“y’u can n’ey change the laws of physics” (The grand design part 6)


Stephen Hawking and Lenonard Mlodinow


I am reading though Stephen Hawking’s new book “the grand design”. While the title seems to be making reference to the theological notion of “design”, in the content God is gently being elbowed out of the picture. Looking at the cover again I notice it’s co authored by Lenonard Mlodinow. While his name is not printed as big as Hawking’s (his name is bigger than the title!), he is never the less an accomplished scientist and author in his own right. He has written a number of exciting sounding books including “How randomness rules our lives”, “Feynman’s rainbow” and has also been a writer for Star Trek : the next generation.

In the original (and best) star treck Scottie used to reply to Captain Kirk’s impossible requests for more speed with the importal phrase “I can ney change the laws of physics cap’in.” Well, what exactly are those laws? I am about to find out in this chapter.

He talks about gravity, the first force to be described in mathematical language. In passing he can’t resist a poke at the Biblical testimony that the sun stood still in the sky for an hour so Joshua could carry on fighting. He notes it would have probably been the earth’s rotation that stopped which would he says, cause everything not nailed down on the surface to carry on moving. But what if God had realized that and made arrangements for that not to happen?

After gravity came models for eclectic and magnetic forces, weak nuclear forces and strong nuclear forces. Maxwell came up with some equations that unified the eclectic and magnetic ones and showed that light was an electro-magnetic field too. Einstein’s special theory of relativity said that light was constant, time relative to the observer and linked with space (space-time). General relativity included gravity and modeled space-time as distorted by mass and energy. In a graphic and timely confirmation of this (Einstein first suggested time was relative 100 years ago) scientists recently placed two very accurate clocks a foot apart in height and recorded a difference in time predicted by Einstein’s theory. This lead one scientific reporter to (Marcus Chown) comment:

” if you want to live longer, buy a bungalow!”

As Hawking has said earlier, things are different at the quantum level. Quantum versions of relativity and electromagnetism are called field theories. The one for electromagnetism is called quantum electromagnetism or QED and was developed by Richard Feynmann et al.

“the division of natural forces into four classes is probably artificial…people heave therefore sought a theory of everything that is compatible with quantum theory. This would be the holy grail of physics.”

Electromagnetism and the week force have been joined together in a quantum theory (which successfully predicted the existence of 3 particles) but not the others. There is not even a quantum theory of gravity. The “standard model” comprises of the joint electro-weak quantum model QED, a separate quantum model of the strong force QCD but no quantum model of gravity.

“it might be that to describe the universe, we have to employ different theories in different situations. Each theory may have its own version of reality, but according to model-dependent realism, that is acceptable so long as the theories agree in their predictions whenever they overlap, that is, whenever they can both be applied.”

He then begins to introduce the idea of multiple universes:

The laws of M-theory …allow for different universes with different apparent laws, depending on how the internal space is curled (up to 10^500 different universes).

So while we can’t change the laws of physics, different universes could have different laws.

“So how did we end up we end up in this universe…and what about those other possible words?”

I will find out no doubt in the next chapter.


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