Where does now come from
Time continues to be the most mysterious dimension of our universe. Paradoxically, especially when it comes to pop-science literature, this means that the subject of time has never been sufficiently explored. A few years ago I chanced upon Time Reborn by a fantastic American physicist, Lee Smolin. Some time before that, I came across From Eternity to Here by the cosmologist Sean Carroll, who is a research professor at Caltech. I have just finished the latest in the genre Now. The Physics of Time, written by Richard A. Muller, a top-class physicist from the University of California, Berkeley. Muller cuts a remarkable figure and boasts many awards for his scientific accomplishments, including for discoveries in the field of cosmic background radiation, accelerating expansion of the universe and dark energy. The Polish translation of his new book will probably take a while to come out in print, as the book was made available to the English-speaking readers less than half a year ago.
I am proud to admit that thanks to such books I now know the only correct answer to nearly all questions concerning the nature of time, which is … No one knows. We don’t know what time is, why it is as it is or rather why it appears to be what we think it might be. We can’t be even sure it exists. Until recently some contemporary physicists clung to the popular theory that time was just a product of our imagination.
Hundreds of years ago, Isaac Newton had no doubts that time is real. Reality was to him something of a theatrical scene delimited by absolute time and absolute space. This somewhat Shakespearean vision of the world had not changed until the arrival of the relativity theory, where time and space had lost their absolute dimension and became an elastic and erratic time and space continuum. Eventually, some time in the mid-60s of the last century, attempts to reconcile quantum mechanics with the general theory of relativity led scientists such as Bryce DeWitt and John Wheeler to conclude that time did not exist. The just mentioned Lee Smolin acceded to this view at first, but in 2013 published his Time Reborn, which amounted to a perfect reversal.
Of course, we can argue that the problem of time belongs in the realm of philosophy, because whatever time is or is not, the letter t in equations cannot be omitted. We simply can’t do without the concept of time. Well, it can hardly be denied that contemporary physics is getting more and more speculative in places (the subject explored by Jim Baggott in Farewell to Reality), but it is equally hard to deny that we owe a lot to Einstein’s one-time fantasies. In Now. The Physics of Time, the author does not hold time unreal. He delves into the origins of time and reaches a very interesting conclusion, which is key to the book. An assertion that time originated with the Big Bang sounds rather trivial, but adding that the explosion continues to create not only new space but also new time makes it more intriguing. After all, the reality of time is made up of our successive now’s, which we can picture as the thinnest possible, newly-formed slice of time and space continuum.
As is often the case with such books, the conclusions bring a closure to a long and fantastic journey during which the reader stands to learn a lot. It is a journey through the world of Newton, the relativity theory, quantum mechanics; it’s a journey to the unknown, because, like I said earlier, the time riddle remains unsolved and many questions are in want of answers.
Time is a very mysterious thing – the reason perhaps why it is so fascinating.