Not Your Parents’ Solar System! It’s Not Your Parents’ Solar System! Dr. Frank Summers Space Telescope Science Institute July 21, 2011

Your Ancient Ancestors’ Solar System

Earth Moon Mercury Venus Sun Mars Jupiter Saturn

Claudius Ptolemy 150 – Almagest

Your Parents’ Solar System

Nicholas Copernicus 1543 – On the Revolutions of Heavenly Spheres

Earth Moon Mercury Venus Sun Mars Jupiter Saturn

Sun Mercury Venus Earth / Moon Mars Jupiter Saturn

Tycho Brahe 1546-1601 Johannes Kepler 1571-1630

Isaac Newton 1687 – Principia

William Herschel 1781 – Discovery of Uranus

Title: Herschel's 7-foot telescope SPL Reference Number: R102/153 Credit: ROYAL ASTRONOMICAL SOCIETY / SCIENCE PHOTO LIBRARY CREDIT MUST BE GIVEN IN FULL Caption Herschel's 7-foot telescope, artwork. This was one of the smaller of the more than 400 telescopes designed and built by the German-born British astronomer William Herschel (1738-1822). The tube was 7 feet (2.1 metres) long. This telescope was easier to use than the large 20-foot and 40-foot telescopes, and was small enough to be moved around on wheels. Herschel's discoveries with his telescopes included the planet Uranus (1781) and several moons of Saturn and Uranus. The discovery of Uranus was made with a 7-foot telescope.

1801 – Planet Ceres (Piazzi)

1801 – Planet Ceres (Piazzi) 1802 – Planet Pallas (Olbers) 1804 – Planet Juno (Harding) 1807 – Planet Vesta (Olbers) 1845 – Planet Astraea (Hencke)

Urbain Le Verrier & John Couch Adams 1846 – Prediction and discovery of Neptune

Mistaken Planets 1851 – Planet at 137 AU 1859 – Planet(s) interior to Mercury – Vulcan 1879 – Error found in 137 AU planet 1916 – General relativity

Clyde Tombaugh 1930 – Discovery of Pluto

Your Parents’ Solar System

Your Parents’ Solar System

Files: moon_size_montage_large_nasa_800x600.jpg Description: size comparison of many moons of the solar system Source: http://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=2823 Usage: NASA, public domain Image Credit: NASA Notes: Moons of the Solar System A selection of our solar system's natural satellites are shown here to scale compared to the Earth and its moon. Large moons composite edited by Frank Summers.

Your Parents’ Solar System

Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Pluto My Very Energetic Mother Just Served Us Nine Pizzas

Facts Are Not Knowledge

Comparative Planetology

Files: four_corners_crop_arizona_modis_1111x1280.jpg Description: four corners region from MODIS Source: http://visibleearth.nasa.gov/view_rec.php?id=1980 Usage: http://visibleearth.nasa.gov/useterms.php NASA, public domain Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC Notes:

Files: four_corners_crop_grand_canyon_modis_1000x750.jpg Description: four corners region from MODIS Source: http://visibleearth.nasa.gov/view_rec.php?id=1980 Usage: http://visibleearth.nasa.gov/useterms.php NASA, public domain Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC Notes:

Files: mars_valles_marineris_viking_1500x533.jpg Description: Valles Marineris on Mars, from Viking Orbiter Source: http://photojournal.jpl.nasa.gov/catalog/PIA00422 Usage: http://www.jpl.nasa.gov/images/policy/ NASA, public domain Courtesy NASA/JPL-Caltech Notes:

Files: mars_globe_viking_1280x1280.jpg Description: Mars globe mosaic, from Viking Orbiter Source: http://photojournal.jpl.nasa.gov/catalog/PIA00407 Usage: http://www.jpl.nasa.gov/images/policy/ NASA, public domain Courtesy NASA/JPL-Caltech Notes:

Files: mars_globe_us_overlay_viking_1280x1280.jpg Description: Mars globe mosaic, from Viking Orbiter Source: http://photojournal.jpl.nasa.gov/catalog/PIA00407 Usage: http://www.jpl.nasa.gov/images/policy/ NASA, public domain Courtesy NASA/JPL-Caltech Notes:

Planetary Comparisons Craters – Earth, Moon, Mercury, etc Volcanoes – Mount St. Helens, Olympus Mons, Io, etc Canyons – Grand Canyon, Mariner Valley Storms, Winds, Seasons, Weather, Ice Floes, Magnetic Fields, Moons, Rings, etc

The 21st Century Solar System Sun Rocky Planets Asteroid Belt Giant Planets Kuiper Belt Oort Cloud

Families of the Solar System Classes of similar objects Size Composition Orbit size Orbit shape Orbit inclination Moons Rings

Hollywood’s View of the Asteroid Belt

Hundreds of thousands of asteroids … … about a million miles apart! 960 million miles Scientific View of the Asteroid Belt

Sizes of the Giant Planets and Earth

Kuiper Belt

Oort Cloud Billions of icy minor planets – comet nuclei Roughly spherical out to 50,000 AU Predicted by Jan Oort Explains long-period comets

http://www.princeton.edu/~willman/recent_work.html http://www.princeton.edu/~willman/tno-comet http://www.princeton.edu/~willman/tno-comet/tnocomet.doc

Sedna

Sedna Orbit 76 – 840 AU Very red color Outer Kuiper Belt? Inner Oort Cloud? Planet at 70 AU?

Families of the Solar System Classification Structure of the solar system Similar objects lie in similar regions Clues to solar system formation and evolution

Sun Rocky Planets Asteroid Belt Giant Planets Kuiper Belt Oort Cloud

Sun Mercury Venus Earth Mars Asteroid Belt Jupiter Saturn Uranus Neptune Kuiper Belt Oort Cloud

Science May View Established Models As Basic Justified Standards Until New Knowledge Bears Out Changes

Sometimes My Very Energetic Mother Also Boils Jumbo Shrimp Using Nine Kettles Bubbling Over Coals

The Inevitable Question …

Why is Pluto No Longer a Planet?

Planet Pluto January 23, 1930 January 29, 1930

Pluto/Charon 1978 – James Christy (USNO)

The Incredible Shrinking Planet Lowell’s Planet X – 7 times Earth 1940’s – 1 times Earth 1980 – 0.1 times Earth 1985 – 0.002 times Earth

The Incredible Shrinking Planet

Rhea Iapetus Titania Oberon Ceres Tethys Dione Ariel Umbriel Charon Pallas Vesta Hygeia Mimas Enceladus Miranda Proteus Io Mercury Europa Moon Triton Titan Ganymede Callisto Pluto

Montage by Frank Summers, based on NASA image Files: moon_size_montage_large_with_pluto_nasa_800x600.jpg Description: size comparison of many moons of the solar system Source: http://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=2823 Usage: NASA, public domain Image Credit: NASA Notes: Moons of the Solar System A selection of our solar system's natural satellites are shown here to scale compared to the Earth and its moon.

Kuiper Belt Objects 1992 – Jewitt & Luu find QB1 Distance of 42 AU First (third?) object discovered in the Kuiper Belt

Kuiper Belt

But Isn’t Pluto Special in Some Way?

Orbit Comparison: Pluto/Charon vs 2004 DW

Kuiper Belt

Moon Pluto and Charon in infrared from Hubble 1995

Moon? Pluto and Charon in infrared from Hubble 1995

KBO 1998 WW31 from Hubble

Haumea, Hi’iaka & Namaka Eris & Dysnomia Makemake Large KBOs and their moons from Mike Brown http://www.gps.caltech.edu/~mbrown/planetlila/moon/figure.jpg Haumea, Hi’iaka & Namaka Eris & Dysnomia

KBO Size Comparison

Pluto vs the Kuiper Belt Orbit similar to KBOs Size similar to KBOs KBO companions common Composition similar to KBOs

Pluto vs the Kuiper Belt Orbit similar to KBOs Size similar to KBOs KBO companions common Composition similar to KBOs Pluto has found its family!!

IAU Definition – August 2006 IAU defines “planet” Orbits the Sun Upper mass limit not massive enough to produce fusion Deuterium fusion occurs at about 15x Jupiter’s mass Lower mass limit Massive enough for gravity to make it spherical About 500 miles in diameter Dominates its orbit Dwarf planets meet 1, 2, 3, but not 4

Mass to mass in zone ratio – Soter paper, What is a Planet? The Astronomical Journal, 132:2513–2519, 2006 December Copyright 2006. The American Astronomical Society. All rights reserved. Printed in U.S.

Sun Rocky Planets Asteroid Belt Giant Planets Kuiper Belt Oort Cloud

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