Wednesday, May 03, 2006

Hawking's Flexiverse is a Real Stretch...

Sometimes I think that these guys go to bed at night saying... I do, I do, I do, I do believe in ghosts.

...Exploring Stephen Hawking's Flexiverse
20 April 2006
by Amanda Gefter

The history of the cosmos has yet to be decided. At last, a chance to play God

HERE'S how to build a universe. Step one: start at the beginning of time. Step two: apply the laws of physics. Step three: sit back and watch the universe evolve. Step four: cross your fingers and hope that it comes out looking something like the one we live in. That's the basic prescription for cosmology, the one physicists use to decipher the history of the universe. But according to Stephen Hawking of the University of Cambridge and Thomas Hertog of the European Organization for Nuclear Research (CERN), the steps are all backward. According to these physicists, there is no history of the universe. There is no immutable past, no 13.7 billion years of evolution for cosmologists to retrace. Instead, there are many possible histories, and the universe has lived them all. And if that's not strange enough, you and I get to play a role in determining the universe's history. ...

It is a very sad statemet about the state of theoretical physics that assumptions about infinites and quantum weirdness have enabled this kind of causality-lacking approach to become the norm for resolving the fine-tuning problem.

...the sum over histories is formed by calculating the various probabilities for a universe like ours to arise out of literally nothing: that means we can never know anything for certain about how our universe got to be as it is.

We shouldn't be surprised, Hertog says: quantum theory has long shown us that it is impossible for us to know everything about the world around us. In "classical" physics, we can predict both the exact momentum and position of a particle at any time, but quantum mechanics doesn't allow it. No one suggests that quantum mechanics is wrong because of this, Hertog points out - and experiments have shown that it is not.

Whoa, wait a minute there, Tom. No one suggeststs that QM is wrong, but a number of respected theorists, like Roger Penrose, think that quantum theory will have to be modified more than relativity will, so don't pretend that your assumptions aren't up for dramatic revision just because you think that you understand something from an interpretation that can be thrown right back in your face given only very little new information.

For many, it remains a difficult argument to swallow. Science since Copernicus has aimed to model a universe in which we are mere by-products, but top-down cosmology turns that on its head, rendering the history of the universe a by-product of our observations. All in all, it is very like the "anthropic landscape" argument that is causing controversy among string theorists.

Which is a really nice way of saying that Hawking too is grasping at infinities and uncertainty, and that is a cop-out on the long-held understanding that there must be a good physical reason, (a stability mechanism), why the universe is the way that it is. Thank "god" that I'm not alone:

Princeton University physicist Paul Steinhardt says:
"It's kind of giving up on the problem. We've all been hoping to calculate things from first principles. Stephen doesn't think that's possible, but I'm not convinced of that. They might be right, but it's much too early to take this approach; it looks to me like throwing in the towel."

Stanford University's Andrei Linde is similarly unconvinced:
There are a number of technical assumptions that make him sceptical. "I don't buy it," he says.

I don't either, but I'm not arrogant enough to believe that first principles can possibly be disassociated from the human evolutionry process in an anthropically constrained universe... *duh*

Sit back and watch it "evolve".



Lady Broadoak said...

Are "they" throwing in the towel" or just throwing sand around in the sand box of academia and literary publishing ...?

Do any of these "guyz" give one fig about the TRUTH ..?

island said...

Nah, they're just following the available directions that "known-to-be" fundamentally flawed theories point them in, but they erroneously beleive that this approach will ultimately correct the flaw.

As I understand it, this just carries and compounds the distorting effect of the flaw.

I'll explain later, but I have work to do right now.

Thanks for the comment... :)

island said...

Okay, I just put up a new blog entry because I realized that I really need to better justify the following statement to anybody that can understand it, that even cares:

The problem goes back to the negative mass absurdity that falls from the Dirac Equation.

Quantum Field Theory makes an "ad hoc" assumption rather than to go back and fix the problem, which only carries and compounds the consequences when extended to Quantum Gravity theories of all varieties.

The cosmological model that actually fixes the problem doesn't include the kind uncertain and infinite rationale that enables theorists, like Hawking to "resolve" problems, while avoiding causality and "real" first-principles.

Pentcho Valev said...


Stephen Hawking: :
"Both Mitchell and Laplace thought of light as consisting of particles, rather like cannon balls, that could be slowed down by gravity, and made to fall back on the star. But a famous experiment, carried out by two Americans, Michelson and Morley in 1887, showed that light always travelled at a speed of one hundred and eighty six thousand miles a second, no matter where it came from. How then could gravity slow down light, and make it fall back."

The experiment of Michelson-Morley contradicts the idea that the speed of light varies with position in a gravitational field? Does Stephen Hawking really think so (then his logical capacities are much below average) or do we have a deliberate fraud? The latter possibility is more probable - he surely knows what his brothers relativists teach:
"So, it is absolutely true that the speed of light is _not_ constant in a gravitational field [which, by the equivalence principle, applies as well to accelerating (non-inertial) frames of reference]. If this were not so, there would be no bending of light by the gravitational field of stars. One can do a simple Huyghens reconstruction of a wave front, taking into account the different speed of advance of the wavefront at different distances from the star (variation of speed of light), to derive the deflection of the light by the star.
Indeed, this is exactly how Einstein did the calculation in:
"On the Influence of Gravitation on the Propagation of Light," Annalen der Physik, 35, 1911.
which predated the full formal development of general relativity by about four years. This paper is widely available in English. You can find a copy beginning on page 99 of the Dover book "The Principle of Relativity." You will find in section 3 of that paper, Einstein's derivation of the (variable) speed of light in a gravitational potential, eqn (3). The result is,
c' = c0 ( 1 + V / c^2 )
where V is the gravitational potential relative to the point where the speed of light c0 is measured."
"Einstein went on to discover a more general theory of relativity which explained gravity in terms of curved spacetime, and he talked about the speed of light changing in this new theory. In the 1920 book "Relativity: the special and general theory" he wrote: . . . according to the general theory of relativity, the law of the constancy of the velocity of light in vacuo, which constitutes one of the two fundamental assumptions in the special theory of relativity [. . .] cannot claim any unlimited validity. A curvature of rays of light can only take place when the velocity of propagation of light varies with position. Since Einstein talks of velocity (a vector quantity: speed with direction) rather than speed alone, it is not clear that he meant the speed will change, but the reference to special relativity suggests that he did mean so."

Pentcho Valev