November 6, 2011
written about 3 or 4 weeks ago
Is it possible for you and me to travel backward………… ?
Shyam : Can You Time Travel ?
Manmohan Dash: NO, but you can sit in your car and act. the reverse gear and go backwards … in space
Shyam Dash: what is … The fourth dimension?
Manmohan Dash: time is called the 4th dimension because at very very high speed it is impossible to differentiate between space and time dimensions, if you do it in one frame in all other frames they will be mixed again, that is if you are sitting at home “what you call a distance will be partly a ditance and partly a time delay for a person sitting in a car that is moving wrt you sitting at home”
Manmohan Dash: distance and time can only be separated in a frame in which these distances are not moving wrt each other, in all other frames of view they are mixed.
Shyam Dash: we are only able to move forward in time…..
Manmohan Dash: On an average, the average being taken at the smallest perceivable scale, we are drifting towards future. But in a virtual way we can say there is a little uncertainty that we did not move forward rather backwards, but a very very little, but in the end it does not matter because it takes us forward in time, on an average. That is why We age, that is why everything around us ages. We do not grow younger, never, nothing in universe is a reversible process ..
There are many arrows of time. eg if two places on earth are separated they have two different time arrows. Because we are advaned enough and can communicate back and forth we say we have the same time (synchronization). But we did not have this priviledge in the past. Also think, if we are not communicating with certain prortions of the universe where a different time scale and arrow may be working we better be out of communication as they will tell us about strange processes in nature. But in essence that is what has been happening when we discover newer processes. WE work them out with what we understand as natures laws but then there are discrepancies, eg we start with gravity and find that there is anti-gravity. But we haven’t soundly formulated all these into the laws as we understand them today … there is plenty of work that needs to be done.