The Dark Scorpion

These long brown streamers winding across the field are LDN 1147 and its neighbour LDN 1148, two dark nebulae in the constellation Cepheus, nicknamed here the Dark Scorpion for their shape. They belong to a small complex of molecular clouds (L1147, 1148, 1152, 1155, 1157, 1158) about 1,060 light years away. Almost nothing here shines by its own light: the cold, dense dust blocks the stars behind it, and the faint diffuse glow filling the frame is a sheet of high-latitude galactic dust, lit obliquely by the combined light of the Milky Way.

What makes LDN 1147 remarkable cannot be seen directly: its chemistry. Its densest cores are rich in carbon-chain molecules, a signature astronomers use as a clock. These molecules are abundant in gas that has not yet begun to form stars, and they vanish once a star switches on. In other words, LDN 1147 is one of the youngest dark clouds known: gas caught just before stars are born.

The rest of the complex tells the next chapters of the story. Close by, in LDN 1148, hides one of the smallest known protostars: an object barely switched on, so faint it may only ever become a brown dwarf. And in LDN 1157, a buried young star drives two jets of matter, one of the most studied molecular outflows in the sky. None of these newborn objects is visible in ordinary light, sealed inside the dust, but they all belong to the same cloud: a genuine timeline of star formation, from sleeping gas to an already active star. Finally, tucked into the lower-right corner sits a far more distant intruder: NGC 6911, a faint background barred spiral galaxy.

Photographing a field like this is an exercise in patience. The dark dust and the reflected veil are very faint targets set against an already bright sky: the whole challenge is to bring out the brown tones without erasing them. The image totals 7 h 20 min of broadband exposure, acquired remotely from Texas.