Our Solar System and Its Place in the Universe

Transcription

1 Our Solar System and Its Place in the Universe The Formation of the Solar System Our Solar System includes: Planets Dwarf Planets Moons Small Solar System bodies Sun Outer portion created Planets and their moons Other interplanetary material Eight major planets and three dwarf planets Planets are divided into three groups Terrestrial planets Outer gaseous planets (known as gas giants) Dwarf planets The Planets Relatively close to the Sun mainly rock Mercury Venus Earth Mars Outer gaseous planets (gas giants) Jupiter Saturn Uranus Dwarf plants Ceres, Pluto, and Eris Neptune Mercury - closest to the Sun 36 million miles No atmosphere Fastest t planet Extreme Temperatures: Night temperature ( ( 300 F) Day temperature (700 F) Surface covered with craters like our moon Rotates in 59 days, orbits the Sun in 87 days (short year!) 1

2 Venus 67 million miles from the Sun Same size as Earth Atmosphere of CO 2 and sulfuric acid clouds - from volcanic eruptions Brightest planet in the sky Temperature in clouds 70 F Temperature below clouds is 800 F (What a Greenhouse Effect!) Surface pressure 90 times that of Earth (ouch!) Extreme temperatures because of greenhouse effect 224 days to orbit the Sun (still a short year) Rotation takes 243 days Sun rises in west and sets in east (weird) Earth 93 million miles from the Sun Only planet in solar system with: Liquid water Ability to support life 365 days to orbit the Sun 24 hours to rotate on its axis Atmosphere of nitrogen and oxygen 2

3 Terrestrial Planets (continued) Mars million miles from the Sun Half the size of Earth Thin atmosphere of CO 2 Day time temperature of 27 F Night time temperature of 117 F F (cold,cold( cold,cold, cold) Clouds of frozen water or dry ice Orbit 686 days (long year), rotation takes 1 day The Gaseous Planets Jupiter 483 million miles from the Sun Largest planet in solar system Composed hydrogen, helium, ammonia and methane gas Cloudy surface composed of ammonia Great red spot storm storm 300+ years old Below atmosphere layers of liquid hydrogen Jupiter (continued( continued) Has three rings Surrounded by at least 39 moons First moons discovered were: Io Ganymede Europa Callisto Europa may contain liquid water and life 3

4 Saturn million miles from the Sun Composed of hydrogen and helium gas Clouds of ammonia and methane Has unique rings 7 Composed of billions of ice particles Orbited by at least 20 moons Largest is Titan Saturn (continued) 2005 Cassini spacecraft launched a probe Penetrated Titan s s atmosphere Discovered hydrocarbon rivers flowing into methane sea Flew by Enceladus (another moon) in 2006 Revealed surface covered in water ice Periodic eruptions of liquid water Both may contain liquid water below ice Uranus billion miles from the Sun Gaseous planet four times larger than Earth 84 years to orbit the Sun, 17 hours to rotate Axis of rotation tilted 90 degrees Composed of ammonia and methane Atmosphere of hydrogen and helium Ring system with at least 18 moons Neptune billion miles from the Sun Composed of hydrogen, helium, and methane Methane causes blue color Orbit 168 years, rotates in 19 hours Has a small ring and eight moons Triton moon 390 F coldest object in space Believe will collide with Neptune in 10 to 100 million years 4

5 The Dwarf Planets A non-luminous object that orbits around a star Has sufficient gravity to form a spherical shape Orbit has not cleared the path of other celestial objects Three named so far: Ceres, Pluto, and Eris (2003 UB 313 ) Ceres Dwarf planet located closest to the Sun Italian astronomer Giuseppe Piazzi discovered in 1801 Once regarded as the largest asteroid Pluto Pluto billion miles from the Sun Previously thought to be our ninth planet but in August 2006 changed its designation to dwarf planet Composed frozen methane, nitrogen, and carbon monoxide One moon called Charon Composed of mostly frozen water Small Solar System Bodies A small solar system body is a category of celestial objects orbiting the Sun that are not classified as planets, dwarf planets, or moons They include objects known as asteroids, meteors, comets, and some trans- Neptunian objects Galaxies Grouping of millions or billions of stars Located millions of light-years from Earth Three main types: Spirals like like a rotating pinwheel Milky Way is a spiral galaxy Solar system is in one of the spiral arms Is about halfway from the galactic center 5

6 Cosmology Universe Total volume in which all energy/matter exists Big Bang Theory Formed universe from a colossal explosion. Current evidence shows that the universe is expanding (like diffusion) and at increasing velocities. This suggests that at one point there must have been and origin from which there might have been a big bang Protoplanet Theory: describes how planets were created. Small moon-sized planetesimals collide via attractive gravitational pulls to create larger planets. Cosmology (continued) Three possible fates of the universe: Closed universe model will collapse on itself Also called the Big Crunch Open model Will expand and contract indefinitely Flat universe model Expansion will slow down and level out 6