Astronomy Picture of the Day

Explanation: The beautiful Trifid Nebulais a cosmicstudy in contrasts.Also known as M20,it lies about 5,000 light-years away toward thenebula rich constellation Sagittarius.A star forming region in the plane of our galaxy,the Trifid does illustrate three different types ofastronomical nebulae;red emission nebulae dominated bylight from hydrogen atoms,blue reflection nebulae producedby dust reflecting starlight, anddark nebulae wheredense dust clouds appear in silhouette.But, the red emission region roughly separated into threeparts by obscuring dust lanes is what lends the Trifid itspopular name.Pillars and jets sculpted by newborn stars, above and right ofthe emission nebula's center, appear in famous Hubble Space Telescopeclose-up images of the region.The Trifid Nebula is about 40 light-years across.Too faint to be seen by the unaided eye, in this deep telescopic viewit almost covers the area of a full moon on planet Earth's sky.