2. Earth in the Universe Or...where the heck did we come from?

3. Origin and age of the Universe The majority of scientists think that the universe is extremely vast and about 14 billion years old. The majority of scientists think that the universe is extremely vast and about 14 billion years old. They’re right, I was there. They’re right, I was there.

4. In the Beginning The Big Bang Theory The Big Bang theory states that about 14 billion years ago all matter and energy started out concentrated in a small area and started expanding after a massive explosion. The Big Bang theory states that about 14 billion years ago all matter and energy started out concentrated in a small area and started expanding after a massive explosion. After approximately a billion years, matter began to organize, forming stars and early galaxies and the universe kept expanding. After approximately a billion years, matter began to organize, forming stars and early galaxies and the universe kept expanding.

6. Evidence of Big Bang Cosmic background radiation (microwaves) from Big Bang mixed with energy given off by stars in all parts of the universe has been detected. Cosmic background radiation (microwaves) from Big Bang mixed with energy given off by stars in all parts of the universe has been detected. Celestial objects are moving away from Earth meaning that the universe is expanding. This is proven by a red shift in the electromagnetic spectrum due to the Doppler Effect. Celestial objects are moving away from Earth meaning that the universe is expanding. This is proven by a red shift in the electromagnetic spectrum due to the Doppler Effect.

7. Red Shift Every element in a star emits energy in specific electromagnetic wavelengths. Every element in a star emits energy in specific electromagnetic wavelengths. By measuring these, scientists see a shift in the colored lines toward the red or blue end of the spectrum. This is due to the Doppler Effect. By measuring these, scientists see a shift in the colored lines toward the red or blue end of the spectrum. This is due to the Doppler Effect. Short Waves Long Waves

8. The Doppler Effect Waves are compressed to the front and extended to the rear of a moving object. Waves are compressed to the front and extended to the rear of a moving object. When something is moving closer to Earth there is a blue shift and moving farther away a red shift. When something is moving closer to Earth there is a blue shift and moving farther away a red shift.

9. Structure of the Universe The basic structural unit of the universe is the galaxy. The basic structural unit of the universe is the galaxy. A galaxy is a collection of billions of stars and various amounts of gas and dust held together by gravity. A galaxy is a collection of billions of stars and various amounts of gas and dust held together by gravity. The average galaxy has over 100 billion stars and there are over 100 billion galaxies. The average galaxy has over 100 billion stars and there are over 100 billion galaxies. Our solar system is part of the Milky Way Galaxy. Our solar system is part of the Milky Way Galaxy.

10. The Milky Way The Milky Way is a spiral shaped galaxy. The Milky Way is a spiral shaped galaxy. Our solar system is positioned between two spiral arms about two-thirds of the distance out from the galactic center. Our solar system is positioned between two spiral arms about two-thirds of the distance out from the galactic center.

11. Milky Way – top view and side view. Milky Way – top view and side view.

12. Stars A star is a large ball of gas held together by gravity, that produces tremendous amounts of energy and shines. A star is a large ball of gas held together by gravity, that produces tremendous amounts of energy and shines. Our sun is Earth’s closest star. Our sun is Earth’s closest star.

13. Energy Production Nuclear fusion is the process of fusing together (or combining) two nuclear particles, such as two protons, or a neutron and a Uranium nucleus. Nuclear fusion is the process of fusing together (or combining) two nuclear particles, such as two protons, or a neutron and a Uranium nucleus. It occurs inside, and is the main way in which stars convert matter energy into electromagnetic energy. It occurs inside stars, and is the main way in which stars convert matter energy into electromagnetic energy.stars

14. Star Classification Stars are classified and grouped by surface temperature compared to luminosity. Stars are classified and grouped by surface temperature compared to luminosity. About 90% of studied stars appear in the main sequence. About 90% of studied stars appear in the main sequence. Our Sun is an average star in the middle of the main sequence. Our Sun is an average star in the middle of the main sequence. SUN

15. Birth of the Solar System The solar system formed about 5 billion years ago from a rotating disk of interstellar dust. The solar system formed about 5 billion years ago from a rotating disk of interstellar dust. Scientists hypothesize that the cloud began to slowly condense and spin due to gravitational attraction between particles. Scientists hypothesize that the cloud began to slowly condense and spin due to gravitational attraction between particles. As the cloud spun faster it collapsed into a disk shape with a dense center. As the cloud spun faster it collapsed into a disk shape with a dense center.

17. Geocentric Model The Geocentric Model of our Solar System, is a description of the cosmos where Earth is at the orbital center of all celestial bodies. This model served as the predominant cosmological system in many ancient civilizations such as ancient Greece. The Geocentric Model of our Solar System, is a description of the cosmos where Earth is at the orbital center of all celestial bodies. This model served as the predominant cosmological system in many ancient civilizations such as ancient Greece.cosmosEarth ancient GreececosmosEarth ancient Greece

18. Heliocentric Model Heliocentrism is the astronomical model in which the Earth and planets revolve around a relatively stationary Sun at the center of the Solar System. Heliocentrism is the astronomical model in which the Earth and planets revolve around a relatively stationary Sun at the center of the Solar System. astronomicalEarth SunSolar System astronomicalEarth SunSolar System

19. The Birth of the Sun As the concentration of gas continued to collapse, temperature and pressure at its center increased. As the concentration of gas continued to collapse, temperature and pressure at its center increased. The temperature and pressure became so great that nuclear fusion reactions began. The temperature and pressure became so great that nuclear fusion reactions began. This was the birth of our Sun. This was the birth of our Sun.

20. The Formation of the Planets The materials in the disk surrounding the young sun became the solar system’s planets and other objects. The materials in the disk surrounding the young sun became the solar system’s planets and other objects. Temperatures within the disk varied and as a result different elements and compounds condensed in different areas of the disk. Temperatures within the disk varied and as a result different elements and compounds condensed in different areas of the disk. Heavier elements condensed in the hotter region closer to the sun and lighter elements condensed farther out. Heavier elements condensed in the hotter region closer to the sun and lighter elements condensed farther out.

21. Celestial bodies smaller than planets called planetesimals at first formed. Celestial bodies smaller than planets called planetesimals at first formed. Through collisions and mergers the planets began to form. Through collisions and mergers the planets began to form. The densest material sank to the center of the forming planets. And the lighter elements formed layers closer to the surface. The densest material sank to the center of the forming planets. And the lighter elements formed layers closer to the surface.

22. For example, dense elements such as iron and nickel make up Earth’s core and less dense elements such as silicon and oxygen make up Earth’s crust.

23. The Terrestrial Planets The inner planets closest to the sun are all rocky and dense. All of the terrestrial planets are close in size to Earth. In order for the sun they are: Mercury, Venus, Earth and Mars.

24. Asteroid Belt The asteroid belt is the region of the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets.Solar Systemplanets MarsJupiter asteroidsminor planets

25. Jovian or Gas Planets The Jovian Planets are far from the Sun and largely gaseous. The Jovian Planets are far from the Sun and largely gaseous. They have relatively large diameters, low densities and no solid surfaces. They have relatively large diameters, low densities and no solid surfaces. These planets have many moons and rings. These planets have many moons and rings. In order from the Sun they are: Jupiter, Saturn, Uranus and Neptune. In order from the Sun they are: Jupiter, Saturn, Uranus and Neptune.

26. Pluto Little is known about Pluto due to its great distance from us. There is debate about whether it is actually a planet or a large asteroid. Currently, Pluto is not classified as a planet.

27. Our Solar System

28. How to Remember the Planets My Very Excellent Mother Just Served Us Nachos. My Very Excellent Mother Just Served Us Nachos. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

29. Motions of the Planets Planet rotation – spinning on an imaginary axis. Planet rotation – spinning on an imaginary axis. Period of rotation – the amount of time it takes for a planet to make one rotation. This determines the length of a planet’s day. Period of rotation – the amount of time it takes for a planet to make one rotation. This determines the length of a planet’s day. Ex. Earth’s period of rotation is 23hrs, 56min, 4 sec. Neptune is 16hrs. Ex. Earth’s period of rotation is 23hrs, 56min, 4 sec. Neptune is 16hrs.

30. Period of revolution – movement around the sun in a path called an orbit. Ex. Earth’s is 365.26 days, Pluto’s is 247.7 years. Period of revolution – movement around the sun in a path called an orbit. Ex. Earth’s is 365.26 days, Pluto’s is 247.7 years. A planet’s period of revolution increases the farther away it is from the sun. A planet’s period of revolution increases the farther away it is from the sun. Earth’s orbit and other planets is in a shape called an ellipse. Earth’s orbit and other planets is in a shape called an ellipse. The degree of flattening of an ellipse is called eccentricity. The degree of flattening of an ellipse is called eccentricity.

31. Revolution Eccentricity How far it is from a perfect circle. A perfect circle is 0, a straight line is 1.

32. How Eccentricity is Calculated distance between foci length of major axis Eccentricity = Major Axis Foci

34. The sun is always one of the focal points. The sun is always one of the focal points. The elliptical shape of planetary orbits causes the planets to vary in distance from the sun during a revolution. The elliptical shape of planetary orbits causes the planets to vary in distance from the sun during a revolution. Aphelion is farthest away and Perihelion is closest. Aphelion is farthest away and Perihelion is closest.

35. Gravity and Orbital Velocity Gravity – the attractive force that exists between any two objects in the universe. Gravity – the attractive force that exists between any two objects in the universe. Larger objects with more mass exert a greater gravitational force. Objects closer together also exert a greater gravitational force. Larger objects with more mass exert a greater gravitational force. Objects closer together also exert a greater gravitational force. When a planet is closest to the sun its orbital velocity increases. Farther away it decreases. When a planet is closest to the sun its orbital velocity increases. Farther away it decreases.

36. Closest to the Sun a planet has the fastest orbital velocity due to the gravitational pull of the Sun. Fastest here Slowest here