Galaxies

Sort the galaxies into the correct categories. Spiral Elliptical Irregular Correctly fill in the blanks. Our galaxy, theMilky Way, is typical: it has hundreds of billions of stars, enough gas and dust to make billions more stars, and at least ten times as much dark matter as all the stars and gas put together. And it’s all held together bygravity.Like more than two-thirds of the known galaxies, the Milky Way has aspiral shape. At the center of the spiral, a lot of energy and, occasionally,vivid flaresare being generated. Based on the immense gravity that would be required to explain the movement of stars and the energy expelled, the astronomers conclude that the center of the Milky Way is asupermassive black hole.Other galaxies have elliptical shapes, and a few have unusual shapes like toothpicks or rings. The Hubble Ultra Deep Field (HUDF) shows this diversity. Hubble observed a tiny patch of sky (one-tenth the diameter of the moon) for one million seconds (11.6 days) and found approximately 10,000 galaxies, of all sizes, shapes, and colors. From the ground, we see very little in this spot, which is in the constellation Fornax. Match the vocabulary word with the correct definition. Astronomical Unit A unit of measurement equal to the distance from the Earth to the Sun Light-Year The distance that light travels in one year 13.7 Billion Years The age of the universe 4.6 Billion Years The age of the solar system Galaxy A system of millions or billions of stars Luminosity The brightness of a celestial (space) object Nebula A cloud of gas and dust in space