Lecture 1

Question 1

What is our place in Universe?

Answer 1

Earth - Solar System - Milky Way Galaxy - Local Group - Local Supercluster

Question 2

A cosmic Inventory

Answer 2

Stars, planets, moons, Asteroids, Comets, Solar System, Nebulae, Galaxies, Galaxies Groups, Galaxy Clusters, Universe

Question 3

Star

Answer 3

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

Question 4

Planet

Answer 4

A moderately large object that orbits a star, it shines by reflected light. Planets may be rocky, icy, or gaseous in composition

Question 5

Moon

Answer 5

An object that orbits a planet

Question 6

Asteroid

Answer 6

A relative small and rocky object that orbits a star

Question 7

Comet

Answer 7

A relatively small and icy object that orbits a star

Question 8

Solar (Star) System

Answer 8

A star and all the material that orbits it, including its planets and moons

Question 9

Nebula

Answer 9

An interstellar cloud of gas and/or dust

Question 10

Astronomical Unit (AU)

Answer 10

Average distance between the Earth and the Sun (150 million kms)

Question 11

Light Year

Answer 11

the average distance that light can travel in 1 year

Question 12

Is light year a distance measurement or a time measurement?

Answer 12

Distance Measurement

Question 13

Where to find the Orion Nebula

Answer 13

The Orion Nebula is about 1350 light years away and 13 light years wide
It is a star forming region

Question 14

Galaxy

Answer 14

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

Question 15

Where to find the Andromeda Galaxy

Answer 15

The Andromeda galaxy is about 2.5 million light years away. It will collide with the Milky Way Galaxy in 4 billion light years

Question 16

Galaxy group

Answer 16

A gravitationally bound group of up to a few dozen galaxies typically a few million light years across

Question 17

Galaxy Cluster

Answer 17

A group of a few hundred to a few thousand galaxies
Abell 1689, about 2.2 billion light years away

Question 18

Light Travels at

Answer 18

Finite speed of 300,000km/s

Question 19

Light travel time to moon

Answer 19

1 second

Question 20

Light travel time to sun

Answer 20

8 minutes

Question 21

Light travel time to Sirius

Answer 21

8 years

Question 22

Light travel time to Andromeda Galaxy

Answer 22

2,5 million years

Question 23

How do we see objects as they were in the past?

Answer 23

The farther away we look in distance, the further back we look in Time

Question 24

Can we see the Entire Universe?

Answer 24

No, we cannot see the entire universe, because the universe is only about 14 billion years old. Its too far away for us to see it

Question 25

How did we come to be?

Answer 25

The Universe is expanding
All galaxies are moving away from each other
Tracing this motion backward leads to a point where the expansion began, referred to as the Big Bang
Gravities drives collapse of matter into galaxies and galaxy clusters
Most galaxies formed within a few billion years after the Big Bang.

Question 26

How did Gravity play a role in “How did we come to be?”

Answer 26

Gravity drives collapse of clouds of gas and dust to form stars and planets

Question 27

Stars go through

Answer 27

Life cycles

Question 28

How did we come to be?

Answer 28

The Big Bang produced hydrogen and helium.
– All other elements were constructed from H and He in stars
and then recycled into new star systems, including our solar
system.
– We are made of elements produced in the nuclear fusion
within the cores of stars.