Chapter 30 Galaxies and the Universe

Front

What is an elliptical galaxy?

Back

A type of galaxy characterized by an oval shape, with stars distributed in a smooth, featureless manner and little to no ongoing star formation.

Front

What is dark matter?

Back

Matter that emits no light at any wavelength, making it invisible and detectable only through its gravitational effects.

Front

What cluster is the Milky Way a member of?

Back

The Local Group, which is a collection of more than 50 galaxies including the Milky Way and Andromeda.

Front

What is a blue shift in the context of astronomy?

Back

A phenomenon where light from an object moving toward an observer shifts to shorter wavelengths, indicating the object is approaching.

Front

What is a spiral galaxy?

Back

A type of galaxy characterized by a flat, rotating disk containing stars, gas, and dust, with spiral arms extending outward.

Front

What is a quasar?

Back

An extremely luminous active galactic nucleus powered by a supermassive black hole, emitting vast amounts of energy.

Front

What is the significance of the Local Group?

Back

It is the galaxy group that includes the Milky Way, Andromeda, and several other smaller galaxies, providing insight into galaxy formation and evolution.

Front

What is the difference between active and inactive galaxies?

Back

Active galaxies have high-energy emissions and often host supermassive black holes, while inactive galaxies do not exhibit such energetic phenomena.

Front

What is the role of dark energy in the universe?

Back

Dark energy is a mysterious force that is driving the accelerated expansion of the universe.

Front

What are the main types of galaxies?

Back

The main types of galaxies are spiral, elliptical, irregular, and active galaxies.