# Who needs Big Bang?

#### Thor

Assume you have a field of particles in a sphere which is twenty billion light years in diameter.

Assume these particles are moving - randomly vectored at random velocities with no extreme bias for direction or velocity.

Assume that as those particles collide, mass attraction causes most of them conjoin into bodies.

At some point in time, all particles/bodies which were destined to collide will have done so and no more collisions will occur.

This means all of the remaining bodies comprised of initial particles must be moving away from each other.

An explosion from a central point of critical mass in not required to explain why celestial bodies are fleeing each other.

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#### Chronos

Gold Member
Your point? No modern theorist considers the Big Bang an 'explosion' in a pre-existing coordinate system.

#### pervect

Staff Emeritus
Thor said:
Assume you have a field of particles in a sphere which is twenty billion light years in diameter.

Assume these particles are moving - randomly vectored at random velocities with no extreme bias for direction or velocity.

Assume that as those particles collide, mass attraction causes most of them conjoin into bodies.

At some point in time, all particles/bodies which were destined to collide will have done so and no more collisions will occur.
It's not only possible, but quite reasonable, that the collisions will never stop totally, but only decrease in frequency.

This means all of the remaining bodies comprised of initial particles must be moving away from each other.

#### Dr.Brain

Assume that as those particles collide, mass attraction causes most of them conjoin into bodies.
Not true . As per QM , particles at large distances will attract and at some equilibrium point will become stationary and when approach too close to each other, they start repelling each other unless the velocities of approach are tremendously high.Mass attraction never merges two particles unless one particle is an antiparticle of the other, in which case, when they approach each other too close, they annihilate releasing energy

BJ

#### Spin_Network

Thor said:
Assume you have a field of particles in a sphere which is twenty billion light years in diameter.

Assume these particles are moving - randomly vectored at random velocities with no extreme bias for direction or velocity.

Assume that as those particles collide, mass attraction causes most of them conjoin into bodies.

At some point in time, all particles/bodies which were destined to collide will have done so and no more collisions will occur.

This means all of the remaining bodies comprised of initial particles must be moving away from each other.

An explosion from a central point of critical mass in not required to explain why celestial bodies are fleeing each other.
Incorrect proposition!..the core Mass Particles(Matter-Density) will have a Time Dependant effect on Particles at the furthest Horizon, this will most definately cause the Field Density( Particles surrounding Core, or Volume of Less Density), to be actually highly attracted in the Direction of the central region Core.

This would be a definate location recognizable as a Universal Density Profile for ordinary Matter?

Assume that as those particles collide, mass attraction causes most of them conjoin into bodies. ..but as the Density increases, it thins out at the farthest extremeties, this would invoke a Phase Transition, or in your model an Inverse Collapse of Matter, which THEN, may have an outward evolution of Field Energies, and guess what your back to Square One!

#### cosmo_boy

Thor said:
At some point in time, all particles/bodies which were destined to collide will have done so and no more collisions will occur.
I think yuou forget the gravity, which works only one way (attraction) . Static solution of gravitating matter is not stable so you need an expanding universe. Once you have an expanding universe then you can not avoind the big bang (initial very hot and denser phase of matter)

#### Thor

Chronos said:
Your point? No modern theorist considers the Big Bang an 'explosion' in a pre-existing coordinate system.
I stated the proposition poorly - tired last night.
Better stated:
Given a finite number of vectors of random direction and velocity within any finite volume, within a finite period of time all collisions which could take place will take place. Unless new vectors are introduced, that finite set of vectors altered by collision will eventually exit the volume, moving away from each other.
It is small wonder the Universe 'seems' to be expanding.

#### chronon

Thor said:
At some point in time, all particles/bodies which were destined to collide will have done so and no more collisions will occur.

This means all of the remaining bodies comprised of initial particles must be moving away from each other.
Such models were considered when the expansion of the universe was first discovered. However the evidence points to a hot, dense beginning, e.g.

1) Singularity theorems of General relativity
3) Helium abundance

#### russ_watters

Mentor
If the universe is a sphere with a boundary, Thor, why can't we see the boundary?

If the universe is a sphere with a boundary, it would also have a center: why can't we see a center - indeed, why can't we see that galaxies are moving away from the center?

#### saltydog

Homework Helper
Thor said:
It is small wonder the Universe 'seems' to be expanding.
Sometimes I imagine myself riding a trajectory in the Lorenz Attractor and wondering what I'd see . . . an expanding Universe all about me?

#### Thor

russ_watters said:
If the universe is a sphere with a boundary, Thor, why can't we see the boundary?
I don't contend the Universe has a boundary. Indeed, many of the collisions indicated in the premise would occur OUTSIDE the 'finite' volume.
If the universe is a sphere with a boundary, it would also have a center: why can't we see a center - indeed, why can't we see that galaxies are moving away from the center?
If the Universe were finite, it would have to feature a geometric center; however, I do not contend the Universe is finite - Euclidean, curved or otherwise.

Given an INfinite Universe, then because infinity is undefined, EVERY point in the Universe may be considered its center: Using any given point in space as an X,Y,Z axis, one may theoretically extend equidistant lines to infinity throughout the spectrum of polar coordinates. The procedure inscribes a sphere which theoretically encompasses the Universe. By definition, the selected point is the center of that sphere - and the center of the Universe. Since the same can be done for all points in the Universe, every point in the cosmos is its center.

(Actually you can use ANY shape and the result would be the same - every point is the geometric center)

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#### Thor

Chronos said:
Your point? No modern theorist considers the Big Bang an 'explosion' in a pre-existing coordinate system.
Yes, the expanding balloon...Big Bang occured EVERYWHERE at once.
Unfortunately, the expanding balloon at T=Ø must have been deflated to a single point. No matter how many logical firey hoops you jump thru it doesn't wash.

To contend that the Universe had a "beginning" is to posit that "once upon a time there was an after which had no before." Sounds rather silly, doesn't it?

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