Presentation on theme: "Role of Symmetry in the Sciences Gautam Mandal Jai Hind College, Seminar on Symmetry, November 18, 2006."— Presentation transcript:
Role of Symmetry in the Sciences Gautam Mandal Jai Hind College, Seminar on Symmetry, November 18, 2006
Geometric symmetry Linear symmetry Parthenon temple, Athens
An object has linear symmetry if it looks the same when the observer moves some distance along a line A lonely desert road, USA Linear symmetry can be discrete (e.g. columns) Can also be along curves… or continuous
Spiral / helical symmetry 54367-spitzer-M81 Helical staircase, Vatican Museum DNA double-helix
Wrong! How about this? Train moves ahead, ball falls back. Sure?
Right! Close the windows. Can’t figure out if the train is moving if the train does not turn or speed up or down. Laws of physics are the same in all references which are in uniform motion with respect to each other.
“Mirror” Symmetry between past and future ! (T-symmetry) If this is possible
We would drop dead if this is what happens to air in this room Is this what will happen?
Second law of thermodynamics H H H H H H T H T T T T H H H improbableprobable (ordered)(disordered) Is THIS what marks the future from the past?Doesn’t this contradict T-symmetry, hence quantum mechanics? No. (Challenging questions, any takers?) Toss 10 coins at once
Black holes What has all that got to do with black holes? Black holes
Black holes are made of very tiny vibrating strings
which are bouncing about, much like air molecules in this room. Hence Hawking’s arrow is just the arrow of thermodynamics. (Dhar, Mandal, Wadia 1996)
Harmony of the spheres The ancient Greeks were not too far wrong…………….
Time Human Evolution Darwin The final frontier: The arrow of life RightWrong (hopefully)
Miller-Urey Experiment Methane, ammonia, hydrogen Amino acid Origin of life But Life From the Primordial Soup is yet another cup of tea. (simulated atmosphere of young Earth) Stanley Miller, Harold Urey, Chicago 1953
DisorderOrderHHHTHHHHHHHHHHTH…… Origin of life Hot primordial soup