Earth

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Earth Space SciencePart 1 Stargazing

• 1.1 Measuring the Universe

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Making Unmanageably BIG Numbers Manageable

• Two Methods
• Scientific Notation
• (Speed of Light 300,000,000 m/s 3.0 x 108m/s)
• Bigger Units
• (Speed of Light 300,000,000 m/s 300 Mm/s)

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1. Scientific Notation

• General Form

x 10
Exponent of places to move decimal
Number between 1 and 10
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Examples of Scientific Notation

• World Population 6,600,000,000
• 6.6 x 109
• US Population 301,000,000
• 3.01 x 108
• Illinois Population 1.28 x 107
• 12,800,000
• Bloomington Population 7.097 x 104
• 70,970

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A Video of Scientific Notation

• Awaits you here.

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Whos biggest?

• Rank the following items in order of INCREASING
  size (smallest ? biggest)

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2. Bigger Units

• Metric Prefixes
• Kilo- 1,000
• Downs ? Wrigley Field 230,000 m
• 230 km
• Mega- 1,000,000
• Downs ? Moon 384,000,000 m
• 384 Mm
• Giga- 1,000,000,000
• Downs ? Sun 150,000,000,000 m
• 150 Gm

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Measuring Distance
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Astronomical Unit (AU)

• Distance from Earth to Sun.
• Useful for measuring distances within solar
  system.
• 1 AU 1.5 x 1011 m 93 million miles
• Sun ? Earth 1 AU
• Sun ? Mars 1.52 AU
• Sun ? Jupiter 5 AU

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Light year (ly)

• Distance light travels in 1 year.
• Useful for measuring distances between stars.
• 1 ly 9.5 x 1015 m 63,200 AU 5.9 trillion
  miles
• Downs ? Alpha Centauri 4.4 ly

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A Comparison of Distance Units(Not even close to
scale)
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Review

• The distance to the moon is 384,000,000 m.
• What is this in scientific notation?
• 3.84 108 m
• How many kilometers is this?
• 384,000 km

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More Review

• What unit would you use to measure the distance
  from Earth to the planet Saturn?
• a) Astronomical Unit b) light year
• What unit would you use to measure the distance
  to Betelgeuse, a star in the constellation Orion?
• a) Astronomical Unit b) light year

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Measuring Mass
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Mass vs. Weight

• Mass Amount of stuff in an object
• An objects mass is the same anywhere in the
  universe.
• Weight How strongly gravity pulls on an object
• An objects weight varies from planet to planet

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More Mass vs. Weight

• On Earth
• Mass of moose 720 kg
• Weight of moose 1200 pounds
• On Moon
• Mass of moose 720 kg
• Weight of moose 200 pounds

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Units of Mass

• Kilogram (kg)
• 1 kg 2.2 pounds
• Example Mass of an astronaut is 90 kg.

An Official Kilogram 1 ½ x 1 1/2 cylinder
of platinum and iridium
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Another Unit of Mass

• Earth Mass
• 1 Earth mass 6.0 x 1024 kg
• Useful for measuring masses of planets
• Example Mass of Jupiter is 318 Earth Masses

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And Another Unit of Mass

• Solar Mass
• 1 Solar mass 2 x 1030 kg 330,000 Earth
  Masses
• Useful for measuring masses of stars
• Example Mass of Betelgeuse is 14 Solar Masses

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Measuring Brightness
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Measuring Apparent Magnitude, m (aka
Brightness)

• Hipparchus (Greece, 200 BC)
• Ranked stars on 6-point scale
• 1st Magnitude 20 brightest stars
• 2nd Magnitude Next brightest
• etc.
• 6th Magnitude Faintest stars visible with naked
  eye
• Similar method used today!

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Todays Apparent Magnitude Scale

• Decimals and numbers outside of 1-6 range OK
• Each increase of 1 in magnitude is an increase of
  2.5x in brightness
• Add scale!
• Examples

Betelgeuse 0.58 Venus -3.7
Sirius -1.47 Full Moon -12.6
Polaris 2.01 Sun -26.7
Pluto 13.7 Dimmest object seen with Hubble ST 30
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What affects brightness?

1. Distance from us
2. Size of star
3. Temperature of star

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Measuring Temperature
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3 Scales to Use

• Fahrenheit
• Celsius
• Kelvin

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A Comparison of Temp. Scales
Fahrenheit Celsius Kelvin
Origin ??? Who knows??? Water Theory
Significance of 0 degrees Nuttin Water freezes Lowest possible temperature (absolute zero)
Freezing point of water 32o F 0o C 273 K
Boiling point of water 212o F 100o C 373 K
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Examples of Temperatures

• Average Earth Temperature
• 58.3o F 14.4o C 287.4 K
• Surface of Sun
• 10,800o F 6000o C 6270 K
• Core of Sun
• 27 million o F 15 million o C 15 million K
• Outer Space
• -454o F -270.3o C 2.7 K