Physics 205Introduction to Astronomy 1

Introductions & Scale of the Universe

Solar System: Sun, planets, and other objects orbiting the Sun

Which is larger, a solar system or a galaxy?

A) A solar system

B) A galaxy

C) They are just different terms for the same thing

Looking back in time

The further away we look …

… the further back in time we see.

The light from which object is older?

A) Pluto

B) The Sun

C) The Andromeda galaxy

D) The Moon

Orion Nebula

~1500 ly away

Andromeda Galaxy

~2.5 million ly away

(Astronomical Unit)13.8 billion ly

The “Observable Universe”

We’re in the middle

In which statement are the words used incorrectly?

A) Light from the Andromeda galaxy is about 2.5 million lightyears old.

B) When we see a supernova explosion that is 150 million lightyears away, the explosion actually happened 150 million years ago. C) Since it takes light 8 minutes to travel from the Sun to the Earth, we could say that the Earth is 8 lightminutes away from the Sun.

Astro-Cash Cab!

Jasmyn Brendle

Joe Gonzales

Isabel Schneider

Quincy Davison

Faleen Labato

Rules…

1) True or False?

It would take light 50,000 years to go from the center of our galaxy to its outer edge.

2) Put the following in order according to size, smallest to largest:

The Milky Way

The Sun

Earth

The Local Cluster

3) Which type of planet is the Earth?

Terrestrial

Jovian

Dwarf

4) The distance light travels in one year is called a(n) …