Physics ain't what it used to be

摘要

Once upon a time, physics dealt with tangible objects — if you couldn't weigh them or smash them together, at least you could observe them. As times changed, physicists started to deal with more ethereal things: electromagnetic fields and space-time metrics, for example. You couldn't see them but you could measure their influence on particle trajectories and so justifiably claim evidence of their existence. Nowadays things have changed. A phalanx of heavyweight physicists and cosmologists are claiming to prove the existence of other expanding universe domains even though there is no chance of observing them, nor any possibility of testing their supposed nature except in the most tenuous, indirect way.