“And god said, let there be light, and there was light;
And god said that the light was good;
And he separated light from darkness.
He called the light day, and the darkness night.”

Mark Jacobson
“Middle Light”
digital photograph

Alison Doane
Curator of Astronomical Photographs at the 
Harvard College Observatory
Orion Nebula


Nebula are earliest stages of star formation made up of dust, hydrogen, helium gas, and plasma. Nebula are formed when portions of the relationships between stars collapse and clump together due to the gravitational attraction of the particles that comprise them. It is this dispersed matter that eventually collapses and forms a nebula. They are the starting and end points of stellar evolution in a nebula-star-nebula cycle.

Before the first matter that could be called the earth gathered within our solar nebula at an outer arm of the milky way, five to fifteen billion years and billions of coalescing events forming the stars of the universe had already occurred. Early earth was hot, with volcanic eruptions releasing carbon dioxide, water vapor, and nitrogen into the early atmosphere. It was lifeless for many millions of years. Rain fell, and water began the work of erosion, wearing away the igneous rocks and slowly dissolving some of the chemicals on the rock surfaces. Rivers carried the chemicals into the seas, and the chemicals were mixed and stirred in the water. Also present were lightening, volcanic activity, and ultraviolet radiation.