I wander about the universal principle of yin yang in relation with the earth. And I’m wandering as a result of the following:
I received an email with an invitation to join a collective meditation for healing on earth. A few days later the bombings in London took place.
Just to be perfectly clear I’m not stating that one had anything to do with the other or the effect of the other. But I am wandering about it.
Based on the yin yang principle, that contains duality, oneness, polarity, balance, I’m thinking: if I’m looking at the forces generated by this collective meditation, could it (according to the yin yang principle) be possible that opposite forces, like hate and destruction, become equally as strong to maintain the balance?

It’s not as black and white as you state it, but the basic principal is correct.
Yin Yang is symbolic for Universal Balance. Basically Yin Yang accommodates the Being of every Energy. The principle that All Is. And that every energy is All. Every imaginable emotion, every imaginable character trait, Every imaginable line of reasoning…
Every energy has that. So every energy has total freedom to choose everything (s)he wants to to crystallize itself. And yes, everything is the effect of a cause. You noticed that well.

It's an enormous reflection of Cause and Effect. And it sounds inconsistently, because how can you send out love and receive hate?
The answer lies in the intention of the meditation. The footing for a lot of people is the thought that ‘evil has to disappear’ and ‘love should conquer’. That footing is based on judgement. Evil is bad, love is good.
Totally ignoring the function of hate, anger etc. At the same time (in a lot of cases, not all) totally ignoring that every situation that touches you, is a personal mirror.
Many meditation are pointed at bringing ‘peace’ into the hearts of the energies you call terrorist. In other words: they want to change another energy. Do you want to quess what the law of Cause and Effect puts in their surroundings?
And then raise a hue and cry because those terrorists are trying to change their world!

The terrorist’s line of reasoning, the essence, the intention, is obtruding their truth upon someone else. Refusing to accept any other truth.
And meditating to ‘change’ a terrorist, is basically the same. Only the implementation differs.
As soon as you’re all able to recognize yourself in each others mirrors and recognize and be acquainted with the terrorist inside yourself, nothing will change. The rejection of hate in someone else is nothing more and nothing less then rejecting your own ‘negative’ emotions. But placing it ‘outside of yourself’ doesn’t contribute to growth and therefore feels ‘meaningless’.

As you can see…there is a connection, but Yin Yang doesn’t have much to do with it. That only symbolizes everything IS balanced. And as soon it can be looked at without judgement, and emotions as anger and hate can be recognized as valuable messengers that help you to see yourself for who you are, this balance will become perceptible. In yourself and in your world.

From Energy to Energy,