Does entropy contradict the Big Bang theory?

[Jonnyb42]

Ok so I am asking two things here. One is, if entropy supposedly always increases, how does that fit with the big bang? The highly dense ball of all matter in the universe mashed together in the beginning seems to have high entropy; where is the organization??

Second, why does it seem time has a biased direction?

(Please put more importance on the first question.)

thanks,
Jonny

 

[edgepflow]

Current thinking in cosmology goes something like this: between the time the universe was created (t=0) and the Planck time (10^-43 sec) all of the fundamental forces of nature were unified; hence the most basic and simple configuration and a low state of entropy.

The 2nd part of your question was a little more subtle I recall. Hawking's popular books discuss this but I do not recall the details.

 

[Andrew Mason]

Ok so I am asking two things here. One is, if entropy supposedly always increases, how does that fit with the big bang? The highly dense ball of all matter in the universe mashed together in the beginning seems to have high entropy; where is the organization??

It doesn't matter what the entropy of the universe was at the time just prior to the Big Bang. The only thing that matters is that entropy increased afterward. The second law does not place any limits on entropy. It only limits the direction of change of entropy.

The volume of the universe increased dramatically after the Big Bang. This increase in volume is analogous to a free expansion of a gas: it involves an increase in entropy.

AM

 

[Jonnyb42]

Ok thanks, I subject I will be studying not too far from now.

 

[Naty1]

Second, why does it seem time has a biased direction?

You mean subjectively? Nobody knows.

Entropy seems to give time a direction as we perceive it, but there is no distinction in physics between past, present, and future...d = vt, for example, fits all three without apparent distinction.

There is a lot of discussion in THE FABRIC OF THE COSMOS by Brian Greene...but not a lot of answers...

From Einstein we learn that space and time are components of the same entity...spacetime... and neither is fixed as we perceive in our everyday lives.

In the quantum world, the concept of past is different than our classical intuition. But it does not seem we can alter the past by actions of today.

 

[sophiecentaur]

I have often wondered - if the 'arrow of time' is associated with increasing entropy, then does time go backwards, locally, in my refrigerator? What price sell-by dates?

 

[Andrew Mason]

I have often wondered - if the 'arrow of time' is associated with increasing entropy, then does time go backwards, locally, in my refrigerator? What price sell-by dates?

Time slows in your refrigerator - for bacteria. For some things it appears go backward. For example, that free-range pork chop that I inadvertantly pushed to the back of the middle shelf in my fridge last September looks an awful lot like the green pasture from whence it came.

AM

 

[Lord Crc]

Second, why does it seem time has a biased direction?

I'm just a layman so this may be just silly, but it makes sense to me:

Perception of time requires storing information in memory to detect that the past is different from the present. Storing a bit of information in memory is an irreversible process and increases the entropy of the system. Thus it seems (to me) that perception of time implies that one perceives time to "flow" in the direction of increasing entropy.