Astro 7N: The Artistic Universe - Unit 4 Review Flashcards

Flashcards covering key vocabulary and concepts from Unit 4 of the Astro 7N course, focusing on astronomy topics such as star clusters, galaxies, dark matter, and the universe's expansion.

Open Star Clusters

Cluster of hundreds to thousands of stars that formed at the same time from the same gas and dust cloud.

Globular Star Clusters

Dense collections of hundreds of thousands to millions of stars, typically older with yellow color, containing many red giants.

Planetary Nebulae

Formation that occurs when a low-mass star runs out of nuclear fuel and ejects its outer layers, leaving a white dwarf at the center.

Novae

A star explosion caused by mass transfer from a binary companion onto a white dwarf, leading to periodic brightening.

Supernovae

Cataclysmic explosions at the end of a massive star's life, with Type II involving massive stars and Type Ia arising from white dwarfs.

Hubble's Law

A law that states the farther away a galaxy is, the faster it appears to be moving away from us, with a relationship defined by v = H0 × D.

Dark Matter

Invisible matter that makes up about 24% of the universe, inferred through gravitational effects on visible matter.

Dark Energy

A mysterious force comprising about 71% of the universe, associated with the acceleration of the universe's expansion.

Milky Way Galaxy

A barred spiral galaxy containing about 400 billion stars, characterized by three main components: bulge, disk, and halo.

Types of Galaxies

Galaxies are classified into types based on their shapes: spiral, elliptical, and irregular.

Galactic Center

The rotational center of the galaxy, featuring a supermassive black hole from which stellar motion is influenced.

Star-Forming Regions

Giant molecular clouds where gravity leads to the formation of new stars.

Accelerating Expansion of the Universe

The phenomenon where the rate of expansion of the universe is increasing, attributed to dark energy.

Galaxy Collision

An event where two galaxies interact gravitationally, often leading to starbursts and new star formation.

Big Bang

The event that marked the origin of the universe, approximately 13.8 billion years ago, which led to the expansion of space.