Astronomy Unit 4: Galaxies Flashcards

True

A halo, bulge, dish, and arms

True

<p>Gravitational lensing</p> Signup and view all the answers

<p>Galaxies</p> Signup and view all the answers

<p>False</p> Signup and view all the answers

<p>False</p> Signup and view all the answers

<p>Gravity that pulls matter in a spiraling matter</p> Signup and view all the answers

<p>Elliptical galaxies</p> Signup and view all the answers

<p>There is a supermassive black hole that is about 15 million miles across</p> Signup and view all the answers

<p>True</p> Signup and view all the answers

<p>Galaxies that are moving farther apart</p> Signup and view all the answers

<p>True</p> Signup and view all the answers

<p>Poor cluster</p> Signup and view all the answers

<p>True</p> Signup and view all the answers

<p>The Milky Way is a 13.5 billion-year-old, average-sized, barred spiral galaxy. It contains four main spiral arms (Perseus, Cygnus, Centaurus, Sagittarius) and approximately 500 billion stars.</p> Signup and view all the answers

<p>Galaxies are typically organized into clusters and distributed across the universe. In clusters, galaxies are held together by the force of gravity. If a cluster contains numerous galaxies, then it is a supercluster. The Milky Way is a part of the Local Group cluster which contains more than 50 other galaxies.</p> Signup and view all the answers

<p>Gravity binds everything together; it keeps galaxy clusters intact. Gravity also forms galaxies into different shapes: spiral, elliptical, and irregular.</p> Signup and view all the answers

<p>Galaxies vary in many ways. They come in different shapes: spiral, elliptical, and irregular. Spiral galaxies look like flying saucers; elliptical galaxies are circular; irregular galaxies do not have a defined shape. Spiral galaxies contain nebulae; elliptical galaxies do not. Spiral galaxies are constantly making new stars, whereas elliptical galaxies do not make new stars. Galaxies also come in different colors. Spiral galaxies are blue; elliptical galaxies are red.</p> Signup and view all the answers

<p>Gravity is what causes stars to form. During accretion, gravity pulls matter into a core, which can be a star, planet, or black hole.</p> Signup and view all the answers

<p>Galaxies change as time passes. Young galaxies are not well organized, but eventually become organized into different clusters. Young galaxies are spiral-shaped; older galaxies are elliptical shaped. Additionally, galaxies change colors, from blue to red, as they get older. The color change is because younger galaxies form new stars (giving off ultraviolet and blue light), whereas older galaxies contain old stars (giving off red light) and create fewer new stars.</p> Signup and view all the answers

<p>There are two theories about how galaxies were formed after the Big Bang. According to one theory, gravity pulled gas and dust together to make stars and planets, which were drawn together to create galaxies. According to the second theory, the universe already contained 'clumps' of matter, that gathered together to form galaxies. This second theory is supported by Hubble Space Telescope photographs of 'clumps' which may be developing into new galaxies. Additionally, small galaxies are often consumed up by larger ones, including the Milky Way.</p> Signup and view all the answers