I know many nebulas are known to have a glow from distant starlight passing through the nebula. But, I seem to recall the gas of a nebula itself may be capable of producing a glow from charged particles, as I recall. Is this correct…the glow could be from either starlight or charged gas particles?
Thanks for the refresher…
You can wind up with the expanding shell of gas from a planetary nebula plowing through the local interstellar medium. The wave front heats the gasses and produces some spectacular views.
The Orion nebula on the other hand is mainly lit by stars nestled deep inside it.
Yes, many nebula glow with the colors of ionized gas. Hydrogen, oxygen, sulfur and other ions contribute to the colors of Emission nebulas. Reflection nebulas are typically colored blue, from the scattering of starlight off cosmic dust. When neither emission or reflection provide colors you end up with a dark nebula, which is visible only when it blocks the light of more distant star fields.
Squink, IIRC the Horsehead Nebula has no distictive color. Is this an example of a dark nebula?
Yes, the Horsehead is a dark nebula. However, it’s surrounded by an emission nebula, unlike the dark cloud I linked to above.
I couldn’t see your reflection nebula image, Squink, so I found one of my own.
http://antwrp.gsfc.nasa.gov/apod/ap030721.html
A more famous example is the nebulosity surrounding the Pleiades.
http://www.seds.org/messier/more/m045_tab.html
SF worldbuilding at
http://www.orionsarm.com/main.html
That’d be because my link was busted. You picked the APOD I intended to link to.