1. Light Years Away ….. Distances to Common Celestial Bodies

2. How Far is a Light Year???? A light-year is equal to: A light-year is equal to: 9,460,730,472,580.8 kilometers 9,460,730,472,580.8 kilometers about 5,879,000,000,000 miles about 5,879,000,000,000 miles about 63,240 astronomical units about 63,240 astronomical units The astronomical unit (AU) is a unit of length equal to the distance from the Earth to the Sun (about 93 million miles). The astronomical unit (AU) is a unit of length equal to the distance from the Earth to the Sun (about 93 million miles).

3. How fast is Light?? Reflected sunlight from the Moon's surface takes 1.2-1.3 seconds to travel the distance to the Earth. Reflected sunlight from the Moon's surface takes 1.2-1.3 seconds to travel the distance to the Earth. The average distance from the Earth to the Moon is 384,403 kilometers or (238,857 miles) The average distance from the Earth to the Moon is 384,403 kilometers or (238,857 miles)

4. How Long From the Sun to the Earth??? It takes approximately 8.31 minutes for light to travel from the Sun to the Earth. It takes approximately 8.31 minutes for light to travel from the Sun to the Earth. This distance is referred to as One Astronomical Unit (AU). This distance is referred to as One Astronomical Unit (AU).

5. What about Pluto??? It takes approximately 5.5 light-hours from light to travel to the surface of Pluto It takes approximately 5.5 light-hours from light to travel to the surface of Pluto Pluto’s orbit takes it from 29 to 49 AU (2.7–4.5 billion mi) from the Sun Pluto’s orbit takes it from 29 to 49 AU (2.7–4.5 billion mi) from the Sun Pluto is mostly brown. No spacecraft has yet visited this distant object in our Solar System

6. What is a Light Day Away?? The most distant space probe, Voyager 1, was about 28 light-hours (round-trip light time) away from Earth in the week ending March 9, 2007. The most distant space probe, Voyager 1, was about 28 light-hours (round-trip light time) away from Earth in the week ending March 9, 2007. It took that space probe 30 years to cover that distance It took that space probe 30 years to cover that distance

7. How fast Can Astronauts Travel??? If we use the calculations from the previous slide, Voyager traveled ½ light day in approximately 15 years. If we use the calculations from the previous slide, Voyager traveled ½ light day in approximately 15 years. If we travel at the speed of the Voyager then it would take approximately 30 years to travel one light day If we travel at the speed of the Voyager then it would take approximately 30 years to travel one light day One light year would take over 11,000 years!!!!! One light year would take over 11,000 years!!!!!

8. The Oort Cloud?? The Oort cloud is nearly a light year from the sun and approximately 2 light-years in diameter. The Oort cloud is nearly a light year from the sun and approximately 2 light-years in diameter. The Oort cloud, is a spherical cloud of comets situated about 50,000 AU from the Sun. The Oort cloud, is a spherical cloud of comets situated about 50,000 AU from the Sun. This is approximately 1000 times the distance from the Sun to Pluto This is approximately 1000 times the distance from the Sun to Pluto Sedna is the outmost celestial body in our Solar System

9. Alpha Centauri is the closest star system to our own solar system at 4.37 light-years away (about 25.8 trillion miles or 277,600 AU). Alpha Centauri is the closest star system to our own solar system at 4.37 light-years away (about 25.8 trillion miles or 277,600 AU). What About the Nearest Star??

10. What About Our Milky Way Galaxy?? The center of our galaxy, the Milky Way, is about 2600 light years away. The center of our galaxy, the Milky Way, is about 2600 light years away. The Milky Way Galaxy as seen from Death Valley, California Infrared image of the Milky Way. Many of the stars in this image cannot be seen in visible light

11. What About the Nearest Galaxy?? The Andromeda Galaxy is a spiral galaxy approximately 2.5 million light-years away. The Andromeda Galaxy is a spiral galaxy approximately 2.5 million light-years away. It is the nearest galaxy to our own, the Milky Way. It is the nearest galaxy to our own, the Milky Way. Andromeda is the largest galaxy of a group of galaxies, which consists of the Andromeda Galaxy, the Milky Way Galaxy, the Triangulum Galaxy, and about 30 other smaller galaxies. Andromeda is the largest galaxy of a group of galaxies, which consists of the Andromeda Galaxy, the Milky Way Galaxy, the Triangulum Galaxy, and about 30 other smaller galaxies.

12. How Far Can I See?? The Triangulum Galaxy is a spiral galaxy approximately 3 million light-years away The Triangulum Galaxy is a spiral galaxy approximately 3 million light-years away The Triangulum Galaxy is the most distant object that can be seen without the use of a telescope The Triangulum Galaxy is the most distant object that can be seen without the use of a telescope

13. Work Cited Slide 3: Surface of the Moon, http://en.wikipedia.org/wiki/Image:Moon-Mdf-2005.jpg August 25, 2007 Slide 3: Surface of the Moon, http://en.wikipedia.org/wiki/Image:Moon-Mdf-2005.jpg August 25, 2007http://en.wikipedia.org/wiki/Image:Moon-Mdf-2005.jpg Slide 4: Surface of the Earth, http://en.wikipedia.org/wiki/Image:The_Earth_seen_from_Apollo_17.jpg August 25, 2007 Slide 4: Surface of the Earth, http://en.wikipedia.org/wiki/Image:The_Earth_seen_from_Apollo_17.jpg August 25, 2007 http://en.wikipedia.org/wiki/Image:The_Earth_seen_from_Apollo_17.jpg Slide 5: Surface of Pluto, http://en.wikipedia.org/wiki/Image:Pluto.jpg August 25, 2007 Slide 5: Surface of Pluto, http://en.wikipedia.org/wiki/Image:Pluto.jpg August 25, 2007http://en.wikipedia.org/wiki/Image:Pluto.jpg Slide 6: Voyager 1, http://en.wikipedia.org/wiki/Image:Voyager.jpg August 25, 2007 Slide 6: Voyager 1, http://en.wikipedia.org/wiki/Image:Voyager.jpg August 25, 2007http://en.wikipedia.org/wiki/Image:Voyager.jpg Slide 7: Space Shuttle in Orbit, http://www.archives.gov/press/press-kits/picturing-the- century-photos/images/space-shuttle-challenger.jpg August 25, 2007 Slide 7: Space Shuttle in Orbit, http://www.archives.gov/press/press-kits/picturing-the- century-photos/images/space-shuttle-challenger.jpg August 25, 2007http://www.archives.gov/press/press-kits/picturing-the- century-photos/images/space-shuttle-challenger.jpghttp://www.archives.gov/press/press-kits/picturing-the- century-photos/images/space-shuttle-challenger.jpg Slide 8: Diagram of the Distance of the Oort Cloud, http://en.wikipedia.org/wiki/Image:Oort_cloud_Sedna_orbit.jpg August 25, 2007 Slide 8: Diagram of the Distance of the Oort Cloud, http://en.wikipedia.org/wiki/Image:Oort_cloud_Sedna_orbit.jpg August 25, 2007 http://en.wikipedia.org/wiki/Image:Oort_cloud_Sedna_orbit.jpg Slide 9: Position of Alpha Centauri, http://en.wikipedia.org/wiki/Image:Position_Alpha_Cen.png August 25, 2007 Slide 9: Position of Alpha Centauri, http://en.wikipedia.org/wiki/Image:Position_Alpha_Cen.png August 25, 2007 http://en.wikipedia.org/wiki/Image:Position_Alpha_Cen.png Slide 10: Infrared Image of Milky Way, http://en.wikipedia.org/wiki/Image:Milky_Way_IR_Spitzer.jpg August 25, 2007 Slide 10: Infrared Image of Milky Way, http://en.wikipedia.org/wiki/Image:Milky_Way_IR_Spitzer.jpg August 25, 2007 http://en.wikipedia.org/wiki/Image:Milky_Way_IR_Spitzer.jpg Milky Way Galaxy from Death Valley, http://en.wikipedia.org/wiki/Image:Deathvalleysky_nps_big.jpg August 25, 2007 Milky Way Galaxy from Death Valley, http://en.wikipedia.org/wiki/Image:Deathvalleysky_nps_big.jpg August 25, 2007 http://en.wikipedia.org/wiki/Image:Deathvalleysky_nps_big.jpg Slide 11: Andromeda Galaxy, http://en.wikipedia.org/wiki/Image:M31_Lanoue.png August 25, 2007 Slide 11: Andromeda Galaxy, http://en.wikipedia.org/wiki/Image:M31_Lanoue.png August 25, 2007http://en.wikipedia.org/wiki/Image:M31_Lanoue.png Slide 12 : Triangulum Galaxy, http://en.wikipedia.org/wiki/Image:PIA03033.jpg August 25, 2007 Slide 12 : Triangulum Galaxy, http://en.wikipedia.org/wiki/Image:PIA03033.jpg August 25, 2007http://en.wikipedia.org/wiki/Image:PIA03033.jpg