Solar System

1. Solar System

2. Our solar system consists of • Sun • 9 planets • Asteroid Belt • Meteors and comets • Interplanetary medium

3. How was it formed? • http://imgsrc.hubblesite.org/hu/db/2003/19/images/f/formats/pdf.pdf • Two Planet Forming Scenarios

4. The Solar System formed when a cold, slowly-rotating cloud of gas and dust collapsed because of its own gravity about 4.5 billion years ago. • As the Sun grew hot enough to ignite the nuclear reactions which sustain it today, it vaporized the cold ices and frozen gasses in the inner solar system, leaving behind the rocky dust and metals which form the inner planets. • The outer Solar System remained cold, and the ices and gas there collected into the giant outer planets

5. Two General Categories • Terrestrial planets (like the Earth) • The terrestrial planets- Mercury, Venus, Earth and Mars- are relatively small and have rocky crusts and small atmospheres. • Jovian planets (like Jupiter). • The Jovian planets- Jupiter, Saturn, Uranus and Neptune- are many times larger and have dense, gaseous atmospheres with no visible surfaces. • Sometimes referred to as gas giants, although it is believed that the cores of these huge planets are liquid if not solid forms of helium and hydrogen • Pluto, the most distant planet, is in a class by itself

6. MERCURY • Timocharis made the first recorded observation of Mercury in 265 BC. • Other early astronomers that studied Mercury include Zupus (1639), who studied the planet's orbit. • Because it is so difficult to make out features on the surface of the planet from Earth, it was not until the 1960s that scientists determined the correct day length rate (59 Earth days) of the planet on its axis. This also showed that Mercury's day length and year length are the same. • 1974 Mariner 10 passed by the planet 3 times and gave us close-up images • 2004 Messenger mission

7. Mercury

9. VENUS • Venus is the second planet from the Sun, and is Earth's neighbor in the solar system. • Venus is the brightest object in the sky after the Sun and the Moon, and sometimes looks like a bright star in the morning or evening sky. • We can't see the surface of the planet because it has a very thick atmosphere filled with clouds that strongly reflect sunlight. Observations of Venus in the ultraviolet show cloud features that relate to characteristics of the planet's atmosphere. • We think that the internal structure of Venus is similar to Earth, with a metallic core, rocky mantle, and crust.

10. The atmosphere of Venus produces hostile conditions at the planet's surface, where temperatures can reach more than 460C (900F), atmospheric pressure is 90 times that at the Earth's surface, and clouds filled with sulfuric acid surround the planet. • spacecraft mapped the surface of the planet from above. These maps reveal a surface covered with craters, over 1600 major volcanoes, mountains, large highland terrains, and vast lava plains. • The 1950's astronomer Robert Richardson noticed that Venus rotates opposite from earth

13. MARS • Mars Student Imaging Project • Lets students pick a spot for the orbiting Odyssey Spacecraft to take a picture • http://msip.asu.edu/index.html • http://marsrovers.jpl.nasa.gov/mission/traverse_maps.html • Latest information on the two Mars rovers, Spirit and Opportunity

14. The uniquely red surface of Mars is marked by many interesting features - some like those on the Earth and others strangely different. The reddish color is caused by rust (iron oxide) in the soil. • Some of these features are; volcanoes, canyon systems, river beds, cratered terrain, and dune fields. • Of these features, the most interesting includes the apparently dead volcano Olympus Mons, which rises 23 km (~75,000 ft) above the surrounding plains and is the highest known peak in the Solar System. • Valles Marines is a giant canyon system that runs about 2,500 miles across the surface of the planet and reaches depths of 6 km or 4 miles • (for comparison, the Grand Canyon is not more than 1 mile deep).

18. ASTEROID BELT • Asteroids are small bodies that are thought to be left over from the beginning of the solar system 4.6 billion years ago. They are rocky objects with round or irregular shapes up to several hundred km across, but most are much smaller. • More than 100,000 asteroids lie in a belt between Mars and Jupiter. These asteroids lie in a location in the solar system where there seems to be a jump in the spacing between the planets. Scientists think that this debris may be the remains of an early planet, which broke up early in the solar system. Several thousand of the largest asteroids in this belt have been given names. • The chances of an asteroid colliding with Earth are very small! But some do come close to Earth, like Hermes (closest approach of 777,000 km).

21. Formation of the Asteroid Belt • One theory suggests that they are the remains of a planet that was destroyed in a massive collision long ago. • More likely, asteroids are material that never coalesced into a planet. • In fact, if the estimated total mass of all the asteroids was gathered into a single object, the object would be less than 1,500 kilometers (932 miles) across - less than half the diameter of the Moon.

24. JUPITER • The Giant planets do not have the same layered structure that the terrestrial planets do. Their evolution was quite different than that of the terrestrial planets, and they have less solid material. • Jupiter's interior composition is primarily that of simple molecules such as hydrogen and helium, which are liquids under the high pressure environments found in the interiors of the outer planets, and not solids. • Motions in the interior of Jupiter contribute in a very special way to the development of the powerful and extensive magnetosphere of Jupiter. Heat generated within • Jupiter contributes to the unusual motions of the atmosphere.

26. Giant Red Spot • A giant, hurricane-like storm system that rotates with the clouds of Jupiter. • It is so large three complete Earths could fit inside it. • Astronomers have recorded this giant storm on Jupiter for over 300 years.

28. Rings • Rings are much smaller and fainter than the famous rings of Saturn • Their composition is small-grained, rocky material; no ice. Contributes to their small albedo (reflectiveness) • Voyager 1 mission scientists decided to look around and were surprised to find them

30. Shoemaker-Levy9 Impact • On 1994 July 16-22, over twenty fragments of comet Shoemaker-Levy 9 collided with the planet Jupiter

31. SATURN • Saturn is the most distant of the five planets known to ancient stargazers. • In 1610, Italian Galileo Galilei was the first astronomer to gaze at Saturn through a telescope. To his surprise, he saw a pair of objects on either side of the planet, which he later drew as "cup handles" attached to the planet on each side. • In 1659, Dutch astronomer Christiaan Huygens announced that this was a ring encircling the planet. • In 1675, Italian-born astronomer Jean Dominique Cassini discovered a gap between what are now called the A and B rings.

33. Saturn is a gas giant. It is made mostly of hydrogen and helium. • volume is 755 times greater than Earth's. • Winds in the upper atmosphere reach 500 meters per second in the equatorial region. (In contrast, the strongest hurricane-force winds on Earth top out at about 110 meters per second.) • These super-fast winds, combined with heat rising from within the planet's interior, cause the yellow and gold bands visible in its atmosphere

36. URANUS • Uranus is the seventh planet from the Sun and is the third largest in the solar system. • It was discovered by William Herschel in 1781. • It has an equatorial diameter of 51,800 kilometers (32,190 miles) and orbits the Sun once every 84.01 Earth years. • It rotates about its axis once every 17 hours 14 minutes. Uranus has at least 22 moons.

38. Uranus is distinguished by the fact that it is tipped on its side. • Its unusual position is thought to be the result of a collision with a planet-sized body early in the solar system's history • In 1977, the first nine rings of Uranus were discovered. During the Voyager encounters, these rings were photographed and measured, as were two other new rings and ringlets.

40. NEPTUNE • Neptune is the outermost planet of the gas giants. • It has an equatorial diameter of 49,500 kilometers (30,760 miles). • If Neptune were hollow, it could contain nearly 60 Earths. • Neptune orbits the Sun every 165 years.

41. Neptune is a dynamic planet with several large, dark spots reminiscent of Jupiter’s hurricane-like storms. • The largest spot, known as the Great Dark Spot is about the size of the earth and is similar to the Great Red Spot on Jupiter. • Voyager revealed a small, irregularly shaped, eastward-moving cloud scooting around Neptune every 16 hours or so. • This scooter as it has been dubbed could be a plume rising above a deeper cloud deck.

45. PLUTO • Tiny (only slightly larger than our Moon) • Orbit is inclined more than 17 degrees compared to the orbits of the other planets, and its • Orbit is also very eccentric (its distance from the Sun varies over the course of its orbit). • It's so eccentric, in fact, that it even crosses Neptune's orbit, so sometimes Neptune is farther from the Sun than Pluto

46. Recently the Hubble Telescope has taken pictures of two moon circling Pluto and Charon. • In 2004 the international science community had re-defined Pluto as a dwarf planet. • Since that time dozens of small Planetoids have be discovered in our Solar system. • Ceres, Eris, Sedna, Biden, VP113,

49. Comparing Rotation

50. Visualizing the Distance Between Planets • http://www.classzone.com/books/earth_science/terc/content/visualizations/es2701/es2701page01.cfm?chapter_no=visualization • This animation is 300 times the speed of light.