Size and Mass in the Universe Mass Kilograms Distance Meters Time Seconds Size and Mass

Planetary Dimensions Power Size Scale (km) 0 20 City 1 200 City to City 2 2000 Continent or Planetary Satellite 3 20000 Planet Size and Mass

The Terrestrial Planets The Solar System The Terrestrial Planets Diameter Mass km Earth 1023kg Distance Mercury 4877 0.38 3.3 0.06 0.39 Venus 12104 0.95 48.7 0.82 0.72 12756 1.00 59.7 Mars 6794 0.53 6.4 0.11 1.52 Size and Mass

The Solar System The Jovian Planets Diameter Mass km Earth 1023kg Distance Jupiter 142984 11.2 18988 318 5.20 Saturn 120536 9.45 5685 95.2 9.55 Uranus 51180 4.01 866 14.5 19.2 Neptune 49528 3.88 1028 17.2 30.1 Pluto 2372 0.18 0.2 0.003 39.5 Size and Mass

Montage Size and Mass

Alternately Size and Mass

Distances in Kilometers In the Solar System Moving Towards The Sun Distances in Kilometers Power Size Scale 4 200,000 Planet - Satellite Separation Earth-Moon: 385000 km Speed of Light=300000 km/s 5 2,000,000 Somewhere in interplanetary space 6 20,000,000 Venus or Mars 7 200,000,000 Past the Sun 1 AU = 149,000,000 km 1 AU = 8 light minutes Size and Mass

The Sun is an “Average” Star The Size of The Sun The Sun is an “Average” Star Angular Size: About 1/2 a degree (30 minutes) Angular Sizes depend on distance The angular size of the Moon is about the same as the Sun but are they the same physical size? Solar diameter = 1,400,000 km Lunar diameter = 3476 km Therefore the Sun must be 1400000/3476 = 403 times further away than the Moon! Solar diameter = 4.7 light seconds Earth’s diameter = 12,756 km = 0.043 light seconds Earth-Moon Separation = 384,400 km = 1.28 light seconds Size and Mass

Angular Size Size and Mass

The Size of Stars Type Diameter km AU Neutron 20 White Dwarf 2000 A Vast Range Type Diameter km AU Neutron 20 White Dwarf 2000 Solar Type 1,400,000 0.009 Giant 14,000,000 0.09 Supergiant 140,000,000 0.99 Size and Mass

Mass Mass of the Earth = 6(10^24) kg Mass of Jupiter = 318 * Mass of Earth Jupiter = 1.9 (10^27) kg Total Mass of the Planets ~ 447 * Mass of Earth Sun’s Mass = 2(10^30) kg = 746 * Total Planetary Mass Jupiter = 0.00095 mass of Sun Earth = 2.99(10^-6) mass of Sun Stars range from about 100 to 0.1 times the mass of the Sun. Size and Mass

Distances in Astronomical Units To The Nearest Stars Distances in Astronomical Units 7 1 Earth-Sun Distance 8 10 Saturn 9 100 Nearby Interstellar Space - Pluto is at 37 AU 10 1,000 Interstellar Space 11 10,000 Interstellar Space 12 100,000 Interstellar Space - About 1/2 way to the nearest star! 13 1,000,000 Into the region of nearby stars Size and Mass

Distances in Parsecs = 206265 AU Interstellar Space Distances in Parsecs = 206265 AU 12 1 About the distance to the nearest star. Typical of distances between individual stars 1 pc = 3(10^13)km. Diameter of Sun = 1.4(10^6) km. Mean separation of stars = 2(10^7) times their diameter. 13 10 Into nearby Interstellar space 14 100 Interstellar Space - Thickness of galactic disk is of order 300 - 500 pc. Molecular clouds (star forming regions) are also of order 100 pc. Large star clusters are of order this size. Size and Mass

Distances in Parsecs = 3.26 ly Nearby Galaxies Distances in Parsecs = 3.26 ly 15 1,000 Interstellar Space 16 10,000 Distance to galactic center~30,000 ly! The Sun is at a radius of about 2/3 of the Milky Way's radius ==> Galactic Radius is about 15,000 pc (Diameter = 30000) pc. 17 100,000 Twice the distance to the nearest galaxies (the Large and Small Magellanic clouds at about 50,000 pc) Size and Mass

The Local Group 18 1,000,000 Beyond the Andromeda Galaxy Distances in Parsecs 18 1,000,000 Beyond the Andromeda Galaxy Well into the Local Group of galaxies (a small group of about 20+ galaxies). The nearest large galaxy is Andromeda. Typical large galaxy separation is about 20 times their radius -very different from stars. Size and Mass

The Local Group Size and Mass

Distances in MegaParsecs The Realm of Galaxies Distances in MegaParsecs 18 1 The Local Group 19 10 Intergalactic Space 20 100 The realm of clusters of Galaxies 21 1000 Superclusters - 3.26 billion ly ==> a “lookback” time of 3.26 billion years. The age of the Universe is <14 billion years. The Galaxy about 10-12 billion years. We cannot go another factor of 10! Size and Mass