News
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Constellation Quiz lab begins on Monday
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You must sign up in advance
Telescope Observing lab begins Monday September 10
Questions from Last Time?
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?
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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?
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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?
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The Sun is embedded in the Milky Way (far from the center).
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We have a myopic perspective.
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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?
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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?
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Infrared light penetrates dust better than visible light.
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An infrared view of the Milky Way reveals the real Galaxy.
Astronomy: A Search for Structure?
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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
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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!!!
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Where did all the structure and organization come from?
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How did it emerge over time?
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What physics/physical processes were important?
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We wish to explain, not just observe.
Astronomy: A Search for Origins!!!
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Where did all the structure and organization come from?
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How did it emerge over time?
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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
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The “Big Bang” brings matter, space and time into existence.
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It happened 13.7 billion years ago.
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
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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.
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The early Universe contained only uniformly distributed Hydrogen and
Helium.
Almost immediately gravity begins to form stars and galaxies.
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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.

but only becomes “complex” ½ billion years ago.
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.

but only becomes “complex” ½ billion years ago.
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.

but only becomes “complex” ½ billion years ago.
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.

but only becomes “complex” ½ billion years ago.
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.

but only becomes “complex” ½ billion years ago.
A Five-Minute History of the Universe

If this history could be compressed into a single year:

The Universe starts on January 1...
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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
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Dinosaurs roamed the Earth for two weeks between
December 10 and December 25
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Humanity (intelligence?) arose at 10 p.m. on December 31
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Recorded history began around 11:59:45 on December 31