Some of the most beautiful objects in the night sky are the various types of planetary, diffuse, and reflection nebulae that adorn it. But beyond just pure aesthetics, nebulae serve as seeds for heavy elements that propel the life cycles of stars. As stars end their stable period of fusing hydrogen into helium and then ever-heavier elements through the periodic table, they finally shed their outer layers, creating vast shells of gas that lay the foundation for the next round of stars, planets, and, in one case that we know of, life.
10. The Lagoon Nebula
This is a rich star-forming region about 5,000 light years distant toward the galactic core in the constellation Sagittarius. Many of the events at the center of our galaxy are hidden from view by interstellar dust, but the Lagoon Nebula is an active stellar nursery that we can actually peer into. An emission nebula, the Lagoon spans an estimated 50 light years across.
9. The Crab Nebula
When Charles Messier created the first systematic survey of deep-sky objects in the 18th century, he gave this fuzzy smudge in the constellation Taurus the designation of M1. We now know, however, that this nebula hosted a violent supernova observed by Chinese astronomers in 1054 A.D. This nebula also contains a pulsar, a super-dense, swiftly spinning neutron star remnant of that cataclysmic event.
8. The Eskimo Nebula
Also known as the Clown-face Nebula, this colorful ball of expanding gas in the constellation Gemini was first identified by William Herschel in 1787. The name planetary nebula was given to this sub-class of objects because their disk-like appearance through the telescope was similar to that of planets in our solar system. The Eskimo Nebula, like the Crab, is also very young, at an estimated 10,000 years of age; the progenitor star is also similar to our own Sun, and it’s sobering to think that our own solar system may take on a similar appearance in its death throes, billions of years from now.
7. The Helix Nebula
This is another fine example of a planetary nebula and is visually one of the largest in the sky, located in the constellation Aquarius. This is because the Helix Nebula is one of the closest to Earth at about 700 light years distant and about 2.5 light years across. We see the helix shape only because of our vantage point in time & space; viewed from the side, other planetary nebulae can take on a diffuse or hourglass shape.
6. The Tarantula Nebula
One of the most picturesque objects in the southern skies, the Tarantula Nebula is an immense star-forming region in the Large Magellanic Cloud, a satellite of our own Milky Way galaxy. For some idea of scale, if the Tarantula Nebula was moved in to the distance of the Helix Nebula, it would cover over half the sky from horizon to zenith. The Tarantula Nebula also hosted one of the closest and well studied of recent supernovae in 1987.
5. The Owl Nebula
Most nebulae only have Messier or NGC/IC catalogue designations, terms that mean little to those outside the world of astronomy; a scant few nebulae with unique properties, such as those on this list, boast more descriptive names. In the case of the Owl Nebula in Ursa Major, the immediate impression through the telescope is a ghostly ball with two mottled eyes. Also designated M97, this is one of the tougher objects in the Messier catalog for deep-sky observers. The Owl Nebula was first noted by Pierre Mechain in 1781, and is about 2 light years in diameter located about 2,600 light-years distant.
4. The Trifid Nebula
One of the most photogenic objects in the heavens, the Trifid is a reflection/emission nebula filled with embryonic stars. Also located in the direction of the core of our galaxy, alternate dark and bright gaps give this nebula its distinctive appearance. The Hubble Space Telescope has detected ionized oxygen and sulfur atoms glowing within the nebula; the Spitzer Space Telescope has peered even further into the infrared spectrum to reveal over 100 new stars embedded within the Trifid Nebula just beginning to shine. Again, nebulae tell us something very fundamental not only about our future, but our past as well; our Sun and present solar system had its beginnings in some far-off unnamed nebula perhaps very similar to the Trifid.
3. The Cat’s Eye Nebula
One of the most beautiful nebulae to happen upon in the eyepiece is NGC 6543, or the Cat’s Eye Nebula located in the rambling constellation Draco. Also a planetary nebula, it derives its name from its lenticular appearance. But did you know that we only see a small bright portion of its inner structure? The Hubble and Spitzer space telescopes have revealed that the Cat’s Eye Nebula is actually embedded in a larger, spiraling structure. How this intricate structure came to be is still unclear… why do some planetary nebulae release homogenous shells, while others have a fine, interlaced structure?
2. The Eagle Nebula
This nebula has given us one of the most enduring astronomical images of our time: the “Pillars of Creation” as seen by the revitalized Hubble Space Telescope. Hubble gave us a poignant look at stars in the act of being born atop pillars of gas light years long. But did you know that the universe as viewed through mere human eyes is actually a very gray place? Yes, those splashy colors are real; but the night vision receptors in our eyes aren’t sensitive to their subtle amounts. Most photographs you see of nebulae are time exposures; most nebulae close up would simply appear gray-to-white.
1. The Orion Nebula
Finally, we come to one of the finest nebulae in the skies. M42, the Great Nebula located in the sword of Orion, exhibits just a tinge of green-gray coloring through a telescope. In fact, this is one of the few nebulae that may just be noticeable to the naked eye. A magnificent stellar nursery, the Orion nebula is one of the nearest active star-forming regions, only 1,500 light years distant … again you’re seeing a snapshot of what the birth of our solar system may have looked like. Looking at M42 and our night sky, sometimes I wonder which stars might have been our stellar siblings, now scattered anonymously about the disk of our galaxy.