Time started from the Big Bang? Why

[Sasaferrato]

Time is.

 

[Karl Masks]

Tight

 

[Puddy_Tat]

 

[A380]

‘If time and space are relative, why didn’t they come to my birthday party?’

 

[existentialist]

Time is.

Time needs space (and space needs time). Without space, there can be no time, and vice versa.

So, until the big bang brought space into being, there could be no time. Which is, arguably, why a big bang which had the necessary parameters to bring this particular universe into being had to happen, as there was no constraint on time to prevent every possible option happening.

At least, that's my take on it.

 

[Yossarian]

According to some researchers, the theory of time starting with the big bang's time is up.

The first, known as the prebig bang scenario, which my colleagues and I began to develop in 1991, combines T-duality with the better-known symmetry of time reversal, whereby the equations of physics work equally well when applied backward and forward in time. The combination gives rise to new possible cosmologies in which the universe, say, five seconds before the big bang expanded at the same pace as it did five seconds after the bang. But the rate of change of the expansion was opposite at the two instants: if it was decelerating after the bang, it was accelerating before. In short, the big bang may not have been the origin of the universe but simply a violent transition from acceleration to deceleration.

The Myth Of The Beginning Of Time

String theory suggests that the BIG BANG was not the origin of the universe but simply the outcome of a preexisting state

www.scientificamerican.com

 

[a_chap]

Time is.

Now, of course.

 

[SysOut]

When did time become important?
We had events such as seasons.
But that is not the same.
Was it accountancy working out interest, productions costs or travel by rail?

 

[Sasaferrato]

Time isn't a thing in the way that a contracting or expanding universe is, it just is.

A period between two events is the passage of time.

If the universe contracted to a pinhead, then exploded, time was taken for the contraction, ergo time must predate the Big bang.

I don't buy this 'time started at the Big bang' theory at all.

 

[Sasaferrato]

When did time become important?
We had events such as seasons.
But that is not the same.
Was it accountancy working out interest, productions costs or travel by rail?

The measurement of time is important so that we all get to the party on the same day and time.

The measurement of time has nothing directly to do with the existence of tine though.

 

[gentlegreen]

There is the theory of the Moebius ....

 

[danny la rouge]

Time is.

Relative.

 

[Karl Masks]

There is the theory of the Moebius ....

And there is the art of Moebius

 

[Signal 11]

I don't buy this 'time started at the Big bang' theory at all.

I don't think there's a theory that says that, but it's likely a common belief and a least as valid a belief as your "it just is".

There are different ways of talking about time which use different zero points depending on what they are used for, like CE is useful to us for talking about history. In cosmology using the big bang as the zero point makes perfect sense.

There is one way in which the big bang is more than a convention though. It is a low entropy state which the Arrow of Time points away from.

But that doesn't mean that nothing preceded it. It's very likely that there was Cosmic Inflation before the big bang although it's still common for people to talk about it as having been the early part of the big bang. See here for discussion about that.

It's also possible that there are more universes / a multiverse like the string theory stuff mentioned above, but that's more speculative.

This is a very good video about how physicists think about time. The series is intended to give a higher view than the typical pop-sci presentations, while still remaining accessible to all.