Distances in Space

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Distances in Space
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Space is Very Large!!

• Astronomers have to use units of length MUCH
  bigger than usual.

3 Ways to measure distance in space.
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Astronomical Unit (AU)

• The average distance between the sun and the
  earth.

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• 1 AU is equal to 93 million miles or 150 million
  kilometers
• An AU is a standard of distance used within the
  solar system

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The Planets of Our Solar System The Inner
Planets Sizes to Scale
Mercury Venus Earth and Moon
Mars
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The Planets of Our Solar System
The Outer Planets
Jupiter
Saturn
Earth Included for Scale.
Uranus
Pluto
Neptune
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SIZES AND DISTANCES IN THE SOLAR SYSTEM

• Sizes
• Diameters of Solar System Members
• Sun 1,392,000 km
• Mercury 4,878 km
• Venus 12,104 km
• Earth 12,756 km
• Mars 6,794 km
• Jupiter 142,984 km
• Saturn 120,536 km
• Uranus 51,118 km
• Neptune 49,530 km
• Pluto 2,304 km

Mean Distance from Sun
57,900,000 km 0.387 AU 108,200,000 km
0.723 AU 149,600,000 km 1.000 AU
227,900,000 km 1.524 AU 778,300,000 km
5.203 AU 1,427,000,000 km 10.07
AU 2,871,000,000 km 19.19 AU 4,497,000,000 km
30.06 AU 5,914,000,000 km 39.53 AU
Earths Moon 3,476 km Mean
Distance from Earth 384,400 km
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Fun Facts About the Planets

• 18 Mercurys would fit inside the Earth.
• Venus is always cloudy.
• Earth is the only planet we know with life.
• Mars is red because it is covered with rust.
• A storm (hurricane) on Jupiter can swallow 2
  Earths.
• Each season on Saturn is more than seven years
  long.
• By the time you get to Uranus, you are only
  halfway to Pluto.
• Neptune is the windiest planet, with winds
  blowing
• over 1,000 miles-per-hour.
• Pluto is a ball of ice and rock and is a dwarf
  planet.

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Light Year (LY)

• The distance a ray of light travels in one
  year
• The speed of the ray of light would be equal
  to
• 7.2 AU per hour or
• 300,000 km/sec or
• 186,000 miles/sec.

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LIGHT YEAR AS A DISTANCE

• 1 LIGHT YEAR5.9 TRILLION MI
• OR 1 LIGHT YEAR 9 TRILLION KM
• SCALE MODEL
• If the Sun and Earth are 1 ft. apart-
• Alpha Centauri is 51 mi away!

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• A Light Year is a standard unit of measurement
  for interstellar distances beyond the solar
  system. (USED TO MEASURE DISTANCES BETWEEN STARS)
• Milky Way Galaxy is approx. 100,000 LY across in
  distance

http//planetquest.jpl.nasa.gov/SIMGuide2Galaxy_50
8.html
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Nearest star to the sun is Proxima or Alpha
Centauri C approx 4.22 LY
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Proxima (or Alpha Centauri C) is a red
dwarf Alpha Centauri A is a yellow star Alpha
Centuari B is an orange star
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Parsec

• One parsec is equal to 3.26 light years
• A parsec is a unit of measurement used for
  distances between very far structures in the
  universe.
• Example
• distances between galaxies

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Andromeda and Milky Way

• The Andromeda Galaxy (M31) is slightly less than
  800 kpc or
• 800,000 parsecs away from Earth.

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