The Solar System

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The Solar System

• Hazel McAndrews
• Los Alamos Space Science Outreach
• July 2008

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L. Huff/P. Frisch The box shows an astrosphere
at the binary star BZ Cam (photo courtesy of R.
Casalegno, C. Conselice et al., WIYN, NOAO).
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Overview
(39.5 m)
(30.1 m)
(19.2 m)
(9.54 m)
(5.2 m)
(1.52 m)
(0.72 m)
(0.38 m)
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The Asteroid Belt
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• Main belt The total mass of the asteroids is
  less than the moon
• 4 largest bodies contain half the mass
• From 950 km to dust sized
• Spread over a very large volume

• Collisions between bodies create dust zodiacal
  light

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The Kuiper Belt

• 30 50 A.U.
• Members include Triton and Pluto.
• 1/10th Mass of the Earth

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The Oort Cloud

• Theoretical cloud of asteroids at 50,000 A. U.
• Contains 40 times the mass of the Earth

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Diameter 4880 km Mass 3 x 1023 kg Year 88
days Day 58 days

• The smallest and densest terrestrial planet
• The oldest surface
• The most extreme temperature ranges

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• Perihelion 46 million km, apheloin 70 million
  km
• General theory of relativity correctly predicted
  the motions

• Very slow rotation, rotates 3 times in 2 orbits
  of the sun (88 days 1 Mercurian year)
• 1 Mercurian day 2/3 of a year!
• -gt very large surface temperature extremes, 90 to
  700 Kelvin (-367 to 243 ºF).

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230 km
NASA/Johns Hopkins University Applied Physics
Laboratory/Carnegie Institution of Washington
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• Crust 100300 km thick
• Mantle 600 km thick
• Core 1,800 km radius

• Mercury's density implies that at least 60 of
  the planet is a metal-rich core, a figure twice
  as great as for Earth, Venus, or Mars!
• To account for about 60 of the planet's mass,
  the radius of Mercury's core must be
  approximately 75 of the radius of the entire
  planet!

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• Miniature version of Earths magnetosphere (
  1.1 the strength of Earths)
• Driven by fluid motions in an outer liquid
  portion of Mercury's metal core.

J. A. Slavin, NASA Goddard Space Flight Center.

• But there is debate about the molten fraction of
  the core as well as whether the field is driven
  by compositional or thermal differences.

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Diameter 12,103 km Mass 4.9 x 1024 kg Year
224.7 days Day 243 days

• Brightest object in the sky (morning/evening
  star).
• Earth's twin
• Thick cloud cover prevents optical imaging of
  surface
• Many spacecraft have flown by, orbited and landed
  on Venus.
• Axis of rotation is inclined 177º, so Venus
  rotates from east to west.

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Missions to Venus (1)

• Venera 1 12 Feb 1961 (Soviet)
• Lost 7 days into the mission 100, 000 km from
  Venus
• Mariner 1 22 July 1962 (USA)
• Lost on launch
• Mariner 2 27 August 1962 (USA)
• First successful interplanetary mission. Passed
  34,833 km above Venus.
• Zond 1 2 April 1964 (Soviet)
• Communications failed
• Venera 3 16 Nov 1965 (Soviet)
• Crash-landed on Venus in March 1966. First
  man-made object to strike the surface of another
  planet. Not able to communicate findings back to
  Earth.

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Missions to Venus (2)

• Venera 4 12 June 1967 (Soviet)
• Entered the atmosphere and deployed experiments
• Very hot surface temperature. Atmosphere 90-95
  CO2.
• Very thick atmosphere slowed probe down too
  much!
• 93 minute descent..

• Mariner 5 14 June 1967 (USA)
• The joint Venera 4Mariner 5 data were analyzed
  by a combined Soviet-American science team in a
  series of colloquia over the following year, in
  an early example of space cooperation.

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Missions to Venus (3)

• Venera 5-6 January 1969 (Soviet)
• Improved strength (100 atmospheres), smaller
  parachutes
• Returned atmospheric data.
• Crushed at 20 km above surface
• Venera 7 17 August 1970 (Soviet)
• Built to withstand 180 bar
• Torn parachute, returned weak signal due to
  harder-than-expected impact
• Provided temperature data for 23 minutes

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Missions to Venus (4)

• Venera 8 27 March 1972 (Soviet)
• 50 minutes of surface data
• Venera 9 10 8 14 June 1975 (Soviet)
• Surface images!
• Pioneer-Venus 1978 (USA)
• Orbiter (13 years!) and multiprobe released 4
  atmospheric probes.

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Missions to Venus (5)

• Venera 11-14 1978-1982 (Soviet)
• All landers, providing first colour images
• Venera 15 16 1983 (Soviet)
• Marked the end of the dedicated Soviet
  exploration of Venus, but.

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Missions to Venus (6)

• Vega 1 2 1984 (Soviet, Hungary, the German
  Democratic Republic, Poland, Czechoslovakia,
  France, and the Federal Republic of Germany)
• On-route to comet Halley they released
  atmospheric probes onto Venus

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Missions to Venus (7)

• Magellan 4 May 1989 (USA)
• Created near-photographic quality, high
  resolution mapping of planets surface

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Missions to Venus (8)

• Flybys by Galileo on its way to Jupiter and
  Cassini-Huygens heading for Saturn.

• 9 Nov 2005 present (ESA)
• Dedicated mission

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• UV image from Venus Monitoring Camera and Visual
  and Infrared Thermal Mapping Spectrometer
  (VIRTIS) on Venus Express
• CO2, N2, thick clouds of Sulphur dioxide
  greenhouse effect (surface temp 860 ºF).

Courtesy ESA
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• False colour UV/visible/IR imager on Venus
  Express
• Surface is isothermal
• Lightening

• Double-eye vortex
• Collar of colder air -gt moving downward.

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Magnetic field

• Magnetic field arises from the interaction of the
  ionosphere with solar wind, no intrinsic field.
• Too weak to protect atmosphere from solar
  radiation
• Lack of field no convection in the core?

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Diameter 12,756 km Mass 5.9 x 1024 kg Year 365
days Day 1 day
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• The Red Planet
• Cratered surface, similar to the moon
• Olympus Mons the largest known volcano in the
  Solar System
• Valles Marineres the largest canyon in the
  Solar System
• Two Moons, Phobos and Deimos

Diameter 6,792 km Mass 6.421023 kg Year 687
days Day 24 hours 39 minutes
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Significant Missions to MarsPast

• Various US and Russian missions in the 60s and
  70s
• Viking 1 2 (Landed 1976, USA)
• First pictures back from Martian surface
• Mars Global Surveyor (USA), launched 1996
• Mapping of Martian surface
• Mars Pathfinder (USA), launched 1996
• Landed exploration vehicle Sojourner

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Significant Missions to MarsPresent

• Mars Odyssey Orbiter USA 2001
• Mars Express ESA Launched 2003
• Orbiter and Beagle 2 lander (lost during descent)
• Spirit and Opportunity USA 2003
• Successfully landed in 2004
• Mars Reconnaissance Orbiter USA 2005
• 2 year science survey
• Phoenix Mars Lander USA 2007
• Landed 2008

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• Image from Spirit at edge of Home plate a
  plateau where it will spend its 3rd winter

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• Surface Stereo imager in June 2008
• Lumps of ice visible

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• Map of Mars from the Hubble Space Telescope as
  observed in 1999

Courtesy ESA
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Diameter 142, 000km Mass 1.9 x 1027 kg Year
11 years Day 9.925 hours
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• Dense core, liquid metallic Hydrogen, outer layer
  of molecular hydrogen
• 90 H2, 10 He plus water, ammonia and rock

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• Views of the deep atmosphere, clouds to a level
  of 3 bar.

• Highest clouds and hazes. Only great red spot
  really seen.

• the indigenous heat from the deep, warm
  atmosphere.

• Temperature and altitude of produced light source

• Deeper clouds, ammonia and methane

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• Europa, 3000 km
• Tenuous O2 atmosphere
• Young and smooth surface with cracks and streaks
• Underlying ocean?

• Ganymede, 5262 km
• Possible saltwater ocean below surface
• Only moon to have a magnetosphere
• Liquid iron core

• Io, 3642 km
• gt 400 active volcanoes
• Most geologically active object in the solar
  system
• Tidal heating from Jupiter

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Diameter 120,536 km Mass 5.0 x 1026 kg Year
29.5 years Day 10 hours 9 mins
Saturnto be continued..
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Diameter 51,118 km Mass 8.6 x 1025 kg Year 84
years Day 17 hours 14 mins
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• Axis of rotation is tilted sideways
• Poles where equators usually are
• Get 42 years of continual sunlight
• Very fast winds in atmosphere

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• 27 named moons, many discovered during Voyager 2
  flyby in 1986.
• Together with small moonlets and rings makes for
  a very chaotic and unstable system.

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Diameter 49, 532 km Mass 1.02 x 1026 kg Year
164 years Day 16 hours 6 mins
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• Great dark spot and bright white cloud
• ½ the size of Jupiters red spot
• 13 known moons

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Diameter 2274 km Mass 1.27 x 1022 kg Year 248
years Day 6 days 9 hours
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Future exploration of the solar system (1)

• Mercury
• BepiColombo (2013) ESA
• Mars
• Mars Science Laboratory (2009) USA
• Mars Sample return Lander (2014 2016) USA
• Mars Scout 2 (2011) USA
• Mars Astrobiology Field Lab Rover (AFL) (2016)
  USA
• Mars Scout 3 (2018) - USA
• Phobos Grunt and Yinghuo-1 (2009) - Russia
  China
• MetNet (2009-2019) - Finland Russia
• ExoMars (2013) ESA

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Future exploration of the solar system (2)

• Jupiter
• Juno Jupiter Polar Orbiter (2011) USA
• Europa Astrobiology Lander (2035) USA
• Laplace (2015-2025) ESA
• Saturn
• Saturn flyby with probes (2015) USA
• Tandem (2015-2025) ESA
• Pluto
• New Horizons (2016 arrival) USA

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