THE BIRTH OF ASTRONOMICAL STUDIESASTRONOMY- study of all matter and energy in the universe

Aim : better understanding of the universeBenefit: celestial navigation , a new perspective of his environment, a view of himself and his environment and stimulation to his imagination brought about by the adventure of exploring

The Solar System

MODELS OF THE SOLAR SYSTEMHeliocentric System (Nicolaus Copernicus, 1543)- the sun is the center of the solar system and the sixth planets ( Mercury, Venus, Mars, Jupiter, Saturn & Earth as sixth planet with the moon were believe in circular paths around the sun.

Ptolemaic System ( Geocentric System) - the earth is the center of the solar system and the sun and other planets are revolving on it.

THEORIES ABOUT THE ORIGIN OF SOLAR SYSTEMNebular Hypothesis ( Immanuel Kant, 1796)- the solar system was derived from the condensation of an enormously dispersed gaseous atmosphere surrounding the sun.1. Beginning as a rotating cloud.2. Most of the mass became concentrated at the center to form the sun, the remaining material condensed and accumulated to form the planets.

Planetisimal Theory - planetary system was formed from the materials removed from the sun by great gravitational attraction.1. Gaseous projection was pulled from the sun by tidal action caused by a passing star2. the projection become masses , cooled and contracted and became solid bodies.

3. the larger bodies attracted smaller ones and became planets. 4. the smaller bodies become asteroids, meteors, and satellites of planets.

Dust Cloud Theory ( Carl Friedrich von Weizacken & Harold Urey, 1945)- Nebula was flattened by its rotation , which was of the planetary type in that the gas molecules moved faster as they were closer to the to the sun. Interactions of the gas molecules accelerated the lighter ones so that they mostly escaped from the nebula forming lumps in the nebula and become planets.

Protoplanet Hypothesis ( Gerald P. Kuoper, 1949)- the original nebula was so massive that on further contraction and flattening, it broke into separate clouds or protoplanets.

The Sun

It is a starSource of light and heat which makes life on earth possibleIt appears as a yellowish disk, noticeably darker near the edge than at the center.1 complete rotation = 25 days (equator)Points near the poles = 35 days (near the pole)Outer part of the sun is fluid.

Temperature 6,000 degree Celsius. At this temp, all known substances are gaseous.

Parts of the Sun

Corona- the extreme upper part of the suns atmosphere.Limb- a sphere with a dark edge (main body)Chromosphere ( color- sphere) a brilliant red ring, a layer of gas about 8,000 miles thick on the surface, flashes.Photosphere (light-sphere) a thin layer of brilliantly glowing glass about 100 miles deep which is the source of light.

Prominences- near the edge of the sun that appear reddish streamers and clouds of glowing gases.

LIFE EXPECTANCYSufficient hydrogen remaining in the sun allow to continue it to continue to producing energy at the present rate for the next 5- 10 billion years.

Moon

Thats one small step for man, one giant leap for mankind July 20, 1969 at 7:56PMApollo 11- Neil Armstrong and Edwin Aldrin Jr. Beginning of a new ear in the exploration of space.Origin: UnknownPossible : original body of earthindependent planet travelling around the sun

Earths natural satelliteDiameter: 3, 456 kmTravel speed: 3, 664 km per hour every 27 days or so.At its closest to the earth: 356,000 km (perigee)At its farthest: 406, 700 km (apogee)There is a presence of lunar craters.

Lunar craters- circular hollows, some having high rims while others have central peaks. In short, holes.

Diameter of holes : few centimeters to over 200 km

PHASES OF THE MOON AND ECLIPSENew Moon occurs when the side facing the earth is in shadow an we cannot see the moon at all.

Crescent Moon happens after 2-3 days when the moon has moved some distance and we can see the thin edge of the lighted side

First Quarter Moon happens a week after the new moon.

Gibbous Moon happens when three quarters of the side facing the earth is lighted up and can be seen clearly.

Full Moon the whole face of the lighted side clearly

KINDS OF ECLIPSESSolar Eclipse when the moon is new , it cover the bright disk of a sun.

Annular Eclipse - when the moon covers only the central part of the solar disk.

Lunar Eclipse takes place when the earth casts a shadow in space.

TIDESMotions caused by the gravitational attraction between the earth, moon and the sun. Due to the moons gravity field, a bulge of ocean water always faces the moon. A second bulge forms on the side of the earth away from the moon. Water to fill the bulges is drawn away form the area of the ocean between the bulges.

TYPES OF TIDESSpring Tides - when the sun and the moon are in line with the earth. These are highest tides.

Neap Tides occur when the sun and the moon are at the right angles to each other.

PLANETSRevolve around the sun and rotate their axes.Undergo 2 motions:1. revolution one motion of body around another2. rotation spinning on their respective axes.

DIFFERENCE BETWEENPLANETRevolves around the sunGives off no light of its ownConsists of non exploding elementsDo not twinkleSTARDoesnt revolveGives off lightMass of exploding gasesAppears twinkling because of the moving layers of air that scatter the light

CLASSIFICATION OF PLANETS ACCORDING TO THEIR DISTANCE FROM THE SUNINNER PLANETS/ TERRESTIAL PLANETSMERCURYVENUSEARTHMARSOUTER PLANETSJUPITERSATURNURANUSNEPTUNEPLUTO

Mercury

Planet nearest to the sunSecond smallest with a diameter of 4, 878 kilometers1/16 size of the EarthMagnetic field is 1% as strong as that of EarthRevolution: 87.97 days (fastest revolving planet)Rotation: 58 days, 15 hours and 28 minutesCan be observed on Earth as the morning and evening star

In March and April, it grows brilliantly in the western sky just after sunset.In September and October, it can be seen as morning star in the eastern sky.Surface is filled with craters and crossridgeTemp : 425 degree Celsius dayside 175 degree Celsius nightside Atmosphere is made up of helium

Venus

The brightest of all the planetsCan be seen as evening and morning starEvening star : during spring and summer months in the western skiesMorning star: during winter in the eastern skies

Revolution: 225 daysRotation: 243 daysEarths twinDiameter: 12, 104 kilometersTemp: -30 degree Celsius to 475 degree Celsius (hottest planet)Atmosphere is made up of more than 90% carbon dioxide and almost no O2.

Features that make Venus a peculiar planetSpins clockwise or retrogradeRotation is longer than revolutionA dense and cloudy atmosphere which is an excellent reflector of light.

Earth

The only planet known to support and have intelligent life1 earth day = 24 hours1 Revolution: 365 daysIt is divided into 3 main layers:1. crust atmosphere, lithosphere, hydrosphere. It is not more than 30 miles thick2. mantle layer of rocks with a depth of 1,800 miles3. core innermost layer, composed of dense molten metal, while the outer core is molten metal

Mars

The earths closest celestial neighbor beyond the solar orbitThe red planetTwo satelites : Phobos fear, Deimos terrorDiameter: 6, 794 kilometersRotation: 24 hours and 37 minutesRevolution: 687 earth daysIts atmosphere is made up chiefly of carbon dioxide. Water vapor, oxygen and nitrogen are scarce.

Temperature: 30 degree Celsius on hot day but when the sun sets, temp drops rapidly to -75 degree Celsius

Jupiter

The giant member of the Planetary systemJovian is the adjective form used by astronomers to describe the planet318 times more mass than earth.Diameter: 142, 796 kmRotation: 9 hours and 55 minutes (fastest rotating planet)Atmosphere is made up of mostly hydrogen and helium.

Satellites of JupiterThe working Group on Planetary System Nomenclature (WGPSN) has assigned the names listed to 11 recently discovered satellites of Jupiter. The satellites are listed in order of increasing distance

ROMAN NUMBERNAMEJupiter XVIICallirhoeJupiter XVIIIThemistoJupiter XIXMegacliteJupiter XXTaygeteJupiter XXIChaldeneJupiter XXIIHarpalykeJupiter XIIIKalykeJupiter XXIVIocasteJupiter XXVErinomeJupiter XXVIIsonoeJupiter XXVIIPraxidike

Galilean Moons

Saturn

Second largest planetDiameter: 9 times that of earthRotation: 10 hours and 39 minsIt has a cloudy hydrogen atmosphere mixed with some methane and ammoniaIt has a magnificent system of rings that is made up of countless ice-coated satellites. They revolve around the planet like tiny satellites

Uranus

Discoved by William Herchel of England in 1781The third largest planet in the solar systemRevolution : 84 Earth yearsRotation : 17 hours and 15 minutesColor: Pale Green Its atmosphere is made up of hydrogen and methaneTemperature: -170 degree Celcius , ammonia gets frozen (iced)

Its axis of rotation is only 8 degrees since it is inclined almost 90 degree Celsius the sun is nearly overhead at one pole.

It has 11 rings barely composed of ice and likely made of dark carbon materials

Neptune

The twin of UranusIts color is pale green due to methane in their atmosphere.According to US Space spacecraft Voyager 2, it has a set of broad sheet rings which extends inward from a distance of 59,000km.Atmospheric gases are hydrogen, methane and ethaneTwo major satellites: Triton and Neteid

Pluto

The location of Pluto was first calculated by Percival Lowell of United States.In 1930, Clyde W. Tombough discovered and named the planet Pluto.Innermost planet in the solar systemJames W. Christy, an American astronomer discovered that Pluto has a moon Charon.

Diameter: 2, 290 kilometersIts composition : 74% water ice, 21% rock and 5% methane iceIt is an icy world with a methanem-coated surface

ASTEROIDSfound in the Asteroid Belt. Ceres largest asteroid discovered. (480 mi)Apollo Asteroids asteroids crossing the Earths orbit pose danger to Earth.

TYPES OF ASTEROIDSAthens lies near the orbit of Mars. Orbits are highly elliptical in shape.

CeresPallasJunoVesta

2. Apollos lies near the orbit of Jupiter. Orbits are highly eccentric.

IcarusGeograpusEros

3. Trojans lies in the main asteroid belt and most stable asteroids.

HectorDiomedes

COMETSAppear as bright objects or star-like bodies with glowing tails.Made up of frozen ice and gas carbon dioxide, ammonia, methane with dust.The tail can reach a length of 150 million km.Orbit : 3, 6 100 yrs.Halleys Comet famous for its long glowing tail takes about 76 yrs. Reappearance : 1986

METEORSMeteoroids small chunks of matter bigger than a dust grain but smaller than asteroid.

Meteor falling stars- the streak light seen when a space rock enters the atmosphere and starts burning

Meteorite a remnant of meteor that landed on the suface of the earth.