20. The one component of the material of the Milky Way Galaxy thatprevents us fr
ID: 1672090 • Letter: 2
Question
20. The one component of the material of the Milky Way Galaxy thatprevents us from seeing and photographing the galactic center atoptical wavelengths isAvery cold hydrogengas.
Binterstellardust.
Cthe glare of light fromnearby stars.
Dhot hydrogen gas. 21. Radio waves of 21-cm wavelength originate from which componentof the interstellar medium?
ACool, carbonmonoxide, CO.
BCold, molecular hydrogen,H2.
CHot, ionized atomichydrogen.
DCool, neutral atomichydrogen. 22. The dimensions of the disk of our Milky Way Galaxyare
Adiameter 10,000light-years; thickness, 28,000 light-years.
Bdiameter 2000light-years; thickness, 100,000 light-years.
Cdiameter 28,000light-years; thickness 2000 light-years.
Ddiameter 150,000light-years; thickness, 2000 light-years. 23. Cepheid variable stars are invaluable in astronomy because ofthe close relationship between
Athe peak wavelengthof their spectra and their surface temperatures.
Bthe red shift of theirspectrum and their distance from the Sun.
Ctheir apparent magnitudeand their pulsation period.
Dtheir luminosity, orabsolute magnitude, and their pulsation period. 24. The event that settled the Shapley-Curtis debate about "spiralnebulae" was
AEdwin Hubblemeasuring the distance to the Andromeda galaxy.
BEdwin Hubble showing thatthe universe was expanding.
CAlbert Einstein showingthat gravity can bend the path of light.
DArno Penzias and RobertWilson detecting the cosmic microwave background radiation. 25. Which of the following could explain the rotation curve of theMilky Way?
AA large amount ofdark matter.
BA large amount of darkenergy.
CA small modification toNewton's law of gravity.
DA and B.
EA and C.
Explanation / Answer
20. The one component of the material of the Milky Way Galaxy thatprevents us from seeing and photographing the galactic center atoptical wavelengths is Avery cold hydrogengas. Binterstellardust. Cthe glare of light fromnearby stars. Dhot hydrogengas. 21. Radio waves of 21-cm wavelength originate from which componentof the interstellar medium? ACool, carbonmonoxide, CO. BCold, molecular hydrogen,H2. CHot, ionized atomichydrogen. DCool, neutralatomic hydrogen. 22. The dimensions of the disk of our Milky Way Galaxyare ( 100,000 l-y x 1,000 l-y) Adiameter 10,000light-years; thickness, 28,000 light-years. Bdiameter 2000light-years; thickness, 100,000 light-years. Cdiameter 28,000light-years; thickness 2000 light-years. Ddiameter 150,000light-years; thickness, 2000 light-years. 23. Cepheid variable stars are invaluable in astronomy because ofthe close relationship between Athe peak wavelengthof their spectra and their surface temperatures. Bthe red shift of theirspectrum and their distance from the Sun. Ctheir apparentmagnitude and their pulsation period. Dtheir luminosity, orabsolute magnitude, and their pulsation period. 24. The event that settled the Shapley-Curtis debate about "spiralnebulae" was AEdwin Hubblemeasuring the distance to the Andromeda galaxy. BEdwin Hubble showing thatthe universe was expanding. CAlbert Einstein showingthat gravity can bend the path of light. DArno Penzias and RobertWilson detecting the cosmic microwave backgroundradiation. 25. Which of the following could explain the rotation curve of theMilky Way? AA largeamount of dark matter. BA large amount of darkenergy. CA small modification toNewton's law of gravity. DA and B. EA and C.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.