Introduction to Astronomy & Tools of Science

(Chapter 1)

Student Learning Objectives

• Diagram your location in space

• Write and interpret numbers in scientific notation

• Define astronomical distance measurements

• Apply the scientific method.

What is our location in space?

We live on planet Earth

In the Milky Way Galaxy (1012 stars)

Part of the Local Group (Galaxy Cluster)

Within in the Virgo Supercluster

One tiny spot in the visible Universe

Practice

Diagram your location in space.

What is Scientific Notation?

Multiples of 10 

The number of multiples/divisions of 10 is indicated as a power.

Blue Light l = 450 x 10-9 meters

Earth-Sun d = 93 x 106 miles

Practice

1) Write 67,000 in scientific notation - Distance from center of galaxy to Sun

 

2) Write 1012 in standard notation - Number of stars in our galaxy

 

3) Write 3.5 x 10−14 in standard notation - A frequency of red light

What is the measurement system used in astronomy?

metric system

Each factor of ten difference results in a single move of the decimal.

Prefix Power of Ten WordMega 106 MillionKilo 103 Thousand

Micro 10-6 One MillionthNano 10-9 One Billionth

Angstrom 10-10

Practice

1) Red light has an average wavelength of 650 nm. Is this a very small or very large number?

 

2) Distances to galaxies are measured in Mega-parsecs. This is (hundreds, thousands, millions) of parsecs. (choose one)

How are astronomical distances measured?

Distances between objects in space are huge!

The astronomical unit (AU) is the average Earth-Sun distance.

1 AU 1.96 x 108 km

9.298 x 107 miles

Light Year

A light year measures distance, not time.

The light-year (LY) is the distance light travels through a vacuum in 1 year.

Light travels 1 AU in about 8 Minutes

Earth - Moon: 1.3 Light Seconds

Earth - Sun: 8 Light Minutes

Earth - Mars: 13 Light Minutes

Earth to Proxima Centauri (nearest star)4.3 Light Years

Earth to the other side of our own galaxy52,000 Light Years

The parsec (pc) is the distance at which 1 AU subtends 1 arcsecond.

1 pc 3.26 LY 206,265 AU

1º = 3600´´

Practice

What is the correct order from smallest to largest?

1 mile 1 pc 1 meter

1 LY 1 nm

Earth’s Diameter 1 AU

What is science?

Science is not simply a collection of facts, but rather an objective process of quantifying what we observe.

The outcomes of science

are laws and theories with repeatable results.

TestedVerified

How is science done?

• Measurements• Observations

Each scientist must be able to obtain the same results.

Example: Atomic Spectra

Observe/Question Hypothesize/Predict Observe/Confirm Theory

Questions to Consider 1) The scientific method is a circular process. Explain

 

2) What do you think happens if scientists cannot obtain the same results?

 

3) Can the scientific method be used to answer all questions?

 

4) What is pseudoscience?

What is astronomy?

Astronomy is a science.

Astronomers study the universe and all objects contained within the universe.