Astronomy Picture of the Day . In the Center of the Trifid Nebula . ... Credit Copyright: GMOS , Gemini Observatory Explanation: Clouds of glowing gas mingle with lanes of dark dust in the Trifid Nebula , a star forming region toward the constellation of Sagittarius . In the center, the three huge dark dust lanes that give the Trifid its name all come together. ... The Trifid, also known as M20 , is only about 300,000 years old, making it among the youngest emission nebula known. ...