How Do You Make Sense of it All?
Astronomy: A Search for Organization?
Stars....
Galaxies....
Astronomy: A Search for Structure?
Astronomy: A Search for Structure?
Our Galaxy (the Milky Way) in
Perspective: How do we fit in?
●
Galaxies, collections of billions of stars assembled and
bound by gravity, are a primary unit of Universal
structure.
Our Galaxy (the Milky Way) in
Perspective: How do we fit in?
●
Any random deep view of the night sky shows a
universe peppered with galaxies – each containing
hundreds of billions of stars.
Us?
Our Galaxy (the Milky Way) in
Perspective: How do we fit in?
A distant galaxy similar to our Milky
Way
The Stars Near Our Sun
Associated WWW Link
Our Galaxy (the Milky Way) in
Perspective: How do we fit in?
●
The Sun is embedded in the Milky Way (far from the
center).
–
We have a myopic perspective.
–
The Milky Way is thin and flat, yet we see a lumpy diffuse band
across the sky because of our proximity.
Our Galaxy (the Milky Way) in
Perspective: How do we fit in?
●
Part of our perspective problem is that dust between
the stars obscures our view.
Our Galaxy (the Milky Way) in
Perspective: How do we fit in?
●
Infrared light penetrates dust better than visible light.
–
An infrared view of the Milky Way reveals the real Galaxy.
Astronomy: A Search for Structure?
●
Hierarchical structure in the Universe leads
to an extended mailing address.....
Earth
The Solar System (in capital letters)
The Milky Way Galaxy
The Local Group
The Local Supercluster
The Universe
●
Implicit in understanding this structure
is knowing how far away things
actually are.... not an easy task!
Understanding Structure: Divining
Depth
Understanding Structure: Divining
Depth
Understanding Structure: Divining
Depth
Understanding Structure: Divining
Depth
Still, we are focusing of
phenomenology....
Astronomy: A Search for Origins!!!
●
Where did all the structure and organization come
from?
●
How did it emerge over time?
●
What physics/physical processes were important?
●
We wish to explain, not just observe.
Astronomy: A Search for Origins!!!
●
Where did all the structure and organization come
from?
●
How did it emerge over time?
●
What physics/physical processes were important?
Hydrogen + Helium + Gravity ⇨ Stars, Galaxies, and
Humans
given about 14 billion years.
A Five-Minute History of the Universe
●
The “Big Bang” brings matter, space and time into
existence.
–
It happened 13.7 billion years ago.
●
–
●
Stars “process” Hydrogen and Helium into heavier elements
like Iron, Calcium, and Oxygen.
After 9 billion years of cosmic recycling (4.6 billion
years ago) our Sun forms from the “ashes” for previous
generations of stars.
–
The early Universe contained only uniformly distributed
Hydrogen and Helium.
Almost immediately gravity begins to form stars and
galaxies.
–
●
a number now known to better than 1 percent!
At the same time system of planets form from debris left in
orbit around the Sun.
●
Life originates quickly on Earth.
A Five-Minute History of the Universe
●
The “Big Bang” brings matter, space and time into
existence.
–
It happened 13.7 billion years ago.
●
–
●
Stars “process” Hydrogen and Helium into heavier elements
like Iron, Calcium, and Oxygen.
After 9 billion years of cosmic recycling (4.6 billion
years ago) our Sun forms from the “ashes” for previous
generations of stars.
–
The early Universe contained only uniformly distributed
Hydrogen and Helium.
Almost immediately gravity begins to form stars and
galaxies.
–
●
a number now known to better than 1 percent!
At the same time system of planets form from debris left in
orbit around the Sun.
●
Life originates quickly on Earth.
A Five-Minute History of the Universe
●
The “Big Bang” brings matter, space and time into
existence.
–
It happened 13.7 billion years ago.
●
–
●
Stars “process” Hydrogen and Helium into heavier elements
like Iron, Calcium, and Oxygen.
After 9 billion years of cosmic recycling (4.6 billion
years ago) our Sun forms from the “ashes” for previous
generations of stars.
–
The early Universe contained only uniformly distributed
Hydrogen and Helium.
Almost immediately gravity begins to form stars and
galaxies.
–
●
a number now known to better than 1 percent!
At the same time system of planets form from debris left in
orbit around the Sun.
●
Life originates quickly on Earth.
A Five-Minute History of the Universe
●
The “Big Bang” brings matter, space and time into
existence.
–
It happened 13.7 billion years ago.
●
–
●
Stars “process” Hydrogen and Helium into heavier elements
like Iron, Calcium, and Oxygen.
After 9 billion years of cosmic recycling (4.6 billion
years ago) our Sun forms from the “ashes” of previous
generations of stars.
–
The early Universe contained only uniformly distributed
Hydrogen and Helium.
Almost immediately gravity begins to form stars and
galaxies.
–
●
a number now known to better than 1 percent!
At the same time a system of planets form from debris left in
orbit around the Sun.
●
Life originates quickly on Earth.
A Five-Minute History of the Universe
●
The “Big Bang” brings matter, space and time into
existence.
–
It happened 13.7 billion years ago.
●
–
●
Stars “process” Hydrogen and Helium into heavier elements
like Iron, Calcium, and Oxygen.
After 9 billion years of cosmic recycling (4.6 billion
years ago) our Sun forms from the “ashes” for previous
generations of stars.
–
The early Universe contained only uniformly distributed
Hydrogen and Helium.
Almost immediately gravity begins to form stars and
galaxies.
–
●
a number now known to better than 1 percent!
At the same time system of planets form from debris left in
orbit around the Sun.
●
Life originates quickly on Earth.
A Five-Minute History of the Universe
●
The “Big Bang” brings matter, space and time into
existence.
–
It happened 13.7 billion years ago.
●
–
●
Stars “process” Hydrogen and Helium into heavier elements
like Iron, Calcium, and Oxygen.
After 9 billion years of cosmic recycling (4.6 billion
years ago) our Sun forms from the “ashes” for previous
generations of stars.
–
The early Universe contained only uniformly distributed
Hydrogen and Helium.
Almost immediately gravity begins to form stars and
galaxies.
–
●
a number now known to better than 1 percent!
At the same time system of planets form from debris left in
orbit around the Sun.
●
Life originates quickly on Earth.
A Five-Minute History of the Universe
●
If this history could be compressed into a single year:
–
The Universe starts on January 1...
●
The Solar System forms in early-September
A Five-Minute History of the Universe
●
If this history could be compressed into a single year:
–
The Universe starts on January 1...
●
The Solar System forms in early-September
–
Life originates in mid-September
–
Life becomes complex in mid-December
A Five-Minute History of the Universe
●
If this history could be compressed into a single year:
–
The Universe starts on January 1...
●
The Solar System forms in early-September
–
Life originates in mid-September
–
Life becomes complex in mid-December
● Dinosaurs roamed the Earth for two weeks between
December 10 and December 25
A Five-Minute History of the Universe
●
If this history could be compressed into a single year:
–
The Universe starts on January 1...
●
The Solar System forms in early-September
–
Life originates in mid-September
–
Life becomes complex in early-December
● Dinosaurs roamed the Earth for two weeks between
December 10 and December 25
●
Humanity (intelligence?) arose at 10 p.m. on
December 31
●
Recorded history began around 11:59:45 on
December 31