- #1
night_sky
- 14
- 0
As per current theory's we know that time did begin with the big bang, what before then and does big bang highlight the explosion or the dense ball which was everything (universe.)
night_sky said:As per current theory's we know that time did begin with the big bang,
what before then and does big bang highlight the explosion or the dense ball which was everything (universe.)
Thanks. But as bigbang is the start of every thing ,is it right to assume that time is proportional(directly or inversly) to some quantity at that instant and why does cosmological time and thermodynamic time point in the same direction but why not physiological time it has 2 directions past and future.Simon Bridge said:There is no "before" for time because the concept of "before" requires time.
The "big bang", despite the name, should not be thought of as an explosion of anything.
The name is sort-of a metaphore.
A good start for this sort of question would be one of Hawkins lectures:
http://www.hawking.org.uk/the-beginning-of-time.html
... gives you a better idea what you are asking about.
What you described is the classical Doppler shift which certainly doesn't explain the big bang in any way; it is a result that appears due to Galilean relativity (at near light speeds we have relativistic Doppler effects as well). The only thing remotely close to what you described is the cosmological redshift effect which helps support the idea of an expanding universe.uzayr said:Our main evidence for the big bang is red shift. E.g if a fire engine is traveling towards us than the frequency is high and the pitch is high.
uzayr said:by looking at the red shift of a large number of stars we can establish that they are moving away from us. However, other stars move away from each other so we can't tell exactly where the universe began. There are the possible ways that the universe could continue. Theory 1 the universe could expand forever. Theory 2 the universe could eventually stop expanding. Theory 3 the universe would expand until a certain point and the collide.
why does cosmological time and thermodynamic time point in the same direction but why not physiological time it has 2 directions past and future.
There are a number of arguments in the philosophical, physical and cosmological literatures for the thesis that time is not fundamental to the description of nature. According to this view, time should be only an approximate notion which emerges from a more fundamental, timeless description only in certain limiting approximations. ...The view that time is real and not emergent is, I will argue, supported by considerations arising from all these issues It leads finally to a need for a notion of law in cosmology which replaces the freedom to choose initial conditions with a notion of laws evolving in time.
Following a line of research that I have developed for several years, I argue that the best strategy for understanding quantum gravity is to build a picture of the physical world where the notion of time plays no role. I summarize here this point of view, explaining why I think that in a fundamental description of nature we must "forget time", and how this can be done in the classical and in the quantum theory. The idea is to develop a formalism that treats dependent and independent variables on the same footing. In short, I propose to interpret mechanics as a theory of relations between variables, rather than the theory of the evolution of variables in time.
Naty1 said:nobody really knows...but increasing entropy seems to set a direction for time flow. However our mathematical models treat future and past equally. Einstein seemed to think our human perceptions of time had to be completely abandoned.
phinds said:THERE IS NO "WHERE" to the beginning of the universe.
night_sky said:By the evidences currently available all objects in the universe are moving away from us, doesn't this mean that a point of origin must exist.
night_sky said:By the evidences currently available all objects in the universe are moving away from us, doesn't this mean that a point of origin must exist.
phinds said:If you had it right then WE would be at the point of origin of the universe (as of course would every other point in the universe)
OCR said:My bold... that's getting pretty close to the definition of everywhere, isn't it?
OCR
phinds said:It had not been my intent to be "getting pretty close to everywhere" but rather to express that it IS everywhere.
OCR said:that's [STRIKE]getting pretty close to[/STRIKE] the definition of everywhere[STRIKE], isn't it?[/STRIKE].
The first question is handled in the link I gave you, as for the second, there is no reason to suppose that physiological time in our bodies is any different from the "time" we measure with any other kind of clock.night_sky said:Thanks. But as bigbang is the start of every thing ,is it right to assume that time is proportional(directly or inversly) to some quantity at that instant and why does cosmological time and thermodynamic time point in the same direction but why not physiological time it has 2 directions past and future.
We can decrease entropy locally, and that does not result in backwards flowing time.night_sky said:But then ,will entropy decrease result in time flowing backwards. If its true then one can be sure that inside black holes time runs backward's
As the others have said: no. It is a very common misconception that the Big Bang is the Universe exploding into being from some point - see Disney's Fantasia for a typical illustration.night_sky said:By the evidences currently available all objects in the universe are moving away from us, doesn't this mean that a point of origin must exist.
Simon Bridge said:A lot of these questions are covered in the lecture I gave you - post #2 - did you follow the link?
The first question is handled in the link I gave you, as for the second, there is no reason to suppose that physiological time in our bodies is any different from the "time" we measure with any other kind of clock.
Our perception of time, on the other hand, is something that happens in our minds. It's relation to the physical world would, therefore, be a mind-body problem. Nobody has solved that one yet.
But if you mean "why do we remember the past and not the future?"
That can be understood in two stages:
1. remember(!) that we call the stuff we remember "the past" because we remember it - it's the definition of "the past". (Lets not get bogged down in ideas about historical past and True past events and false memories etc please? You know what I mean - thanks.)
2. our memories are not magic - they must be laid down by some physical process. To be persistent, which they must be to be called "memory", the process must be irreversible. Thus "memory" must be one way ... irreversible processes go in the direction of increased entropy - therefore, so does our memory of the order of events.
Hawking actually covered this in "A Brief History of Time" quite a while ago and many others have written on it since (and before).We can decrease entropy locally, and that does not result in backwards flowing time.
But you should be careful what you mean by "backwards" and "forwards" in the context of time. These are directions relative to something ... what would time be moving back or forth with respect to?
We see time flowing in the same direction as the increase in total entropy.
When local entropy decreases, it does so against the flow of total entropy change.
If total entropy were to decrease - would we notice?
For us to notice we'd have to see our clocks turn backwards ... which would mean that our local entropy (in the mechanism that lays down our memories) would be running the opposite way to the total entropy. So which is going backwards, time, or us?
Dan Dennet talks about how memory works in his provocative "Consciousness Explained" - his recent TED talks are largely about perception. They will help you here I think.
Inside a black hole there is no reason to suppose time "runs backwards" there either - though that is a whole different kettle of piranhas.
My favorite link for what happens inside a black hole - as near we can make out - is:
http://www.jimhaldenwang.com/black_hole.htm
I think this goes beyond the concepts you are wresting with though.
As the others have said: no. It is a very common misconception that the Big Bang is the Universe exploding into being from some point - see Disney's Fantasia for a typical illustration.
You should read the link in Phinds' sig.
Note: the ideas you are trying to work through are very big - there is no way anyone can provide complete answers in these forums. That is why we give you links and pointers for further reading. Do go read them.
night_sky said:By the evidences currently available all objects in the universe are moving away from us, doesn't this mean that a point of origin must exist.
A parallel Universe may be one which might have been but wasn't without violating the idea that the Universe is everything there is.As we all know that universe is defined as every thing we know then how can one think of possibility of existence of parallel universe's . This one doesn't cope up with the definition because as per definition parallel universe must also be included in the known universe.
Please explain me about big crunch. Big crunch does state a single point where all of the universe will be one.(Please correct me if i am wrong.)Simon Bridge said:A parallel Universe may be one which might have been but wasn't without violating the idea that the Universe is everything there is.
Since "Universe" is a label we are free to come up with other uses for it - words are our tools not our masters. Certainly it is not useful to define the Universe as "everything we know" - for surely the Universe also contains many things we have yet to discover?
But that is a different topic... and it does not appear to follow on from what I wrote or from the original topic. You should ask it in a different thread perhaps?
Have you taken in what people are trying to tell you?
Have you read the links provided?
night_sky said:Please explain me about big crunch. Big crunch does state a single point where all of the universe will be one.(Please correct me if i am wrong.)
phinds said:You are wrong. The "big crunch" scenario says the universe, that started off as an incredibly hot dense plasma of possibly infinite extent and which has since expanded enormously, will contract back to the original incredibly hot dense plasma of possibly infinite extent. There is no "point" involved in either the beginning or the end of the big crunch.
night_sky said:Then is it wrong to take that incredibly hot dense plasma as origin or end...
night_sky said:Then is it wrong to take that incredibly hot dense plasma as origin or end...
Drakkith said:Wrong? Not really. It is just more like the end of our ability to predict what happens in either the past or the future beyond those points in time. It is unknown if that is actually the start or end points.
Then does time stop at the event horizon.
night_sky said:Is there a possibility of existence of other dimension other than the existing one inside black hole.