I noticed the thread entitled “Is there a future?” and got to thinking about the arrow of time.
Are the questions about the future meaningful on a cosmological scale? I mean does the second law of thermodynamics imply we are doomed to a totally entropic universe? Is the universe in effect a perfectly closed system and what does the ‘future’ imply?
Just wondering about before and after?
An interesting take on our singular universe and the concept of time…
There has been much conjecture as to whether the chicken or the egg came first, but what about humans (and other mammals)? What came first, the parent or the child (and, yes, I appreciate that the correct answer is the father, rather than the mother), but how would a baby survive without a parent (mother in this case)? Conversely, unless you accept without question the biblical version of events, just how did creation occur without procreation (and vice-versa)?
As imply, it is one man's theory but thought provoking nonetheless.
As for the energy state of the universe I assume the energy state of the preceding universe would fuel the next big bang if you will. I suppose Penrose is implying a closed system in which no energy is lost or gained but I will see if I can find any other points he has made relevant to the question you raise.
Sorry NF but as the man said, there is no "before" the big bang as time does not exist "before" the big bang! But please don't ask me to explain that.
But this clip reminds me why I dislike this programme - the combative and/or patronising attitude of the presenters gets tedious, supposedly in the guise of "cutting journalism" or whatever they call their rudeness. Oh, and how they toady and grovel when there is a pop star or celebrity as a guest.
I had it explained to me that under the current theories that cosmologists work with to wind the clock backwards, time t = 0 is undefined. Time t >0, even a tensy tiny bit greater than zero, is within the definition. Within that constraint, they are still wrangling their way backwards a few nano seconds at a time.
Last edited by Lonewolf_50; 20th Jul 2010 at 20:18.
No defensiveness from me with respect to Penrose's theory anyway as I am still mulling it over, trying to decide what I think about it.
Maybe we could consider that in an inifintely energetic universe, that time which can be thought to be synonymous with frequency (as per Planck's equations) is infinite and therefore meaningless. Energy and mass can still be thought to have existed before this singular point... as Penrose explains here.
The first ingredient is one that many popular science readers will be familiar with — the idea of time dilation. You may know that if you travel in a train at high velocity then you actually experience time more slowly relative to a person on the ground. This is not too noticeable on the Eurostar train, as you have to be close to the speed of light for the effect to be significant (I make it about 0.2 nanoseconds less time experienced on the trip London to Paris).
But, as Penrose observes, for a photon of light itself, time is so stretched that it experiences no time at all! So it is that a photon could traverse the 10 billion year history of the Universe and quite easily carry information to its infinite future and, according to Penrose, beyond it.
Sorry NF but as the man said, there is no "before" the big bang as time does not exist "before" the big bang! But please don't ask me to explain that.
That is my (rudimentary) understanding also. Time doesn't exist without the universe so it is pointless to try and understand what happened 'before' the big bang.
As for the question 'Is there a future?', one possible answer is 'only if we collectively believe there is'
Ani Fule Kno that the Universe is expanding (like an inflating balloon) and when the balloon reaches its limit it will burst and there will be a big bang . . .
. . . so the big bang is not the beginning, it is, in fact, the end of existence.
. . . so the big bang is not the beginning, it is, in fact, the end ...
It may be the end for the kernel but it is the beginning for the popcorn. Are we where we think we are or in a really big microwave bag slowly going round and round as the universe warms around us until one day
*POP*
I think I just discovered the true cause of global warming!!!
G-CPTN- That analogy is interesting- The reason a balloon pops is because there is matter inside wanting to get out, but being held back by a thin layer of strong but flexible material.
If the analogy were true, what would the rubber of the balloon be?.....and perhaps more importantly, is God at the neck of the balloon blowing in? Or has he tied it up and let it fall to the floor only to be trodden on by some drunken angel at a party inside the pearly gates?
Time doesn't exist without the universe so it is pointless to try and understand what happened 'before' the big bang
In the conventional theory at the singularity, the breakdown of normal physics due to a pethora of infinite mathematical terms is the major embarrassment for physicists and thus the theory holds that there is no time 'before' the big bang.
Space itself is said to have entered a quantum state of indeterminacy under such high energy conditions. Hawking characterised this state as having been transformed by quantum fluctuations from 3 space and 1 time dimension into a 4 dimensional space, devoid of any time metric. In such a quantum 'space', time itself becomes irrelevant.
Of course Penrose is not the first and only 'heretic' to attempt to look at what happened 'before' the big bang.The physicist Sean Carroll has also ventured here...
Another big surprise about our universe comes from actual data from the WMAP (Wilkinson Microwave Anisotropy Probe) spacecraft which has been studying the Cosmic Microwave Background (CMB) the "echo" of the Big Bang.
"The WMAP snapshot of how the early universe looked shows it to be hot, dense and smooth [low entropy] over a wide region of space," said Carroll. "We don't understand why that is the case. That's an even bigger surprise than the inventory problem. Our universe just doesn't look natural." Carroll said states of low-entropy are rare, plus of all the possible initial conditions that could have evolved into a universe like ours, the overwhelming majority have much higher entropy, not lower.
But the single most surprising phenomenon about the universe, said Carroll, is that things change. And it all happens in a consistent direction from past to future, throughout the universe.
"It's called the arrow of time," said Carroll. This arrow of time comes from the second law of thermodynamics, which invokes entropy. The law states that invariably, closed systems move from order to disorder over time. This law is fundamental to physics and astronomy.
One of the big questions about the initial conditions of the universe is why did entropy start out so low? "And low entropy near the Big Bang is responsible for everything about the arrow of time" said Carroll. "Life and death, memory, the flow of time." Events happen in order and can't be reversed.
"Every time you break an egg or spill a glass of water you're doing observational cosmology," Carroll said.
Therefore, in order to answer our questions about the universe and the arrow of time, we might need to consider what happened before the Big Bang.
Ani Fule Kno that the Universe is expanding (like an inflating balloon) and when the balloon reaches its limit it will burst and there will be a big bang
Lucretius would probably have disagreed with you...
Things go on happening all the time through ceaseless movement in every direction; and atoms of matter bouncing up from below are supplied out of the infinite. There is therefore a limitless abyss of space, such that even the dazzling flashes of the lightning cannot traverse in their course, racing through an interminable tract of time, nor can they even shorten the distance still to be covered. So vast is the scope that lies open to things far and wide without limit in any dimension.
