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What Is A Nebula?

Nifty Nebula completed poster

There are four types of nebulae that you can explore and collect for yourself using Slooh’s Online Telescope and integrated NGSS-aligned Quest learning activities. This is one of 60+ curriculum-aligned STEM Quest learning activities on Slooh for students from 4th grade to college.

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What is a Nebula?

A nebula is a large cloud made up of gas and dust in space. Until a hundred years ago, many objects observed by astronomers were classed as nebulae. Other than the stars and planets, most astronomical objects appeared as faint, fuzzy, misty clouds through their telescopes. It comes as no surprise that the word nebula is Latin for cloud or fog. There are four main types of nebulae.

Emission Nebulae are huge clouds of ionized gas that emit their own light in the same way that a neon sign glows. The nebula's gas cloud is energized by hot, young stars emitting high-energy ultraviolet radiation – invisible to your eyes.

The ultraviolet light from the hot, young, massive stars ionizes the gas clouds to create emission nebulae. However, the stars also emit lower-energy light in the visual, infrared, and radio spectra. Remember that the visual spectrum is the range of light that your eyes can detect. This visible light reflects off the dust in these enormous gas and dust clouds, and this is what we see as a Reflection Nebula.

Dark Nebulae are dense clouds of gas and dust – so dense that they obscure, or block, the starlight beyond them. There are no foreground stars close enough to energize or illuminate the side facing Earth to turn them into emission or reflection nebulae.

Planetary Nebulae are small clouds of gas surrounding a hot, old star called a white dwarf that emits its own light. The hazy vaporous sphere of gas is composed of the old stellar layers of a once young star, and it glows because of the ultraviolet energy from its central white dwarf star – the old stellar core – in the last stages of its life.


More About Slooh’s Nifty Nebula Quest

In this Quest, you’ll learn about and build a stunning collection of each type of nebula. You’ll start by capturing the vast, colorful clouds of dust and gas making up Emission and Reflection Nebulae before hunting down mysterious Dark Nebulae. You’ll end your exploration by capturing a star in a spectacular Planetary Nebula at the end of its life.

Learning Objectives

By the end of this Quest, students will be able to answer the following questions:

  • What are the four classes of nebulae found in the Universe and how are they giving off light?

  • How do light waves reflect, absorb, and transmit through clouds in space?

  • How does the light energy travel from the nebula in space to our eyes?

Vocabulary Words

Standards Addressed

NGSS Performance Expectations


NGSS Science & Engineering Practices

Developing and Using Models; Analyzing and Interpreting Data; Obtaining, Evaluating, and Communicating Information

NGSS Disciplinary Core Ideas

​PS4.B, PS3.A, PS3.B

NGSS Crosscutting Concepts

Scale, Proportion, and Quantity; Energy and Matter; Cause and Effect


​RST.9-10.1, RST.9-10.2, RST.9-10.3, RST.9-10.4, RST.9-10.5, RST.9-10.7, RST.9-10.9, RST.9-10.10, WHST.9-10.2.B, WHST.9-10.2.D, WHST.9-10.2.E, WHST.9-10.2.F

More About Slooh’s Astronomy NGSS Aligned Learning Activities

Slooh’s Online Telescope is a learning platform designed to support any educator in teaching astronomy to meet NGSS requirements by collecting and analyzing real-world phenomena. No previous experience with telescopes is necessary to quickly learn how to use Slooh to explore space with your students.

You can join today to access Slooh's Online Telescope and all 60+ Quest learning activities if you are able to make astronomy a core subject of study for the semester or year. If you only have a few weeks to study astronomy, we also have a curriculum designed to fit your busy academic schedule and budgetary limitations. To learn more about our offers, click here.