This composite image from the Hubble Space Telescope’s Advanced Camera for Surveys and its Wide Field Camera 3 shows a huge cluster of galaxies some six billion light years away known as PSZ23 G138.61-10.84. The image is from an observing programme called the Reionization Lensing Cluster Survey, or RELICS. The RELICS project has studied 41 galaxy clusters to help locate the brightest distant galaxies for follow-on observations by the James Webb Space Telescope, scheduled for launch in 2020.
The first stars appeared about 100 million years after the Big Bang. When the universe was about 3 billion years old, star formation activity peaked at rates about ten times above current levels. Why this happened, and whether the physical processes back then were different from those today, are among the most pressing questions in astronomy.
Eta Carinae is the most luminous and massive stellar system within 10,000 light-years of Earth. A long-term study led by astronomers at NASA’s Goddard Space Flight Center used satellites, ground-based telescopes and theoretical modelling to produce the most comprehensive picture of Eta Carinae to date.