Transcript The Milky Way, Schroedinger's Cat, and You

The Milky Way,
Schroedinger’S cat,
and You
Galaxies, the Building Blocks of the Universe
Raja Guha Thakurta
(in collaboration with Sandra Faber)
UCO/Lick Observatory
University of California at Santa Cruz
Thursday, September 23, 2004
Kresge Town Hall
Astronomy 2 (ASTR –002-02)
Overview of the Universe
Your Cosmic History
(an astronomer’s perspective)
You! molecules: Earth and Sun:
Protein
Sun’s ancestral stars:
Basic
building
blocks
of
life
Home
of
the
C,N,O
atoms
from
which
Galaxy:
Their nuclear fusion reactions
these
protein
molecules
were
assimilated
Large family
produced these C,N,O atoms
of stars
You are here!
Relatives of the Milky Way
Milky Way
Where did the Milky Way
Come From?
The Answer Will Take Us
Back to the Earliest
Moments of the Universe
The Cosmic Web of Galaxies
Formation of Cosmic Structures
Under the Influence of Gravity
A Computer Simulation
+
-
Points to Ponder
•
Our bio-chemical history links us to galaxies
•
The Milky Way and other galaxies
•
Galaxies like to live near one another
•
The formation of galaxies: The growth of
primordial density fluctuations under the
influence of gravity
But Where Did the
“SeedS” of coSmic
Structure Come From?
Universe
of the per
density
Energy
minute
perminute
decays
popping
kernels
of radiactive
of
Number
Number
1.0000
1.0
0.9995
0.5
1.00000
0.99995
40
00
20
1.000
0.995
Quantum Noise
0
10
20
Position
in Space
Time
30
Schroedinger’S cat
(a “thought experiment” by Erwin Schroedinger)
…or…
???
Inflation
A rapid and dramatic phase of expansion shortly after the Big Bang
blows up these quantum fluctuations and “freezes” them into the
fabric of the Universe. These are the seeds of cosmic structure.
Points to Ponder
•
The Universe is Nature’s ultimate example of
Schroedinger’s cat
•
Inflation is a very, very brief period of extremely
rapid expansion in the infancy of the Universe
•
We have quantum mechanics and gravity to
thank for the existence of galaxies like our
Milky Way and indeed for our own existence
Prediction #1
Galaxy collisions
should be common
and easily visible
Computer Simulation of
Colliding Galaxies
and thiS iS What We See…..
Prediction #2
“infant” galaxieS
should look different
from mature galaxies
Zooming into Deep Space, Looking
Back in Time
Zooming into Deep Space, Looking
Back in Time
Distant Galaxies Are Small and
Ragged
Infant
galaxy
Young
galaxy
Mature
galaxy
Deepest Image of Distant Galaxies
The Hubble Space Telescope is in
orbit above the Earth’s atmosphere and so
is able to take sharp pictures……but…..
….. it is prohibitively expensive to build
telescopes that are based in space
A new method called “Adaptive
Optics” allows us to sharpen the vision
of telescopes that are on the ground, by
correcting for the blurring caused by the
Earth’s atmosphere
Prediction #3
The farthest things
we see should be the
early seeds of galaxies
Early Seeds: Fluctuations in the
Microwave Background
Radiation Maps
Points to Ponder
•
Galaxy cannibalism is a common phenomenon
in which small serve as building blocks from
which larger galaxies are assembled
•
Telescopes are time-machines that enable us to
peer into the Universe’s distant past
•
The after-glow from the Big Bang and early
hot phase of the Universe is visible today and
indeed even the wrinkles on the face of the
early Universe are visible
completing the cycle……
Infant
galaxy
Spiral galaxy
like our own
Sun’s stellar
ancestors
You!planet & star
Our
Protein molecule