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gJ08bzp For an example, I would express the expansion of space thus: Assume there are 10 Billion Light years between point A and B. If within the time of 1 year, space expansion adds just a bit more than a distance of 1 light year between A and B, then the total separation between A and B increases faster than light (a bit more than a light year per year). Locally, that is an expansion rate of 1/10 Billion, a fairly small number, hardly noticeable. On Mon, Feb 25, 2019 at 10:17 PM Keith Lowe <Mythos25@live.com> wrote: > > “Exactly so!” > > > > “So, if I understand correctly, space between A and B can expand at speeds greater than the speed of light; strange” > > > > Now taking us back to David’s first post. I’m still not sure about the physical speed and the extra distance being added due to the expansion/creation of new/stretching of space. People seem to be including both types of motion when they speak of expansion of the universe, correct? To have two points in space receding away from each other faster than light in our universe as it is today it must include both physical speed and the stretching of space? I believe I read where objects near our observation limit are receding an extra 75k per second give or take relative to us due to expansion on top of their physical speed and if so that 75k per second must be the fastest space expands that we know of? > > > > Keith > > > > From: naturens-owner@chebucto.ns.ca <naturens-owner@chebucto.ns.ca> On Behalf Of Patrick Kelly > Sent: Monday, February 25, 2019 9:35 PM > To: naturens@chebucto.ns.ca > Subject: Re: Re[4]: [NatureNS] Big Bang? > > > > > > One thing about the speed of light that surprises people is that it is possible to go faster than the speed of light, if it is not in a vacuum! > > > > The speed at which light propagates through transparent materials, such as glass or air, is less than c; similarly, the speed of electromagnetic waves in wire cables is slower 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 299,700 km/s , which is about 90 km/s slower than c. On the other hand, the refractive index of diamond is 2.42 so light travelling through it only goes at c / 2.42 ≈ 120,000 km/s. > > > > The blue glow that you see in water tanks containing nuclear fuel rods is called Cherenkov and is caused by electrons emitted from the radioactive material travelling faster than light. https://en.wikipedia.org/wiki/Cherenkov_radiation > > > > Pat > > > > > > On Feb 25, 2019, at 8:53 PM, David wrote: > > > > So, if I understand correctly, space between A and B can expand at speeds greater than the speed of light; strange. And I suppose any expansion between A and B at rates slower than the speed of light would increase the wavelength of light. > > > > > Patrick Kelly > > 159 Town Road > > Falmouth NS B0P 1L0 > > Canada > > > > (902) 472-2322 > >
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