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Question 7 1 observation of the different components

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QUESTION 71.Observation of the different components of the Milky Way galaxyindicates that thespiral armscontain very different populations of stars andother material from those inglobular clusters. In what way are theydifferent?Spiral arms contain young stars, dust and gas within which starformation continues, whereas globular clusters contain older starpopulations, with no dust, gas or on-going star formation.Globular clusters contain dust and gas and are the only locations wherestar formation continues in the galaxy at the present time. The olderstars in the spiral arms have no surrounding dust or gas.Both spiral arms and globular clusters contain about the samepopulations of stars both young and old but, in contrast to the spiralarms, there is no dust, gas, star formation, or nova explosions in globular
clusters.Spiral arms contain older, more developed, and hence brighter and bluerstars, whereas globular clusters are composed largely of young, red starsin the early stages of formation and development.2 pointsQUESTION 81.The cosmological redshift of the light from very distant galaxies iscaused by
2 pointsQUESTION 91.How many quarks are there in a proton (or a neutron)?
2 pointsQUESTION 101.In cosmology, the phrase “critical density” refers to thesmallest density that will produce inflation of the universe.density below which stars will never form.density above which the universe is opaque to radiation.density needed to produce precisely flat space, on average,throughout the universe.
2 pointsQUESTION 111.For which objects in the universe has the Hubble relation been shownto hold experimentally?only stars in the near neighborhood of the Sun, in ourgalaxy
distant galaxies onlygalaxies in the Local Group, in the near vicinity of the MilkyWayall objects in the universe, from planets and stars out to thefarthest galaxies2 pointsQUESTION 121.Interstellar matter blocks our view of the disk of our Galaxynot at all at any wavelength.more-or-less equally at all wavelengths from radio waves to light waves.most at radio wavelengths, where hydrogen absorbs radio wavesefficiently, and least at optical wavelengths.more at optical wavelengths, less in the infrared, and not at all at radiowavelengths.
2 points

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Term
Spring
Professor
Kelley Davis
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