- #1
windy miller
- 301
- 25
Is there any way to measure time without reference entropy? i.e suppose the universe has maximum entropy , is there any way to define a sense of time "after" that?
windy miller said:Is there any way to measure time without reference entropy? i
Is the wrong answer. Unless you manage to wriggle yourself (and clock) outside the universeVanadium 50 said:With a clock.
OK but what can you use as a clock in maximal entropy universe?Vanadium 50 said:With a clock.
I am unclear on the concept of "maximum entropy". If the universe is expanding, in what sense it its entropy at a maximum? I am also unclear about the concept of measuring time as used in the original question. If the universe is expanding, then the universe itself "measures" time. If hypothetically our universe is finite and then contracts after a finite time, how is the total entropy of such a universe defined?windy miller said:i.e suppose the universe has maximum entropy , is there any way to define a sense of time "after" that?
It's certainly possible to define time in the abstract as a distance between timelike events, but without entropy it's not possible for there to be a meaningful direction of time.windy miller said:Is there any way to measure time without reference entropy? i.e suppose the universe has maximum entropy , is there any way to define a sense of time "after" that?
windy miller said:maximal entropy universe
SleepDeprived said:many well known physicists have used entropy as the proof of the existence of time
SleepDeprived said:Part of the reason it's so hard to talk about time is because I don't think there is a well agreed upon definition of time
SleepDeprived said:the photon which based on our the Lorentz transformation has zero mass which means it can be everywhere at the same time
SleepDeprived said:Could time be defined something that is similar to, for example, "temperature"?
Hi @windy miller:windy miller said:OK but what can you use as a clock in maximal entropy universe?
My problem is that I see ambiguities regarding the terms you use. I am not an expert re thermodynamics, so my discussion below may well have errors, in which case i hope someone will correct me.windy miller said:suppose the universe has maximum entropy , is there any way to define a sense of time "after" that?
SleepDeprived said:Could time be defined something that is similar to, for example, "temperature"?
... In LQC-LQG. There is no distinction of time or proper time. Time is not fundamental. It is a relational and a timeless universe (not exactly but treated differently). It is intrinsic observer-independent time variable--According to Rovelli. BTW I am not an expert. Clarifications sake : https://www.physicsforums.com/threads/global-emergent-time-how-does-tomita-flow-work.660941/. Kudos to the late Marcus.windy miller said:But assume its correct. What are the implications of that? We are used to defining the notion of before and after as lower entropy in the past and higher entropy into the future. So let's assume we can watch video tape of the history of the universe in reverse. The universe is expanding so as we wind the tape back we see it contracting. We get to the bounce point and then see the universe expanding again. However can we say the contracting region is in the past? Its not necessarily lower entropy but on the other hand if we extend the timeline of our universe"before" the big bang according to this model there is still something there. So people in the LQC community will say the universe was expanding before it was contracting but from an entropy perspective how do we define that or can we define it without notions of entropy? very confusing.
windy miller said:Imagine a universe that is just particles in thermal equilibrium, can there still be raidacotve decay in such a universe?
windy miller said:the notion of time ticking representing the movement from low entropy to high entropy is not a necessary one as long as there is some sort of mass that can decay?
Time is currently measured using entropy through the second law of thermodynamics, which states that the entropy of a closed system will never decrease. This is used to measure time by observing the changes in entropy over a period of time.
There is interest in finding alternative ways to measure time without using entropy because the current method is limited by the accuracy of measuring changes in entropy. Additionally, entropy can only be used to measure time in closed systems, limiting its applicability.
Yes, there have been attempts to use other physical phenomena such as the decay of radioactive elements, the oscillations of a pendulum, and the vibrations of a quartz crystal to measure time. However, these methods still rely on the concept of entropy in some way and have their own limitations.
Currently, there is no known way to measure time without any reliance on physical phenomena or entropy. The very concept of time is closely tied to the physical world and the passage of events. However, there are ongoing research and discussions about the possibility of a truly fundamental and universal way of measuring time.
The potential implications of being able to measure time without using entropy are vast and could have significant impacts on various fields such as physics, mathematics, and technology. It could lead to a better understanding of the fundamental nature of time and potentially open up new avenues for research and technological advancements. Additionally, it could also challenge our current understanding of the universe and our place in it.