C11. The question regarding why galaxies have differentshapes relates to both the origin and evolution of agalaxy. These in turn depend on a variety of factorssuch as how large a particular proto-galaxy was, howmany neighboring galaxies are formed (cluster), therotation rate of the proto-galaxy, how quickly starsform, how many collisions the galaxy experiences,and other properties. The importance of any onefactor is under active research. Complete parts a-gof this question.a. The drawings below represent a side view offour different rotating protogalaxies. Assumingthat each one started out approximatelyspherical in shape, and considering that the rateof rotation influences the shape, put in a numberfrom 1-4 below each diagram starting with Ifor the slowest rotation.positions of stars at different distances from thenucleus of the galaxy. Assume the motion ofstars at A, B and C are such, that the time it takesA to go around the nucleus once, B goes aroundtwice, and C goes around four times. Diagram2 illustrates the positions of stars A, B and Cafter A has gone 4 of a rotation. Note that in thesame time, stars at B have gone twice as faralong their orbit and stars at C, 4 times as far.By connecting the stars at their new positionsand intermediate points between these stars, thespiral structure for one arm of the galaxybecomes apparent. Applying these ideas, drawthe shape of the spiral arm, on diagram 3, afterstars originally at position A have moved halfway around the galaxy.AxisofRotationAxisofRotationb. If rotation is an important protogalaxy property,which type of Hubble class galaxy represents thefastest protogalaxy rotation rate?c. One theory regarding the differences in thesub-classes of spiral galaxies is based on thehypothesis that protogalaxies are approximatelyspherical in shape. The differences subsequent-ly develop as star formation begins in theprotogalaxy. The cause of the differences is thatstars tend not to loose their space motionperpendicular to the "equator" of the galaxybecause of their mass and relatively small size.Thus the motion of stars "remembers" theearlier distribution of mass in the protogalaxy.However, until the dust and gas form stars, it caninteract, loose this perpendicular motion andform a disk. Of the galaxies in images B, F andI on the Supplementary Data Sheet, which mostlikely experienced the earliest star formation?d. Two natural types of rotation are: 1) rigid bodyrotation in which all parts of an object have thesame period of rotation, and 2) differentialrotation in which the rotational period decreasesas we go away from the center of rotation. Indiagram 1, in the next column, A, B and C areshown in a straight alignment representing the3e. Which of the drawings below best represents thespiral structure of the galaxy in part d after onerotation of star A? Note that two spiral arms.have been illustrated in each diagram.f. Most spiral galaxies only show 1 to 1½rotations of the spiral arms, but the universe isknown to be old enough for most regions ofouter stars of spiral galaxies to have completedmore than five rotations. Explain why thisobservation proves differential rotation is not thecause of a spiral pattern.g. The diagrams below show the results of a com-puter calculation showing the close approach oftwo normal galaxies. Which galaxy on the backof the Supplemental Data Sheet looks the mostlike the result of this simulated near miss?3(A. and Toome)(AD Hale O8

Question

C11. The question regarding why galaxies have differentshapes relates to both the origin and evolution of agalaxy. These in turn depend on a variety of factorssuch as how large a particular proto-galaxy was, howmany neighboring galaxies are formed (cluster), therotation rate of the proto-galaxy, how quickly starsform, how many collisions the galaxy experiences,and other properties. The importance of any onefactor is under active research. Complete parts a-gof this question.a. The drawings below represent a side view offour different rotating protogalaxies. Assumingthat each one started out approximatelyspherical in shape, and considering that the rateof rotation influences the shape, put in a numberfrom 1-4 below each diagram starting with Ifor the slowest rotation.positions of stars at different distances from thenucleus of the galaxy. Assume the motion ofstars at A, B and C are such, that the time it takesA to go around the nucleus once, B goes aroundtwice, and C goes around four times. Diagram2 illustrates the positions of stars A, B and Cafter A has gone 4 of a rotation. Note that in thesame time, stars at B have gone twice as faralong their orbit and stars at C, 4 times as far.By connecting the stars at their new positionsand intermediate points between these stars, thespiral structure for one arm of the galaxybecomes apparent. Applying these ideas, drawthe shape of the spiral arm, on diagram 3, afterstars originally at position A have moved halfway around the galaxy.AxisofRotationAxisofRotationb. If rotation is an important protogalaxy property,which type of Hubble class galaxy represents thefastest protogalaxy rotation rate?c. One theory regarding the differences in thesub-classes of spiral galaxies is based on thehypothesis that protogalaxies are approximatelyspherical in shape. The differences subsequent-ly develop as star formation begins in theprotogalaxy. The cause of the differences is thatstars tend not to loose their space motionperpendicular to the &#34;equator&#34; of the galaxybecause of their mass and relatively small size.Thus the motion of stars &#34;remembers&#34; theearlier distribution of mass in the protogalaxy.However, until the dust and gas form stars, it caninteract, loose this perpendicular motion andform a disk. Of the galaxies in images B, F andI on the Supplementary Data Sheet, which mostlikely experienced the earliest star formation?d. Two natural types of rotation are: 1) rigid bodyrotation in which all parts of an object have thesame period of rotation, and 2) differentialrotation in which the rotational period decreasesas we go away from the center of rotation. Indiagram 1, in the next column, A, B and C areshown in a straight alignment representing the3e. Which of the drawings below best represents thespiral structure of the galaxy in part d after onerotation of star A? Note that two spiral arms.have been illustrated in each diagram.f. Most spiral galaxies only show 1 to 1½rotations of the spiral arms, but the universe isknown to be old enough for most regions ofouter stars of spiral galaxies to have completedmore than five rotations. Explain why thisobservation proves differential rotation is not thecause of a spiral pattern.g. The diagrams below show the results of a com-puter calculation showing the close approach oftwo normal galaxies. Which galaxy on the backof the Supplemental Data Sheet looks the mostlike the result of this simulated near miss?3(A. and Toome)(AD Hale O8

Accepted Answer

Due to a multitude of characteristics such as their creation history, interactions with neighbouring…