The Size and Distance Scale Of The Solar System

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The Size and Distance Scale Of The Solar System
EARTH AND THE SOLAR SYSTEM

• Our Earth is just one of several Planets that
  revolve around our Sun, the primary and central
  object of our Solar System.
• Since the entire Solar System, including our
  Earth, was created about the same time (about 4.6
  billion years ago), our understanding of the
  origin and properties of the Solar System, the
  Sun, and its other members are important to our
  understanding of Earth itself.
• We consider the size of our Earth to be very
  large, in comparison with most sizes and
  distances we deal with in our daily lives.
• However, the size of the Earth is very small
  compared to the size of the Solar System, which
  consists of the Sun and its family of planets, of
  which our Earth is only about average in size.

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The Size and Distance Scale Of The Solar System
EARTH AND THE SOLAR SYSTEM

• When we observe the night sky, the planets, stars
  and galaxies appear to be close together.
• Remember
• some objects are closer to the Earth than others
• enormous distances separate us from other objects
  in the universe.
• As we gather information from the farthest
  reaches of the universe, we can learn about the
  history of the universe.

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The Size and Distance Scale Of The Solar System

• In turn, the size of our Solar System is very
  large compared to the size of our Earth, or even
  the largest planet, Jupiter.
• The distance from our Earth to the Moon
• 238,000 miles or 384,000 kilometers
• (nearly 100 times Earths diameter, or about 30
  times the distance around the Earth at its
  equator)
• The distance from our Earth to the Sun
• 93,000,000 miles or 149,600,000 kilometers
• (more than 390 times the distance to the Moon)
• The most distant major planet from the Sun,
  Neptune, is 30 times Earths distance from the
  Sun.
• The nearest stars in our Galaxy, the star system
  of Alpha Centauri, is 9,000 times Neptunes
  distance from the Sun!

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Why dont we use the kilometer?

• kilometer is just too small to be useful
• numbers become so large that it becomes hard to
  write and hard to interpret
• so astronomers use other units of distance.
• next nearest big galaxy- the Andromeda Galaxy
• 21 quintillion km
• 21,000,000,000,000,000,000 km.

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Units of Measurements

• light-year
• AU
• parsec

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light-year

• A light-year is a unit of distance.
• distance that light can travel in one year.
• Light moves at a velocity of about
• 300,000 kilometers km/ second (299,792 km/second)
• 186,000 miles/second (186,282 miles/second)
• In one year, it can travel about
• 10 trillion km or
• 5.8 trillion miles
• More precisely, one light-year is equal to
  9,460,000,000,000 km
• 9.46 x 1012 kilometers

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http//www.youtube.com/watch?vRj1sDWjvgjM

• light units

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Units of Light Measurement

• Visible light travels 186,000 miles per second
• Light second

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Units of Light Measurement

• Visible light travels 186,000 miles per second
• Light minute

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Units of Light Measurement

• Visible light travels 186,000 miles per second
• Light hour

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Units of Light Measurement

• Visible light travels 186,000 miles per second
• Light day

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Units of Light Measurement

• Visible light travels 186,000 miles per second
• Light week

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Units of Light Measurement

• Visible light travels 186,000 miles per second
• Light month

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Units of Light Measurement

• Visible light travels 186,000 miles per second
• Light year

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AU

• astronomical unit (AU)
• used only in our solar system
• average distance between the Earth and the Sun
• approximately 150 million km (93 million miles)
• Earth is 1 AU from the Sun
• Mercury is 1/3 of an AU from the Sun
• Pluto averages about 40 AU from the Sun

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parsec

• used for distances to other parts of the Milky
  Way Galaxy (or even further)
• equal to 3.3 light-years
• Crab supernova remnant- 4,000 light-years away
• Milky Way Galaxy- 150,000 light-years across
• Andromeda Galaxy- 2.3 million light-years away

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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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Earth and Moon to Scale
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Sizes and Distances in the Earth-Moon System
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Relative Sizes of Planets in Our 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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Size Comparisons In Our Solar System
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THE SIZE AND DISTANCE SCALE OF THE SOLAR SYSTEM

• The distances between the members of our Solar
  System are much larger than the sizes of the
  members (even the Sun).
• The distance from the Earth to the Sun is
• 150,000,000 km (about 93,000,000 miles) in
  comparison to the Suns diameter of about
  1,392,000 km (about 110 times that of Earth).
• The region beyond the orbit of Neptune, called
  the Kuiper Belt, contains a large number of
  smaller objects (including Pluto and at least one
  recently discovered slightly larger object), all
  (as yet known) smaller than our Moon.
• The Kuiper Belt objects known to date can reach
  distances of more than 90 times Earths distance
  from the Sun.

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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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Orbits of the Inner Planets
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Orbits of Jupiter and Saturn
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Orbits of the Outer Planets
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The Kuiper Belt

• The Kuiper Belt is a zone beyond the outermost
  major planet, Neptune, in which many of the
  comets that pass through the inner part of the
  solar system travel, and may have originated in
  the early years of our solar system.
• Surveys of the outer part of the solar system,
  beyond the orbit of Pluto, have recently found
  several additional objects comparable to Pluto in
  size.
• Most recently, an object apparently larger than
  Pluto has been found, which would (if verified)
  make it the 10th planet of our solar system.
• The detection of this (as yet un-named) object,
  called (temporarily) UB313, was made using the
  ground-based 48-inch Samuel Oschin telescope at
  Palomar Observatory.
• The object is 97 times Earths distance from the
  Sun, or more than twice Plutos greatest
  distance.
• It is likely that, with continuing very deep sky
  surveys with both ground-based and space-based
  telescopes, that more objects of these types will
  be discovered.

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Orbit of the newly discovered object, 2003 UB313,
compared to those of Pluto and the giant outer
planets. Note, the orbits of Pluto and UB313, in
red, are tilted relative to the plane of the
inner giant planet orbits.
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The Size and Distance Scale of The Solar System

• The size of our Solar System, if defined by the
  diameter of Plutos orbit, is about 40 times the
  diameter of Earths orbit around the Sun.
• If we consider also the most distant Kuiper Belt
  objects discovered to date, up to 90 times
  Earths distance from the Sun, the diameter of
  our solar system would be increased accordingly.
• However, the distance to the nearest star other
  than our Sun is vastly larger than the size of
  our Solar System.
• The distances to stars can be estimated by
  comparing their observed brightnesses with that
  of our Sun, if they are known to be similar to
  our Sun in other respects (as determined, for
  example, by spectroscopic measurements).
• The nearest stars to our solar system, the star
  system Alpha Centauri, is at a distance about
  9000 times Neptunes distance, or 6800 times
  Plutos maximum distance, from our Sun!
• If our solar system were scaled to the size of a
  quarter (with Plutos orbit about 1 inch in
  diameter) the Alpha Centauri system would be at a
  distance of about 285 feet!