9/7/18 Our Place in the Universe Flashcards Preview

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Flashcards in 9/7/18 Our Place in the Universe Deck (17)
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1

a large, glowing ball of gas that generates heat and light through nuclear fusion

sun

2

a moderately large object that orbits a star; it shines b y reflected light, rock or gaseous

planet

3

an object that orbits a planet

moon / satellite

4

a relatively small and rocky object that orbits a star, not big enough/not enough gravity to be a sphere, typically has an irregular shape

asteroid

5

a relatively small and icy object that orbits a star

comet

6

What is the difference between an asteroid and a comet?

asteroid is rocky
comet is icy

7

a star and all the materials that orbit it, including its planets and moons

solar (star) system

8

a great island of stars in space, all held together by gravity and orbiting a common center

gravity

9

a collection of galaxies bound together by gravity

local group

10

a gigantic region of space in which many groups and clusters of galaxies are packed more closely together than elsewhere in the universe

supercluster

11

the sum total of all matter and energy; that is, everything within and between galaxies

universe

12

astronomical unit

-Earth's average distance from the Sun
-150 million km (1.5E8 km)
-Describes distances within our solar system

13

light year

-the distance light can travel in 1 year
-about 10 trillion (10E13) km (6 trillion miles)
-unit of distance, not of time

14

measured age of the universe

14 billion years

15

at great distances, we see objects...

as they were when the universe was younger

16

Why do we see the Andromeda Galaxy as it looked 2.5 million years ago?

It's 2.5 million lightyears away

17

Earth's cosmic address from smallest to largest (5)

Earth
Solar System
Milky Way
Local Group
Universe