1 / 64

Are we alone? The search for life elsewhere in the universe Summary lecture John Webb

Are we alone? The search for life elsewhere in the universe Summary lecture John Webb Session 2, 2004. Our Place in the Universe Charley Lineweaver. Where are we? How old is the Universe? What is the Universe made of?. Where are we? How old is the Universe? What is the Universe made of?.

alain
Télécharger la présentation

Are we alone? The search for life elsewhere in the universe Summary lecture John Webb

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Are we alone? The search for life elsewhere in the universe Summary lecture John Webb Session 2, 2004

  2. Our Place in the Universe Charley Lineweaver

  3. Where are we?How old is the Universe?What is the Universe made of?

  4. Where are we?How old is the Universe?What is the Universe made of?

  5. 14 Gyr Age of Universe 13.4 +/- 1.6 Gyr Sievers02 WMAP03 Lineweaver 1999

  6. Star and Planet Formation Maria Hunt

  7. Organic Molecules in the Interstellar Medium Maria Hunt School of Physics UNSW

  8. Chemical Evolution of the Universe Big Bang Atoms Molecules Life

  9. What Are Organic Molecules? • Organic molecules are the molecules of life and contain carbon. • Only carbon (and perhaps silicon) have a chemistry complex enough to form life.

  10. What Molecules Are Out There? • We have found 123 different molecules, with up to 11 atoms • We see complex organic molecules in molecular clouds, including alcohol and vinegar. • We may also have seen the amino acid glycine. • But, to detect these in molecular clouds with our radio telescopes on Earth requires incredible quantities.

  11. How do we “see” molecules?

  12. A Better Place to Look? • Carbonaceous chondrites are meteorites that date back to the formation of the solar system. • They fall to earth on a regular basis. • They are found to contain many complex organic molecules, including amino acids. • Comets are also remnants of the presolar nebula.

  13. Carbonaceous chondrite, found to contain organic molecules with both left and right hand spiral structure

  14. The History of Life on Earth Malcolm Walters

  15. 3 branches: Bacteria Archea Eucarya

  16. Universal tree of life: • most life is microscopic • hyperthermophiles at base of tree • abundant hydrothermal deposits in the rock record • good but still controversial evidence of life at 3.5Ga • early Earth like early Mars

  17. The Origin and Evolution of Life Charley Lineweaver

  18. Stanley Miller 1953

  19. primordial soup in a warm little tidal pool hydrothermal vents Where? Mars

  20. Origin of LifeEvolution of LifeWhat is Life?

  21. Searching for Extra-solar Planets John Webb

  22. Methods for detecting extrasolar planets 1. Astrometry (measuring stellar positions) 2. Doppler method (planet and star orbit a common centre of mass) 3. Gravitational lensing (spacetime distortion) 4. Reflected light (like looking at the planets from Earth) 5. Eclipse (or occulting or transit) method

  23. Maybe we can detect an atmosphere! ~1% relative drop

  24. TPF - terrestrial planet finder Are We Alone? • IR interferometer, 5 cooled 3.5m mirrors • ~75-1000 m baseline • Separate spacecraft for configuration flexibility • 1 milli-arcsec (mas) • Spectral Resolution 20-300 • Operate at 1 AU for 5 years • Launch date 2011? What does 1 mas mean? If you put TPF on Earth, you could resolve a man’s face on the Moon! (For comparison, the AAT could only just resolve the building we are in).

  25. TPF eliminates light from host star using “NULLING” Are We Alone? 3. Time-series as TPF rotates 2. Target through TPF interference fringes 1. Simulated target

  26. The Drake equation Are We Alone? No. of advanced civilisations which we might contact: N = (N*f) x (Np/* fsuitable) x (fislifefsmart) x (Ladv/Lmw) Things we can guess (on the basis of our solar system): Np/*= no. of planets per star = 9 (as for our Sun) fsuitable = fraction suitable for life = 1/9 fislife = fraction of the above WITH life = 1 fsmart = fraction of the above with ADVANCED life = 1 Lmw = lifetime of Milky Way Galaxy; upper limit = age of universe = 14 billion years Things we know well: N* = no. of stars in MW galaxy = 300 billion f = fraction “similar” to our Sun = 1/3 Things we haven’t got a clue about: Ladv = lifetime of civilisation in its advanced phase = 200 years (assuming we last that long!) NB: 1 billion = 1000 million = 109

  27. Artificial Intelligence- Our Future? Michael Ashley

  28. Overview • Artificial life • Robotics/nanotechnology • The exponential growth of computing power • The human brain as a computer • Can a computer be intelligent? (Turing test) • The near-term future for life on Earth • Speculations about the long-term future

  29. Exponential growth in computing - historical data • 1900 Babbage’s Analytical Engine. • 1910 Mechanical calculators • 1943 Colossus • 1946 ENIAC • 1951 Univac I • 1960 IBM 1620 • 1966 IBM 360 model 75 • 1976 PDP-11 • 1979 DEC VAX 11/780 • 1982 IBM PC • 1993 Pentium • 2002 Pentium 4

  30. Plot of Moore’s Law

  31. Exponential growth - an example • One grain of rice on the first square. • Two on the second. • Four on the third. • And so on, doubling with each square. • The result? • At the half-way point, 4 billion grains of rice (about one large field). • After 64 squares, you would need a field twice as large as the Earth’s surface. • NOTE: no one really noticed the problem until the half-way point. • And that is where we are with computers today... The Emperor of China was so impressed with the game of chess, that he asked the inventor to name his price.

  32. Can we stop the machines? • In 1962, if you turned off all the computers in the world, it would have had little effect. • In 2004, the same experiment would have devastating consequences (e.g., financial system collapses, no electricity, no water, no fuel, no public transport). • This process will accelerate. • There will come a point when the machines are in control. • We are becoming more dependent on computers with each passing year. So, we can not stop them. But this may not be such a bad thing.

  33. New Aproaches to SETI Paul Davies

  34. Was itchanceorlaw?

  35. ‘Man at last knows that he is alone in the unfeeling immensity of the universe, out of which he emerged only by chance.’ Jacques Monod

  36. Biological determinism Life

  37. “The universe is pregnant with life…” “Life is a cosmic imperative!” “Life is almost bound to arise… wherever physical conditions are similar (to Earth).”

  38. Better “message-sending” strategy: use nanomachines Self-repairing Self-replicating Adaptive Living cells!

  39. The Anthropic Principle Joe Wolfe

  40. Weak anthropic principle (WAP) If we think that our existence requires certain conditions/laws of nature/... then discovering that those conditions/laws apply is not surprising. Strong anthropic principle (SAP) Our existence requires certain conditions/laws. These conditions/laws are improbable therefore (?) the Universe/laws of physics are that way in order for us to exist, therefore .....

More Related