7' Origins

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7. Origins

• We are ALL star dust

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Origin of the Universe

• 13.7 billion years old
• small to big Inflation (continuing to expand)
• Big Bang ? pre-particles (hot) ? particles (cool)
  ? elements (cooler)
• Early Universe contained mostly Hydrogen
• Current size 78 billion light years
• Light year distance light travels in 1 year
• about 5.8 trillion miles
• The nearest known star (other than the
  Sun) Proxima Centauri, is about 4.22
  light-years away

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Origin of the Universe
Early Universe Mostly hydrogen Other
elements rare No galaxies No planets
http//www.dailygalaxy.com/photos/uncategorized/20
07/04/01/resizenowmap.jpg
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Early elements Hypernova
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Hypernova

• Early stars 100x of the Sun
• Life span 2-3 million years
• Form early elements in the Universe

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Formation of Light Elements
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Light Elements

• Stars generally made of Hydrogen and Helium
• Uses Fusion to make energy by combining elements
• 3 Helium nuclei fuse ? Carbon
• Another Helium ? Oxygen
• All light elements on the periodic table until
  Iron (Iron barrier)

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Formation of Heavy Elements
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Heavy Elements

• Death of a star
• Iron barrier
• Fuel exhaustion
• Collapsing star
• Supernova explosion

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Prebiotic Period of Earth
Refers to before life Early Earth contained
little Oxygen Oxygen prevents complex molecules
from forming Formation of more complex organic
molecules had to predate biological life How?
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Origin of life's building blocks Miller-Urey
Experiment
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Abiogenesis

• Miller-Urey Experiment
• Same gases as in Earths early atmosphere
• electric current Amino acids

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Other Organic Sources Meteorites (Murchison)
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Other Organic Sources Space Dust
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Other Organic Sources Comets
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Sources of Organics

• Earth Miller-Urey Experiment basic elements in
  the atmosphere electricity
• Meteorites bring with them organics (amino
  acids)
• Star Dust organics fall to Earth from space
  (collected by U2 aircraft)
• Comets carry amino acids but collision with
  Earth causes more to be produced and Peptide
  formation
• Peptides make up proteins

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What is Life? Basis for Life?

• Complex
• Organized
• Utilize energy
• Growth
• Reproduce
• Evolve

Carbon (or Silicon) Liquid water Certain
Environment Temperature Pressure pH Salt
concentration
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Container for Life
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Container for Life

• Cell membrane
• use Murchison meteorite building blocks
• grow primitive containers that can
• Grow
• Divide
• Accumulate gene like materials
• RNA world (most likely)
• Self-replicate

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From Organics to Genes
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Creating Life

• Make membranes
• Make genes from scratch
• But.Life is much more complicated
• Bacteria (E. coli) 4,100 genes
• Humans 30,000 genes
• Fewest genes Mycoplasma genitalium, bacteria
  that causes urinary tract infections, 381 genes
• ButScientific advances are likely to solve these
  issues

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Is anyone out there?

• Within our solar system?
• Mars, Europa (moon of Jupiter)
• From outside our solar system?
• How will we find them?
• Drake equation (prediction)
• Search for Extraterrestrial Intelligence (SETI)
• Looking for Exoplanets

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Europa
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Life on Europa

• Outer layer of ice
• ice crust 10-15 km (6-9 miles)
• Liquid subsurface ocean
• 90 km (56 miles) deep
• Heat generation
• Interaction with Jupiter

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Mars
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Life on Mars

• Mars Rover Program
• 2003 (Spirit and Opportunity)
• Liquid water existed
• Once had a thicker atmosphere
• Ice there now

http//marsrovers.nasa.gov/gallery/press/spirit/20
050527a/1116518822_13678-4_dd_enhanced_486a-A496R1
.gif
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Life elsewhere? Drake Equation
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Drake Equation

• N - Tells you how many civilizations capable of
  communiction exist within our galaxy
• R - stars
• fp - stars have planets
• ne - support life
• fl - develop life
• fi - intelligent life
• fc - communicate
• L - Longevity
• N 1 to billions
• Problem most values are guesses

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Life elsewhere? SETI
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SETI

• Uses radio telescopes to listen for Intelligent
  signals
• Argument of Scale Universe is so vast, even if
  chance of life is very tiny, life would be a
  certainty
• Draw backs
• Can only scan a small part of the Universe at a
  time
• Takes lots of time

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Life elsewhere? Exoplanets
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Exoplanets

• Uses space-based telescopes to find Earth-like
  planets in other solar systems

First direct image of an exoplanet
This 2006 Hubble Space Telescope optical image
shows the belt of dust and debris (bright oval)
surrounding the star Fomalhaut and the planet
(inset) that orbits the star every 872 years and
sculpts the inner edge of the belt. A coronagraph
(center) on the Advanced Camera for Surveys
blocks out the light of the star, which is 100
million times brighter than the planet. (Paul
Kalas/UC Berkeley, NASA, ESA)
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Summary
The origin of all chemical elements are in
stars Biological elements have mainly come from
outside of the Earth Prebiotic conditions could
have led to life Life exists under certain
conditions We are on the verge of being about to
create simple life from the parts Life is likely
to exist elsewhere, and we have a variety of
ways of looking for it
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ENDUniverse
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Next timeExam 1 everything up to today (125
pts)OrganismNext topic CommonalitySections
10.1-10.411.1, 11.212.1, 12.2, 12.4, 12.722.3