Astronomy Picture of the Day

Explanation: Can you see nebulas in other galaxies? Yes, some nebulas shine brightly enough -- if you know how to look. Clouds of hydrogen and oxygen emit light at very specific colors, and by isolating them, astronomers and astrophotographers can reveal structures that would otherwise be too faint to notice. This deep, 50-hour exposure highlights glowing hydrogen (red) and oxygen (blue) across galaxy NGC 55, viewed nearly edge-on. Also known as the String of Pearls Galaxy, NGC 55 is often compared to our Milky Way's satellite galaxy the Large Magellanic Cloud (LMC), although NGC 55 lies much farther away at about 6.5 million light-years. The resulting image uncovers a sprinkling of emission nebulas within and sometimes above the galaxy's dusty disk, offering a detailed look at distant star-forming regions.