SETI Flashcards
Who carried out the first SETI observations?
Frank Drake in 1960 and 1961
What was Project Ozma?
SETI experiments in 1960
What was the aim of Project Ozma?
Search for signs of life through interstellar radio waves
What radio telescope did they use for Project Ozma?
43m radio telescope in Green Bank
What did they do to search for Project Ozma?
Search for any regular patterns that would not occur naturally
Who dominated SETi in 1960s-1970s?
Soviet Union
US
What happened to the SETI program in the US in the 1980s?
1981 - funding removed from NASAs budget
1984 - All NASA funding observations gone
Who established the SETI institute?
Carl Sagan
What year was the SETI institute established?
1984
What happened in 1994 to SETI insitute?
US gov cancelled all NASA funding fully so SETI became privately funded
What was Project Phoenix?
Study of 800 sun-like stars within 200 lyr.
Using rented telescopes from 1995-2004
What was the conclusion of Project Phoenix?
We live in a quiet neighbourhood
Who donated to SETI in 2000?
Paul Allen to build huge array for SETI
What is the Allen Telescope array made up of?
350x 6.1 m dishes
What is the Drake Equation?
Estimate number of civilisations in the Milky way today able to communicate with us
What are the two types of extraterrestrial signals?
Passive signals
Active signals
What is Ns in the Drake Equation?
Number of relevant stars in the milky way.
Roughly 100 billion
What is fs in the drake equation?
Fraction of solar-type stars
Roughly 1/200
What is Np in the drake equation?
Number of planets per solar-type star
Estimated 0.1
What is fe in the drake equation?
Fraction of planets that are Earth-like
Estimated 0.1
What is fi in drake equation?
Fraction of Earth-like planets on which life develops
Estimated 0.2
What is fc in the drake equation?
Fraction of planets with life that develop civilisation
Estimated 0.5
What is L in the drake equation?
lifetime of civilisation as a fraction of the lifetime of the Milky Way
Estimated X/10 power of 10
What is the overall value calculated from the drake equation?
X/20000
If civilisations last for one million years what is estimation for number of civilisations in the galaxy?
50
What would be the average seperation in the galaxy?
5500 ly
What is the quietest part of the EM-spectrum?
3cm < x < 30cm
Why is the wavelengths 18-21cm especially quiet?
It is the water hole
Strongest hydroxyl radical OH radiates at 18cm and Hydrogen at 21cm
What is Pioneer 10?
Active SETI
Carry plaque in case its found by intelligent life-forms
12 billion km away
How have humans been unintentionally sending out transmittions into space?
Radio, TV, radar
How far away can we be detected?
4000 ly
900 million stars at this distance
What message was sent out in 1974?
Sent by Arecibo to globular cluster M13
23 rows by 74 columns
What messages have been recieved?
Wow signal 1977
Ohio State Uni radio observatory
30x above background noise
What is a low frequency array?
Radio telescope working at lowest frequency accessible from earth.
Combine receives with computing
LOFAR in the UK?
Near Winchester opened in 2010
Where was green bank telescope tuned to?
21cm emission come from interstellar hydrogen
What are the 4 things on Pioneer plaque?
Outline of humans
Position of sun relative to 14 pulsars
Map of our SS
Transition in neutral hydrogen
