Thursday
Speed of Light -and- The Universe
A look at the speed of light, the ultimate speed limit enforced by the laws of the universe, and how scientists are looking for ways to exceed it; a look at what happens when we reach the "light barrier"; what could happen if we surpass it, and how the "cosmic constant" can be manipulated.
What is the Mass of Light?
This question came up in one of my conversations with a friend. What is the mass of light? Well, there are a couple of equations relating to energy and light. The most famous was developed by Albert Einstein: E = mc2, where E is energy, m is the rest mass, and c is the speed of light in a vacuum (3.0 x 108m/sec)
Another very famous equation is Planck's relation: E=hc/y, where E is energy, h is Planck's constant (6.626 x 10-34 J s), c is the speed of light in a vacuum (3.0 x 108 m/sec), and y is the wavelength of light.
So putting these equations together gives the following: E = mc2 = hc/y. Thus m = h/cy. The wavelength of visible light is from 400 to 700 nm. So to calculate the rest mass of light in the visible range, that has a wavelength of let's say 500 nm, we plug in the information and get the following:
m = 6.626 x 10-34 J s/ (3.0 x 108 m/s x 500 x 10-9 m)
m = 4.417 x 10-36 kg
So there you have it. The rest mass of a single photon of light at a wavelength of 500nm is 4.417 x 10-36 kg. Since light is never at rest, this number is actually the "effective" mass of a photon of light.
Another quick calculation is the momentum of a photon of light. Momentum is defined by the following equation: p = mv where p is the momentum, m is the mass, v is the velocity. Using the above mass for light at 500nm wavelength, and plugging the numbers into the momentum equation gives:
p = (4.417 x 10-36 kg) x (3.0 x 108 m/s)
p = 1.325 x 10-27 kg m/s
So the effective momentum of light is 1.325 x 10-27 kg m/s.
Source: http://open.salon.com/blog/kwatts59/2009/02/18/physics_what_is_the_mass_of_light
Another very famous equation is Planck's relation: E=hc/y, where E is energy, h is Planck's constant (6.626 x 10-34 J s), c is the speed of light in a vacuum (3.0 x 108 m/sec), and y is the wavelength of light.
So putting these equations together gives the following: E = mc2 = hc/y. Thus m = h/cy. The wavelength of visible light is from 400 to 700 nm. So to calculate the rest mass of light in the visible range, that has a wavelength of let's say 500 nm, we plug in the information and get the following:
m = 6.626 x 10-34 J s/ (3.0 x 108 m/s x 500 x 10-9 m)
m = 4.417 x 10-36 kg
So there you have it. The rest mass of a single photon of light at a wavelength of 500nm is 4.417 x 10-36 kg. Since light is never at rest, this number is actually the "effective" mass of a photon of light.
Another quick calculation is the momentum of a photon of light. Momentum is defined by the following equation: p = mv where p is the momentum, m is the mass, v is the velocity. Using the above mass for light at 500nm wavelength, and plugging the numbers into the momentum equation gives:
p = (4.417 x 10-36 kg) x (3.0 x 108 m/s)
p = 1.325 x 10-27 kg m/s
So the effective momentum of light is 1.325 x 10-27 kg m/s.
Source: http://open.salon.com/blog/kwatts59/2009/02/18/physics_what_is_the_mass_of_light
Tuesday
Creative Machines Principle
Artificial intelligence inventor Stephen Thaler perturbs portions of his software simulated neural networks. The induced stress and noise would cause creativity. His creativity machine already helped design a new toothbrush, musical compositions, info warfare, flexibly learning object recognition systems, and self-developing neural networks. These could someday populate the internet, support transhuman cognition augmentation and appear as an intelligent entity, capable of learning, knowledge-backed reasoning, planning, talking and pursuing goals. Eventually, mind uploads would be carried on free of body by a consciousness simulating artifact. But even if the self-enhancing entities run virtualized, fragmentary personalities of selected individuals, this will differ from human consciousness.
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