introduction to astronomy & tools of science (chapter 1)
TRANSCRIPT
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
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.