Tracing the growth of Milky Way-like galaxies
This composite image shows examples of galaxies similar to our Milky Way at various stages of construction over a time span of 11 billion years.
The galaxies are arranged according to time. Those on the left reside nearby, while those at the far right existed when the cosmos was about 2 billion years old. The bluish glow from young stars dominates the colour of the galaxies on the right. The galaxies on the left are redder from the glow of older stellar populations.
Astronomers found the distant galaxies in two NASA/ESA Hubble Space Telescope surveys: 3D-HST, and the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey, or CANDELS. The observations were made in visible and near-infrared light by Hubble's Wide Field Camera 3 and Advanced Camera for Surveys. The nearby galaxies were taken from the Sloan Digital Sky Survey.
This image traces Milky Way-like galaxies over most of cosmic history, revealing how they evolve over time. Hubble's sharp vision resolved the galaxies' shapes, showing that their bulges and discs grew simultaneously.
Link:
- NASA Press release
- The present and early Milky Way (artist’s illustration)
- Artist's Illustration of the present Milky Way
- Artist's Illustration of the early Milky Way
NASA, ESA, P. van Dokkum (Yale University), S. Patel (Leiden University), and the 3D-HST Team
