Download 14_creationism

The Design of the Universe
Spiral galaxy M100
from my driveway
Lecture Fourteen, Feb. 17, 2003
Course Project
• Project background (3-5 pages) Mar. 28, 2003.
• Project (10 pages) April 25.
• Happy to talk to you about your project or
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suggest sources.
Popular topics: Dinosaurs, Mars, Movie
Armageddon, Big Bang…
Adding source suggestions to web site.
Tree
of
Life
• Organisms with nearly the
same 16S ribosomal RNA
are closely related and
nearby on the tree.
Last Time: Information Content of
Life
• Each rung of DNA can be one of four bases.
• Need two bits to specify which of 4 bases. 22=4
• A Gene is a functional length of DNA about 1200
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base pairs long, that codes for a specific protein.
A gene has about Ngene=2 x 1200 = 2400 bits of
information.
This information is copied when DNA replicates
and is used when messenger RNA is made.
Information Content of Organsims
• Virus [~50 genes] 50 x 2400 ~ 120,000 bits.
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Note, a virus is often not considered alive
because it needs a host to function.
E. Coli [~2500 genes] ~ 6 x 106 bits = 0.75
Megabytes (1 byte is 8 bits).
Man [~35,000 genes] 35,000 x 2400 = 8.4 x 107
bits = 10.5 Megabytes.
You can fit main part of DNA blueprint of Man on
8 floppy disks.
Earth Life
• Uses only 20 different amino acids (simple
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molecules with amine (N) and acid (COOH)
groups.
These are strung together amine to acid group
in long chains to make complex proteins.
Information to do this is stored in DNA.
Random errors in DNA copying leads to
mutations which are tested by survival of the
fittest and this causes life to evolve.
“Nonscientific” Alternatives to
Evolution
• Creationism: Bible is literally true. Earth is only
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6000 years old (not 4.6 billion years old).
Organisms don’t evolve, they were created,
complete, by god.
Lots of evidence that Earth is much older then
6000 years and you can watch organisms evolve
in the laboratory.
Example “god created that rock only 6000 years
ago but he made it look old and put that very
old looking fossil in it”.
Intelligent Design
• Acknowledges that earth is billions of years old
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and that organisms change with time. But
claims that the astounding complexity and
beauty of the earth’s plants and animals could
not have “just happened” through natural
selection.
In short, evolution happened as scientists say,
but it happened because the hand of god was
behind it.
What was intelligently designed?
• Man (of course)
• Monkeys?
• Corn?
• Amebas?
• Slime mold?
• E. Coli?
• Life!
What about inanimate objects?
• Was earth intelligently designed? It is
remarkable how stable the climate and
how hospitable earth is.
• Was solar system intelligently designed?
– Sun puts out enough light that earth can be a
safe distance away. But sun still lasts a long
enough time for evolution.
– Jupiter’s gravity deflects many comets /
asteroids to keep earth safe.
Was Universe Intelligently Designed?
• Laws of physics allow stars to make
chemical elements and shine at an
appropriate rate. Gravity does not
collapse universe to quickly…
• Was the diamond in my wife’s wedding
ring intelligently designed? How about
the snow flakes outside…
What is designed?
• If science discovers something “ugly”, it is just
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science.
If science discovers something “beautiful” (read
Man), it is because of intelligent design.
How do we tell if something is “too complicated
for evolution alone”?
Is intelligent design a testable theory? It
appears not.
What do I think?
• Intelligent design is not science and many
of its proponents appear to underestimate
the extraordinary power of the “blind”
survival of the fittest algorithm.
• Nevertheless, I completely agree with
many of these proponents that Man and
many of gods other creations are
extraordinarily complex and beautiful.
I Concentrate my Wonder in Three
Areas.
• The universe we live in. Many of its properties appear to
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be just right to allow intelligent life.
The origin of life. This is such an extraordinary event
and “achievement”. Perhaps life is so complex that the
origin of life is a lot less likely than we think. This is
testable. As we search the universe we may be unlikely
to find even primitive life.
The origin of intelligence. Perhaps primitive life may be
common in the universe but intelligent life very rare.
This is the position of Ward and Brownlee in their book
Rare Earth.
Review
Our place in Space
Formation
of Star
and
Planets
Andromeda Galaxy with hundreds of billions of stars
What is our role in such a grand
galaxy and universe?
• It would be a great waste of space, if we are
indeed alone.
Hubble
space
telescope
image of
many
galaxies.
Let There Be Light
Electromagnetic Spectrum
High frequency

Low frequency
Short wavelength

Long wavelength
Eyes are adapted to the Sun
• Our eyes are sensitive to
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these frequencies
because Sun shines
brightest here and water
vapor in atmosphere is
transparent at these
frequencies.
One can speculate about
alien eyes for alien stars.
Note, stars come in many
sizes and colors.
Curve A, Sun, Curve B after atmosphere
Spectral Lines
• How do we know the composition of distant Stars and
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Galaxies?
Each chemical element has a set of unique spectral lines.
These are particular frequencies of light (electromagnetic
radiation) that the element absorbs or emits.
Chemical elements are characterized by their atomic
number Z. This is the number of electrons that orbit the
nucleus. Hydrogen Z=1, Helium Z=2, Lithium Z=3 …
Uranium Z=92.
Quantum mechanics says these electrons can only have
discrete energies when they are orbiting the nucleus. A
spectral line is emitted when an electron jumps from one
energy to another.
Example, Sodium Glows Yellow
• Spectrum of Sodium shows green, bright yellow, orange.
and red spectral lines. Light from a glowing discharge
containing the element sodium is split by a prism with
short wavelengths (blue) on the left and long (red)
wavelengths on the right.
• Seeing these lines in the spectrum of a star or galaxy
implies that the distant object contains sodium.
Doppler shift of Spectral Lines
• If an object is moving away from you, the sound
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or light that it emits is Doppler shifted to lower
frequencies.
The lowest frequency visible light is red.
Therefore we call this a red shift.
If the object is moving towards us, the light is
shifted to higher frequencies and we call it a
blue shift.
Can use the Doppler shift to measure the
velocity of distant galaxies.
Doppler Shift of Light from Galaxy
• The top figure compares spectral line (black line) from
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distant galaxy to same spectral line on Earth, yellow
marks at top and bottom.
If galaxy is moving away (middle figure) spectral line is
shifted to the red. If galaxy is moving towards us
(bottom), spectral line is shifted towards blue.
Hubble’s Law
• E. Hubble found that light from distant galaxies
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was red shifted by an amount proportional to
distance (from us).
The velocity of a distant galaxy v (inferred from
the red shift) is related to its distance d,
v=H d
Hubble’s constant H has dimensions of 1/time.
Age of universe is about 1/H. Exact value
depends on how expansion rate depends on
time.
This expansion age is about 13 B. years.
Alchemy of The Heavens
View, low in
the East, early
in the morning
of July 5,
1054 shows
the Crab
Supernova
Lecture Eight, Jan. 25, 2002
Life of a Star
• Birth: collapse of gas cloud forms protostar.
• Main sequence: center of star becomes hot
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enough to burn Hydrogen into Helium. Our Sun
will be on main sequence for 10 billion years.
Red Giant: Outer part of star expands and
cools. Core contracts and starts to burn He into
Carbon and other heavier elements.
Star dies: either as a planetary nebula (low mass
star) or as a supernova (high mass star).
Supernova
• Stars with more then 8 solar masses die in
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gigantic explosions called supernovae. Note,
plural of supernova is supernovae.
A single star that explodes as a supernova can
outshine an entire galaxy (billions of stars).
Hard to imagine the violence of the explosion.
Core of star imploded to form neutron star or
black hole.
Outer part of star ejected into space with new
chemical elements.
Life is Old
• Life arose about 3.8
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billion years ago.
Clear fossils in 3.5
billion year old rocks.
Problem, few older
rocks have survived.
Great bombardment
and very hostile
conditions 4 billion
years ago and earlier.
For Next Time
• Read chap. 6 of Text pages 93-109,
“Origin of Life on Earth”. Review “T.rex
and the Crater of Doom”, pages 59-76 in
your course packet.
• I am happy to answer questions or make
suggestions for your project.
• Next lecture, “Review”.