nebula

Approximately 5 billion years ago, our solar nebula was formed as gravitational forces pulled interstellar gas and dust into a swirling mass around out newly formed sun.

A nebula is an interstellar cloud of dust, hydrogen, helium and other ionized gases.

American astronomer Edwin Hubble published a paper in 1924 demonstrating that M31, known then as the Andromeda Nebula, lies far outside our own galaxy.

We don't yet know which stars were formed in the same nebula as our sun.

Do you know what a nebula is?

At the time the photogravures were ordered no large scale photograph of the Trifid nebula had, so far as I am aware, ever been published.