Just curious... Both electricity and light are both slower than c when not in vacuum. I guess electricity is slowed down more by the dielectric constant, than light is slowed down by the reflective index...
Speed of electricity >From Wikipedia, the free encyclopedia ============================================================================ ============================================================================ ========== The speed at which energy or signals travel down a cable is actually the speed of the electromagnetic wave, not the movement of electrons. Electromagnetic wave propagation is fast and depends on the dielectric constant of the material. In a vacuum the wave travels at the speed of light and almost that fast in air. Propagation speed is affected by insulation, so that in an unshielded copper conductor ranges 95 to 97% that of the speed of light, while in a typical coaxial cable it is about 66% of the speed of light.[1] <snip> ============================================================================ ============================================================================ ========== Speed of light >From Wikipedia, the free encyclopedia ============================================================================ ============================================================================ ========== The speed of light in vacuum, commonly denoted c, is a universal physical constant important in many areas of physics. Its value is 299,792,458 metres per second, a figure that is exact because the length of the metre is defined from this constant and the international standard for time.[1] In imperial units this speed is approximately 186,282 miles per second. According to special relativity, c is the maximum speed at which all energy, matter, and information in the universe can travel. It is the speed at which all massless particles and associated fields (including electromagnetic radiation such as light) travel in vacuum. It is also the speed of gravity (i.e. of gravitational waves) predicted by current theories. Such particles and waves travel at c regardless of the motion of the source or the inertial frame of reference of the observer. In the theory of relativity, c interrelates space and time, and also appears in the famous equation of mass-energy equivalence E = mc2.[2] The speed at which light propagates through transparent materials, such as glass or air, is less than c. The ratio between c and the speed v at which light travels in a material is called the refractive index n of the material (n = c / v). For example, for visible light the refractive index of glass is typically around 1.5, meaning that light in glass travels at c / 1.5 ? 200,000 km/s; the refractive index of air for visible light is about 1.0003, so the speed of light in air is about 90 km/s slower than c. <snip> ============================================================================ ============================================================================ ========== -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of retired mainframer Sent: Thursday, January 17, 2013 12:24 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: silicon photonics - faster than copper While photonic components (switches, etc) may be faster than the current semi-conductor ones, can the wiring really be a factor. Don't both electricity and light move at c? :>: -----Original Message----- :>: From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On :>: Behalf Of John McKown :>: Sent: Thursday, January 17, 2013 4:25 AM :>: To: IBM-MAIN@LISTSERV.UA.EDU :>: Subject: OT: silicon photonics - faster than copper :>: :>: http://www.computerworld.com.au/article/446722/intel_prepares_use_lasers :>: _light_shuffle_data_between_computers/ :>: <quote> :>: Intel is taking the first steps to implement thin fiber optics that :>: will use lasers and light as a faster way to move data inside :>: computers, replacing the older and slower electrical wiring technology :>: found in most computers today. :>: </quote> ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
