Physics

Galaxy

Bulge

Astronomy

Lenticular galaxy

Brightest cluster galaxy

Galaxy formation and evolution

Interacting galaxy

Galaxy merger

Billion years

Astrophysics

Science

Early assembly of a galaxy disk and bulge Galaxy formation in the early Universe is thought to have been a chaotic process, producing disturbed and asymmetric galaxy morphologies. Over billions of years, galaxies dynamically relaxed to form stable morphological features. Lelli et al. observed a distant galaxy at a redshift when the Universe was 1.2 billion years old (see the Perspective by Wardlow). They used gas and dust emission to measure its kinematics, and then modeled the mass distribution within the galaxy. The authors found that the galaxy contains a massive stellar bulge and a regularly rotating disk, features that models predict take billions of years to form. These results indicate that galaxy evolution is a more rapid process than previously thought. Science , this issue p. 713 ; see also p. 674

A massive stellar bulge in a regularly rotating galaxy 1.2 billion years after the Big Bang