new worlds and old © 2010 john sheff consulting services
TRANSCRIPT
SOLAR SYSTEM DISCOVERIESNew Worlds and Old
© 2010 John Sheff Consulting Services
John Sheff
Solar System Ambassador Program, Jet Propulsion Laboratory
http://www2.jpl.nasa.gov/ambassador/
http://ww.jsheff.com
http://www.bostonastronomy.net
Solar System Ambassador Program
Solar System Discoveries
At first, all we knew about the planets was that they were "wanderers" against the background stars. Four hundred years ago, Galileo first turned the telescope to the sky, and the planets became "worlds." A half century ago, the first unmanned space probes started their explorations and the planets became "landscapes." What have we learned since about the planets of our Solar System and others? Is our Solar System unique? Are we close to finding another Earth? And -- most importantly of all -- what ever happened to Pluto?
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Typical Ancient Astronomy
7 Planets (including the Sun and Moon, but not Earth):
Mercury Venus Mars Jupiter Saturn
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Greek Astronomy
Nicolaus Copernicus (1473 – 1543)
Giordano Bruno (1548 – 1600)
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Tycho Brahe (1546 – 1601)
Galileo Galilei (1564 – 1642)
Galileo’s Discoveries
Lunar features Stars in Milky Way
Galileo’s Discoveries
Moons of Jupiter Phases of Venus
Johannes Kepler (1571 – 1630)
Isaac Newton (1643 – 1727)
William Herschel (1738 – 1822)
Discovery of Uranus - 1781
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Uranus
Titius-Bode Law
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1 0 4 0.4 0.39 Mercury
2 3 7 0.7 0.72 Venus
3 6 10 1.0 1.00 Earth
4 12 16 1.6 1.52 Mars
5 24 28 2.8 2.77 ?
6 48 52 5.2 5.20 Jupiter
7 96 100 10.0 9.54 Saturn
8 192 196 19.6 19.2 Uranus
9 384 388 38.8 30.6 ?
10 768 772 7.72 39.44 ?
Ceres
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Pallas, Juno, Vesta
Pallas Vesta
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Vermin of the Skies
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Irregularities of Motion - Uranus
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Discovery of Neptune - 1846Urbain Jean-Joseph Le Verrier John Couch Adams
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Neptune
Irregularities of Motion - Mercury
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Irregularities of Motion - Neptune
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Lowell Observatory
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Pluto – found at last!
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1992 QB1
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Eris (2003 UB₃₁₃)
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The IAU Meeting: Prague 2006
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An Inventory of the Solar System
8 (or 9, 0r 13, or ?) Planets 169+ Moons 2 “Asteroid” Belts, with 100,000+
bodies ea 1012 Comets 1 G2 Star Interplanetary Medium
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The Inner Solar System
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The Asteroid Belt
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The Outer Solar System
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The Kuiper Belt
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The New Solar System
Dwarf Planets and Some Contenders
Solar System Roadmap
• Flagship Missions (> 650 M$)• Cassini• Galileo
• New Frontiers (425 M$ - 650 M$)• New Horizons• Juno
• Discovery (< 425 M$)• NEAR• Messenger• Dawn
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Coming Up:
Venus Climate Orbiter/PLANET-C launch (5/2010)
Hayabusa return to Earth ? (6/2010)
Rosetta asteroid Lutetia flyby (7/10/2010)
Deep Impact Comet 103P/ Hartley 2 flyby (10/11/2010)
Venus Climate Orbiter/PLANET-C arrival (12/2010)
Stardust Comet Tempel 1 flyby (2/14/2011)
MESSENGER Mercury orbit (3/18/2011 – 3/18/2012)
Dawn Vesta orbiter (7/2011 – 7/2012)
Juno launch (8/5/2011)
MSL launch (10/2011) Phobos Grunt launch (10/2011) BepiColombo launch (8/2013) Maven launch (11/18/2013 –
12/7/2013) Maven Mars orbit (9/16/2014) Dawn Ceres orbiter (2/2015 –
7/2015) New Horizons Pluto flyby
(7/2015) ExoMars launch (4/2018 ) Juno Jupiter polar orbit (8/2016
– 10/2018) BepiColombo Mercury orbit
(8/2019 – 8/2020)
Mercury
Why is Mercury so dense?
What is the geologic history of Mercury?
What is the nature of Mercury’s magnetic field?
What is the structure of Mercury’s core?
What are the unusual materials at Mercury’s poles?
What volatiles are important at Mercury?
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Mercury Exploration
Mariner 10 (1973-74)
MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) (2004 – 2012)
Bepi-Columbo (2014-2020)
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Venus
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Venus Missions
Mariner 2 (1962) Mariner 5 (1967) Venera 4-16 (1967 –
1983) Pioneer Venus
(1978) Vega (1984 – 1986) Magellan (1989 –
1994) Venus Express (2005
- Planet C
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Venus below the clouds
Venera 13 Venera 14
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Lunar Exploration - LRO
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Lunar ScienceSouth Pole / Aitken Basin Sample Return
Potential mission goals:
– Test cataclysm idea by dating SPA and superimposed basins
– Determine compositions of impacting bodies
– Decipher composition of mid- to lower crust (maybe mantle)
– Unravel basaltic history
Complicated set of goals
Complicated geologic setting
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Mars
Strategy: From “Follow the Water” to “Explore Habitable Environments”
Determine if Life Ever Arose on Mars Characterize the Climate of Mars Characterize the Geology of Mars Prepare for Human Exploration of Mars
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Mars – Mariner 9 (1971)
Mars – Viking 1 & 2
Viking 1 & 2 (1975-80)
Viking 1: Chryse Planitia
Viking 2: Utopia
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Mars Exploration Rovers
Spirit & Opportunity
6+ Years on Mars Spirit: 4:80 miles Opportunity: 11.94
miles
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Mars Science Lab – “Curiosity”
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Mars Sample Return – 2020 ?
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Dawn - 2007
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Dawn Targets
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Juno - 2011OriginsDetermine the ratio of oxygen to hydrogen, giving an idea of the abundance of water on Jupiter.
Obtain a better estimate of Jupiter's core mass, which will help distinguish among prevailing theories linking the gas giant's formation to the solar system.
InteriorPrecisely map Jupiter's gravitational and magnetic fields to assess the distribution of mass in Jupiter's interior, including properties of the planet's structure and dynamics.
AtmosphereMap the variation in atmospheric composition, temperature structure, cloud opacity and dynamics to depths far greater than 100 bars at all latitudes (In 1995, the Galileo probe reached only ~ 22 bars at a single location).
MagnetosphereCharacterize and explore the three dimensional structure of Jupiter's polar magnetosphere and its auroras.
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Europa Explorer
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Europa Explorer
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Europa Astrobiology Lander
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“Far” Future (2040 – 2050) ?
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Europa Submersible
Saturn System
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Iapetus Flyby Sept. 10, 2007
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Enceladus Flyby, Mar 12 2008
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Cassini-Huygens at Titan
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Beyond the XM
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Cassini XXM “Solstice” Mission
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Cassini Mission Overview
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Cassini EOM Option
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Titan Explorer
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Titan Explorer
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Titan Lake Submersible
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New Horizons
Launch: 2006 Jupiter Flyby
Gravity Assist: 2007
Pluto / Charon Encounter: 2015
KBO Encounters: 2016-2020
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387 Detected as of November 2009 281 single planets around single normal
stars 98 multiple-system planets around single
normal stars 1 around red dwarf / white dwarf binary 1 around subdwarf B star / red dwarf binary 1 around pulsar / white dwarf binary 3 orbit single pulsars 1 orbits single subdwarf B star 1 orbits single brown dwarf
Exoplanets
Pulsar Planets
Two planets discovered in 1992 around the millisecond pulsar PSR 1257+12.
These were the first two extrasolar planets discovered, and the first multi-planet extrasolar planetary system discovered, and the first pulsar planets discovered.
(b) had period of 66 days and mass of 4.3 Earths.
(c) had period of 98 days and mass of 3.9 Earths.
Two additional planets of lower mass were later discovered by the same technique
51 Pegasi
First exoplanet around a main-sequence star (1995)
50 light-years away
Mass: > 1 Jupiter Period: 4 days “ Hot Jupiter”:
surface temperature 1000 ° C (1800 ° F)
HD 222582 b
The planet orbiting this G3 star has one of the most eccentric planet orbits known to date. The 572-day orbit takes it from 0.39 AU to 2.31 AU from its star. It is located in the constellation Aquarius, 137 light-years distant. The water on this world's satellite, if one exists, goes through seasonal periods of melting and refreezing.
HD 177830 b
HD177830 b is a 1.52 Jupiter mass planet orbiting the K0 star HD177830, located 192 light-years away in the constellation Vulpecula. This planet is likely to be within its habitable zone. A moon found here could have liquid water and look similar to our own home world.
Upsilon Andromedae
The first planetary system ever found around a normal star consists of three planets in orbit around Upsilon Andromedae.
The innermost (and first known) of the three planets, Upsilon Andromedae b, contains at least three-quarters of the mass of Jupiter and orbits only 0.06 AU from the star. It traverses a circular orbit every 4.61 days.
The middle planet contains at least twice the mass of Jupiter and it takes 242 days to orbit the star once. It resides approximately 0.83 AU from the star, similar to the orbital distance of Venus.
The outermost planet has a mass of at least four Jupiters and completes one orbit every 3.5 to 4 years, placing it 2.5 AU from the star.
55 Cancri
Five confirmed planets (most in any system)
The innermost planet (e): 2.8 day orbit, discovered in 2004. Mass: 11 Earth masses.
The next planet (a), discovered in 1996; 14.7-day orbit. Mass: .824 Jupiters.
Planet ( c ), with an orbit of 44.3 days. Mass: 56 Earth masses.
The fourth world (f) is the newest discovery, having 45 Earth masses and an orbit of 260 days. It is near the star’s “habitable zone”!
The farthest world out (d)has an orbit comparable to Jupiter's. Period: 14.6 years.
Gliese 581
At least four planets are believed to be orbiting Gliese 581.
A fourth planet, Gliese 581 e, was discovered in 2009. This planet, at an estimated minimum mass of 1.9 Earths, is currently the lowest mass exoplanet identified around a normal star. It takes 3.15 days to orbit Gliese 581- but it’s too hot!
Gliese 581 b is at least 16 times as massive as Earth (similar to Neptune's mass) and completes a full orbit of Gliese 581 in only 5.4 days.
Gliese 581 c is probably a rocky planet with a radius 1.5 times that of Earth and a mass of roughly five times Earth—or one third that of Neptune. Gliese 581 c orbits just inside of the habitable zone of its parent star. It is notable as it is the planet with lowest minimum mass yet discovered in the habitable zone of another star, making it the most earthlike exoplanet found to date.[The mean blackbody surface temperature has been estimated to lie between -3 °C (for a Venus-like albedo) and 40 °C (for an Earth-like albedo), however, the temperatures could be much higher (about 500 degrees Celsius) due to a runaway greenhouse effect akin to that of Venus. Gliese 581 c completes a full orbit in just under 13 days.
Observations of the star also revealed a third planet, Gliese 581 d, with a mass of roughly 7 Earths, or half a Uranus, and an orbit of 66.8 Earth days. It orbits just inside of the habitable zone of its star, which makes it a potential candidate for being able to support life. “Water world?”
Kepler Mission
Launched : March 6, 2009 First Light: April 16, 2009 Checkout Ended: May 13,
2009 Data Collection: 3.5 years Will monitor field of
223,000 stars Should find:
~ 30 outer-orbit giant planets ~ 135 inner-orbit giant
planets ~ 640 Super-Earths ~ 50 Earth-mass planets
A New Earth?
Within the next 5 years, we will probably find another Earth-like planet – an Earth-sized world in a stable orbit in a HZ of a Sun-like star
John Sheff
Solar System Ambassador Program, Jet Propulsion Laboratory
http://www2.jpl.nasa.gov/ambassador/
Background:
John Sheff has explored some remote parts of our planet on adventure travel journeys and mountaineering expeditions. His lifelong background as an amateur astronomer and space buff has him just as excited about the exploration of other planets. He enjoys participating in star parties, particularly inner-city ones, organized by his local club – the Amateur Telescope Makers of Boston (ATMoB). He also loves to share views of the sky through the observatory telescope he operates during Public Nights at the Harvard-Smithsonian Center for Astrophysics in Cambridge. In his day job he’s had a career as a freelance Network Admin and IT Manager, and now does consulting in web development and science education. When on Earth, he lives in Cambridge, MA.
Portions of this PowerPoint Slide Show - as well as a free installable PowerPoint Viewer - are available for download on John Sheff’s website:
http://www.jsheff.com
Solar System Ambassador Program
© 2010 John Sheff Consulting Services