Our Solar System includes: The Sun (our one star) Eight planets and their natural satellites

1. Our Solar System includes: • The Sun (our one star) • Eight planets and their natural satellites • a)Mercury • b)Venus • c)Earth • d)Mars • e) Jupiter • f) Saturn • g) Uranus • h) Neptune • Asteroids • Comets • Meteors, Meteoroids • Dwarf Planets Our Solar System Mrs. Degl

2. There are two main groups of planets in our Solar System: 1. Terrestrial Planets 2. Jovian Planets • Terrestrial Planets – Earth like • The first 4 planets from the Sun • Mercury, Venus, Earth, Mars • These are the smaller planets • These planets are more dense • These planets are made of solid • rock. (You can stand on them) • Jovian Planets – Gas Giants • The next 4 planets • Jupiter, Saturn, Uranus, Neptune • Does not include Pluto • These are very LARGE planets • These are low density planets • These planets are made of GAS • You cannot stand on them • These planets have very thick • atmospheres Pluto is not in either group. Mrs. Degl

3. Mercury • The innermost planet • The smallest planet • Has no atmosphere • Has a lot of craters • Is very dense • Rotates slowly • Revolves quickly • Day temps are @ 800ºF • Night temps are @ -280ºF Mrs. Degl

4. Venus • Very similar to the Earth as far as size and density. • Has a very thick atmosphere of over 97% carbon dioxide. • Surface temperature is 90 times hotter than Earth. • Has a runaway greenhouse effect because of the high amount of • CO2. • The surface was mapped and showed that 80% of the surface was • once volcanic. • There are very few impact craters. Why? _________________ Mrs. Degl

5. Mars • The Red Planet • The atmosphere is 1% as dense as the Earths. • The small atmosphere is mostly CO2. • Has visible polar caps of frozen water and CO2. • Very dry planet with many large dust storms. • Numerous extinct volcanoes (Olympus Mons-largest in our Solar System) • The tectonic plates are not moving like Earth’s are. • No running water (only frozen on the caps) • There are stream drainage patterns found on the planet from • running water at some point long ago. Mrs. Degl

6. Jupiter • Largest planet. • 2.5 times greater mass than all of the other items on our solar • system combined. • If it grew only 10x larger, it would have become a star (we will • learn about this when we discuss stars) • Rotates in 10 hours. • Multicolored atmosphere caused by the thick gasses swirling • around. • Has the Great Red Spot, the largest storm in our Solar System. • Surface may be an ocean of liquid hydrogen (not rocky) • Has a ring system. • Has many moons, but two are promising for life. • a) Europa – Has a cracked icy surface, which means that it may have life in a warmer ocean underneath • b) Io – Very volcanically active (cooling lava creates steam, • which can create water, which can hold life) Mrs. Degl

7. Io Mrs. Degl

8. Saturn • Very similar to Jupiter as far as atmospheric conditions. • Most prominent ring system (about 1000 rings) • a) the total ring thickness is 40,000 km • b) each ring is about 100 m thick • c) particles in the ring are mostly icy particles, the size of buses. • Rings were discovered by Galileo in 1610. • The Cassini spacecraft traveled through the rings • in July 2004. • Has at least 21 moons (Titan is the largest moon in our Solar • System) • Enceladus, another Moon, is geologically active. It is spraying water vapor and ice into space. This was discovered in December 2005. Enceladus Mrs. Degl

9. Uranus and Neptune are considered the twin planets Neptune Uranus • Very thick atmosphere • Has the Great Dark Spot, which • is a large storm • One Moon (Triton) revolves • opposite to rest of our Solar • System members. It also has the • lowest temp. in the Solar System. • Rotates on it’s side (it is • tipped over) • Also has a ring system • Many large moons • Very thick atmosphere Mrs. Degl

10. What is Pluto now? Pluto • Is not visible to the naked eye. • Highly elliptical orbit, which causes • it to travel into the orbital path of • Neptune. • 3. Pluto is now classified as a "dwarf planet" • 4. Pluto might be a captured old comet or a previous moon of Neptune. • 5. The average temp. on Pluto is -210ºF • 6. Pluto’s main moon Charon is almost the same size as itself. Charon Click here to learn about the future mission to Pluto Mrs. Degl

11. Ceres? Charon? Eris (2003 UB13)? Now Charon will continue to be considered Pluto's satellite, and the three other worlds will be dubbed "dwarf planets" rather than full-fledged planets. The planets are drawn to scale, but without correct relative distances. Mrs. Degl

12. The 2006 definition of "planet" by the International Astronomical Union (IAU) states that, in the solar system, a planet is a celestial body that: • 1. is in orbit around the Sun • 2. has sufficient mass so that it assumes a hydrostatic equilibrium (nearly round) shape • 3. has "cleared the neighborhood" around its orbit • A non-satellite body fulfilling only the first two of these criteria is classified as a "dwarf planet", whilst a non-satellite body fulfilling only the first criterion is termed a "small solar system body" (SSSB). The definition was a controversial one, and has drawn both support and criticism from different astronomers. • According to the definition there are currently eight planets and three dwarf planets known in the solar system. Mrs. Degl

13. UB313 (ERIS) - an icy body that lies beyond the planet Neptune. It is about three times as far from the Sun as is Pluto. Scientists determined 2003 UB313's diameter is about 1,864 miles (3,000 kilometers), which is 435 miles (700 kilometers) larger than Pluto. Eris is now considered a ‘Dwarf Planet” Mrs. Degl

14. Quaoar – a cold new world It was once believed that another planet, called Planet X, resided out there. But that has been disproved. However, there is an object orbiting around the Sun in a nearly perfect circular orbit, called Quaoar. It is more than 1 billion miles past Pluto. It is 1300 km (800 miles)in diameter and definitely part of out solar system Mrs. Degl

15. Kuiper Belt The Kuiper Belt is an area in our Solar System that is similar to the Asteroid Belt. It is very far away and yet is hold many larger objects. Some of these objects are not much smaller than the size of Pluto. The Kuiper Belt is a disk-shaped region past the orbit of Neptune extending roughly from 30 to 50 AU from the Sun containing many small icy bodies. It is now considered to be the source of the short-period comets. Mrs. Degl

16. Asteroids The Asteroid Belt, which is where most of the asteroids are, lies between Mars and Jupiter. One of the largest in our Solar System is 620 miles in diameter. Asteroids tend to have very eccentric orbits and irregular shapes. Asteroids have always collided with the Earth. This does not happen very often, because most are very far away. Every once in while, the orbit of an asteroid comes pretty close to the Earth’s orbit. (The closest has been double the distance to the Moon from Earth… that is pretty close) It is believed that the extinction of the dinosaurs and many other species was caused by an asteroid impact of some sort, 65 million years ago. A huge undersea crater off of Mexico is believed to the the impact site. A great deal of an element called Iridium was found around it. Iridium is found on the surface of the Earth. It is found in space rocks. Mrs. Degl

17. Comets Comets are sort of like“large dirty snowballs” Comets are composed of frozen gases that cover rocky materials. Comets tend to have very eccentric orbits. Comets develop a tail that points away from the Sun. This is caused by blowing solar winds and/orpartial melting when the comet gets closer to the Sun. The most famous comet is “Halley’s Comet”. It has an orbital period of 76 years. It was last here in 1985. It will return in 2061. Another famous comet is “Hale Bopp” (It was here in 1997). Mrs. Degl

18. Meteors and Meteoroids Meteors are pieces of space rock that enter the Earth’s atmosphere. Meteoriods are pieces of space rock that make it to the ground. When you see a shooting star, you are looking at a meteor that has entered the Earth’s atmosphere as it burns up. Meteor showers occur when the Earth enters the path of a comet or other space debris, during it’s orbit around the Sun. The Leonid Meteor Shower is very popular and a great time to go out at night and look for shooting stars. This happens every November. Shooting stars are really the size of a nickel, give or take a few centimeters. Most meteors are made of iron and nickel. Others are made of carbon. This helps us determine what is inside the Earth’s core and what is in the rest of our Solar System. Mrs. Degl

19. Meteor Crater Arizona Mrs. Degl

20. Mrs. Degl

21. Oort Cloud The Oort cloud is an immense spherical cloud surrounding the planetary system and extending approximately 3 light years, about 30 trillion kilometers from the Sun. This vast distance is considered the edge of the Sun's orb of physical, gravitational, or dynamical influence. The statistics imply that it may contain as many as a trillion comets. Unfortunately, since the individual comets are so small and at such large distances, we have no direct evidence about the Oort Cloud. Mrs. Degl