Science has sought to explain time, but on close examination it remains mysterious. Even Einstein said that time was an illusion. This panel discussed the challenges of time in relation to quantum physics, biology and evolution. Humans think that time moves in one way, from the past through the present to the future, like an arrow, but physics does not distinguish between the three stages. Panellists discussed the relationship between the arrow of time, entropy, and the second law of thermodynamics, as well as the limits to mortality in relation to time.
The panel was moderated by science writer Jennifer Ouellette. Panelists included cosmologist Sean Carroll (Caltech), physicist James Hartle (UC Santa Barbara), a Santa Fe Institute External Professor, and David Krakauer, President and William H. Miller Professor of Complex Systems at the Santa Fe Institute.
Key message: The structures in the universe will ultimately disappear, leaving dark, cold, empty space expanding forever, so we should appreciate the time that we can experience now.
Watch some of the highlights:
[James Hartle (JH), Sean Carroll (SC), David Krakauer (DK) and Jennifer Ouellette (JO)]
6:47 (JH) Time as we know it today started just after the Big Bang over 14 million years ago.
10:24 (JH) In a quantum universe, the notion of time breaks down close to the beginning of the universe.
12:24 (JH) Fluctuations in the structure of the early universe are the origin of the arrow of time.
14:57 (SC) The features of time today are absolutely dependent on the conditions during the Big Bang.
17:40 (SC) The present theories on the laws of physics treat the past, present and the future as the same.
19:50 (DK) Charles Darwin’s theory of natural selection gave us the adaptive arrow of time related to the development of life itself.
23:00 (JO) Do we need physics at all when we are talking about life?
23:46 (DK) Is complexity and life universal? The mechanisms of life are not unique to biology.
25:20 (JH) The basic laws of physics do not explain the reality that we have today.
27:20 (SC) If the entropy of the universe increases with the passage of time, how did life, which is essentially ordered, evolve?
29:50 (JO) Can we reverse the entropic process relative to life?
30:50 (DK) Organisms do indeed reverse entropy as they organize themselves, but at the same time, their metabolic processes are increasing the entropy that leads to their death.
33:20 (SC) Entropy will increase then slowly decease as the universe ages and life itself will have no influence on that.
35:24 (JH) Life could only have developed in an epoch with some level of complexity and disorder.
36:00 (JO) Does time flow smoothly?
37:00 (SC) The operation of our bodies demands that time flows smoothly.
39:15 (JH) Our individual ‘schema’ or understanding of the universe implies that smooth moment of time.
40:17 (DK) Do we move forward into time or does it flow over us?
57:00 (JO) Will time ever end?
57:27 (JH) Yes, if the universe stops expanding and crunches back to nothingness.
58:40 (SC) We do not know if time is a fundamental part of the laws of physics; rather it may emerge from quantum mechanics, so it will stop at the end of the universe.
59:50 (JH) An ensemble of space-times emerge from the wave function of the universe.