Question 1

Which telescope imaged the center of the Milky Way Galaxy at a wavelength of 8 microns to reveal the distribution of the dusty interstellar medium?

Accepted Answer

A)  Spitzer Space Telescope 
B)  infrared telescope 
C)  European Southern Observatory 
D)  X-ray telescope 
E)  radio telescope

Question 2

H I clouds can be observed using _____.

Accepted Answer

A)  optical telescopes above the earth's atmosphere 
B)  21-cm radiation 
C)  x-ray radiation 
D)  infrared radiation 
E)  ultraviolet radiation

Question 3

The interstellar medium is composed of mainly _____.

Accepted Answer

A)  equal parts of gas and dust 
B)  mostly dust and some gas 
C)  mostly gas and some dust 
D)  dust only 
E)  gas only

Question 4

Molecules in the interstellar medium emit radiation at what wavelengths?

Accepted Answer

A)  radio 
B)  microwave 
C)  visible light 
D)  ultraviolet 
E)  X-ray

Question 5

Match between columns Premises: A chaotic shape that is usually twisted, flattened, and tangled Highly ionized state The hot space of ISMs with temperatures of a few thousand K and a density of only 0.1 atom per cubic centimeter found between the cool H I clouds Clouds of gas and dust with densities ranging from 100s-1000s particles per cubic centimeter, found deep inside the ISM, where it is protected from UV photons ISM clouds of cool gas of only about 100 K and dust with densities ranging up to 100 atoms per cubic centimeter and observed only at infrared and radio wavelengths The coolest temperature The part of the ISM that can only be detected with X-ray telescopes have has temperatures of 10 ⁶ K or higher

Accepted Answer

The Answer of H I cloud and Molecular clouds and is...

Question 6

Observing at a wide range of wavelengths, astronomers have detected more than ______ different molecules in the ISM.

Accepted Answer

A)  10 
B)  20 
C)  50 
D)  100 
E)  150

Question 7

Which mission is mapping the heliosphere's boundary?

Accepted Answer

A)  Cassini-Huygens 
B)  Interstellar Boundary Explorer 
C)  Voyager I 
D)  Voyager II 
E)  Kepler

Question 8

Which type of nebula is produced when a star, hotter than 25,000 K, excites the gas near it to produce an emission spectrum producing a distinctive pink color?

Accepted Answer

A)  emission nebulae 
B)  H I 
C)  reflection nebulae 
D)  dark nebulae 
E)  spectral type B6

Question 9

The ground state of hydrogen has two closely-spaced energy levels, where oneelectron is spinning up and the other is spinning down. This energy transition corresponds to releasing excess energy as a photon at what wavelength?

Accepted Answer

A)  21 centimeters 
B)  21 millimeters 
C)  21 meters 
D)  22.2 centimeters 
E)  22.2 millimeters

Question 10

______________ are cool, with temperatures of about 100 K and densities of ten to a few hundreds of atoms per cubic centimeter.

Accepted Answer

The answer of ______________ are cool, with temperatures of about...

Question 11

Interstellar extinction and the reddening of light by the interstellar medium (ISM) are both caused by _____.

Accepted Answer

A)  atoms and molecules in the ISM 
B)  only  atoms in the ISM 
C)  only molecules in the ISM 
D)  only dust in the ISM 
E)  dust, atoms and molecules of the ISM

Exam 10: The Interstellar Medium