The Horsehead Nebula, B33, is the dark nebula in front of the bright red emission nebula IC 434. Along with the Orion Nebula, these nebulae near the Horsehead are part of a very large complex that is a stellar nursery where stars are forming out of the dust and gas. Located about 1,500 light years away, this complex is the closest star forming region to our own solar system. The Flame Nebula, NGC 2024, is to the lower left of Alnitak, Zeta Orionis, the easternmost star in the three distinctive stars in the Hunter's belt of Orion, and the brightest star in this photo. To the lower left of the Horsehead is the blue reflection nebula NGC 2023. Dark Nebulae are clouds of dust in space that obscure the stars behind them. Emission nebulae are clouds of glowing ionized gas. Reflection nebulae do not shine by their own light, but are visible because they reflect the light of nearby stars.