Extraterrestrial

Life

Antígona Segura Peralta

Penn State University, College of Earth and Mineral SciencesPenn State Astrobiology Research Center

They do exist!

Astrobiology

Astrobiology is the science that studies the origin, evolution and distribution of life in the Universe

The origin of life on Earth

4 billion years ago

What does life need?

Raw materials: hydrogen, carbon, oxygen, nitrogen and minerals like iron and sulfur.

Energy: Sun, volcanoes

A liquid: Water

Planets, the perfect place

They contain raw materials

Energy sources

They can have liquid water

Our Solar System

Mercury Venus Earth Mars

Jupiter SaturnUranus

Neptune

Pluto

The terrestrial planets

Very near the Sun

Very hot because its atmosphere

No atmosphere, cold but…

Mercury

Venus

Mars

Mars today

Mars, an interesting past

Ancient volcanoes

Ancient rivers?

Mars might be like this

Little martian?

The giant planets

JupiterSaturn

UranusNeptune

Europa, Jupiter’s moon

Europa

Europa

Milky Way

100 billion of stars!

Where the stars are born

Molecular cloud

Formation of stars and planets

Beta Pictoris, a newborn star

Formation of stars and planets

Beta Pictoris disk (artist conception)

Extrasolar planets

The life of the stars

Yellow dwarf10 billion years

Red Giant

Panetary nebula and white dwarf

The life of the starsBlue giants

Supernova

Supernova remmanent and neutron star

100 million years

A habitable world

Characteristics:

Distance from its star, not too far, not too close

Size, not too big, not too smallAtmosphere to keep the planet warm

and water liquidWater

BiomarkersThose features whose presence or

abundance can be attributed to life

Signatures of life?

Small things can make big changes

Cyanobacteria

How to find a planet?Problem:

The stars emit light (a lot!) and planets doesn’t, 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

Looking for habitable worldsKepler:

Look for terrestrial planets around 100,000 stars.

Launch on 2006.

Looking for habitable worldsTerrestrial 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

Looking for habitable worldsEddington:

Looking for planets bigger than Mars around 500,000 stars.

Launching on 2008.

Darwin:

Look for terrestrial planets around 1,000.

Launching after 2014.

Looking for habitable worlds

Intelligent life?

Arecibo Antenna, Puerto Rico

Globular Cluster M13

The Pioneer mesage

Voyager

SETI: Search for extraterrestrial life

Allen array

Project Phoenix

A habitable world