Astronomers using NASA’s Hubble Space Telescope have established that mature-looking galaxies existed much earlier than previously known, when the Universe was only 2.5 billion years old.
They used Hubble’s Wide Field Camera 3, Advanced Camera for Surveys and the Hubble’s Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) to explore the shapes and colors of 1,671 extremely distant young galaxies over the last 80 percent of the Universe’s history.
“Finding them this far back in time is a significant discovery,” said Dr Bomee Lee of the University of Massachusetts Amherst, lead author of the study reported in the Astrophysical Journal (preprint at arXiv.org).
Dr Lee’s team confirms for an earlier period than ever before that the shapes and colors of the galaxies fit the visual classification system introduced in 1926 by Edwin Hubble and known as the Hubble Sequence. It classifies galaxies into two main groups: elliptical and spiral galaxies, and lenticular galaxies as a transitional group.
Study second author Dr Mauro Giavalisco, also from the University of Massachusetts Amherst, said: “why modern galaxies are divided into these two main types and what caused this difference is a key question of cosmology.”
Hubble Zooms in on Galaxies in Early Universe
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