On fundamental physics

2006-07-13

in Science

Grafitti near the Oxford CanalWatching this video about the Large Hadron Collider (a particle accelerator under construction at CERN), I was reminded of something I was wondering about a few weeks ago. People talk about the universe being the size of a grain of sand, or the size of a marble, in the moments immediately following the big bang. That seems comprehensible enough, but there is a fundamental problem with the analogy. The marble sized thing isn’t just all the mass in the universe, expanding into space that existed prior to the ‘explosion.’ Instead, space and time were supposedly unfurling simultaneously.

The big question, then, is how it can be said that it was expanding at all? If there was nothing to expand into, how is this process of explosion something that is comprehensible, as such? To imagine it requires a perspective where the camera is outside our universe, an idea that invalidates the notion that the big bang was the origin of our universe. And, even if our universe is embedded in a higher dimensional space, the emergence of our lower-dimensional realm still requires some explanation. I wonder if it will ever become an object of knowledge for us: both as a species with a certain amount of information about how the universe works – verified through repeated experiments and predictive power – and as a collection of individuals who almost never know more than a tiny fraction of what all people know as a collective.

The video is a bit over-hyped, as well as a transparent attempt to defend spending a great deal of money on pure research, but perhaps it will interest some people regardless. Some of the prospects associated with the LHC – such as looking for evidence of supersymmetry or investigating the nature of gravity – are very exciting indeed, from the perspective of advancing our basic understanding about the nature of matter, and the kinds of interaction that take place in our universe.

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{ 10 comments… read them below or add one }

Tristan Laing July 13, 2006 at 12:05 pm

Our comprehension of the universe is limited by the way we represent it – as an object of representation (or, as you say, an “object of knowledge” – good Kantian term there). So long as we think of the world as something essentially knowable, an idea that didn’t exist before Plato, at least not as explicitely, we will always be guilty of thinking we know more than we know and thereby of some sort of intellectual arrogance. Knowing existence involves knowing not only the ways that existence reveals itself to us (through science, for example), but also the ways it conceals itself. This is exactly what you’ve touched on by pointing out the inadaquacy of our representational thinking when it comes to the big bang. In fact, if we believe Kant on the intuitive forms of space and time (that they are a prori constructs required for us to have experience at all), then any comprehension of relativity is essentially impossible. Physicists disagree with this of course, and dismiss Kant – but perhaps it is not possible to concieve of the big bang without an outside camera perspective (which pre supposes space and time).

The real question seems to me – do these kinds of indaquacies of representational thinking point to a more complex, developed representational thinking which could contain the problems, or do they point to recognizing representational thinking as one form of thinking amoungst others? What would the others be?

Milan July 13, 2006 at 2:24 pm

Tristan,

I do believe that the world (in the broadest possible sense, including whatever our universe is embedded in) is essentially knowable, though perhaps not to us. We may be like a goldfish that has lived all its life in a blacked-out bowl, unable to see beyond and quite limited in cognitive and physical means for investigating the world beyond. The limitations of the goldfish have nothing to do with whether there is an Eiffel Tower and a Stanford Linear Accelerator Centre out there.

We are rather better off than the fish, in many ways, but we may still be subject to equivalent limitations, when it comes to big questions about the nature of the universe. We may be forever bounded in terms of our ability to understand it (though we may be able to make machines that can deal with some aspects we can’t tackle ourselves), but I share RKs hope that we will one day be able to apply knowledge of fundamental physics for the betterment of all people: whether in something as modest as safe and efficient electricity generation through nuclear fusion or something as impressive as a wormhole into the molten core of Io, from which impressive amounts of geothermal power can be extracted.

R.K. July 13, 2006 at 11:45 am

If you want evidence that we know things collectively about the Big Bang that hardly anyone can individually understand, try looking up the Friedmann-Lemaître-Robertson-Walker (FLRW) metric.

R.K. July 13, 2006 at 11:48 am

On your question, Wikipedia says:

“As the universe can be described by [conformal coordinates in which so-called comoving distances and conformal times remove the expansion of the universe], the Big Bang is not an explosion of matter moving outward to fill an empty universe; what is expanding is spacetime itself. It is this expansion that causes the physical distance between any two fixed points in our universe to increase. Objects that are bound together (for example, by gravity) do not expand with spacetime’s expansion because the physical laws that govern them are assumed to be uniform and independent of the metric expansion. Moreover, the expansion of the universe on today’s local scales is so small that any dependence of physical laws on the expansion is unmeasurable by current techniques.”

R.K. July 13, 2006 at 11:50 am

They have a picture, also.

R.K. July 13, 2006 at 12:09 pm

As long as we eventually figure out how to send information and people faster than light, I will be happy. Being able to arbitrarily connect different points in our universe (as by wormholes) would also be pretty awesome, as well as solving all our energy problems.

As for thinkina about the universe, the problem might be that we can’t think of time in a way that allows us to understand even our universe (much less, more complicated external ones).

Tristan Laing July 14, 2006 at 7:19 pm

What grounds your belief in the essential knowability of being? Why should we expect being to be the kind of thing that can be known determinately, rather than indeterminately? We certainly know a lot about being, but since even our highest physical principals can be proved inadaquate, we know that we know being incorrectly.

Plato – being is false being. Real being is the forms which being shows itself in, which are permanent and essentially knowable.

2500 years of science – tries to determine the rules of beings self-showing. Always falls short, gives us practical results, does not include in any of its structures even the mechanism whereby we would judge absolute correctness.

Heidegger – being’s self showing includes self-concealing. Plato was wrong about the permanent endurance of absolute catagories/essences. Sure there are essences, but they evolve over time and shift with culture.

Kuhn – scientific truths are never absolute but always relative to a paradigm. No one true paradigm. No completeness, rather paradigms strive towards completeness but produce contradictions in that striving which require a paradigm shift.

Milan July 14, 2006 at 7:39 pm

I never asserted that human beings would ever know everything about the universe: simply expressed the hope and belief that we will learn much more.

I agree with R.K. that the best yardstick of our understanding is the degree to which it empowers us to predict and act.

Milan December 29, 2006 at 10:12 pm
. October 17, 2007 at 3:57 pm

Particle collider is on schedule… just

CERN’s new machine still aiming for 2008 debut.

Geoff Brumfiel

Rumours of construction delays at the world’s largest particle accelerator have exaggerated the size of the problem, according to the project’s head. “There have been no show stoppers,” wrote Robert Aymar, director-general of CERN, the particle physics lab near Geneva, Switzerland, in the 8 October issue of the lab’s CERN Bulletin. “We can all look forward to the LHC producing its first physics in 2008.”

His reassuring announcement came after gossip on physics blogs of new problems that could set the lab’s Large Hadron Collider (LHC) even further behind its already delayed start date. But for all the reassurance, the LHC schedule remains tight, says project leader Lyn Evans. Relatively small mishaps could push the opening back beyond July 2008, when the LHC is supposed to start doing physics.

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