Earth Science

1. Earth Science An overview of the Solar System

2. Definiton • The family of celestial bodies grouped around the (our) sun. • Members • Major: The Sun and the Planets and their satellites • Minor: Comets, Asteroids/Planetoids, Meteors, Meteorites, Meteoroids

3. Properties of the Solar System • 1. The orbits of all the planets are almost in the same plane. This means that the solar system is flat. • 2. The planetary orbits are nearly circular. The elliptical orbits depart only slightly from being a perfect circle.

4. Properties of the Solar System • 3. The orbits of the planets are nearly in the same plane as the rotation of the sun. • 4. The planets rotate in the same direction as they revolve around the sun, with the exception of Venus and Uranus.

5. Properties of the Solar System • 5. The distances of the planets from the sun can be expressed in a simple relationship called BODE’S LAW named after the German astronomer Johann Bode (1747 – 1826). • The calculated distances (using Bode’s Law) and the observed distances of the planets from the sun are almost the same with the exception of Neptune and Pluto.

6. Properties of the Solar System • 6. The satellite systems of Jupiter and Saturn are nearly identical in their arrangements with the solar system. The distances of the satellites from the planets follow the Bode’s Law. • 7. The satellites and planets contain almost all the rotational motions of the solar system.

7. The Sun • The sun is the biggest, brightest, and hottest object in the solar system. • The sun is an ordinary star. • The sun is made of about 70% hydrogen and 28% helium.

8. Some Info on the Sun • Diameter: 1,140,000 km • Volume: take in a million earths ++ • Period of Rotation: Equatorial - 25 days • Polar - 33 days • Sun’s Interior: • Helium Core • Radiative Zone • Convective Envelop

9. Some Info on the Sun • Sun’s Atmosphere: • Corona • Chromosphere • Photosphere

10. Some Facts on Planets • 1. All the planets revolve around the sun in a counterclockwise direction as viewed from Polaris. From an inside view, the direction of revolution is west to east. • 2. All the planets, except for Uranus, rotate in a counterclockwise direction as viewed from Polaris.

11. Some Facts on Planets • 3. The orbits of all the planets are ellipses, with the sun at one of the foci. • 4. All the planets shine because they reflect sunlight. • 5. All the planets have the shape of oblate spheroids.

12. Mercury • Mercury is solid and is covered with craters. • Mercury has almost no atmosphere. • Mercury is the eighth largest planet.

13. MERCURY • The innermost and smallest planet • Has a very high temperature and a very low gravity • Is seen as an evening star just after sunset, and as a morning star just before dawn • Period of Rotation: 59 days • Period of Revolution: 88 days

14. Venus • Venus is the sixth largest planet. It’s about three-fourths the size of earth. • The surface is rocky and very hot. The atmosphere completely hides the surface and traps the heat.

15. VENUS • Once considered as Earth’s twin due to similarity in mass, size, and having an atmosphere

16. Findings of the PIONEER Probe • Venus is quite round • Has a much smoother surface than Earth (as revealed by VENERA also). • No bulging at the equator and no flattening at the poles • Retrograde rotation (i.e. east to west direction or clockwise) versus that of Earth which is prograde (i.e. west to east direction or counterclockwise)

17. Findings of the PIONEER Probe • Has no moon or natural satellite; no water. • Is a very hot planet (compared to Earth and Mercury) due to its nearness to the sun and the Green House Effect due to its very thick atmosphere mostly clouds of sulfuric acid and carbon dioxide. • Due to the thickness of its atmosphere, it is sometimes referred to as the “VEILED PLANET.”

18. VENUS • Other surface features: • APHRODITE TERRA – the largest continent on the surface • ESTHAR TERRA – a volcano on the surface • EVE – name of the crater on the surface • M. LOMOSOV - discovered that Venus has an atmosphere which is about 48 – 58 km thick. Period of Rotation: 243 days Period of Revolution: 225 days

19. Earth • Earth is the fifth largest planet and the third from the sun. • Liquid covers 71 percent of the Earth’s surface. • The Earth has one moon.

20. Moon

21. Mars • Mars is the fourth planet from the sun. • Mars has a thin atmosphere that contains mostly carbon dioxide. • Mars has two small moons.

22. MARS • Has a thin atmosphere • VIKING space probe reveals the ff: • Soil … contains peroxide • Atmosphere … CO, CO2, N, Ar, O, O3, Kr, Xe, clouds and fogs • No liquid water … water in other forms in atmosphere and beneath the surface • Frozen carbon dioxide … found in thin mist atmosphere and polar caps.

23. MARS MARINER 9 which orbited Mars revealed: • Mar’s surface is heavily cratered in some parts with ridges. • Bright circular plains and deserts in the remaining parts. • Craters are shallow with very flat bottoms. • Canals are actually chains of dark-floored craters. • Plains are result of the leveling effect of winds and dust storms.

24. Moons of Mars Phobos (irregular in shape) Deimos (believed to be a captured asteroid)

25. MARS • In the 1890’s, Percival Lowel, a US astronomer, built an observatory at Flagstaff, Arizona to specially observe Mars and its surface • OLYMPUS MONS – a volcano on Mars; the largest in the solar system

27. MARS • Is a red planet due to the presence of Carbon suboxide, a foul smelling compound which when struck by ultra-violet light imparts an orange or reddish-brown color. • The bright pink sky of Mars is due to the effect of the scattering of light when radiation hit dust particles. • The red dust of Mars is due to Iron (III) oxide or rust.

28. MARS • Exhibits changes in seasons due to its angle of inclination of 25 degrees. • The great ellipticity causes more unequal heating of the northern and southern hemispheres. • Period of Rotation: 1.37 days • Period of Revolution: 1.88 years

31. Jupiter

32. JUPITER • The largest planet with a diameter 11x of Earth and a mass 2.5x that of all planets put together. • Rotates in less than 10 hrs. (2.4x faster than Earth). The fast rotation causes the equator to bulge and its poles to flatten more than any other planets. • Period of Rotation: 9.55 hours • Period of Revolution: 12 years

33. JUPITER • Surface is marked with light and dark bands, and spots, streaks, plumes, swirls, loops and irregular patches. These are caused by high wind speeds and powerful Coriolis Force. • Zones – light bands; varies from white to pale yellow in color and are regions of rising gases. • Belts – darks bands in various shades of reddish brown and are regions of descending gases.

34. JUPITER • Coloration of band is due to ammonium compounds and the organic and inorganic compounds present in the atmosphere. • The atmosphere contains Hydrogen, Helium, Methane, and Ammonia. • The Great Red Spot is the most prominent feature, with a length of 30,000 km, a width of 12,000 km and a height of 8 – 10 km; located along the south tropical zone known as the “hurricane belt.”; has been seen for 300 yrs; a huge and violent storm.

36. Jupiter’s Red Spot • The Great Red Spot, a huge storm of swirling gas that has lasted for hundreds of years. • Jupiter does not have a solid surface. The planet is a ball of liquid surrounded by gas.

37. JUPITER • Interior is believed to be made of a solid iron-silicate core, an inner layer of liquid metallic hydrogen, and an outer layer of liquid molecular hydrogen. The inner layer of hydrogen is believed to be the main source of Jupiter’s large and powerful magnetic field. Convection currents within are deflected by rotation, generating electric current and giving rise to a magnetic field. Strong magnetic field gives off strong radio signals into space.

41. JUPITER • Jupiter’s magnetic field is about 20 to 30 times stronger and larger than that of the Earth. • Has a thin ring believed to come from volcanic eruptions in one of its natural satellites named Io.

42. Moons of Jupiter Jupiter has four large Galilean moons, twelve smaller named moons and twenty-three more recently discovered but not named moons. We’ll take a look at the four large Galilean moons which were first observed by Galileo in 1610.

43. Io • Io is the fifth moon of Jupiter. It’s the third largest of Jupiter’s moons. • Io has hundreds of volcanic calderas. Some of the volcanoes are active.

44. IO • Diameter: 3,130 km • Circles Jupiter at an average distance of 421,600 km • Probable Structure: sulfur and sulfur dioxide crust, molten silicate interior, and possible solid core. • The surface is the youngest known in the solar system.

45. Europa • Europa is the sixth of Jupiter’s moons and is the fourth largest. • It is slightly smaller than the Earth’s moon. • The surface strongly resembles images of sea ice on Earth. There may be a liquid water sea under the crust. • Europa is one of the five known moons in the solar system to have an atmosphere.

46. EUROPA • Diameter: 3,130 km • Circles Jupiter at an average distance of 670,900 km • Probable Structure: ice crust, silicate interior and possible solid core • Is rocky, but most is covered with frozen water

47. Ganymede • Ganymede is the seventh and largest of Jupiter’s known satellites. • Ganymede has extensive cratering and an icy crust.

48. GANYMEDE • Diameter: 5,270 km • Orbit Jupiter at an average distance of 1,070,000 km • Probable Structure: ice crust, convecting water or soft ice mantle surrounding silicate core. • The largest moon of Jupiter and the second largest in the solar system.

49. Callisto • Callisto is the eighth of Jupiter’s known satellites and the second largest. • Callisto has the oldest, most cratered surface of any body yet observed in the solar system.

50. CALLISTO • Diameter: 4,850 km • Orbit Jupiter at an average distance of 1,880,000 km • Probable Structure: thick ice crust, convecting water or soft ice mantle surrounding silicate core • The oldest of Jupiter’s moon • Has a highly cratered surface