The colors around Rho Ophiuchi
All the colors of the Cosmos in one image. The region around Antares (the brightest star, below) and Rho Ophiuchi (above) is a treasure chest full of colorful gems, unique in our sky. In this image different colored stars are easily noticed (the blue ones are hotter than the red-orange ones), two globular clusters and a thick fabric of chiaroscuros in different tones. The long dark rivers are populated by very cold gas, at around -436°F, and large quantities of dust. The blue region near the top is a reflection nebula, like the one of the Pleiades. The small red region at right, on the other hand, is an emission nebula, with the typical color produced by the rearranging of hydrogen atoms (there isn’t just hydrogen, but you can only see hydrogen’s imprint: they’re two different things!). In short, the orange nebula on top of Antares is an extremely rare case of an orange reflection nebula. Usually, the gas illuminated by starlight, but not heated enough to beco...