Lecture 39. Does Life Elsewhere Seem Likely? The Psychological Impact of Finding Life Elsewhere. reading: Chapter 14

Does Life Elsewhere Seem Likely? Heavy elements/protoplanetary disks/extrasolar planets are abundant, and likely increasing with time The chemical elements that comprise life and water are pervasive in the universe Organic compounds are also pervasive in the universe - interstellar medium - PAHs, amino acids, simple organics in meteorites and comets - organic synthesis on the early Earth Life seems to have appeared early in Earth’s history

Does Life Elsewhere Seem Likely? Life on Earth is robust - life in extreme environments/life is pervasive - has survived very nasty extinction events Life is adaptable - Darwinian evolution has resulted in pervasive life - filling niches - natural selection has made that life very successful - adept at competition for resources The vastness of space/number of galaxies/number of stars in the galaxies

The Rare Earth Thesis Peter Ward and Don Brownlee at the University of Washington, microbial life should be widespread in the universe -complex life such as plants and animals will be extremely rare -Earth is “lucky” -complex Earth life is the result of an extraordinary set of conditions and random chance events -microbial life appeared quickly; complex life recently -Earth is also special: -in the habitable zone -life-friendly atmosphere -Jupiter and the Moon beneficial -placid part of the galaxy

Again, the question: Is life a natural product of habitable planetary systems? OR Is life rare - a rare coming together of unlikely events?

How To Answer These Questions? Put this in the scientific context of hypothesis testing. -study of early life on Earth -exploration of our solar system (Mars, Europa) -search for terrestrial extrasolar planets -search for signatures of life on extrasolar planets -search for ETL by SETI-type searches

What Would Be The Psychological Impact of Finding Life Elsewhere? Intense public interest in the exploration of life on Mars and elsewhere in the galaxy. We are part of a vast cosmos. We are part of the Earth and the solar system. Finding evidence for life elsewhere would change our perspective on the world and the cosmos. Copernicus, Galileo, Kepler, and Newton changed our world view. Darwin and Wallace also changed how we view organisms changing through time.

The War of the Worlds Radio adaptation by Orson Welles of the H.G. Wells’ classic novel. Performed by Mercury Theatre on the Air on Halloween, Presented as a series of radio news bulletinsseries of radio news bulletins

Mysterious Martian CanalsMartian Canals 1877 Map of martian canali by astronomer Giovanni Schiaparelli

Mysterious Martian Canals, cont. Percival Lowell wealthy amateur astronomer founder of Lowell Observatory, Flagstaff, AZ strong proponent of canals used for irrigation dark spots at their intersections were oases changed with the seasons canals constructed to channel Mars’ scanty water supply

Fundamental Questions About Life in the Solar System Are other planets sterile? Is it related to Earth life? Is it an independent origin of life? Does it use similar molecules as Earth life? How do we look for an independent origin of life if it is completely different?

Microbial Life vs. Intelligent Life Which would have a more profound impact on our lives? Many Americans think only discovery of intelligent life will have a profound effect. But most scientists think that discovery of microbial life will be just as profound. The origin of life is not a unique event. Hard to predict just how people and society will react.

Alien Contact in Science Fiction 1.ETs could be a source of help in solving society’s problems (assumes we need outside help to solve our problems and ET would be willing to help) or learning about the secrets of the universe. 2.Fears about destruction or bodily harm (either deliberately or accidentally) 3.Analogies with human history - (contact between modern and non-technical societies results in subsuming of the non-technical into the modern, with loss of the non-technical culture)

SETI is Prepared! Declaration of Principle Concerning Activities Following the Detection of Extraterrestrial Intelligence: 1.verify the most plausible explanation of the evidence is ETL rather than natural phenomena. If it can’t be verified, may disseminate the info as an unknown phenomenon. 2. before announcing it, must inform all other observers or research organizations party to the declaration to confirm by independent observation. Inform national authorities. 3.Inform observers throughout the world via Central Bureau for Astronomical Telegrams of the International Astronomical Union. Inform secretary general of the UN. Inform: Intl Telecommunication UnionIntl Academy of Astronautics Committee on Space ResearchIntl Institute of Space Law Intl Astronomical FederationCommission 51 of the Intl Commission J of Intl Radio Science UnionAstronomical Union 4.Confirmed detection disseminated promptly, openly, and widely by discoverer through scientific channels and the public media

SETI is Prepared! 5.All data made public to international scientific community 6.Evidence should be recorded and stored permanently in a form to make it available for analysis and interpretation 7.Seek international agreement to protect the appropriate electromagnetic frequencies. 8.No response to a signal will be sent until appropriate international consultations have taken place. 9.SETI and Intl Astronomical Union will conduct a continuing review on the procedures for detection and the handling of data. An international committee of scientists will serve to analyze data and provide advice on release to the public. Maintain lists of people to contact if contact is made.

Astrobiology as a Science Exploring how planets and moons work. Exploring stars and galaxies to understand how the universe works. Learn more about the fundamental nature of life in the context of the solar system and the universe. How did life come to exist - how did it change with the planet? What does it mean to be alive and what does it mean to be human?

Have A Wonderful Summer!