Deck 73: Gas and Dust in the Milky Way

Question 1

The Pleiades show the characteristic blue color of ___________________ .

A) a reflection nebula
B) an emission nebula
C) a dark nebula
D) an HII region

Answer 1

a reflection nebula

Question 2

Cold hydrogen gas produces ____ electromagnetic radiation by its spin flip.

A) 21 m
B) 21 mm
C) 21 cm
D) 21 km

Answer 2

21 cm

Question 3

When light travels through thick dust and gas and all visible light is stopped, this is known as _____.

A) reddening
B) bluing
C) extinction
D) absorption

Answer 3

extinction

Question 4

As light travels through dense gas, the gas scatters the blue waves and the light slowly ______.

A) blues
B) X-rays
C) reddens
D) shortens

Question 5

Gas and dust between the stars is called the ____.

Question 6

_______________ occurs when material near the star cast shadows on gas farther away.

Question 7

An HII region is cold hydrogen.

Question 8

An HI region is ionized hydrogen.