Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

December 8, 1997
See Explanation.  Clicking on the picture will download 
 the highest resolution version available.

The Trifid Nebula in Red, White and Blue
Credit & Copyright: Jason Ware

Explanation: Three dark dust lanes give the picturesque Trifid Nebula its name. The red and blue colors of the Trifid Nebula are present in different regions and are created by different processes. A big bright star near the center of the red region appears white hot and emits light so energetic it knocks electrons away from gas surrounding it. When an electron is recaptured by a proton, red light is frequently emitted. The blue region is centered on another bright star but this region's dust reflects light to us. The two regions are thus called an emission nebula and reflection nebula, respectively. The Trifid Nebula can be seen in Sagittarius toward the Galactic Center with a small telescope.

Tomorrow's picture: Mysterious Features on Ganymede

< Archive | Index | Search | Calendar | Glossary | Education | About APOD >

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA/ GSFC
&: Michigan Tech. U.