ただし私自身は、エーテルを不要にしたのは、あくまでも量子論だったと考えています。この点はアジモフの文章を紹介しましたが、もう１つ、2000年頃シカゴ郊外の書店で購入した「Way Science Works」（科学ライターのMarek Walisiewiczが編集責任者）の中の「Action at a distance」という項目からの抜粋を転記します。
Forces seem to be able to act across empty space, almost as if interacting particles were "aware" of each other. It is now thought that each of the four fundamental forces is transmitted by a messenger particle. This flies between two particles, carrying the force which acts on the recipient particle, just as a catcher recoils with the momentum of a thrown ball. Protons and neutrons influence each other via strong nuclear force, carried by gluons. Two negatively charged electrons repel one another via the electromagnetic force, carried by short-lived photons.
