Let's Be Clear About Nebulae Trivia Quiz

Answer: Hydrogen

Like stars and the interstellar medium (ISM), which is all the matter between stars, nebulae are mostly made up of hydrogen. Helium is typically the next most common constituent because it is the second most common element in the universe. Up to about 1% of a nebula may be interstellar dust particles made up of silicates (similar to sand) and soot (similar to diesel exhaust).

"The stuff that dreams are made of" is a line of dialogue from the film "The Maltese Falcon" (1941).

Answer: False

Nebulae are indeed denser visible regions of the (ISM). However, the (ISM) makes up 10 to 15% of the mass in the visible Milky Way galaxy. Although the ISM is very low in density, the amount of space between stars is enormous so the matter in these vast regions adds up.

Answer: True

The French astronomer Charles Messier compiled the first extensive catalogue of "nebulous" objects in the sky. What are now known as Messier objects are a set of 110 astronomical objects listed in the "Catalogue des Nébuleuses et des Amas d'Étoiles" ("Catalogue of Nebulae and Star Clusters") with the preliminary edition published in 1774. Messier was primarily interested in finding comets and the objects in the catalogue were fuzzy images which were not comets. The designations from his catalogue are still in use today, such as M31 for the Andromeda galaxy.

The studies of the renowned astronomer Edwin Hubble (1889-1953) were critical in explaining the vast and varied nature of the universe. His meticulous studies of what were known as spiral nebulae proved that these objects are galaxies, such as Andromeda, outside of own Milky Way galaxy.

Answer: True

Stars evolve to different endings based on their mass. One of the possible endings is a supernova explosion. After the explosion, the material from the explosion may then collapse into a neutron star or black hole. Alternatively, the material may continue to expand, forming a diffuse nebula. This is one of several processes which can form nebulae.

The Crab Nebula was the first astronomical object recognized as being connected to a supernova explosion. In the early 1900s, analysis of photographs of the nebula over previous years revealed that it was expanding. Tracing the size backwards in time indicated that the nebula was likely from a supernova explosion which should have been visible on Earth about 900 years before. Historical records revealed that a new star, bright enough to be seen in the daytime, had been recorded in the corresponding part of the sky by Chinese astronomers in 1054.

The Crab Nebula is the first object listed in Messier's catalogue of nebulae and therefore has the designation M1.

Answer: False

Because there are several processes which form nebulae, their size varies greatly. Our solar system is roughly two light-years (about 19 trillion kilometers or 12 trillion miles) in diameter. The size of the Crab Nebula is approximately 11 light-years.

The largest known nebula, the NGC 262 Halo Cloud (NGC stands for The New General Catalogue of Nebulae and Clusters of Stars), surrounds a large galaxy and is 1.3 million light-years in size!

Answer: 1600s

The Orion Nebula is one of the brightest nebulae in the night sky and is visible to the naked eye. It is located in the constellation of Orion and is considered to be the middle object in the sword of Orion.

The discovery that the Orion Nebula is a diffuse object rather than a star is generally credited to French astronomer Nicolas-Claude Fabri de Peiresc when he made a record of observing it with a refracting telescope in 1610. The first published observation of the nebula was by Johann Baptist Cysat of Lucerne in his 1619 monograph on comets.

Answer: William Herschel

"The Catalogue of Nebulae and Clusters of Stars" was first published by William Herschel in 1786 and initially contained records of 1,000 objects based on the observations of him and his sister Caroline. In 1789, another 1,000 entries were added and, in 1802, 500 more entries were added bringing the total number of objects in the catalogue to 2,500.

Christiaan Huygens (1629-1695) improved the design of telescopes, studied the rings of Saturn and discovered its largest moon, Titan.

Johannes Kepler (1571-1630) is best known for formulating the laws of planetary motion and he also invented an improved version of the refracting telescope.

Edmond Halley (1656-1742) recorded a transit of Mercury across the Sun and computed the periodicity of a comet. It was named after him upon its predicted return in 1758 which he, unfortunately, did not live to see.

Answer: False

Two kinds of nebulae are emission nebulae, which emit light, and reflection nebulae, which reflect the light of nearby stars. So not all nebulae predominantly emit light themselves.

Emission nebulae emit light due to energized gasses, especially hydrogen. Some are also known as H II regions because of hydrogen emissions of light. The discovery that nebulae can emit light was made by William Huggins, with his wife Margaret, beginning in 1864 using spectral analysis. Emission nebulae have a predominance of specific colors of light which are emitted by gasses, such as hydrogen, when they drop from higher energy states back down into lower energy states.

Reflection nebulae have a more continuous spectrum because they are reflecting the white light of stars.

Answer: True

A dark nebula, or absorption nebula, is a region of interstellar matter (ISM) that is dense enough that it obscures the light from objects behind it. Dark nebulae occur in molecular clouds (so called because they contain molecules, especially molecular hydrogen) which are cooler regions of the ISM distinct from more energetic areas that have predominantly ionized gas.

The light is absorbed by dust grains, often coated with frozen carbon monoxide and nitrogen, located in the coldest densest parts of the region. Isolated small dark nebulae were first observed by Bart Bok in the 1940s and are known as Bok globules.

Answer: True

At an age of about 7 billion years, the Sun will have expanded in size and brightness to the point of becoming a red giant star. At the same time, the Sun's core will contract and heat up. When the core temperature reaches about 100 million K, the helium will begin to fuse into carbon.

The ignition of helium fusion is a sudden and explosive event known as the helium flash. This will release huge amounts of energy and raise the core temperature to about 300 million K. Furthermore, as much as one-third of the Sun's mass will be hurled out into space forming what is called a planetary nebula. The term planetary nebula is a misnomer since it has nothing to do with planets. Because it is largely made up of ionized gas, a planetary nebula is a type of emission nebula.

One example of a planetary nebula is the Cat's Eye Nebula in the constellation Draco which was the first planetary nebula to be observed with a spectroscope by William Huggins in 1864. His spectrographic findings showed that it is an emission nebula.