Learning the types of nebulae enhances any astronomer’s view of the universe as it’s currently known. These vast clouds, often measuring two hundred light years across, feature a differing characteristic that help define the various types. Each nebula belongs within one of the five different types. Each type of nebulae remains visible with the correct astronomical equipment; some even remain visible to the naked human eye such as M42 just south of Orion’s Belt.
• Emission Nebulae
Emission nebulae exist as vast clouds of high temperature gas. The atoms contained within the emission nebulae cloud become energized trough the bombardment of ultraviolet light from any nearby star. This UV light forces the emission nebulae to emit radiation as they flux between higher and lower energy. Emission nebulae usually exhibit a red glow, as hydrogen (the most common element in space), glows red when charged with ultraviolet light. Often emission nebulae allow for the formation of new stars. M42 in Orion’s Belt remains a prime example.
• Reflection nebulae
Defining the beauty of Reflection nebulae focuses the fact that they’re giant clouds of dust reflecting the light of nearby stars. Reflection nebulae form the basis for the formation of new stars from the multitude of dusts present in the nebulae. Reflection nebulae remain traditionally blue as this colour travels with greater efficiency in the vacuum of space. Interestingly both reflection nebulae and emission nebulae can exist in the same confines of space. Diffuse nebulae remains the term used to describe such collaboration. The faint blue cloud surrounding Pleiades remains a prime example of reflection nebulae.
• Dark nebulae
The dark nebulae’s defined by the way it blocks light from behind the cloud in relation to the earth’s position. Often similar to reflection nebulae, dark nebulae however appear different due to the way the backlight illuminates their shapes. However the size of these nebulae indicates their sheer scale often measuring in excess of two hundred light years across. The Horsehead Nebula exists as a key example of dark nebulae.
• Planetary nebulae
These nebulae exist due to the near-death of accommodating stars. As a star reaches the end of its life the explosive starts to create a shield of gas that expels into space. Their size indicates a smaller appearance than the vast dark nebulae, often only reaching one light year across. The name “planetary nebulae” refers to the shape of the gas cloud as it travels away from the dying planet. M57 or as it’s known the “Ring Nebula” remains a key example of planetary nebulae.
• Supernova remnants (SNR)
The remnants of a supernova feature as the last type of nebulae. As a star reaches the end of its life an amazing force of energy signals the death of the star. This energy, often more powerful than the energy in a whole galaxy, lights up the universe with intense energetic forces. After the final explosion the remnants propel into space creating a supernova remnant nebulae. The average size for such nebulae remains at an average two light years across. M1 or the “Crab Nebula” remains a key example.
Understanding the difference between emission, reflection, dark, planetary, and supernova remnant nebulae helps to understand how the universe functions in the vastness of space. Exploring the nebulae with telescopes, binoculars, or even the naked eye enhances every astronomer’s wonder of the beauty of the universe as it stands today.