Phys 1810: Lecture 36 Life on Other Worlds continued.

1. Phys 1810: Lecture 36 Life on Other Worlds continued. Today is last office hour. Coming up: Can we communicate with aliens? Hunt for them? Review for exam. Example of Extremophiles: Tardograde

2. Life as we know it – searching for Mr. Spock. Term 1  More accurately determined. Term 2  Term 3  Term 4  Term 5  Difficult to estimate. • N = the number of civilizations now = # of stars in the Milky Way * fraction of appropriate stars * fraction of those stars with planetary systems * # of planets suitable for life in each exoplanet system *fraction of suitable planets upon which intelligent life appears * fraction of planets that produce a civilization with interstellar communication * lifetime of that civilization / time that appropriate stars have existed. Term 6  Term 7  Term 8 

3. Life as we know it – searching for Mr. Spock. Discuss with your neighbour how long civilizations last. Consider the Egyptians right through to how long radio broadcasts have existed. Does nuclear war or climate change play a role in your estimate of a technological civilization’s lifetime? • N = lifetime of that civilization / 30 • N = 120 * lifetime of that civilization • N = lifetime of that civilization / 10 * 10**9 • N = lifetime of that civilization Calculate how many civilizations that we might be able to communicate with could exist in the Milky Way.

4. afternoon: less than 1 

5. Given your estimates, should we send signals or travel by spaceship? • Spend all our resources on building spaceships. • Broadcast messages. • Lurk – study EM signals from space and see if we can see any sign of them and then decide. Can we expect to communicate with them even if we travel at the speed of light? E.g. send/receive signals.

6. Communicating Over the Vastness of Space • Adopt 10 million years for lifetime of a technological civilization that wants to communicate.

9. Communicating Over the Vastness of Space Is this estimate reasonable? • Adopt 10 million years for the lifetime of a technological civilization. • 1 communicating civilization within a sphere with radius of 420 ly. • sends out a message at the speed of light, we receive it and return a message. • 840 yrs to say “hi” to each other. • If the civilization lifetime is about 1000 years, radius of sphere is about 10,000 years (i.e. longer than the lifetime of the civilization).

10. Closer? • statistically 1 in every 5 stars has an Earth-sized planet in HZ • http://www.keckobservatory.org/recent/entry/one_in_five_stars_has_earth_sized_planet_in_habitable_zone  Only 12 ly away – but it doesn’t mean it is inhabited or has a technological civilization!

11. Potentially Habitable Planets • Planetary Habitability Laboratory • Life, not necessarily technological civilization

12. Kepler Space Mission 42 CCDs • Now have 405 planetary systems with planets M<10*M_Earth. (333 multiple planet systems) • 885 planets • Transit method (photometry)

13. Search for Extra-terrestrial Intelligence - SETI • “water hole” for sending & receiving radio signals • molecules for water, presuming H20 is alien’s solvent • galactic & atmospheric transmission relatively low

14. Search for Extra-terrestrial Intelligence - SETI • Dr. Shelley Wright (U. Toronoto) Oct 2014 • What if they want to communicate? • near-infrared detectors • designing & constructing a new SETI instrument • search for pulsed laser signals in near-infrared: 900 - 1700 nm • optical lasers with strong pulsed signals at nanosecond (or faster) intervals are distinguishable from astrophysical sources, & give a sufficiently high intensity over optical background noise.

15. Search for Extra-terrestrial Intelligence - SETI The SETI Institute just held a workshop on non-human communication that examined the complex languages used by other life forms on this planet. The insights that we gain into the fundamental aspects of communication from those types of studies inform us potentially about communication with non-terrestrial life forms.”

16. JWST & SETI • upcoming James Webb Space Telescope (JWST) should be able to detect chlorofluorocarbons (CFCs) -- ozone-destroying chemicals used in solvents and aerosols – if signal of CFCs atmospheric levels were 10 times those on Earth. • "We consider industrial pollution as a sign of intelligent life, but perhaps civilizations more advanced than us, with their own SETI programs, will consider pollution as a sign of unintelligent life since it's not smart to contaminate your own air," says Harvard student and lead author Henry Lin.

17. Search for Extra-terrestrial Intelligence - SETI • SETI@home – help look for signals in radio telescope data • http://setiathome.ssl.berkeley.edu/

18. Search for Extra-terrestrial Intelligence - SETI How do you feel about the vastness of our Galaxy and the effort to search for signs of other life?

19. How do you think encountering another life form would impact us?

20. Have we evidence of alien visitations? (In the realm of “belief” or myth.)

21. Crop Circles Are Made By Aliens

22. The Ream of Belief: Crop Circles - Context Photo: G. Steinmetz • Spiral Jetty by Robert Smithson 1970. • Art movement creating “earthworks” • Dealing with themes of environment, nature, mortality, etc.

23. The Ream of Belief: Crop Circles • Flattened crops ppeared in the mid-1970’s in farmer’s fields in the UK. • A person studying crop circles is called a cereologist. • They claim these are impossible to be made by humans so the causes must range from UFOs to a “higher force”.

24. The Ream of Belief: Crop Circles – Hoaxes and/or Artwork • However crop circles can be made by humans. Anything drawn with a compass can be made into a crop circle. • Artists Doug Bower and David Chorley acknowledged their work in the early 1990s. • Documented themselves making crop circles for the BBC

25. The Ream of Belief: Crop Circles – Hoaxes and/or Artwork Circlemakers using a Stalk Stomper to flatten crop. • Received the Ig Nobel prize from Improbable Research for PHYSICS • “David Chorley and Doug Bower, lions of low-energy physics, for their circular contributions to field theory based on the geometrial destruction of English crops.”


26. The Ream of Belief: Crop Circles – Hoaxes and/or Artwork • Taken on by Circlemakers and others around the world. • See http://www.circlemakers.org • At the beginning of August 2004 circlemakers John Lundberg, Rod Dickinson and Wil Russell were asked by National Geographic TV.

27. The Ream of Belief: Crop Circles – Hoaxes and/or Artwork • Magician Brian Brushwood. • http://www.youtube.com/watch?v=zAsTZHtc9XQ • 3 hour documentary on YouTube (listed on my class website) has “artists statements” – they don’t think of them as making hoaxes. • Also YouTube videos of Matthew Williams who was convicted of making crop circles and stridently debunks them.

28. The Realm of Belief: Debunking Hoaxes Overall Context: Myth Akhenaten and Family 1348-1336 BC Museum of Berlin • Learned while studying art history that the only way to replace a myth is with a counter-myth. • E.g. Egypt’s pantheon of many deities replaced with one deity and then back to the pantheon.

29. The Realm of Belief: Debunking Hoaxes Overall Context: Myth Tarkovsky’s Nostalghia • University’s role is not to replace myths but to produce critical thinkers. • Let’s assume, like the movie maker Andrei Tarkovsky (e.g. Nostalghia, Solaris, The Sacrifice, The Stalker) that peoples actions are not predicated on reason but on their beliefs.

30. The Realm of Belief: Debunking Hoaxes Overall Context: Myth • Some people want to know if their beliefs are: • “Well”-founded: that they have other supports besides pure faith. (“Is my belief related to factual truth?”) • Ethical: the beliefs don’t negatively impact other people. • If people feel their beliefs are not well-founded or ethical then perhaps they may modify their belief.

31. The Realm of Belief: Debunking Hoaxes Overall Context: Truth “Truth” and Philosophy. • Plato (Greek about 428-347 BC; The Republic) • Truth is the “ideal” and not of our material world. • Boethius (about 480-525; Christian Roman) • Truth is beautiful.

32. Scientific Method: Gottfried Wilhelm Von Leibniz • There are 2 kinds of truths; those of reasoning and those of fact. • Truths of reasoning are necessary, and their opposite is impossible. • And those of fact are contingent, and their opposite is possible.

33. The Realm of Belief: Debunking Hoaxes Overall Context: Truth • Michel Foucault (1926 – 1984) • The most relevant to hoaxes. • "... by truth I do not mean 'the ensemble of truths which are to be discovered and accepted,' but rather 'the ensemble of rules according to which the true and the false are separated and specific effects of the power attached to the true,' ..." (Power/Knowledge: Selected Interviews and Other Writings)

34. The Realm of Belief: Debunking Hoaxes Overall Context: Building a Perspective (on the Universe) • An analogy: There are 2 ways to build the tallest building. Look around and see which buildings are the tallest. Then either • actually build a building taller than the others, or • tear down all the tall buildings and claim your building is the tallest. If “tall” == “truth” then using experiments and observations is analogous to 1. Using pseudo-science is analogous to 2.

35. The Realm of Belief: Debunking Hoaxes Overall Context: Building a Perspective (on the Universe) Clementine/NASA 1994 • We did #1 since this is a science class. It provides lasting empowerment.