Astronomy Chapter 16 Flashcards

A spiral galaxy in which the spiral arms begin from the ends of a bar running through the nuclear bulge.

A collection of a few hundred to a few thousand galaxies bound by their mutual gravitational attraction.

A galaxy with an elliptical shape, little interstellar matter, and no spiral arms.

<p>A collision between two galaxies of unequal mass and size in which the smaller galaxy is absorbed by the larger galaxy.</p> Signup and view all the answers

<p>A collision and subsequent merger of two roughly equal-sized galaxies.</p> Signup and view all the answers

<p>The distortion of the appearance of an object by a source of gravity between it and the observer.</p> Signup and view all the answers

<p>A system of classifying galaxies according to their appearance into one of four broad categories: spirals, barred spirals, ellipticals, and irregulars.</p> Signup and view all the answers

<p>The constant of proportionality in the relation between the recessional velocities of remote galaxies and their distances.</p> Signup and view all the answers

<p>The recession of the galaxies caused by the expansion of the universe.</p> Signup and view all the answers

<p>The relationship that states that the speeds of remote galaxies moving away from us are directly proportional to their distances from Earth.</p> Signup and view all the answers

<p>Gas located between the galaxies within a cluster of galaxies.</p> Signup and view all the answers

<p>An unevenly distributed group of galaxies bound together by their mutual gravitational attraction.</p> Signup and view all the answers

<p>An asymmetrical galaxy having neither arms nor elliptical shape.</p> Signup and view all the answers

<p>A disk-shaped galaxy without spiral arms.</p> Signup and view all the answers

<p>The cluster of about 40 galaxies of which our own Galaxy is a member.</p> Signup and view all the answers

<p>A cluster of galaxies with only a few galaxies.</p> Signup and view all the answers

<p>An evenly distributed group of galaxies bound together by mutual gravitational attraction.</p> Signup and view all the answers

<p>A cluster of galaxies with many members.</p> Signup and view all the answers

<p>A spiral-shaped pressure wave that orbits the disk of a spiral galaxy and induces new star formation.</p> Signup and view all the answers

<p>A flattened, rotating galaxy with pinwheel-like spiral arms winding outward from the galaxy's nuclear bulge.</p> Signup and view all the answers

<p>An object whose known luminosity can be used to deduce the distance to a galaxy.</p> Signup and view all the answers

<p>A galaxy undergoing an exceptionally high rate of star formation.</p> Signup and view all the answers

<p>A gravitationally bound collection of many clusters of galaxies.</p> Signup and view all the answers

<p>A galaxy with its spiral arms pointing away from the direction of rotation, characteristic of all but one known spiral galaxy.</p> Signup and view all the answers

<p>A correlation between the width of the 21-centimeter line of a spiral galaxy and its absolute magnitude.</p> Signup and view all the answers

<p>Giant ellipticals.</p> Signup and view all the answers

<p>Promoting star formation.</p> Signup and view all the answers

<p>Superclusters are all moving apart.</p> Signup and view all the answers

<p>Supersonic boom.</p> Signup and view all the answers

<p>Classes O and B are found only in spiral arms.</p> Signup and view all the answers

<p>A system that categorizes galaxies into spirals, barred spirals, ellipticals, and irregulars.</p> Signup and view all the answers