Someone (several someones) said that "people generally get the leaders they deserve." That goes for universes. The Universe in which we live reflects the culture that gave rise to the concepts that are used to describe it. When did Cro-Magnon people, or perhaps Australopithecenes before them, first spin myths about the lights in the sky at night, and moon and sun? Things had come a long way by the time of Albert Einstein's gedankenexperimenten with railway carriages and elevators. Now, with our supercollider experiments and pocket telephones that idle along with cycle times measured in picoseconds, a few professional worriers are worrying out what might have happened during the first billionth of a billionth of a yoctosecond (that's 10-42 or 10-43 seconds, folks).
The time scales pertinent to a farmer are days and quarter-days, months and seasons in the yearly round. The Sun is the only clock needed. For the first few centuries after the invention of mechanical clocks, they had an hour hand only. The word "minute", pronounced my-nyoot', just meant really small; a "second" was the guy who backed you up in a duel. At some time these words, with fresh new pronunciations, became the go-to words for "1/60 hour" and "1/3600 hour". Now look what we have:
Each of the successive words in this graphic means 1/1000 of the one to its left. This Google Ngram shows the percent of books using the words indicated. Clearly, a century ago people got along just fine without dividing time up smaller than a second. Then Hertz and Marconi came along, and radio frequencies necessitated new words to describe their cycle times. The millisecond and microsecond came into their own with the invention of ENIAC. Note the sudden surge in "nanosecond" beginning about 1955. Early particle accelerators began making mesons and other "resonances" that only stayed around for a billionth of a second or less, and about every decade since there has been the need to write a lot about the next level of "tiny time". We're just getting going with attoseconds. In one attosecond (1 as = 10-18s), light moves about three Ångstrom units, or 0.3 nm, the length of a water molecule. Attosecond computer cycles are unlikely to be achieved. The present record for overclocking a CPU chip is 8.429 GHz, which is a cycle time of 118.6 ps, or 118,600,000 as. The computer I am using right now hums along at a comfortable 3.05 GHz, a cycle time of 328 ps.
It does remind me of something said by Data in a Star Trek: Next Generation episode. Asked if he had considered betraying Captain Picard, he said, "Yes, for 1.78 seconds." Picard smiles with relief, until Data says, "Of course, to an android, that is an eternity." Well, Data may think on a picosecond or even femtosecond time scale, but our human brains still run on cycle times of 50 milliseconds or longer.
So there is one thing the Greeks got right when they mythologized about their cosmology: The oldest and most powerful god was named Chronos, or "time". How we think about time has changed over the past tenth-of-a-million years. Time itself? Not so much. But that may be about to change. In his new book About Time: Cosmology and Culture in the Twilight of the Big Bang, Adam Frank takes us on a journey through human culture, right to the brink of the theories that just may do away with time. What will replace it? Zeus replaced Chronos; will power replace time? Let's remember that Zeus was famously anarchistic (and promiscuous).
A central thesis of the book is that time and space are as much constructs of our consciousness as they are its source. A key phrase is "material engagement," the continual back-and-forth of our growing cultural concepts as mediated by our involvement in the material world. Einstein thought about events that seemed simultaneous as seen by a ticket-seller in a train station, and how they would be perceived by the conductor aboard the train. Particularly if the train were moving at a speed approaching 300,000 km/s. He compared it to the "perception" of a light ray itself, racing between railway station and the carriage, to convey the news about an event the station master wished to time. This kind of thinking led to the special theory of relativity, which still requires a strong dose of "de-befuddling" by physics teachers, so students can think properly about phenomena that occur rapidly at "relativisitic" speeds.
But what is material engagement? I got this quote from the man who coined the term, Lambros Malafouris:
"In the dynamic tension that characterises the processes of material engagement, sometimes it is the thing that becomes the extension of the person. At other times, however, it is the person that becomes the extension of the material agent. … Agency as an emergent property cannot be reduced to any of the human - nonhuman components of action."(p 34 in Material Agency: Towards a Non-Anthropocentric Approach; Carl Knappett and Lambros Malafouris, eds. 2008). That is about as clear as Dr. Malafouris gets; his prose is mostly impenetrable. The key phrase here is "dynamic tension". It simply means that the material things in the world in which we live mediate what we can think about. Culture and cosmology define one another. A strong message of Dr. Frank's book is that now we have a language to describe cosmology that is more complete than anything previous. Pushing it to its limits (worrying about that first quintillionth of a yoctosecond), we have come to the limits of our ability to think about time.
Thus, the book culminates in the work of four "rebel" scientists in three areas. First James Barbour would convince us that there is no time, there are just "NOWs"; that causality is an illusion (although I suspect S.J. Gould, were he still with us, would have something to say about "contingency" mediating what is possible). Secondly, Andreas Albrecht, an early proponent of inflation cosmology (which I heartily reject), finds that the choice of one's clock determines the model of the universe that we must adhere to. An example is given (which I confess I found hard to follow), that by choosing what you use to measure time, you can transform the equations describing an electron's motion to equations that pertain to photons. If that is true, it is truly world (or universe-) shaking. In my physics education (before I turned to geophysics), bosons were bosons and fermions were fermions; never would the twain meet, at least not mathematically! Finally, Lee Smolin and Roberto Unger "look across the landscape of modern cosmology with its extra dimensions and other universes, declare them fictions and set off to deliberately forge another path" (p315).
Is it any surprise that such anti-establishment views can arise now, where we are on the verge of technologies that might just abstract us from the world? Is The Matrix to become true after all? And can machine-mediated thinking drive our thought processes into Data-like android territory? If time becomes malleable, it is no surprise that new cosmology theories will arise to match. That is the lesson of material engagement. Cultural shifts change the way we think, often in radical ways ("How you gonna get 'em back on the farm, after they've seen L.A.?"). Our ability to probe cosmology brings about a new cosmology. Then we push that cosmology to its limit. In the process, culture shifts, and new thoughts about cosmology become possible.
A final question is asked: "How much of the cosmos do we have objective access to?" (p 330). It seems, just considering matter, that some 75% of it is invisible, not reacting to photons. So-called "dark matter" is needed in copious amounts to keep galaxies from dissipating or galaxy clusters from evaporating. Maybe one day we'll discover "rubindium" and its sister meta-elements as postulated in Star Trek. But then there's "dark energy", which seems to be driving an accelerated expansion of the visible universe. I have been looking hard, and have yet to see anyone explore the notion that a Type 1a supernova in an extra-low-metallicity system (i.e., a very early one) might have a different intrinsic luminosity than a Type 1a supernova in a system with Z in the solar range. Until that question is fully dealt with, the "evidence" for acceleration is not just shaky, it is practically nonexistent.
A simpler way to ask the question is, "What can we really see?" In practical terms, we can see what we are looking for, and it takes a long time to see what we are not looking for. I appreciate those four rebels very much. They are not just asking the right kinds of questions, they have the intellectual tools to work towards answers to their questions. Not all of them will be right, but I would not bet against them. One or the other is likely to do work that will one day put the Big Bang on the shelf, along with Ptolemy's epicycles.