Understanding Gravity at Long Distances

[sophiecentaur]

I have spent quite a lot of time on virtual particles (via Google) and have reached at surprising conclusions as follows:
1. An electron and positron approach each other. It is told that they exchange virtual particles and thus get attracted.

I simply don't get this. If they throw virtual particles (that transfer the momentum) at each other, they should be repelled and not attracted.

etc. etc.

[/B]

You need to pause, at this stage. Consider why the theories of fundamental particles, QM and Relativity have presented so many problems and difficulties to so many really clever brains, over the years. If it really were as simple as you seem to want, then it would be within the capabilities of any schoolchild to understand it all.
You are trying to interpret what you have been reading in terms that were already familiar to you. You read the word 'particle' and you immediately think it must be like a little bullet. That is very far from the case. Personally, I feel that the word 'particle' was an unfortunate choice (back to the corpuscular theory of light). I guess that some of the original properties that are attributed to photons made it an attractive term to use but people, fresh to the subject, all carry the name and the analogy too far.
To increase the level of confusion, the term 'virtual photon' was then introduced - as a natural extension. This makes life even more difficult. The concept of particles flinging other particles at each other as they go past is a tempting one but, as you have shown, it leads people even deeper into the mire of misunderstanding.
You will stand a much better chance of getting to know a bit more about all this is if you use the word 'particle' in mental inverted commas, whenever it's in the context of advanced Physics. That will remind you that you just cannot make assumptions about how it will behave on the grounds of how bullets and snooker balls behave. Follow all the rules of advanced Physics and don't ever try to think in terms of Classical Mechanics and everyday experience. This will be very hard. It's hard for everyone and there is no easy way into this.

 

[Vanadium 50]

This thread is all over the map. It's no longer about the original topic, and I sense a growing frustration with people trying to answer the OP's questions - which seem to be at least partially uncoupled to the answers.