Phys1160
PHYS 1160
Introductory Astronomy and the Search for Life Elsewhere Lecture 1 Introduction to Astronomy
This Lecture
• What is Astronomy • The Discovery of our Place in the Universe - A brief history • The Scale of the Universe
2
What is Astronomy?
• The scientific study of celestial objects
– e.g. Planets, Stars, Galaxies, and the Universe as a whole.
• It encompasses the study of everything outside the Earth’s atmosphere. • The name comes from the greek words astron ("star") and nomos ("law").
3
Other “Astro” words
• Astrology is the idea that positions of celestial bodies provide information on personality, human affairs etc. Astrology is not a science. • Astrophysics is the study of the physics of celestial objects. • Astrobiology is the study of the origin, evolution and distribution of life in the universe. • Astrometry is the science of measuring the positions of celestial objects such as stars and planets. • Astronautics is the study of space flight. It is a branch of engineering.
4
A Brief History of Astronomy
• Here we will look at the history of astronomy • We will focus on the development of ideas on our place in the universe.
5
An Ancient Science
• The study of astronomy goes back at least to the ancient civilizations of Mesopotamia (present day Iraq). • The Sumerians developed the first form of writing (cuneiform) before 3000 BC.
– They studied the motion of celestial bodies and developed the practice of dividing the circle into 360 degrees, and the degree into 60 minutes
6
Ancient Observatories?
• Many ancient cultures left structures with astronomical alignments.
– Pointing, e.g. to the rising or setting Sun on specific dates.
• It is hard to know exactly what role these structures performed.
Stonehenge (about 2500 BC)
7
Ancient Greek Astronomy
• The philosophers of ancient Greece developed ideas about the structure of the universe that were to be influential for two millenia. • As early as
Introductory Astronomy and the Search for Life Elsewhere Lecture 1 Introduction to Astronomy
This Lecture
• What is Astronomy • The Discovery of our Place in the Universe - A brief history • The Scale of the Universe
2
What is Astronomy?
• The scientific study of celestial objects
– e.g. Planets, Stars, Galaxies, and the Universe as a whole.
• It encompasses the study of everything outside the Earth’s atmosphere. • The name comes from the greek words astron ("star") and nomos ("law").
3
Other “Astro” words
• Astrology is the idea that positions of celestial bodies provide information on personality, human affairs etc. Astrology is not a science. • Astrophysics is the study of the physics of celestial objects. • Astrobiology is the study of the origin, evolution and distribution of life in the universe. • Astrometry is the science of measuring the positions of celestial objects such as stars and planets. • Astronautics is the study of space flight. It is a branch of engineering.
4
A Brief History of Astronomy
• Here we will look at the history of astronomy • We will focus on the development of ideas on our place in the universe.
5
An Ancient Science
• The study of astronomy goes back at least to the ancient civilizations of Mesopotamia (present day Iraq). • The Sumerians developed the first form of writing (cuneiform) before 3000 BC.
– They studied the motion of celestial bodies and developed the practice of dividing the circle into 360 degrees, and the degree into 60 minutes
6
Ancient Observatories?
• Many ancient cultures left structures with astronomical alignments.
– Pointing, e.g. to the rising or setting Sun on specific dates.
• It is hard to know exactly what role these structures performed.
Stonehenge (about 2500 BC)
7
Ancient Greek Astronomy
• The philosophers of ancient Greece developed ideas about the structure of the universe that were to be influential for two millenia. • As early as