As all atoms are probably 95% vacuum, that makes us probably 95% vacuum, so why isnt dark energy accelerating our expansion in the same way it is supposedly accelerating the expansion of the universe. Is it only an effect of cumulative vacuum, or are we too expanding at the same rate, but cant notice it as everything is expanding at the same rate. If everything was expanding at the same rate, then we wouldnt be able to notice the expansion of the universe. I am confused.

Dark energy is a theory made because the expansion of the universe (ie. galaxies and solar systems all becoming more spaced out) is accelerating.

 

To accelerate like this an energy (a force) must be supplied. This force acts like the opposite of gravity. This is what is meant by dark energy.

 

So why isn't dark energy making all atoms more spaced out? Because with the galaxy seperations the dark energy can be very weak, as it only needs to overcome the weak gravity between the galaxies. For an atom there are strong forces holding the atom itself together, I assume that dark energy is not strong enough to overcome this strong attractive force.

 

(The force holding atoms together is known as 'The Strong Force', I've been using the word strong representing it's strength)