1. The Big Bang! Unit 1

2. Origins How and when did the: How and when did the: universe form? universe form? solar system / Earth form? solar system / Earth form? Moon form? Moon form? What were early Earth conditions? What were early Earth conditions? How Do We Know?

3. Origin of the Universe Big Bang Big Bang occurred 13.7 billion years ago occurred 13.7 billion years ago model for the beginning of the universe model for the beginning of the universe

4. http://rainbow.ldeo.columbia.edu/courses/v1001/7.html - infinitely dense point not governed by our physical laws or time - all matter and energy contained in one point Building a Universe

5. http://rainbow.ldeo.columbia.edu/courses/v1001/7.html - instantaneous filling of space with all matter Building a Universe

6. Edwin Hubble Hubble’s Law States… Universe is continuously expanding Universe is continuously expanding Galaxy’s velocity is proportional to its distance (galaxies that are twice as far from us move twice as fast) Galaxy’s velocity is proportional to its distance (galaxies that are twice as far from us move twice as fast) taken every galaxy the same amount of time to move from a common starting position to its current position

7. Hubble’s Evidence Doppler shifting - wavelength emitted by something moving away from us is shifted to a lower frequency Sound of a fire truck siren - pitch of the siren is higher as the fire truck moves towards you, and lower as it moves away from you Visible wavelengths emitted by objects moving away from us are shifted towards the red part of the visible spectrum The faster they move away from us, the more they are redshifted. Thus, redshift is a reasonable way to measure the speed of an object (this, by the way, is the principal by which radar guns measure the speed of a car or baseball) When we observe the redshift of galaxies outside our local group, every galaxy appears to be moving away from us - universe is expanding.

8. Evidence for Big Bang Red shift - as light from distant galaxies approach earth there is an increase of space between earth and the galaxy, which leads to wavelengths being stretched In 1964, Arno Penzias and Robert Wilson, discovered a noise of extraterrestrial origin that came from all directions at once - radiation left over from the Big Bang In June 1995, scientists detected primordial helium in the far reaches of the universe - consistent with an important aspect of the Big Bang theory that a mixture of hydrogen and helium was created at the beginning of the universe

9. When Did the Universe Form? 10 to 20 billion years ago (13) 10 to 20 billion years ago (13) How do we know? How do we know? spreading (Red Shift) spreading (Red Shift) know distances, rates of retreat, relative positions know distances, rates of retreat, relative positions afterglow of the Big Bang afterglow of the Big Bang Orion Nebula - http://stardate.utexas.edu/resources/ssguide/planet_form.html

10. Features of Our Solar System Sun 8 planets 101 known moons (satellites) a tremendous number of asteroids most orbit the Sun between the orbits of Mars and Jupiter millions of comets and meteorites interplanetary dust and gases

11. Relative Sizes of the Sun and Planets

12. Solar System Configuration

13. Origin of Our Solar System Solar nebula theory formed a rotating disk formed a rotating disk condensed and collapsed due to gravity condensed and collapsed due to gravity forming solar nebula forming solar nebula with an embryonic Sun with an embryonic Sun surrounded by a rotating cloud surrounded by a rotating cloud cloud of gases and dust cloud of gases and dust

14. The Planets Terrestrial Planets Terrestrial Planets Mercury Mercury Venus Venus Earth Earth Mars Mars small, composed of rock, with metal cores small, composed of rock, with metal cores Jovian Planets Jovian Planets Jupiter Jupiter Saturn Saturn Uranus Uranus Neptune Neptune large, composed of hydrogen, helium, ammonia, methane, relatively small rocky cores large, composed of hydrogen, helium, ammonia, methane, relatively small rocky cores – Pluto?

15. Pluto Not classified as a Terrestrial planet because of its low density and small size Not classified as a Terrestrial planet because of its low density and small size Not classified as a Jovian planet due to its solid surface Not classified as a Jovian planet due to its solid surface Atmosphere composed of unknown quantities of methane and nitrogen Atmosphere composed of unknown quantities of methane and nitrogen