From the June 2009 issue

What determines the particular shape of nebulae like the Dumbbell, Trifid, and Lagoon?

Cristian Lares, Goldsboro, North Carolina
By | Published: June 22, 2009 | Last updated on May 18, 2023

Key Takeaways:

August 2009 Trifid Nebula
In the Trifid Nebula (M20), three dense dust lanes cut across glowing gas clouds. The combination creates the object’s distinctive appearance.
Jim and Janet Castano/Adam Block/NOAO/AURA/NSF

A nebula is a vast cloud of gas and dust. The physical processes that shape its appearance differ depending on whether it is an emission nebula or a planetary nebula.