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?