Posts Tagged ‘Anti-matter’

@physorg_com This is my Janet and John idea of dark matter. Please point out errors

March 23, 2017

Maybe Dark Matter doesn’t form atoms.

 The big bang theory says from nothing we got matter and anti-matter but there’s no evidence of large quantities of anti-matter, in the Universe today

OK, so all the anti-matter met matter and was annihilated leaving a bit of this real matter which we see as stars etc.

I don’t like the idea and it takes  some weird maths., which I can’t follow, to support it.

My Maths just isn’t good enough to get it, so I can’t contradict it, nor can I accept it.

Much later Cosmologists decided that they needed dark matter because?

From http://www.thehindu.com/opinion/blogs/blogs-the-copernican/article5309773.ece

I’ve copied out these:

 Phenomenon #1

When the universe was created in a Big Bang, matter was released into it and sound waves propagated through it as ripples. The early universe was very, very hot, and electrons hadn’t yet condensed and become bound with the matter. They freely scattered radiation, whose intensity was also affected by the sound waves around it.

 About 380,000 years after the Bang, the universe cooled and electrons became bound to matter. After this event, some radiation pervading throughout the universe was left behind like residue, observable to this day. When scientists used their knowledge of these events and their properties to work backwards to the time of the Bang, they found that the amount of matter that should’ve carried all that sound didn’t match up with what we could account for today.

 They attributed the rest to what they called dark matter.

 Phenomenon #2

 Another way this mass deficiency manifests is in the observation of gravitational lensing. When light from a distant object passes near a massive object, such as a galaxy or a cluster of galaxies, their gravitational pull bends the light around them. When this bent beam reaches an observer on Earth, the image it carries will appear larger because it will have undergone angular magnification. If these clusters didn’t contain dark matter, physicists would observer much weaker lensing than they actually do.

 Phenomenon #3

 That’s not all. The stars in a galaxy rotate around the galactic centre, where most of its mass is located. According to theory, the velocity of the stars in a galaxy should drop off the farther they get from the centre. However, observations have revealed that, instead of dropping off, the velocity is actually almost constant even as one gets farther from the centre. This leaves the outermost stars rotating about the galactic centre at velocities that should ‘fling’ them away from the galaxy. Evidently that isn’t the case. So, something is also pulling the outermost stars inward, holding them together and keeping them from flying outward and away. The incredible prowess of this inward force astrophysicists think could be due to the gravitational force of dark matter.

There’s no mention of dark matter in my simple version of the Big bang theory but why is it needed? Anti-matter would answer those three phenomena.

It doesn’t need to have mutually annihilated with matter, which it repels according to the inverse square law.

The only anti-matter, of which we are aware, exists as individual particles,  which we detect from high speed impacts with ordinary matter particles (high speed to overcome the repulsion).

We only detect them from the gamma photons created by their annihilation.

We see matter because it forms atoms, where electrons moving between different excitation levels absorb and emit visible light.

Suppose anti-matter doesn’t form atoms. (why should it?)

It would be dark matter. Individual particles would want to clump but wouldn’t have a mechanism to coalesce into stable forms.

Such clumps would be dispersed on the approach of condensed matter.(Like waving your hand through a swarm of midges.)

The idea seems coherent to me. I don’t know why dark matter theorists require 5x more matter than dark matter but maybe they assume it would be as clumpy as real matter, whereas, if it’s easily dispersed by matter, then it would more likely appear, as stable clumps, in the voids in Space.

The only way that we might get evidence might be by firing a Maser into such a void and hoping to see a few gamma photons.

 What about dark energy?

Well apparently that’s needed, because the expansion of the Universe is accelerating.

How?

It isn’t matter pushing itself apart but Space expanding, as though matter is simply flotsam

Now it gets iffy, for me.

What is Space and how does energy come into it?

Energy is just work done by forces acting on matter, so are we to understand that Space is providing

the force, doing the work, creating the energy. Before we can posit Dark energy providing the acceleration of this expansion, I need to get my head around how and why Space is providing this energy. What is Space?

What I’ve read seems to contradict the concept of matter riding like flotsam on a sea of expanding Space.

The concept that appears to be used in the Janet and John versions, which I’ve read, is one of matter pushing itself apart and taking Space with it.

Then again,  matter doesn’t push.  At least it doesn’t push matter but it does push anti-matter and anti-matter pushes back at it.

  1. so my version of dark matter provides a push but as the Universe expands and this lot moves apart, the push decreases (inverse square law, again), so the expansion should be decelerating. Somehow the force should be increasing to give an accelerating expansion and this is where my brain gets tied in a knot, because the next bit sounds like sophistry, to me.

The accelerating expansion is being seen at the edge of the observable Universe, which is really what the Universe was like eons back in time, nearer to the Big Bang, when there would have been more matter and anti-matter, which had not yet been annihilated. The force would have been bigger so the rate of expansion would have been greater.

Does my head in but that seems sort of logical. As more chance annihilations take place, the rate of expansion of my immediate Universe will decrease, meaning that the edge of the Universe, will, by comparison, appear to be accelerating.

I know that the experts are much better Mathematicians than me, so where am I going wrong?

@ProfBrianCox Where did all the anti-matter go?

February 19, 2012

I quite like Prof. Brian Cox’s explanation of the creation of the Universe but his constant iteration of Physics being simple and beautiful is spoilt for me by an over-simplification.

It’s an aspect that is never covered in such descriptions.

All matter is created from nothingness, as in 0 = +1 plus -1, where the =1 refers to matter and the -1 refers to anti-matter.

The big problem is that there doesn’t seem to be any anti-matter Galaxies out there.

The only attempt to explain this, which I have come across, blithely states that when matter condensed out, there was an asymmetry that caused a slight excess of matter (?), with all the anti-matter being annihilated by matter.

Quite apart from “0 = +1 plus -1 “becoming “0 = +(1 + a little bit) plus -1 ” , there’s a lot of energy there that we aren’t seeing. Is it this energy which is driving the expansion of The Universe?

I’d like to see a clearer explanation of what’s going on.

Just to compound matters. Prof. Brian Cox says that when you stick two protons together, one becomes a neutron, making Deuterium.

O.K. I know he’s dumbing down but when a proton becomes a neutron, it must be by releasing a positron. I.e. the anti-matter version of an electron.

In the Universe there are equal numbers of protons and electrons (unless someone knows better) and 1 to 3 neutrons for every proton.

So where have all those positrons gone?

If they’ve been annihilated by electrons, there must have been a lot of electrons to start with. More interestingly, each annihilation would have been accompanied by the production of a pair of 1.4MeV Gamma Rays.

There would be enough of these to make a noticeable blip in the background radiation but I’ve not read of any.

I’m not a Cosmologist and I don’t have the Math to follow these stories, so it would be nice if someone, somewhere did a little piece to clarify these issues for me.