Help to understand the Big Bang

[joseph nicholas]

No one really knows.  It´s really foolish to spend limited resources on this to find an answer.  Let math sort it out.  Please stop using inane emogies.

[timelessbeing]

maybe branes were always there.

No one really knows.  It´s really foolish to spend limited resources on this to find an answer.  Let math sort it out.  Please stop using inane emogies.

you must be fun at parties
        

[bsudbrink]

But I still find it interesting to speculate...

Have you heard of a Boltzmann brain?

Yes, and I've seen other lectures by Dr. Susskind but not this one.  Thanks!

[bsudbrink]

As I understand it, all of the mass in the universe will be in the form of iron atoms.  It will no longer be possible to concentrate enough energy to split or fuse them.  They will be the indivisible particles, the point masses.

After black holes evaporate, won't there just be white and brown dwarfs and neutron stars accelerating apart?

If I remember correctly, that's "only" about ten to the thirtieth or so years in the future.  Eventually, barring the "big rip", you get iron.

"big rip" theory says that eventually even matter will decay into fundamental subatomic particles.

I think the "big rip" is just as good as "pinching off" another universe.  To my mind, a "big rip" looks like the "other side" of a "big bang".  I would think the process is "allowed" (whatever that really means) to change physical constants and scale.  Again, you end up with "our" universe existing in the "big bang" of someone else's universe.

[AngraMelo]

You guys hijacked my thread! hahahahaha Im just kidding!
Very interesting discussions, I guess Im realizing how pathetic I am when trying to imagine nothingness and what lies after the particles on the edge of the expanding universe.
When I started learning about the space being made of fields and the basic particles as being waves, that fucked with my brain big time.
It seems that scientists have thought about the universe being made of fields for a long time and with the recent discoveries (Higg's Boson) there is still a huge gap between what is taught in schools and the recent convictions of science in that area.

Im trying to close this gap by reading but boy the math is insanely complicated and even the thought experiments and explanations are mind boggling

[bsudbrink]

You guys hijacked my thread!

Sorry 'bout 'dat.

[AngraMelo]

Perhaps a more interesting discussion about this, that seems to be somewhat rising from the conversation here is: will we ever be able to teach the average IQ human about what science is doing today? Because it seems so complicated and it takes so much effort and discipline to learn even a bit of the math, the logic, the experiments that it starting to seem to me that we might not be able to teach this to the average joe in school. Im a simple minded individual with a bit of curiosity and a passion for learning but I dont consider myself in anyway less capable than the average human and this topic is incredibly complicated and dense, and Im talking about understanding just the BASIC of it. Maybe an argument can be made that the frontier of any area demands special individuals but what Im trying to say is that the curiosity (and maybe even the necessity of mandatory explanations about where we came from) that we all have even as kids kinda demands that this subject be taught in schools and I cant imagine a bunch of 16yo sitting down and facing the universe as fields where "particles" can behave as waves but if you measure them they behave as particles.
I hope I was clear.

[AngraMelo]

You guys hijacked my thread!

Sorry 'bout 'dat.

Dont worry about it! I was just kidding!
Im enjoying the conversation!

[MrMobodies]

I think of space as one big gas kind of bubble or even liquid that is so dense that there isn't enough for us to absorb it or see it well apart from the radiation and UV rays.

They say that space is also expanding.

It is like everything in slow motion.
Slow motion maybe to preserve life to evolve in smaller life forms where time appears longer (in a shorter life span) and space appears to move slower.

[silly]I think it started off as an idea from something that is not human and maybe in the form of a plant or something non moving that creates the illusion of life itself.[/silly]

Those are just my ideas and you can call them silly if you want.

[RoGeorge]

I always thought of the Big Bang as being the beginning of everything. There was nothing. No space, no black emptiness, no energy, no nothing. Just a big nothing that we cant even picture in our minds.

Nope.  That's the most common misconception.  The coined term of "Big Bang" is only about the explosive part of the expansion that we suppose it started back then.

There are no currently accepted explanations about what was before the "Big Bang", only speculations.

The "Big Bang" is not trying to explain where from all the energy came from, and why it was all there, and if back then there was time and space or not, or why there is something instead of nothing, and so on.  None of these.

The "Big Bang" is only about what happened during the expansion of that primordial "something":



 

[dnwheeler]

I'm not sure if it will help, but Lawrence Krauss has a great presentation called "A Universe from Nothing" on YouTube:

[timelessbeing]

there is still a huge gap between what is taught in schools and the recent convictions of science in that area.

Much of this stuff is still only conjecture. In fact we may never prove our theories. I am sure they are being discussed at higher levels of University for those who chose to pursue the field.

will we ever be able to teach the average IQ human about what science is doing today?

Only in a superficial way.

I cant imagine a bunch of 16yo sitting down and facing the universe as fields where "particles" can behave as waves

Quantum field theory and such is not part of the compulsory curriculum. It is not needed for most occupations, and would only confuse what people need to know. I first learned it at the 1st year University level.

[timelessbeing]

They say that space is also expanding.

It is like everything in slow motion.

We have measured how fast it's expanding. The Hubble constant is around 70km/s.

Slow motion maybe to preserve life to evolve in smaller life forms where time appears longer (in a shorter life span) and space appears to move slower.

The evolution of life on Earth is a microscopic instant in the history of the Universe.

[silly]I think it started off as an idea from something that is not human and maybe in the form of a plant or something non moving that creates the illusion of life itself.[/silly]

You're not far off. We think the first forms of life were neither plant or animal, but a distant ancestor of both. I think it would have been something very simple and lacking its own locomotion.

[radioactive]

I cant imagine a bunch of 16yo sitting down and facing the universe as fields where "particles" can behave as waves but if you measure them they behave as particles.

You might find this interesting..  I know I did when I recently ran across it.

https://en.wikipedia.org/wiki/Pilot_wave_theory

From the history section of the link:

In 1932, John von Neumann published a book, part of which claimed to prove that all hidden variable theories were impossible.[11] This result was found to be flawed by Grete Hermann three years later, though this went unnoticed by the physics community for over fifty years[citation needed].

In 1952, David Bohm, dissatisfied with the prevailing orthodoxy, rediscovered de Broglie's pilot wave theory. Bohm developed pilot wave theory into what is now called the de Broglie–Bohm theory.[12][13] The de Broglie–Bohm theory itself might have gone unnoticed by most physicists, if it had not been championed by John Bell, who also countered the objections to it.

In 1987, John Bell[14] rediscovered Grete Hermann's work, and thus showed the physics community that Pauli's and von Neumann's objections "only" showed that the pilot wave theory did not have locality.

[G7PSK]

If as some theorists think space time curves in on itself, the universe will expand back into itself at which point there will be a big bang or crunch, so we are just at some point in a continuous cycle.

[RoGeorge]

They say that space is also expanding.

It is like everything in slow motion.

We have measured how fast it's expanding. The Hubble constant is around 70km/s.

Actually, nobody measured how fast is expanding.

We have measured some other indirect indicators (i.e. Doppler shift), then try to interpret the results in such a way that it will make the most sense, according to current knowledge.
- So far, the best explanation to what we measure was that the Universe expands.
- Then, if the Universe is now expanding, then it must have been smaller in the past. (<- many tacit assumptions here, e.g. a continuous inflation)
- Then, we measured that some galaxies are spinning other than we expect (according to our known laws of Physics), we also measured that apparently the assumed expansion is accelerating, and thus we come up with something called "Dark Matter" and "Dark Energy", and "blame" those two for messing with our expectations, and so on.

What I am trying to say is the "Big Bang" was NOT probed, tested or measured directly.  The Big Bang theory is our best story that fits with what we know for now as the law of physics.

Not trying to demolish the Big Bang theory here.  So far, the Big Bang is the best match for what we measured in many, many other experiments or observations (not only the Doppler Shift).

The point is: Question everything.
Yet, don't deny what we have, unless some other better scientific explanation (that matches all the data) can replace the already established explanation.

[srce]

They say that space is also expanding.

It is like everything in slow motion.

We have measured how fast it's expanding. The Hubble constant is around 70km/s.

Actually, nobody measured how fast is expanding.

We have measured some other indirect indicators (i.e. Doppler shift), then try to interpret the results in such a way that it will make the most sense, according to current knowledge.
- So far, the best explanation to what we measure was that the Universe expands.
- Then, if the Universe is now expanding, then it must have been smaller in the past. (<- many tacit assumptions here, e.g. a continuous inflation)
- Then, we measured that some galaxies are spinning other than we expect (according to our known laws of Physics), we also measured that apparently the assumed expansion is accelerating, and thus we come up with something called "Dark Matter" and "Dark Energy", and "blame" those two for messing with our expectations, and so on.

What I am trying to say is the "Big Bang" was NOT probed, tested or measured directly.  The Big Bang theory is our best story that fits with what we know for now as the law of physics.

Not trying to demolish the Big Bang theory here.  So far, the Big Bang is the best match for what we measured in many, many other experiments or observations (not only the Doppler Shift).

The point is: Question everything.
Yet, don't deny what we have, unless some other better scientific explanation (that matches all the data) can replace the already established explanation.

The CMB is surely pretty strong evidence.

[timelessbeing]

[T3sl4co1l]

FYI, it is generally assumed that the universe is properly infinite; any finiteness of the universe is determined only by the horizon we can see.  Which is 13.8 Gly proper distance, or ~45Gly of visible universe (which includes matter that has since passed beyond our horizon).

The expansion of space-time should not be understood as a mechanistic motion of bodies.  It is the consequence of setting up boundary conditions, and solving for the field equations over time:
https://en.wikipedia.org/wiki/Friedmann%E2%80%93Lema%C3%AEtre%E2%80%93Robertson%E2%80%93Walker_metric
As it turns out, if you fill space with a constant density of matter, it is the nature of space that it expands over time.  There is a single parameter corresponding to the density of matter, and its consequential expansion rate and history (the curvature of spacetime).  A parameter which, so far as we can tell, is very nearly neutral (the curvature is flat), so that the universe is expanding precisely fast enough to avoid falling back in on itself (a "big crunch" would be spiritually satisfying, but is not supported by any data), which also gives the longest possible lifetime of the universe before objects fall out of each others' horizons ("big rip", give or take if the expansion accelerates or not, which currently it looks like it is tending to accelerate).

So, considering where we are now, if we wind the clock back, the universe remains infinite in extents, though there is much more matter within a given horizon.

Distance itself is not changing over time.  Size scales are fixed.  Particles and objects are the same sizes they've always been (well, as far as we can tell).  The distances between reference points are what's changing.

At least, we have no particular reason to doubt that objects have the same dimensions as usual -- that, for example, in the early history of the universe, the highest stable density of an object is still given by the same formula and constants as we observe today.  So, for example, not so much the Chandrasekhar limit which has to do with white dwarfs (which weren't seen until much later in the history of the universe), but, the Schwarzschild radius should be the same.  That is, the radius within which matter collapses to form black holes -- primordial black holes are predicted to have been produced in the early universe.  Or the relations of energy to wavelength (Planck's constant), stuff like that.

If we continue winding the clock back, we expect ever-higher energy levels, with ever-higher mass densities, eventually culminating in some exotic states of matter in the earliest zeptoseconds of the universe.

At time zero, the universe is still infinite, but its size is zero.  All particles are within each others' horizons (if particles are even a meaningful concept at this scale), density is infinite, energy is infinite...  Suffice it to say: it isn't meaningful to think about physics at zero time -- you're looking at a point where the value is undefined.  It's only meaningful to consider the limit up to, approaching, that point.

Some have toyed with the idea of complex time, as an analytical tool.  Where a real-ranged function gives an infinite or undefined result, we can look beside the point, at complex values (assuming a complex analytical extension to the function exists, and is reasonable), and try to go around it instead.  We can still get reasonable answers out of this method, even if we've performed the analysis through completely unreasonable means (what the fuck is "complex time" supposed to mean?  Nothing, so don't worry about it!), and as long as we understand that those means may or may not be applicable to all cases.

I forget if anything significant came of imaginary time; this,
https://en.wikipedia.org/wiki/Imaginary_time
looks like it's a casual thing, as much a quirk of how one chooses to write the equations, as it is useful to solving them, so not remarkable in and of itself.  ("Complex numbers" are another one of those things in mathematics that's regrettably named.  The domain is really not much more complicated than the reals -- which I say are named even worse, there's nothing "real" about them -- and indeed the complex numbers are more general, so you don't have stupid special cases like not being able to say sqrt(-1), or not being able to solve x^2 + 2x + 2 = 0, or not needing half a dozen trig functions when only one (exp) will do, or...)

Tim

[Mechatrommer]

big bang is just a theory, nobody really knows what. there is clue though from indisputable text that big bang is true (or something alike), but how and what is unknown to human. leave big bang alone, ask a simpler question like "help me to understand a black hole", well the real answer is nobody knows, you can watch all videos, youtubes, documentaries all you like, they are all just very good made up dramas (hypothesis). if black hole is a singularity, big bang is super singularity. there is scientific movement to fight or rule out big bang theory (mainly due to unreligious bias) but they are not popular since observation says otherwise (in favor of big bang theory). as einstein quoted... "there is logical implication" (if big bang is theorized)... he was trying to avoid that by introducing a universe constant, but it is inevitable.

[timelessbeing]

leave big bang alone ...

... like you did just now?

[Mechatrommer]

I'm not sure if it will help, but Lawrence Krauss has a great presentation called "A Universe from Nothing"

ohh please, trying to solve the bigger issue, the smallest issue still cant be answered... nothing made universe... universe made astronomers. cosmological selection?

[Mr. Scram]

I always thought of the Big Bang as being the beginning of everything. There was nothing. No space, no black emptiness, no energy, no nothing. Just a big nothing that we cant even picture in our minds.
But then I started checking out lectures and written material (that I could understand, given that Im not in the area) and got a bit into the Higg's Boson/field and matter itself.
Now I wonder if I got my interpretation of the Big Bang all wrong. Is the big bang just the creation of matter? I started to imagine just empty space. Thinking of the universe before the big bang as if it was a section of the deadest, emptiest and darkest part of the universe after the big bang. Then, BANG and matter shows up.
Im having a really hard time to interpret the nothingness before the big bang, imagining there was no canvas for matter to exist.
Do we know if before the big bang there was a place for matter to exist? Or that is the very concept of the big bang? As it being the creation of matter and a place for it to exist?
Do scientist refer to the word "universe" as being the place where matter can exist? Or the place where matter travelled through or has the potential of traveling through? Because if it is the first "definition", what prevents the edge of particle that is the furthest on the edge of the universe to be the thing creating the universe? I mean, if the big bang created the space for matter to exist doesnt it mean that it either created the space for matter to exist instantly and infinitely in all directions or the very first particles (or waves, or whatever) that left the big bang and are now the ones defining the boarder of the universe are the ones creating the space for matter to exist as they travel?

As I understand it space and time as we know it were created at or around the Big Bang. There wasn't emptiness, as that implies something being present and being empty. Empty time and space aren't the same as nothingness.

[Mechatrommer]

As I understand it space and time as we know it were created at or around the Big Bang. There wasn't emptiness, as that implies something being present and being empty. Empty time and space aren't the same as nothingness.

i'm not a relativistic expert but the way i see... time is our own definition... one may invent or call whatever they like but its nothing more than just a... "the occurence between two observable/senseable events" some atomic clock in our case https://en.wikipedia.org/wiki/Time_standard . since it is based on some tangible matter, "our" definition of time does not exist when there is no "matter". but if we change definition of time to something "unobservable", then there is time, it just different kind of time. we (the holy grail of scientists) just created our own "frame of reference" and play around it. when euclid played around flat plane of reference (sum of internal angles of a triangle is 180 degree), another scientists created curved type space reference and found out internal angles sum is 270 degree, now euclidan space collapsed, of course it collapse you genius! time, just like space may warp just like doppler effect, atomic oscillate differently relatively between 2 objects at different speed, hence our time is also relative, because we define time from something that exists in "space" (or matter) axis

otoh, talking about emptiness, that genius Lawrence Kauss talked about energy that existed (dark or not dark regardless) around those "emptiness" in the beginning of "time" to create that big bang in the first place, the golden question is... where do those energies comes from? oh i forgot... there are 2 possibilities...
1) they always be (omnipotent or omnipresent or whatnot)... so that ruled out ID...
2) they are from nothing... similar to this universe. so there is no ID involved.
right!

ps: why the heck i'm looking at this section, yeah last night i got 502 bd gateways, so i looked around what happened. so it seems big bang happened 

[timelessbeing]

the smallest issue still cant be answered... nothing made universe... universe made astronomers. cosmological selection?

Is there point somewhere here in this nonsense? If there is, can you please explain it for us that don't understand sentence fragments?

All I see is a video of Richard Dawkins, heavily edited by a cretin. Again, please explain...