. Show all posts

15 November 2014

What Gives Gold that Mellow Glow?


In discussions of special relativity, you occasionally encounter a claim like, “The effects of special relativity only matter to particle physicists and others working with extreme energies and velocities. Relativity has no consequences in everyday life.” Well, these days, anybody who relies upon the Global Positioning System(GPS) to navigate their car or the airliner in which they're travelling uses both special and general relativity, because without correction for their effects, GPS would be so inaccurate as to be useless. But GPS is a recent innovation, and the relativistic corrections are both complicated and hidden from the user in the software in the receiver and on board the satellites. But there's an effect of special relativity which was observed, if not understood, by the ancients: the yellow gleam of gold.


With an atomic number of 79, gold is in the last row of theperiodic table containing stable elements, and only four stable elements (mercury, thallium, lead, and bismuth) have greater atomic number. With 79 protons in its nucleus, the electrons of the gold atom are subjected to an intense electrostatic attraction. Using the naïve Bohr “solar system” model of the atom for the moment, electrons in the 1s orbital, closest to the nucleus, would have to orbit with a velocity v of 1.6×108metres per second to have sufficient kinetic energy to avoid “falling into” the nucleus. This is more than half the speed of light: c≈3×108 m/s

15 November 2011

Science Inside | Lytro

About Living Pictures The way we communicate visually is evolving rapidly, and people's expectations are changing in lockstep. Light field cameras offer astonishing capabilities. They allow both the picture taker and the viewer to focus pictures after they're snapped, shift their perspective of the scene, and even switch seamlessly between 2D and 3D views. With these amazing capabilities, pictures become immersive, interactive visual stories that were never before possible – they become living pictures. Take a Deeper Dive Want to learn more? Check out the Lytro Blog. Want to learn a lot more? Read our CEO's dissertation

Being amazed is getting ordinary...