How many planets are there in our solar system? Currently: 8 planets Why did Pluto lose status?
Why did Pluto lose planet status? Planet definition
Definition of a Planet RESOLUTION 5A, August 24, 2006: The IAU therefore resolves that "planets" and other bodies in our Solar System be defined into three distinct categories in the following way:(1) A "planet" is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit. Note: The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. (2) A "dwarf planet" is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape , (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite. Note: An IAU process will be established to assign borderline objects into either dwarf planet and other categories.(3) All other objects except satellites orbiting the Sun shall be referred to collectively as "Small Solar-System Bodies". Note: These currently include most of the Solar System asteroids, most Trans-Neptunian Objects (TNOs), comets, and other small bodies.
The Sun, the closest star to Earth? At a mere 93 million miles distant, it takes light from the Sun only eight minutes to arrive on Earth. Fact: 1 Earth-Sun distance is defined as an AU. The next closest are three members of Alpha Centauri and are just over 4 light years from Earth. There are 10 star systems located within 12 light years of Earth.
Mercury • Distance From Sun: • 36 Million Miles • Average Temp: 332oF • Low: -270oF • High: +800oF • Diameter: 3,000 miles • Orbital Period: 88 days • Moons: 0 Venus
Venus • Distance From Sun: • 67 Million Miles • Average Temp: 867oF • Diameter: 7,500 miles • Orbital Period: 225 days • Moons: 0 under clouds
Under the clouds of Venus earth moon
Distance From Sun:93 Million Miles • Average Temp: 59oF • Diameter: 8,000 miles • Orbital Period: 1 year • Moons: 1 Earth mars
Mars • Distance From Sun: • 142 Million Miles • Average Temp: -85oF • Diameter: 4,200 miles • Orbital Period: 1.9 years • Moons: 2 rovers
Mars 2003 MER (twin Mars Exploration Rovers) Spirit: Launched: June 10, 2003 Landed: January 4, 2004 Opportunity: Launched: July 7, 2003 Landed: January 24, 2004 The Mars 2003 mission consists of two identical rovers, Spirit and Opportunity, which will be a large (~130 kg) vehicles based on the Athena Rover design that was originally considered for the Mars 2001 mission. The rovers will be landed using an airbag system similar to that used on Mars Pathfinder but without the stationary lander. The rover, Spirit landed 4 January 2004 and the Opportunity will land 20 days later on 24 January. The landing sites have been selected, and are on opposite sides of Mars. The mission should last for at least 90 days each, until late April. The rovers are designed to cover roughly 100 meters each martian day, or sol (approximately 24 hours, 37 minutes). They will carry a scientific packages which will include a panoramic camera (Pancam), a rock abrasion tool (RAT) to expose fresh surfaces of rock, a miniature thermal infrared spectrometer (MiniTES), a microscopic camera, a Mossbauer spectrometer, and an alpha-proton-X-ray spectrometer (APXS). A goal for the rover is to drive up to 40 meters (about 44 yards) in a single day, for a total of up to one 1 kilometer (about three-quarters of a mile).
Spirit photo of hill on Mars (looking forward) Looking back
Oportunity photos on Mars Meteorite Hematite (proof of liquid water)
Rocky outcrop A crater in the distance? MRO
Mars Reconnaissance Orbiter (MRO) Launched: August 12, 2005 Arrived: March 10, 2006 • Major Instruments: • Context Camera (CTX) • Mars Color Imager (MARCI) • High Resolution Imaging Science Experiment (HiRISE) • Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) • Shallow Radar (SHARAD) (can see up to 1 km into ground) Victoria from above
MRO • 'Victoria Crater'
Opportunity at Victoria Crater In crater
Opportunity in Victoria Crater NASA's Mars Exploration Rover Opportunity has reached its science team's first destination for the rover inside Victoria Crater, information received from Mars late Tuesday confirms. Opportunity has descended the inner slope of the 800-meter-wide crater (half a mile wide) to a band of relatively bright bedrock exposed partway down. The rover is in position to touch a selected slab of rock with tools at the end of its robotic arm, after safety checks being commanded because the rover is at a 25-degree tilt. skylights
NASA Orbiter Finds Possible Cave Skylights on Mars Sept 21, 2007 - PASADENA, Calif. -- NASA's Mars Odyssey spacecraft has discovered entrances to seven possible caves on the slopes of a Martian volcano. The find is fueling interest in potential underground habitats and sparking searches for caverns elsewhere on the Red Planet. Very dark, nearly circular features ranging in diameter from about 100 to 250 meters (328 to 820 feet) puzzled researchers who found them in images taken by NASA's Mars Odyssey and Mars Global Surveyor orbiters. Using Mars Odyssey's infrared camera to check the daytime and nighttime temperatures of the circles, scientists concluded that the temperatures of the holes change only about one-third as much as the change in temperature of surrounding ground surface. Phoenix
Mars Phoenix Lander 2007 Launched 8/4/2007 PHOENIX WILL LAND AT MARS' ICY NORTH POLE, 5/25/2008, and dig into the ice cap with a robotic arm.
Mars - A Feast For Your Eyes QuickTime Movie of Mars from MRO Images
Asteroid Belt (gold colored specs) • Distance From Sun: • 260 Million Miles to center • over 166,000 asteroids • Largest: • Ceres 1/3 of all mass • 600 miles in diamter Our inner solar system Ceres Vesta
Dwarf Planet 600 mi dia Largest Asteroid 350 mi dia A "dwarf planet" is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape , (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite. dawn
Launch 9/27/07 gaspra
Asteroid Photos 1st ever closeup photo of an asteroid. Gaspra (12x7 miles) Ida
Asteroid Photos Ida (35 miles long) Dactyl
Asteroid Photos Ida (35 miles long) and Dactyl (1 mile diameter) impact?
Meteor Crater in New Mexico Crater is about 1 mile in diameter and 570 feet deep. Debris was found over 300 miles from the crater. This was caused by a rock 50 – 100 feet in diamter. Imagine what a Gaspra or Ida sized boulder would do? Half way Jupiter
Jupiter • Distance From Sun: • 483 Million Miles • Average Temp: -166oF • Diameter: 88,000 miles • Orbital Period: 12 years • Moons: 63 saturn
Galileo Mission to explore Jupiter and its 61 moons Launch: 10/18/1989 Orbit Jupiter: 12/7/1995 Mission End: 9/21/2003 First two years focused on Jupiter. Extended mission (6 years) focused on Jupiter's moons, with emphasis on Europa, Callisto, Ganymede, and Io. On it’s journey to Jupiter, Galileo did gravity sling shots around Venus, Earth, and Earth in a 2.5 year speed-building phase that achieved a velocity exceeding 100,000 miles per hour. The Galileo mission ended September 21, 2003 when the remaining fuel was used to splash the spacecraft into Jupiter. Gaspra and IDA
Galileo Jupiter Moons Images (4 of Jupiter’s 61 moons) Io (with active volcanos) Europa Liquid Oceans? Ganymede Callisto
Jupiter Icy Moons Orbiter by 2011 This proposed mission would orbit three planet-sized moons of Jupiter -- Callisto, Ganymede and Europa -- to make extensive investigations of their makeup, their history and their potential for sustaining life. Will use Prometheus Nuclear-Electric Propulsion.
Casini and Huygens Mission to Saturn and its largest moon Titan. Launch: 10/15/1997 Orbit Saturn: 7/1/2004 Huygens Release: 12/2004 Landed on Titan: 1/12/2005
Saturn • Distance From Sun: • 888 Million Miles • Average Temp: -220oF • Diameter: 75,000 miles • Orbital Period: 29 years • Moons: 47
Cassini Images of Saturn rings Moon in ring gap
Cassini Images of Saturn Moons Hyperion Enceladus Evidence of atmosphere and liquid ocean under ice.
Cassini images of Saturn’s moon Titan Continents visible? Dense atmosphere
Titan surface from under the clouds (during Huygens Probe descent) River Channels showing evidence of liquid flow