Key Terms

By Formative Library

Last updated over 2 years ago

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cold dark matter
slow-moving massive particles, not yet identified, that don’t absorb, emit, or reflect light or other electromagnetic radiation

cosmological principle
the assumption that, on the large scale, the universe at any given time is the same everywhere—isotropic and homogeneous

dark energy
an energy that is causing the expansion of the universe to accelerate; the source of this energy is not yet understood

evolution (of galaxies)
changes in individual galaxies over cosmic time, inferred by observing snapshots of many different galaxies at different times in their lives

galactic cannibalism
a process by which a larger galaxy strips material from or completely swallows a smaller one

homogeneous
having a consistent and even distribution of matter that is the same everywhere

hot dark matter
massive particles, not yet identified, that don’t absorb, emit, or reflect light or other electromagnetic radiation; hot dark matter is faster-moving material than cold dark matter

isotropic
the same in all directions

Local Group
a small cluster of galaxies to which our Galaxy belongs

merger
a collision between galaxies (of roughly comparable size) that combine to form a single new structure

starburst
a galaxy or merger of multiple galaxies that turns gas into stars much faster than usual

supercluster
a large region of space (more than 100 million light-years across) where groups and clusters of galaxies are more concentrated; a cluster of clusters of galaxies

void
a region between clusters and superclusters of galaxies that appears relatively empty of galaxies

Please take the time to check out the source for this material from Openstax if you plan to use this in your lesson plan!: https://openstax.org/books/astronomy/pages/28-key-terms