Our Space Time Coordinates: Time, Distances, and Sizes

http://cecs.wright.edu/~tkprasad

• Universe• Milky Way Galaxy• Solar System (including the star Sun, the

planet Earth, the moon Moon(!), etc)• Planet Earth• Seven Continents and Four Oceans

• North America, South America, Europe, Africa, Asia, Australia, Antartica• Pacific, Atlantic, Indian, Arctic

• Countries, States, Cities• United States of America, Ohio, Dayton

• Russ Engineering Center, Wright State University, 3640, Col. Glenn Highway

Measuring Distances

• Average Distance between Sun and Earth = 93 million miles

(1 Astronomical Unit) (Speed of light = 186000 miles per

second) (1 light second = 186000 miles ) = 500 light second = 8.33 light minutes

Visualizing Distances

• If 1 inch is the distance between sun and earth, • then 1 mile is equivalent to

1 light year.

• 1 parsec = 3.26 light years

Solar System scaled to Football fieldBody Diameter Semi-major axis

Sun 0.85 in (21.5 mm) zero

Mercury 0.003 in (0.08 mm) 1.0 yard (0.9 m)

Venus 0.007 in (0.19 mm) 1.9 yard (1.7 m)

Earth 0.008 in (0.20 mm) 2.5 yard (2.3 m)

Mars 0.004 in (0.10 mm) 3.8 yard (3.5 m)

Ceres 0.001 in (0.02 mm) 7.0 yard (6.4 m)

Jupiter 0.085 in (2.16 mm) 13.1 yard (12.0 m)

Saturn 0.071 in (1.8 mm) 24.2 yard (22.1 m)

Uranus 0.029 in (0.73 mm) 48.6 yard (44.4 m)

Neptune 0.028 in (0.7 mm) 76.1 yard (69.6 m)

Pluto 0.002 in (0.05 mm) 100.0 yard (91.4 m)

Eris 0.002 in (0.05 mm) 171.4 yard (156.7 m)

α Centauri A 0.94 in (23.9 mm) 396 mile (637 km)

Distances to nearby objectsHeavenly Body Average Distance from Earth

Moon 1.3 light seconds

Sun 8.3 light minutes

Mars 12 light minutes(0.5 – 2.5 AU)

Jupiter 42 light minutes

Saturn 1.2 light hours

Pluto 4 light hours

Comets – outer reaches of solar system

Light months

Distances to StarsStars Distinction Distance from Earth

(light years)Proxima Centauri Nearest Star 4.2 light years

Sirius Brightest Star (in night sky)

8.6 light years

Pole star North star, Cepheid Variable

300 light years

Rigel/Betelgeuse Blue/Red giant in Orion 800/600 light years

Deneb Blue giant in Cygnus 1500 light years

Andromeda Galaxy Nearest galaxy 2 million light years

*HST Image* Most distant galaxy 13 billion light years

Age vs Distance

Universe Distances

• http://micro.magnet.fsu.edu/primer/java/scienceopticsu/powersof10/index.html

• http://cass.ucsd.edu/public/tutorial/scale.html• http://cass.ucsd.edu/public/tutorial/Intro.html

Universe Timeline

• http://www.pbs.org/deepspace/timeline/index.html

• http://www.historyoftheuniverse.com/tl1.html

Sizes of planets and stars

• Planets, Stars, Nebulae, Galaxies - Universe Size Comparison [HD High Definition]

http://www.youtube.com/watch?v=WcZkAZebK1U&NR=1

https://www.youtube.com/watch?v=oNb3H9kICbA