Comparing Galaxy Sizes

Thanks to the expanding Universe, galaxies observed at different distances from us are observed at different cosmological epochs. Thus, observing galaxies at a variety of distances allows us to study galaxies at a variety of evolutionary stages. Comparing galaxy sizes at different cosmological epochs can reveal clues to galaxy evolution. We compare here the infrared sizes of galaxies observed at two different epochs, 1.4 billion and 13.8 billion years after the Big Bang, utilizing data from the Atacama Large Millimeter/submillimeter Array and the Herschel Space Observatory.