CC #38: Galaxies, part 1

What did astronomers in the early 20th century call the faint, fuzzy objects in the sky with various shapes?

• Comets

• Stars

• Planets

• Nebulae

In 1920, what was one of the competing ideas about the Universe?

• Black holes are the center of the Universe

• The Milky Way contains all of the Universe

• The Universe is static

• The Universe is infinite

Who argued that the Milky Way was all there is to the Universe?

• Edwin Hubble

• Heber Curtis

• Harlow Shapley

• Isaac Newton

What type of stars did Edwin Hubble and Milton Humason observe in the Andromeda Nebula which allowed them to determine how far away it is?

• White dwarfs

• Cepheid variables

• Red giants

• Neutron stars

How far away did Hubble and Humason measure Andromeda to be?

• 100,000 lightyears

• 900,000 lightyears

• 1,800,000 lightyears

• 2,500,000 lightyears

What are the four major types of galaxies?

• Active, Passive, Dormant, Dead

• Elliptical, Spiral, Peculiar, Irregular

• Circular, Rectangular, Triangular, Hexagonal

• Red, Blue, Yellow, Green

What characteristic do spiral galaxies have?

• They are the smallest type of galaxies

• They have a central bulge and rotating disks

• They consist only of gas and no stars

• They are completely shapeless

How do astronomers think elliptical galaxies form?

• From the remnants of supernovae

• From the accumulation of dark matter

• By galactic collisions

• It is the natural evolution of individual galaxies to end up as ellipticals

Which of the following does NOT regularly occur when galaxies collide?

• The stars inside the two galaxies collide and explode

• The nebulae in the two galaxies merge and trigger new star formation

• The gravitational interactions tear the galaxies apart and distort their shapes

• They eventually merge and form new types of galaxies

What is a peculiar galaxy?

• A galaxy with an odd or distorted shape due to collisions

• A galaxy that does not emit any light

• A galaxy made entirely of dark matter

• A galaxy with a stable and regular shape