Does the idea of a "big bang" make any sense?

[Cam]

I have been confused in this area, being a biologist and not a cosmologist. I'd be grateful for clarification and am sure it will be easy for some of you guys. Before my main question I'd like some insight into the big bang, remembering I'm not into heavy maths.

 

So, is it presumed to be like a firework in the sky where all matter, stars etc radiate outward from a central point? Or is it more like a lava flow with a degree of continuous explosion from a supposed singularity?

 

It seems generally accepted that the universe is expanding and will continue to do so (we seem to attribute this to dark energy to fill the knowledge gap). If we are a passenger within this expansion what speed are we travelling at from the point of origin compared to the speed of light?

 

It seems to be accepted that we cannot be expanding faster than light speed. Therefore chances are we are moving slower. If we are moving slower then any light generated by the big bang will have accelerated, or at least passed, beyond us. It is accepted that if we perceive a star 10 light years away in our time it will have moved 10 light years from that point by the time we perceive the star. However if we accept the "firework" type of big bang then that star will be on the same perimeter of matter as we are and 10 years is nothing compared to the age of the universe. If we take a star on the other side of the perimeter it will be still on the same perimeter as earth but we will perceive it as it was much longer ago.

 

My impression is that the further we probe away from earth the further back in time we can perceive. Presumably there is some kind of limit here as if light is faster than us and the bang was brief then everything ( I suppose I mean light, visible, invisible, CMB) should have escaped from the point of origin faster than the matter and so how can we look back in time to perceive the origins of the universe?

 

Clearly I am missing something elementary but would be interested to gain insight.

 

 

[swansont]

I have been confused in this area, being a biologist and not a cosmologist. I'd be grateful for clarification and am sure it will be easy for some of you guys. Before my main question I'd like some insight into the big bang, remembering I'm not into heavy maths.

 

So, is it presumed to be like a firework in the sky where all matter, stars etc radiate outward from a central point? Or is it more like a lava flow with a degree of continuous explosion from a supposed singularity?

 

 

Neither. The big bang is the "explosion" of space itself. The 2D analogy often used is blowing up a balloon. The balloon is not coming out of your mouth, and the surface has no center. The expansion is happening everywhere.

[Cam]

Thank you. But using the balloon analogy, it expands from a central point, let's say the centre of a circle or the centre of a spheroid. What is inside the perimeter of the balloon - energy? matter? nothing?

[swansont]

Thank you. But using the balloon analogy, it expands from a central point, let's say the centre of a circle or the centre of a spheroid. What is inside the perimeter of the balloon - energy? matter? nothing?

It's an example in 2D: only the spherical surface matters. Thus, there is no center, there is no edge. The expansion happens everywhere.

[WWLabRat]

A better, less often used, analogy would be that of a loaf of bread being baked in an oven. Think about it as though you had raisins spread across throughout the inside and outside of the loaf. As that loaf is baking, it's going to rise and spread out at a constant rate. As it does this, the raisins will all start to spread out from each other at a constant rate, with none of the raisins getting closer. With them spreading out, no matter where you are viewing from, all of them would appear to be expanding from each other at an equal rate.

[Cam]

I can grasp the fact that we are moving away from the rest at a constant rate and that this can be perceived whichever raisin you may be viewing from. But, after 13.5 billions years or so I seem to feel that there should be a big hole in the middle of the loaf - is that correct?

[WWLabRat]

In order for there to be a hole in the middle of the universe, there would have to be a center. Unfortunately, we still don't know exactly what "shape" the universe is. However, in order for something to have a shape, and therefore a center, it would have to have an edge, which it doesn't, according to our current understanding of physics.

[Cam]

I appreciate your patience!

 

Sadly I have had no formal education in this area but it does fascinate me. I take your point about the lack of an edge of the / this universe. If it is true (is it?) that the matter of the universe is derived from a single point then is it possible to have an "edge" being the furthest extent that matter has so far reached from the point of origin? If the matter is moving away from other matter, ie expanding, it is moving into something - space? So, like a tsunami, the edge must be the boundary between where it is and where it is not.

 

Maybe I could better understand if I knew what the universe was from a physicists or cosmologist point of view - is it just the expanding matter and energy related to the matter from the original explosion or is it more?

[Delta1212]

I can grasp the fact that we are moving away from the rest at a constant rate and that this can be perceived whichever raisin you may be viewing from. But, after 13.5 billions years or so I seem to feel that there should be a big hole in the middle of the loaf - is that correct?

You can think of it as space being created between points. Stuff isn't expanding out from a central point; distances are just getting bigger. There is also no center of the universe any more than there is a center of the surface of the Earth. Anywhere you stand on Earth could look like the center and anywhere you stand in the universe will look like it's the center. The difference being that the 2D surface of the Earth will make it appear that you're standing at the center of a giant circle, while the 3D nature of space will make it appear that you're in the middle of a giant sphere.

 

Stuff was closer together at the start of the Big Bang simply because there was less space to move around in. As space expanded, there was more room available and stuff started spreading out.

 

We're not inside a giant container that is holding space and that has a center though. This can be, unfortunately, rather hard to wrap your head around as we're not really equipped by our daily experiences to conceptualize things like that very well.

[Cam]

Yes, I think you have nailed it - difficult to conceptualise. We are limited by various boundaries in our daily lives. We can see beyond some of them eg a fence. I have never been able to rationalise the concept of infinity and I hear my mathematical friends talking of big infinity and little infinity as a concept. Of course I understand there are more points on a football than a pin head although the number is infinite for both.

 

As far as the universe is concerned (multiverse?) I cannot feel the fact that it goes on forever. Or if there is a limit then I cannot grasp the lack of anything outside of it or perhaps there is not "an outside" of it. As you rightly say, it is not within human experience to be able to relate to. I envy the most talented mathematicians who have insight into this far beyond any capability of mine!

[pears]

As an aside, as far as big infinities and small infinities go, we say some groups of numbers are countably infinite (natural numbers 1,2,3... onwards) and some are uncountably infinite (the real numbers between 1 and 2 for example, because between any two numbers in that group, there will be infinitely many between them).

 

As far as picturing the universe goes, I try not to any more, because it gives me a headache. I just try and accept it. Some things are simply beyond human intuition (at least beyond mine anyway)

Edited September 5, 2013 by pears

[Cam]

Thanks, It looks like I won't be able to understand as it is beyond my capability too. I had some notion of a series of big bangs occurring "out there" creating a series of parallel universes.

 

I guess things will progress in time. It was not long ago that mankind thought the earth was flat and it must have been a great leap to find out about and then comprehend a spheroidal planet. I don't know who discovered this. It seems it may have been discovered by ancient civilisations but no-one told the European populations until later. So if you are brought up with a flat earth and what you perceive is a flat earth it's a leap of comprehension to suddenly believe it's a ball, actually. It would be so interesting to travel back in time and speak to scientists at various points in time and tell them what we now know and see how they handle the news!!

So let me pose another question. What, briefly, did the universe look like a fraction of a second after the start?

[Strange]

What, briefly, did the universe look like a fraction of a second after the start?

 

Hot and dense. (A bit like Jessica Simpson.)

[ADreamIveDreamt]

Philosophers in Egypt used to study the travel of sperm from Man into a Woman to then a form of a Babe,they then they placed the Baby in the form of the Big Bang.I believe the Sumerians and Babylonians did also...

[Cam]

Thought provoking. Presumably e=mc² is in your view a something rather than a nothing. Is this a view you accept?

[Colin58]

To me the idea of the so called "Big Bang" theory is just a flawed theory along with many others. How can you have nothing...nothing...nothing... then nothing explodes to create the Universe!!! How do we know the Universe is expanding?? We dont. Red shift is another flawed theory. As is Dark Matter. Created to make the computer model of the Universe work!! How is that good science!!??

If the Universe were expanding and all the stars and planets were racing away from each other, how come the constellations are the same now as in Ancient Egyptian times ??

If you take the view that everything you have been taught is wrong....thats a very good place to begin.

The bible quote of "as above, so below" I feel has great meaning here. As in the Universe is within ius and without us. (Im not religious by the way) To be honest we can have no idea if the universe is infinite or not. If it is...how can we know this?? If you were able to travel a quadzillion light years and still did not come to the visible end of the Universe...you still would not have the answer to this question.

We cannot put these things in nice little packages for the sake of science. We simply dont know. Its an awesome subject and is brain busting for sure. i love it!! I made up the word quadzillion by the way.

[WWLabRat]

First and foremost, if you're going to challenge an established theory, such as the Big Bang Theory, the forum rules dictate that you need to provide evidence to show how it is incorrect. Same goes for the other two you mentioned. Also how are they flawed?

 

The reason the constellations appear the same is two-fold. First is that all matter is expanding at a constant rate and relative to each other. This would mean that all the stars in each of the constellations would stay in the same position relative to each other. Think about looking at an object under a microscope at 10x. Now, without moving the slide, enhance the view to 100x. Nothing you are viewing actually changed its position, but it does appear larger. Second is that we are viewing those constellations as they were millenia ago and the light is just now reaching us.

 

The bible is not a valid source. This is a science forum and as such, anything religious in nature belongs under the religion subforum. Also along that line, "As above, so below" is a pagan and alchemy belief, not a christian one. Check your sources when quoting.

 

Mathematically it would be impossible for us to reach the "end of the universe" whether visible or not. The universe is not in any shape that we can conceive. It is expanding at the same rate from all points equally. In order for us to reach the present edge, even travelling at light speed, it would still take us 14 billion years to reach where the present "edge" is at which point it would already have expanded another 14 billion light years.

 

If we can't put these things into a nice little package, why have you attempted to do so?

[Airbrush]

"....If the Universe were expanding and all the stars and planets were racing away from each other, how come the constellations are the same now as in Ancient Egyptian times ??"

 

Who said that all stars and planets are racing away from each other? Only supercusters of galaxies are moving away from other superclusters of galaxies.

 

This means you are not aware that ALL constellations consist of stars that are ALL in our OWN galaxy. Constilations will change a little over time, but not AT ALL from the expansion of the universe.

 

If you are not even aware of this, then your knowledge of astro/cosmo is limited. That is why I don't take your criticism seriously.

Edited September 24, 2013 by Airbrush

[Strange]

To me the idea of the so called "Big Bang" theory is just a flawed theory along with many others.

It is true that all theories are flawed but ...

 

 

How can you have nothing...nothing...nothing... then nothing explodes to create the Universe!!!

I don't know. Why would you ask such a thing. It has nothing to do with the big bang theory.

 

 

We dont. Red shift is another flawed theory.

No, it is an observation not a theory.

 

 

As is Dark Matter.

No, it is a hypothesis to explain a number of different observations.

 

 

If the Universe were expanding and all the stars and planets were racing away from each other, how come the constellations are the same now as in Ancient Egyptian times ??

Because that isn't what the big bang theory says.

 

 

If you take the view that everything you have been taught is wrong....thats a very good place to begin.

It certainly seems to be true in your case. You don't seem to know anything about the science that you are criticizing.

 

 

I made up the word quadzillion by the way.

You seem to have made up a lot of other things as well.

[Sharanjeet Singh Mand]

 

 

 

 

 

 

 

 

 

 

Haw can this alleged start of time occur when there wasn't any time before time in which it would start?

 

Time is merely a measurement of some sort of difference between two happenings so you may consider time as forth dimension.but as stated above time cannot exist until some thing happens , we are not very sure if there was some thing before bigbang or not. Einstein some where tried to prove that energy is subjective to time and matter is subjective to energy so time would have been the first thing to come in existence.But both are contradictory !!iam not sure of any dimension called hypertime but i feel there can be many more but hyper time will be a extraordinary measure of time only.

[Strange]

Haw can this alleged start of time occur when there wasn't any time before time in which it would start?

 

There is no "alleged start of time". There is all sorts of speculation about what might have happened in the early universe: a quantum fluctuation, a "big bounce", God, Hawking, a black hole forming in another universe, etc. etc.

 

Currently, they all seem to have roughly equal standing as science (i.e. not much).

[WWLabRat]

 

 

 

 

 

 

 

 

 

 

 

Haw can this alleged start of time occur when there wasn't any time before time in which it would start?

 

Time is merely a measurement of some sort of difference between two happenings so you may consider time as forth dimension.but as stated above time cannot exist until some thing happens , we are not very sure if there was some thing before bigbang or not. Einstein some where tried to prove that energy is subjective to time and matter is subjective to energy so time would have been the first thing to come in existence.But both are contradictory !!iam not sure of any dimension called hypertime but i feel there can be many more but hyper time will be a extraordinary measure of time only.

 

 

How could time be nonexistent? Something may not be happening on the perceivable scale, but even something solid is going to be moving. The molecules that constitute a table are going to be constantly bumping into each other despite the appearance that the table is solid. The movement of atoms is dependent on what we know as time. Without time to separate each individual moment, they would all happen and appear at once. Say, for example, we were to trap a single Hydrogen atom in a container and within this container time didn't exist, we would see that the single Hydrogen atom fills the entirety of it because it is occupying all possible points within the box at all possible times.

 

Obviously we don't have the technology to be able to remove time, but my assumption is that we would see something similar to what I stated above.

[Airbrush]

"Haw can this alleged start of time occur when there wasn't any time before time in which it would start?"

 

Before the big bang there wasn't any time related to this universe. However, we don't know anything about what was around before the big bang. There was certainly something around that allowed a big bang to happen, on ITS' time. There had to be some kind of time before the big bang, just not OUR kind of time, maybe there was a "multiverse time" before universe time began.

Edited October 15, 2013 by Airbrush

[Sharanjeet Singh Mand]

"How could time be nonexistent? Something may not be happening on the perceivable scale, but even something solid is going to be moving. The molecules that constitute a table are going to be constantly bumping into each other despite the appearance that the table is solid. The movement of atoms is dependent on what we know as time. Without time to separate each individual moment, they would all happen and appear at once. Say, for example, we were to trap a single Hydrogen atom in a container and within this container time didn't exist, we would see that the single Hydrogen atom fills the entirety of it because it is occupying all possible points within the box at all possible times.

Obviously we don't have the technology to be able to remove time, but my assumption is that we would see something similar to what I stated above. " - Byron.

Iam talking of the time before Big bang therefore , most probable assumption is that there was only negative energy before that , there was no solid, if according to you molecules were already there then big bang will not be considered as beginning of our universe???/!!!!You may consider the flow of energy waves as a happening but i dont thing so that negative energy has any

waves. till now the best assumption is there was nothing before before big bang ,if some one says that there was a parallel or multiple universes then the question of beginning of everything and beginning of our universe will not reaming same . will both have different answers?

[WWLabRat]

But wasn't the Big Bang believed to have originated with matter condensed to a single point that was infinitely small and infinitely dense?