The Origin and possible existence of Life in the Universe

Do you think there is life  even just primitive forms of life  on other worlds? Poll Question:

Do you think there is intelligent life on other worlds? YESNOUNDECIDED

The Electromagnetic Spectrum

Use a stamp “X” to select the most abundant element in the universe. neonnitrogenhydrogenoxygen heliumcarbonsodiumiron

Axis of rotation Approx. 1 light year Axis of rotation Rotation retards collapse in this direction Slowly spinning interstellar cloud Gravity makes cloud shrink. As it shrinks it spins caster and flattens into a disk with central bulge. Approx. 100 AU

Big Questions in Science Where did we come from? Are we alone? Questions about origins: Other astrobiology questions: 1.How did life on Earth form? 2.Should we expect life on many other worlds? 3.Is life on other worlds like life on Earth? 4.How can we detect life elsewhere?

Poll Question: What chemical elements were created by the Big Bang?

The Life Cycle of Stars…

NH 3 H2H2 CH 4 H2OH2O

Put a stamp on the most abundant element in life on Earth. neonnitrogenhydrogenoxygen heliumcarbonsodiumiron

The Most Abundant Chemical Elements  in the Universe and in Life H He O C N In the UniverseIn Life H O C N

Life on Earth is carbon-based. Life on Earth requires liquid water The amino acids in life are easily formed. A few facts about Life on Earth

Finding Life First find planets. One way uses the Doppler Effect.

Another way to find planets is to look for transits.

Kepler Terrestrial Planet Finder

Signs of Life (not yet possible to detect with current technology) Seasonal changes Unusual abundances of gases Gases produced by life Unusual patterns of electromagnetic radiation (e.g., radio or TV broadcasts, the nighttime glow of cities)

Bacterial fossils 3 billion years old on the earth. Will we find them on Mars or elsewhere?

Records of Life on Earth Life elsewhere could be similar to any of These stages, or entirely different.

Current Life Forms We can study these in detail to get DNA, etc.

Amino Acids: building blocks of life. Some of these were produced in the lab by Harold Urey out of primeval gases like methane, ammonia, carbon dioxide-- by zapping them with electricity (lightning). (1950s)

Human DNA Nobody has produced this artificially or even hopes to. Too complicated. 50,000 genes. However, the total makeup Of a human being requires More information.

The distance between civilizations in the Milky Way N=no. of civilizations. R=radius of spherical galaxy r = average separation. 4 pi (r/2) 2 N = 4 pi R 3 /3 implies r = 2R/N 1/3.

The Drake Equation

N = N* fp ne fl fi fc fL N* represents the number of stars in the Milky Way Galaxy Question: How many stars are in the Milky Way Galaxy? Answer: Current estimates are 100 billion. fp is the fraction of stars that have planets around them Question: What percentage of stars have planetary systems? Answer: Current estimates range from 20% to 50%. ne is the number of planets per star that are capable of sustaining life Question: For each star that does have a planetary system, how many planets are capable of sustaining life? Answer: Current estimates range from 1 to 5.

The Drake Eqn. continued N = N* fp ne fl fi fc fL fl is the fraction of planets in ne where life evolves Question: On what percentage of the planets that are capable of sustaining life does life actually evolve? Answer: Current estimates range from 100% (where life can evolve it will) down to close to 0%. fi is the fraction of fl where intelligent life evolves Question: On the planets where life does evolve, what percentage evolves intelligent life? Answer: Estimates range from 100% (intelligence is such a survival advantage that it will certainly evolve) down to near 0%. fc is the fraction of fi that communicate Question: What percentage of intelligent races have the means and the desire to communicate? Answer: 10% to 20%

The Drake Eqn. continued N = N* fp ne fl fi fc fL fL is fraction of the planet's life during which the communicating civilizations live Question: For each civilization that does communicate, for what fraction of the planet's life does the civilization survive? Answer: This is the toughest of the questions. If we take Earth as an example, the expected lifetime of our Sun and the Earth is roughly 10 billion years. So far we've been communicating with radio waves for less than 100 years. How long will our civilization survive? Will we destroy ourselves in a few years like some predict or will we overcome our problems and survive for millennia? If we were destroyed tomorrow the answer to this question would be 1/100,000,000th. If we survive for 10,000 years the answer will be 1/1,000,000th. N, the number of communicating civilizations in the galaxy.

SETI—Search for Extraterrestrial Intelligence Over 30 messages suspiciously intelligent. They are using home computers to scan for messages.

Mars had ( and has) water. Does it have current life?

Summary We have learned an enormous amount about the origins of stars and planets. We are just starting to learn about life in the universe. These explorations require a team effort involving scientists from many disciplines. There is still much more to explore. Students will be able to make discoveries and help us learn even more!

NASA’s Navigator Missions: Origins Education Forum:

Poll Question: Do you think there is life  even just primitive forms of life  on other worlds?

Do you think there is intelligent life on other worlds? YESNOUNDECIDED