1. Question The theory which resolves both the horizon and flatness problems is called: A) Decoupling B) Relativity C) Inflation D) Big Bang

2. Question The main difference between a “normal” galaxy and an active one is: A) fuel supply B) active galxies have a black hole at the center, but “normal”galaxies don't C) “normal” galaxies can only be Elliptical D) an active galaxy is a Quasar

3. Question We know that all the Galaxies must have been at one point in the distant past because ___________. A) all observations of distant galaxies show that they are moving away from us with a velocity proportional it their distance from us B) the Universe is flat C) local galaxies are sometimes moving towards us and sometimes moving away from us D) space-time can travel faster than the speed of light

4. Extraterrestrial Life (as We Know It)‏ “Life as we know it” is generally taken to mean carbon- based life that originated in a liquid-water environment. Requirements?

5. Extraterrestrial Life (as We Know It)‏ “Life as we know it” is generally taken to mean carbon- based life that originated in a liquid-water environment. Requirements? Liquid water, protection from radiation, temperate climate What are some important characteristics of living organisms?

6. Characteristics of a Living Organism Reacting to environmental stimuli Taking in nourishment and growth/healing Reproducing and passing on characteristics Genetic changes (mutations/evolution)

7. Extraterrestrial Life Assumptions of mediocrity: Life on Earth depends on just a few basic molecules. Elements are common to all stars. Laws of physics the same everywhere => life fairly common in the cosmos.

8. The Miller-Urey experiment attempts to recreate the chemical conditions of the primitive Earth in the lab, and synthesize building blocks of life.

9. ET Life in the Solar System? Besides the Earth, which bodies in our solar system are most likely to harbor life?

10. The Moon and Mercury lack liquid water, protective atmospheres, and magnetic fields.

11. Venus has far too much atmosphere.

12. Planet most likely to harbor life Mars, but No Liquid water Atmosphere is thin Lack of magnetism and ozone layer Jovian moons Titan and Europa!

13. The Drake Equation number of technological, intelligent civilizations in the Milky Way rate at which new stars are formed (avg. over galactic lifetime)‏ = x fraction of stars having planetary systems x average number of habitable planets within those planetary systems x fraction of those habitable planets on which life arises x fraction of those life-bearing planets on which intelligence evolves fraction of those planets with intelligent life that develop technological society average lifetime of a technological civilization x x Each term is less certain than the preceding one! Only in last ten years have we addressed the second term.

14. Contact? How might we go about trying to determine whether or not technologically advanced civilizations exist in our galaxy?

15. SETI Search for ExtraTerrestrial Intelligence - Listens for radio signals from alien worlds Clear window on the cosmos? - Electromagnetic spectrum, as viewed from Earth, is a noisy place Microwave Window - in radio part of EM spectrum - Photons travel relatively unhindered through the interstellar medium, at the speed of light - Natural noise is at a minimum

16. The Water Hole Barney Oliver dubbed the spectral region between H and OH the Cosmic Water-Hole. "Where shall we meet our neighbors?" he asked. "At the water-hole, where species have always gathered." The Water Hole