Universe & Galaxies Study Guide

Question 1

How old is the universe?

Answer 1

13.8 billion yrs

Question 2

How old is the sun?

Answer 2

4.5 billion yrs

Question 3

How fast is the speed of light?

Answer 3

300,000 km/sec

Question 4

Our galaxy

Answer 4

Milky Way

Question 5

Our cluster

Answer 5

Virgo Cluster

Question 6

Our nearest star neighbor

Answer 6

Alpha Centauri

Question 7

Our nearest galaxy neighbor

Answer 7

Andromeda

Question 8

Milky Way is

Answer 8

A large barred spiral galaxy

Question 9

Spiral Galaxies

Answer 9

have a distinctive shape with spiral arms in a relatively flat disk and a central “bulge”

Question 10

elliptical galaxies

Answer 10

are round or oval, with stars distributed fairly uniformly throughout. They have a bulge and halo, like spiral galaxies, but don’t have the flat disk of stars.

Question 11

Irregular galaxies

Answer 11

have no identifiable shape or structure to them. They are often chaotic in appearance, without a bulge or any trace of spiral arms.

Question 12

star

Answer 12

a fixed luminous point in the night sky that is a large, remote incandescent body like the sun.

Question 13

light year

Answer 13

a unit of astronomical distance equivalent to the distance that light travels in one year.

Question 14

galaxy

Answer 14

a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction

Question 15

universe

Answer 15

all existing matter and space considered as a whole; the cosmos. The universe is believed to be at least 10 billion light years in diameter and contains a vast number of galaxies; it has been expanding since its creation in the Big Bang about 13 billion years ago.

Question 16

cluster

Answer 16

a group of stars or galaxies bound by gravity

Question 17

What is the nearest star to Earth?

Answer 17

sun

Question 18

What are the three basic types of galaxies?

Answer 18

spiral, elliptical, and irregular

Question 19

Solar System

Answer 19

the sun together with all the planets and other bodies that revolve around it. a similar system with celestial bodies revolving around a star other than the sun.

Question 20

Planet

Answer 20

a celestial body moving in an elliptical orbit around a star.

Question 21

Interstellar matter

Answer 21

Interstellar matter, composed primarily of gas and dust, occupies the regions between the stars. It contains information about evolution of the universe and our galaxy.

Question 22

Supercluster

Answer 22

A supercluster is a large group of smaller galaxy clusters or galaxy groups; it is among the largest known structures of the universe.

Question 23

the big bang theory

Answer 23

The Big Bang is how astronomers explain the way the universe began. It is the idea that the universe began as a single point and then expanded into what we know today, and is still expanding.

Question 24

George Lemaitre

Answer 24

formulated the modern big-bang theory, which holds that the universe began in a cataclysmic explosion of a small, primeval “super-atom” then expanded

Question 25

Albert Einstein

Answer 25

Albert Einstein published the theory of special relativity, explains how space and time are linked for objects that are moving at a consistent speed in a straight line.

Question 26

Edwin Hubble

Answer 26

His research helped prove that the universe is expanding, and he created a classification system for galaxies that has been used for several decades.