Exoplanets and extraterrestrial life
Silvana Buscemi
Camilo Díaz
Ruth Pérez
Aitor Gallego
EXOPLANETS
• Exoplanet: planet that doesn’t orbit the sun,
instead orbits a different star.
• 1800 exoplanets have been discovered.
• Nearest exoplanet to the Earth: Alpha Centauri
Bb.
DETECTION METHODS
Direct methods:
1. Direct imaging:
• It is extremely difficult, and in most cases impossible.
• Being small and dim planets are easily lost in the brilliant glare of the giant stars they orbit.
• It works best for planets that orbit at a great distance from their stars.
Indirect methods:
1. Transit method.
• When a planet crosses in front of its star as viewed by an observer, the event is called a transit.
• It can determine the radius of a planet.
• Transits by terrestrial planets produce a small change in a star's brightness .
DETECTION METHODS
2. Astrometry:
• It involves precise measurements of the positions and
movements of stars and other celestial bodies.
• It provides information on the kinematics and physical
origin of our Solar System and our galaxy, the Milky Way.
3. Radial velocity:
• It is based on the detection of variations in the velocity of
the central star
• When the star moves towards us, its spectrum is blue
shifted, while it is red shifted when it moves away from
us.
Habitable exoplanets • The circumstellar habitable zone
• 12 confirmed habitable planets
• Habitable exoplanets are ranked trough their size: terran,subterran and superterran.
• They are also classified according to their temperature:hypopsychroplanet if they are below -50c, psychroplanet 0c/-50c, mesoplanet which is the ideal from 0 to 50c andthermoplanets which are very hot.
Gliese 667 Cc
Gliese 667 cc is the most similar planet to earth that is
scientifically proved to be a possible planet with live as
we know it.
• This planet has about 4 and a half times the mass of
the earth.
• It orbits around the star Gliese 667 C which is a
member of the Gliese 667 triple star system.
• The star Gliese 667 C hosts at least 7 planets and 3 of
those, all rocky planets , are within the habitable zone.
• It is a bit warmer than the earth but complex life could
exist at that temperature.
HISTORY OF DETECTION
• Early speculations.
• Confirmed discoveries.
• Unconfirmed Kepler
Candidates.(candidate planets)
• Total planets.
EARLY ESPECULATIONS
• Guiordano Bruno. (16th century)
• Isaac newton. (18th century)
• Otto struve. (20th century)
CONFIRMED DISCOVERIES
• First published by Bruce Campbell, G.H.A
Walker and Stephenson Yang in 1988. (Gamma
Cephei)
CONFIRMED DISCOVERIES
• First definitive detection of an exoplanet orbiting
51 Pegasi star by Michel Mayor and Didier
Queloz. (1995)
UNCONFIRMED KEPLER
CANDIDATES
• Alpha Centuri Bb planet in 17 October 2012.
What is the SETI? When and how did this idea began?
• It is the science used to search the skies for signals from alien civilizations.
• The idea of SETI began in 1959.
• Giuseppe Cocconi and Philip Morrison published a paper discussing the possibility of the existence of alien civilizations.
• Method of detection: Radio waves. Why? because they are capable of traveling the vast distances between stars
• First search: Project Ozma in 1960.
PROJECT OZMA
• It started in 1960, by a young
astronomer named Frank
Drake.
• It was the humanity's first
attempt to detect interstellar
radio transmissions.
• Stars chosen for the project:
• - Tau Ceti in the Constellation
Cetus (the Whale)
• -Epsilon Eridani in the
Constellation Eridanus (the
River).
PROJECT PHOENIX
• It was the most ambitious search for extraterrestrial intelligence ever undertaken.
• From February 1995 to March 2004.
• Project Phoenix observed about 800 stars.
• Where did the project take place?
-Australia
-West Virginia
-Puerto Rico.
• No ET signals were detected.
FERMI PARADOX
• It is the apparent contradiction between high estimatesof the probability of the existence of extraterrestrialcivilization and humanity's lack contact with.
Arguments:
• The Sun is a typical star, and relatively young.
• some of these stars will have Earth-like planets, some ofthese planets may develop intelligent life.
• Some of these civilizations may develop interstellartravel.
• The galaxy can be completely colonized in a few tens ofmillions of years.
• Hence Fermi's question, "Where is everybody?"
QUIZ for the audience.
Rules:
• First of all the class is divided into the groups
assigned for the PPTs.
• In each group there will be a speaker and
questions will be asked randomly between
the speakers of each group so be prepared!!
• Mr. Cuesta can of course ask questions to
any of you even if you are not speakers if you
are not paying attention.
QUIZ.
• 1 What is the SETI?
• 2 Can you explain how it works any of the detection methods we explained?
• 3 What is the circumstellar habitable zone?
• 4 So according with our explanations is Gliese 667 Cc a terran, subterran or superterran planet?
QUIZ
• 5 Did project Ozma or project Phoenix proved something about extraterrestrial life?
• 6 When was the first exoplanet discovered?
• 7 How many stars did project phoenix observed?
• 8 Do you think it could be anybody out there after this PPT?