someone please help me understand the "big bang" better

If it don't go elsewhere, it goes here.
Timsup2nothin
Posts: 115
Joined: Sun Oct 15, 2017 3:24 pm

Re: someone please help me understand the "big bang" better

Post by Timsup2nothin » Tue Dec 12, 2017 1:24 am

There was a bang, and it was big. By its nature it is basically incomprehensible. It is to physics what a point is to geometry: the axiomatic singularity that has to just be accepted upon which everything else in the subject is built.

Lexicus
Posts: 92
Joined: Mon Oct 16, 2017 9:52 pm

Re: someone please help me understand the "big bang" better

Post by Lexicus » Thu Feb 15, 2018 3:36 pm

Time in physics is distinct from time as it is experienced or thought about by humans. The problem with time in physics is that defining it in a way that is not circular or self-referential is very difficult if not impossible. Most definitions of physics time that I've seen are something along the lines of "what a clock measures". An important part of the conversation there is the "thermodynamic arrow" which refers to the reversibility of certain processes (ie, a quantum particle interaction can easily be imagined happening "backwards" but a tree burning and turning into ashes will never happen "the other way": a pile of ashes will never turn into a tree). Another aspect of this is that as time passes the amount of total entropy in the universe always increases.

In relativistic physics time is treated as one dimension in a geometric construct called "spacetime." This sort of helps me think about time in relation to the Big Bang - space and time as different aspects of a single entity, spacetime, and spacetime came into being along with the universe.

User avatar
Lohrenswald
Posts: 8
Joined: Mon Feb 05, 2018 8:22 pm

Re: someone please help me understand the "big bang" better

Post by Lohrenswald » Fri Feb 16, 2018 8:04 am

If I remember correctly, the idea that the universe started in like a singularity and expanded was first proposed by an astronomer who also was a catholic priest. The term "big bang" was coined by someone mocking him for putting religious views into science. They tried to have an open mind back then, and speculated that the universe had always existed. But it turned out the priest was probably right, and I'm wondering if the fact that part of "western" worldview fits relatively well with what seems to be the actual reality has had some effect on the general populous' ability to like imagine or speculate over these things.

And also, personally I think time is getting an "unfair" amount of curiosity. There's a famous saying that "everybody understands what time is until they have to explain it", but it's not like length or mass for example are that much easier to define.
"What was before the big bang?" is a hard question to answer, but so is "what is next to all of existence?", which is a pretty similar question.
Personally, I think I've spent more effort trying to grasp my head around the concept of energy than the concept of time, which I think is at least equally as tricky a subject

I realise this post isn't very helpful in trying to explain anything, and is kinda just making up more problems, so I apologise for that

User avatar
Valka D'Ur
Posts: 208
Joined: Fri Sep 22, 2017 10:09 pm

Re: someone please help me understand the "big bang" better

Post by Valka D'Ur » Fri Feb 16, 2018 8:19 am

You're thinking of Georges Lemaître.
The above post is certified as having been Made In Canada.

Lexicus
Posts: 92
Joined: Mon Oct 16, 2017 9:52 pm

Re: someone please help me understand the "big bang" better

Post by Lexicus » Fri Feb 16, 2018 7:39 pm

Yep, that's the guy. And Lohr, you do remember correctly, 'big bang' was initially a derisive insult from those who believed in the steady-state theory of the universe (which was almost everyone at that time, including Albert Einstein). Hubble's discovery that the universe was expanding made the first cracks appear in that and the decisive discovery was the cosmic microwave background radiation which made the big bang the consensus theory.

Post Reply