Gadianton wrote:i even have an argument to justify why there is no point in trying to know; maybe will post later.
This ^ I would like to hear.
Gadianton wrote:i even have an argument to justify why there is no point in trying to know; maybe will post later.
DrW wrote:Gadianton wrote:
i even have an argument to justify why there is no point in trying to know; maybe will post later.
This ^ I would like to hear.
Physics Guy wrote:I'm about as good an expert on quantum measurement as you're likely to find. My name is on some significant papers about environment-induced decoherence, and I once held a US visa for the stated purpose of "investigating the effects of quantum mechanics on the universe." That was just a bureaucrat's garbled phrasing but I actually was doing a post-doc for related stuff.
I don't know what's going on with quantum measurement, and I don't believe anyone else really does, either. In the 1990s multiverse interpretations—"Many Worlds"—were a fad among hungry young post-docs who were embracing a startling idea in order to show off how brilliant they were, and I think the current wave of endorsement of this in popular science is just the afterglow of that old fad. I was unimpressed even then, for two basic reasons.
Firstly, there's a ton of evidence for something like wave function collapse apparently happening, but it's all about microscopic events with just a few photons or electrons really involved....
DrW wrote:Doctor CamNC4Me wrote: If I'm wrong feel free to correct me, but space itself moves FTL.
- Doc
Doc,
Space isn't actually moving as much as it is expanding. As described on another thread, the rate of expansion is 68 km/s per megaparsec.
That means if one were to put a point on a star map one megaparsec from Earth, that point would be receding from Earth at a speed of 68 km/s, or very roughly 152,000 mph. The speed of light is 3.0 x 10^8 m/s.
A parsec is about 3.6 light years or about 31 trillion km. A magaparsec would be a million times that or about 3.6 million light years.
By my calculations, a galaxy would need to be roughly 4,400 megaparsecs (or roughly 15 billion light years) away from Earth before it would be receding at the speed of light.
The visible universe is approximately 46 billion light years across, so galaxies receding at the speed of light are a long way out there. By comparison, our local group of galaxies is about 10 million light years across.
Also remember that FTL refers to the local speed of light. While a galaxy 15 billion light years from us may be receding at more than 3.0 x 10^8 meters per second, its speed in a local inertial frame is nothing close to that.
________________________
*Just read a more recent estimate that increased the rate of expansion from 68 to 71 km/s per megaparsec. So, let's round off to 4000 megaparsecs, or about 13.5 light years out before a galaxy is receding at the speed of light.
Physics Guy wrote:Natural theology has its high points and low points. Big Bang cosmology looks awfully nice for theology; Darwinian evolution of nasty parasites, not so much. Quantum measurement is just neutral, I'd say, because our current understanding of quantum measurement is about like the understanding of gravity held by Plato and Aristotle. They could have debated long and hard about whether higher or lower regions were the proper spheres of earth or fire, but all their philosophizing was really pointless, because there were too many essential facts that they just didn't know. We're like that now, with quantum measurement.
Gadianton wrote:Re: an argument to justify why there is no point in "trying to know"
<SNIP>
Physics Guy wrote:This was a good idea because in Maxwell's time mechanics was the most developed part of theoretical physics, so mechanical models were the most powerful conceptual tools to be had. He himself took the ether seriously as a genuine physical object—the largest object in the universe, he once called it, because it filled all of space. He was wrong about that, but his example still shows that intuitive pictures can work very well, as means rather than ends—if you know how to use them.