Bellwork 10/20 Happy Friday  What features or events do we need to consider when searching for extraterrestrial life in our galaxy?

Thursday: Astrobiology lab design & proposal Next week (3-day week) This week: Today: Search for Extraterrestrial Life--Locations of astrobiology research Thursday: Astrobiology lab design & proposal Next week (3-day week) Monday: Astrobiology lab set-up Wednesday: Astrobiology lab data collection & write-up Hand out Unit 2 review --Test Thursday Nov. 3rd

“How many red cars are there in the city of Chicago?” Bellwork 10/23 Happy 3-day-week  “How many red cars are there in the city of Chicago?” …What information would you need to start figuring out the answer to this question

Coming Up… Today: Habitable Zones, Drake Equation, Search for Exoplanets Monday 10/23: Finish Exoplanets, Intro to Astrobiology, Set up practice Lab Wednesday 10/25: Collect practice lab data, complete research proposal Tuesday 10/31: Set up astrobiology lab, review Thursday 1/2: TEST (and collect data) Monday 11/6: Finish data collection & write up

Search for Extraterrestrial Life How do we do this? Where have we looked? Where will we look?

What pieces of information would we need to start calculating this? “The Drake Equation” Calculating the possibility of life capable of communication in our galaxy What pieces of information would we need to start calculating this?

R*,the rate of formation of stars in our galaxy X-ray photograph of the centre of our galaxy. More info: http://chandra.harvard.edu/photo/2003/0203long/

fp, the fraction of stars that have planets around them Image credits: http://nix.larc.nasa.gov/info;jsessionid=9tdfdearf9q4h?id=GPN-2000-000930&orgid=12 This stellar swarm is M80 (NGC 6093), one of the densest of the 147 known globular star clusters in the Milky Way galaxy. Located about 28,000 light-years from Earth, M80 contains hundreds of thousands of stars, all held together by their mutual gravitational attraction. Globular clusters are particularly useful for studying stellar evolution, since all of the stars in the cluster have the same age (about 15 billion years), but cover a range of stellar masses. Every star visible in this image is either more highly evolved than, or in a few rare cases more massive than, our own Sun. Especially obvious are the bright red giants, which are stars similar to the Sun in mass that are nearing the ends of their lives.

ne, the number of planets that could develop an ecosystem in each planetary system

fl the fraction of suitable planets which develop life

fi the fraction of life-bearing planets which develop intelligent life

ft the fraction of intelligent life bearing planets which develop technology

L, the length of time the civilization releases signals into space What if they’ve already tried to contact us and we missed the call?

To work out the number of civilizations in our galaxy with whom we might have a hope of communicating, we multiply all these factors together.

Different astronomers and cosmologists use different values for each of these factors. There are problems with the Drake equation…lots of things have changed since 1961… Used as a tool to estimate & to analyze what needs to be considered in the SETI However, it is generally thought that there is a finite chance of contacting extraterrestrial intelligent beings.

Where are we looking? Within our Solar System Moons, Asteroids, Comets Rethinking the habitable zone Outside of our Solar System Exoplanets

“Minor Members” of the Solar System Comets, Asteroids, Meteoroids These objects formed at various times throughout the birth of the solar system Kepler’s Laws still apply here!

Comets Often called "dirty snowballs“ Large, icy bodies Formed at the start of Solar System formation Composition Frozen gases Rocky and metallic materials

Where do Comets come from? Short-period comets originate in the Kuiper belt (in orbit beyond Neptune) Halley’s Comet: Period of 76 years Long-period comets originate in the Oort cloud (a “shell” of icy objects in the outermost reaches of our Solar System) How would the Kuiper belt have formed?

Asteroids Most lie between Mars and Jupiter Large, rocky bodies with an irregular shape Orbits can be very eccentric Origin is uncertain, but likely formed during planetary formation Jupiter might be at fault here…

Meteoroids, Meteors, Meteorites?!

Meteoroids Meteoroids are referred to as meteorites when they are found on Earth Small, rocky bodies Created through collisions with larger objects OR fragments of comets & asteroids

What is a Meteor Shower? Meteor Shower: Orionids Occur when Earth passes through the path of a comet As the comet burns up & pieces fall off, creating meteoroids (Which then fall through Earth’s atmosphere) Meteor Shower: Orionids October 2th-November 7th Peak night: Oct. 20-22 ~20 meteors/hr (a moderate year)

So, we know where to look…but how do we look?

Great! But how do we search for E.T. life? Within our Solar System: Sending satellites/probes to moons Enceladus: moon of Saturn Europa: moon of Jupiter Studying minor members of the Solar System

Great! But how do we search for E.T. life? Outside our solar system 1. Kepler telescope & photometer—searching for possible life-supporting exoplanets How: “Transit method”—astronomers measure distant stars’ light curves to detect orbiting planets Demo “To detect an Earth-size planet, the photometer must be able to sense a drop in brightness of only 1/100 of a percent. This is akin to sensing the drop in brightness of a car's headlight when a fruit fly moves in front of it! The photometer must be space based to obtain this precision.” --Kepler.nasa.gov

Kepler Website

How can we study these places if we cannot reach them? Astrobiology labs on Earth! “The Astrobiology Analytical Laboratory is dedicated to the study of organic compounds derived from sample return missions, meteorites, lab simulations of Mars, interstellar, proto-planetary, and cometary ices and grains, and instrument development.”--NASA

Research Location Proposal Google Doc