# Would a Universe be considered part of the standard model?

1. Mar 5, 2013

### NWH

From my basic understanding of the standard model it tries to identify the different kinds of particles, understand their functions and their subsequent sub atomic particles. But as particles and forces break down into smaller components, do they also build up into bigger components? For example; just like a particle is built up of a mixture of sub atomic particles, is our universe is built up of a mixture of forces? Can we look at the universe and its forces in the same way we look at a particle? As in if we changed the mixture of forces can we predict the outcome and say that a different selection of possible universe potentially exists out there?

2. Mar 5, 2013

### Staff: Mentor

I don't understand what you mean with "mixture of forces".
Without gravity, and if the SM is complete, it would (at least in theory) allow to predict the time-evolution of the whole universe.

3. Mar 5, 2013

### phinds

Yeah, I'm with mfb in not having a clue what you are talking about on "mixture of forces"

As for particles, your terminology shows clearly that you would do well to spend some time studying the standard model. You talk about particles having "sub-atomic particles" but ALL of the particles in the Standard Model ARE subatomic particles and the reason they are part of the standard model is that they DO NOT HAVE sub-particles. If they had sub-particles, then THOSE particles would be what is shown in the standard model.

Last edited: Mar 5, 2013
4. Mar 5, 2013

### aemla

Not sure what you mean about forces, but standard model was designed to show most fundamental particles know to us at this moment. When proton, neutron, and electron were discovered, they were thought of as the most fundamental particles. But now we know there are quarks and leptons and force carriers. At this time standard model shows the smallest substance you can physically find when you break down a substance.

5. Mar 5, 2013

### fzero

First, we can understand our universe on large scales fairly well using the Standard Model and general relativity. At the present, gravity is the most important factor in describing large scale structure, while electromagnetism and the strong and weak interaction are important when you investigate the properties of the universe at very early times. To a very large extent, this is due to the fact that the strong and weak interactions are short-range interactions, so when we look at large scales, they can only have a very small effect, which we can usually ignore. Electromagnetism is a long-range interaction, but since stars and galaxies are generally electrically neutral, the electromagnetic interactions between them are also negligible, so we're left with gravity.

Now, your question about changing the mixture of forces is a question that can be studied. We could ask how the universe might be different if the relative strengths of the SM interactions were different. For example, if the electromagnetic interaction was very weak, then atoms and molecules would not be as strongly bound and it might be hard to make complex organic molecules like DNA. The notion that there might be other "universes" where the laws of physics are different from our own is associated with a line of research called the "multiverse." That wikipedia article seems to give a balanced overview of the ideas, along with a discussion of some very reasonable criticism of the more esoteric versions of the multiverse framework.