A decade before Hubble made his observations, a number of physicists and mathematicians had established a consistent theory of the relationship between space and time by using Einstein's field equations of general relativity.
I tiåret før Hubble foretog sine observationer, havde flere fysikere og matematikere udformet en konsistent teori for forholdet mellem rum og tid ved at benytte Einsteins feltligninger fra den generelle relativitetsteori.