Britannica Sources used in this answer

How far does diffuse ionized gas extend above and below the plane of the Milky Way Galaxy?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

H II region Centre of the Orion Nebula (M42). Astronomers have identified some 700 young stars in this 2.5-light-year-wide area. They have also detected over 150 protoplanetary disks, or proplyds, which are believed to be embryonic solar systems that will eventually form planets. These stars and proplyds generate most of the nebula's light. This picture is a mosaic combining 45 images taken by the Hubble Space Telescope.

Diffuse ionized gas extends more than 3,000 light-years above and below the galactic plane of the Milky Way Galaxy.1

This distribution is significantly more extensive than the 300-light-year thickness observed for molecular clouds, H II regions, and O and B-type stars. While these stars are primarily located within the galactic plane, they are able to ionize passages through surrounding clouds, allowing a substantial portion of their ionizing radiation to escape into these regions far from the plane.1