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.
Sunday
CERN: Neutrino particles travel faster than light speed
I think this is the first step in unleashing practical research in Time Travel.
Tuesday
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Saturday
Tuesday
Monday
How to Destroy a Tornado
Will satellites one day forestall a tornado's formation, instead of just recording its aftermath?
Reader Robert Hayes of Kailua-Kona, Hawaii, asks: "Is there some way a small, nondeadly atomic bomb could somehow blow apart a tornado as it forms, averting any damage the storm might bring?"
While some might assume this idea to be an absurd one, we were willing to check it out (even the "nondeadly atomic bomb" part). And lo, it turns out that researchers are currently hard at work devising ways to control the weather—particularly disastrous weather systems like tornados and hurricanes—and hope to put their ideas to the test in the coming decades. Any storm depends on a host of complex, interrelated drivers, like heat flows and wind movements. The basic anti-storm strategy is to take the smallest of these factors, the one most amenable to change, and change it—in the manner, say, of throwing a wrench into the smallest cog at a factory in hopes that disrupting one part of the system will cause the entire assembly line to shut down.
Yet disrupting even one little part of a storm system, especially a system as massive as a hurricane, which can produce as much energy as the total global power output, will be mighty difficult. Here are three ideas in the works:
1. Recent research indicates that in order to form, a tornado needs both a cold, rainy downdraft and a warm updraft. To stop a tornado from forming, just heat this cold downdraft until it's cold no longer. And how would one do this, you ask? Simple: Blast it with beams of microwaves from a fleet of satellites. The satellites would collect solar energy, transform it into microwaves, and send a beam down to Earth. The beams would be focused on cold downdrafts, heating them like last night's leftovers. The European Space Agency has funded initial studies on building this type of satellite, though it hopes to use the satellites as high-altitude solar-power stations, not as weather modifiers.
2. Hurricanes get most of their energy from evaporating seawater, which is why they quickly die out over land. To prevent this evaporation, spray a thin layer of oil over the water. This should stop, or at least weaken, a Caribbean hurricane before it devastates Miami.
3. Divert the path of a hurricane by heating the atmosphere in front of it, presumably with the aforementioned microwave satellites, or with a giant orbiting mirror that reflects the sun's energy.
All this, as should be expected, is still at the extreme hypothetical stage. Not only will we need to develop the ability to monitor storms on a much finer scale than is currently possible, we'll also have to create and coordinate the intervening energy sources. Yet localized weather control is not pure fantasy: A study published last year in Nature showed that high-altitude jet contrails create lower day-to-night temperature swings—without even blowing anything up.
Source: http://www.popsci.com/scitech/article/2003-07/how-destroy-tornado
Thursday
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