Extraterrestrial

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Extraterrestrial Life
Antígona Segura Peralta
Penn State University, College of Earth and
Mineral Sciences Penn State Astrobiology Research
Center
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They do exist!
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Astrobiology
Astrobiology is the science that studies the
origin, evolution and distribution of life in the
Universe
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The origin of life on Earth
4 billion years ago
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What does life need?

• Raw materials hydrogen, carbon, oxygen, nitrogen
  and minerals like iron and sulfur.
• Energy Sun, volcanoes
• A liquid Water

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Planets, the perfect place

• They contain raw materials
• Energy sources
• They can have liquid water

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Our Solar System
Uranus
Pluto
Saturn
Jupiter
Neptune
Venus
Mercury
Earth
Mars
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The terrestrial planets
Very hot because its atmosphere
Mercury
Mars
Very near the Sun
No atmosphere, cold but
Venus
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Mars today
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Mars, an interesting past
Ancient volcanoes
Ancient rivers?
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Mars might be like this
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Little martian?
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The giant planets
Jupiter
Saturn
Neptune
Uranus
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Europa, Jupiters moon
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Europa
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Europa
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Milky Way
100 billion of stars!
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Where the stars are born
Molecular cloud
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Formation of stars and planets
Beta Pictoris, a newborn star
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Formation of stars and planets
Beta Pictoris disk (artist conception)
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Extrasolar planets
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The life of the stars
Red Giant
Panetary nebula and white dwarf
Yellow dwarf 10 billion years
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The life of the stars
100 million years
Supernova remmanent and neutron star
Supernova
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A habitable world

• Characteristics
• Distance from its star, not too far, not too
  close
• Size, not too big, not too small
• Atmosphere to keep the planet warm and water
  liquid
• Water

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Biomarkers
Those features whose presence or abundance can be
attributed to life
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Signatures of life?
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Small things can make big changes
Cyanobacteria
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How to find a planet?
Problem The stars emit light (a lot!) and
planets doesnt, they just reflect the light from
their parent star.

• How to solve it?
• Cover the star!!!!
• Measure the effects of the planets on the stars
• Stars wobble because of the planets
• Stars dim when a planet crosses in fron of them

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Looking for habitable worlds

• Kepler
• Look for terrestrial planets around 100,000
  stars.
• Launch on 2006.

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Looking for habitable worlds

• Terrestrial Planet Finder (TPF)
• Look for terrestrial planets around 100 nearby
  stars.
• Analyze the planets to detect those that may be
  habitable
• Launching on 2012-2015

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Looking for habitable worlds

• Eddington
• Looking for planets bigger than Mars around
  500,000 stars.
• Launching on 2008.

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Looking for habitable worlds

• Darwin
• Look for terrestrial planets around 1,000.
• Launching after 2014.

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Intelligent life?
Arecibo Antenna, Puerto Rico
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The Pioneer mesage
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Voyager
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SETI Search for extraterrestrial life
Allen array Project Phoenix
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A habitable world