The UniverseThe Universe

Three Theories about the Origin of Three Theories about the Origin of the Universethe Universe

Big Bang Theory – Edwin HubbleBig Bang Theory – Edwin Hubble

Steady State Theory – Herman Bondi, Steady State Theory – Herman Bondi, Fred Hoyle and Thomas Gold Fred Hoyle and Thomas Gold

Oscillating Universe Theory – Fred Oscillating Universe Theory – Fred HoyleHoyle

1. The Big Bang Theory1. The Big Bang Theory The universe started from very hot and dense The universe started from very hot and dense

fire ball also known as fire ball also known as YLEMYLEM that explodes. that explodes. Bringing streams of gases containing proton, Bringing streams of gases containing proton, neutron, and electron to immerse in the vast neutron, and electron to immerse in the vast ocean of radiation. After the explosion, the ocean of radiation. After the explosion, the ylemylem cooled and contract giving birth to the cooled and contract giving birth to the universe.universe.

The The universe that exist today is a product of universe that exist today is a product of continuous expansion and contractioncontinuous expansion and contraction. The . The expansion still continues and the distance expansion still continues and the distance between galaxies continue to increase.between galaxies continue to increase.

Big Bang TheoryBig Bang Theory

Two Evidences Supporting the Two Evidences Supporting the BBTBBT

1. The Law of 1. The Law of Conservation of Conservation of Matter and Matter and EnergyEnergy

Matter or energy Matter or energy is neither created is neither created nor destroyed it nor destroyed it can only be can only be transformed into transformed into another form.another form.

2. The Law of the 2. The Law of the Expanding Universe. Expanding Universe.

Edwin Hubble and Milton Edwin Hubble and Milton HumasonHumason were able to were able to determine at which determine at which galaxies are moving away galaxies are moving away from each other. from each other.

55 km per million parsec55 km per million parsec = the rate by which = the rate by which galaxies are moving. galaxies are moving.

Our Universe is ExpandingOur Universe is Expanding In the 1920’s, In the 1920’s, Edwin HubbleEdwin Hubble discovered that galaxies discovered that galaxies

were moving away from us when he observed the were moving away from us when he observed the red shift in light wavelengths emitted by galaxies.red shift in light wavelengths emitted by galaxies.

This is known as This is known as Hubble’s law Hubble’s law which which states that the states that the further away a galaxy is, the greater it’s red shift and further away a galaxy is, the greater it’s red shift and the faster it is moving away from usthe faster it is moving away from us. This led to the . This led to the calculation of the point where the Big Bang started. calculation of the point where the Big Bang started.

Today Today with the Hubble Space Telescope scientists with the Hubble Space Telescope scientists have observed that most of the have observed that most of the galaxies are moving galaxies are moving away from us away from us and this means that our and this means that our universe must universe must be moving outwards and expanding. be moving outwards and expanding.

Vesto Slipher Vesto Slipher = He studied the = He studied the spectrum of light emitted by 15 nearby spectrum of light emitted by 15 nearby galaxies and noticed that galaxies and noticed that the the wavelength of the spectrum shifted to wavelength of the spectrum shifted to the red indicating that it is moving the red indicating that it is moving away.away.

2. Steady State Theory2. Steady State Theory This theory proposes that the Universe is the This theory proposes that the Universe is the

same everywhere and for all time, both in the same everywhere and for all time, both in the past and in the future. But calculations suggest past and in the future. But calculations suggest that the universe is still expanding, so in order that the universe is still expanding, so in order to maintain this constant state, to maintain this constant state, matter must matter must constantly be created out of nothingconstantly be created out of nothing..

A A steady-state universe has no beginning or steady-state universe has no beginning or end end in time; and from any point within it the in time; and from any point within it the view on the grand scale--i.e., view on the grand scale--i.e., the average the average density and arrangement of galaxies--is the density and arrangement of galaxies--is the same same

SSTSST

Evidence Supporting the SSTEvidence Supporting the SST

Robert DickeRobert Dicke – the sky is filled with – the sky is filled with radiation that was formed during the radiation that was formed during the birth of the universe.birth of the universe.

Wilson and PenziasWilson and Penzias – detected the – detected the presence of radiation in the form of presence of radiation in the form of radio sounds.radio sounds.

3. Oscillating Universe Theory3. Oscillating Universe Theory Most astronomers agree that the Universe Most astronomers agree that the Universe

is expanding. is expanding. Some believe that at some stage in the Some believe that at some stage in the

future, the future, the Universe will stop expanding Universe will stop expanding and begin to contract. and begin to contract.

This is what is meant by oscillating which is This is what is meant by oscillating which is the the forward and backwards forward and backwards motion of the motion of the expansionexpansion and and contractioncontraction of the Universe. of the Universe.

Big CrunchBig Crunch

Theories About the Possible Fate Theories About the Possible Fate of the Universeof the Universe

1. Open Universe1. Open Universe 2. Close Universe2. Close Universe 3. Flat Universe3. Flat Universe

Theories About the Possible Fate Theories About the Possible Fate of the Universeof the Universe

1. Open Universe1. Open Universe 2. Close Universe2. Close Universe 3. Flat Universe3. Flat Universe

Big Bang theoryBig Bang theory Oscillating Oscillating

UniverseUniverse Steady StateSteady State

FATE OF THE UNIVERSEFATE OF THE UNIVERSE

Design of the UniverseDesign of the Universe

Galaxy - basic unit Galaxy - basic unit the universe is the universe is made of.made of.

Galaxy is made up Galaxy is made up of billions of stars.of billions of stars.

LightyearLightyear

The distance traveled the beam of light in The distance traveled the beam of light in one year.one year.

6 million million miles = 6 trillion miles6 million million miles = 6 trillion miles 186,000 miles/sec x 60 sec/min x 60 186,000 miles/sec x 60 sec/min x 60

min/hr x 24 hrs/day x 365 days/yearmin/hr x 24 hrs/day x 365 days/year AlphaCentauriAlphaCentauri = 4.3 lightyears away from = 4.3 lightyears away from

us. It is the nearest star from our planet.us. It is the nearest star from our planet.

DESIGN OF THE UNIVERSEDESIGN OF THE UNIVERSE

AGE OF THE UNIVERSEAGE OF THE UNIVERSE

Galaxies have three main Galaxies have three main components:components:

1. The bulge is a spherical 1. The bulge is a spherical structure found in the center structure found in the center of the galaxy. This feature of the galaxy. This feature mostly contains older stars. mostly contains older stars.

2. The disk is made up of 2. The disk is made up of dust, gas, and younger stars. dust, gas, and younger stars. The disk forms arm structures. The disk forms arm structures. Our Sun is located in an arm Our Sun is located in an arm of our galaxy, the Milky Way. of our galaxy, the Milky Way.

3. The halo of a galaxy is a 3. The halo of a galaxy is a loose, spherical structure loose, spherical structure located around the bulge and located around the bulge and some of the disk. The halo some of the disk. The halo contains old clusters of stars, contains old clusters of stars, known as known as globular clustersglobular clusters. .

GALAXYGALAXY

Edwin HubbleEdwin Hubble – the – the man who classified the man who classified the galaxies based on galaxies based on shapeshape

CLASSIFICATION OF CLASSIFICATION OF GALAXYGALAXY

1. Elliptical1. Elliptical 2. Spiral2. Spiral 3. Irregular3. Irregular

Tuning ForkTuning Fork

EllipticalElliptical ( (EE)) galaxies appear to be elliptical galaxies appear to be elliptical in their two dimensional image and are in their two dimensional image and are assumed to be ellipsoidal in three assumed to be ellipsoidal in three dimensional space. dimensional space.

Elliptical galaxiesElliptical galaxies have no spiral or bar have no spiral or bar patterns. Instead they range from nearly patterns. Instead they range from nearly perfect spheres (E0) to highly flattened perfect spheres (E0) to highly flattened ellipses (E7). ellipses (E7).

Spiral galaxies are divided Spiral galaxies are divided into two subclasses:into two subclasses:

1. Ordinary1. Ordinary (designated S or SA) - the arms originate (designated S or SA) - the arms originate directly from the nucleus of the galaxy. directly from the nucleus of the galaxy.

2. 2. Barred Barred (designated SB). - a bar of stars cuts through the (designated SB). - a bar of stars cuts through the center of the galaxy and the arms originate from the ends center of the galaxy and the arms originate from the ends of the bar. of the bar. – Both have spiral arms, with two arms generally placed Both have spiral arms, with two arms generally placed

symmetrically about the center of the axis of the rotation. symmetrically about the center of the axis of the rotation. – Both ordinary and barred galaxies are further classified, starting Both ordinary and barred galaxies are further classified, starting

from `a' to `c' according to how tightly the arms are wound.from `a' to `c' according to how tightly the arms are wound.– In `Sa' and `SBa,' the arms are tight and they form an almost a In `Sa' and `SBa,' the arms are tight and they form an almost a

circular pattern; circular pattern; – in `Sb' and `SBb,' they are more open and in `Sb' and `SBb,' they are more open and – in `Sc' and `SBc' the nuclei are small and have extended arms. The in `Sc' and `SBc' the nuclei are small and have extended arms. The

intensity of the spheroidal component of the spiral galaxies, around intensity of the spheroidal component of the spiral galaxies, around their nucleus,their nucleus,

Irregular GalaxiesIrregular Galaxies

Irregular galaxies have Irregular galaxies have no symmetrical or no symmetrical or regular structureregular structure

Milky way galaxyMilky way galaxy

Since the galaxy rotates, the Sun "orbits" Since the galaxy rotates, the Sun "orbits" the centre, taking the centre, taking 200 million years to 200 million years to complete one circuit.complete one circuit.

Milky Way GalaxyMilky Way Galaxy

Spiral in shapeSpiral in shape 100,000 ly – diameter100,000 ly – diameter 20,000 ly = distance of the 20,000 ly = distance of the solar systemsolar system

from the edge of the milky wayfrom the edge of the milky way 3000 lightyears – diameter of the central 3000 lightyears – diameter of the central

corecore

StarsStars

These are large spheres of These are large spheres of incandescent gas much like incandescent gas much like our own sun.our own sun.

It begins as a cloud of dust It begins as a cloud of dust and gas.and gas.

It shines due to the light It shines due to the light they produce.they produce.

PROPERTIES OF STARSPROPERTIES OF STARS

1. Distance1. Distance Friedrick Wilhelm BesselFriedrick Wilhelm Bessel – introduced a – introduced a

method of measurement called method of measurement called parallax.parallax. Parallax – Parallax – the apparent change in the the apparent change in the

position of the star due to the change in the position of the star due to the change in the position of the observer.position of the observer.

Parallax of the star is actually an angle.Parallax of the star is actually an angle.

PARALLAXPARALLAX

The farther the star is the smaller is the parallax The farther the star is the smaller is the parallax angle formed and the nearer the star is the bigger angle formed and the nearer the star is the bigger is the parallax angle formed.is the parallax angle formed.

PARSECPARSEC

Parsec is defined as the distance at which Parsec is defined as the distance at which an object has a parallax of one secondan object has a parallax of one second

ParsecParsec = = 11 secsec 1 parsec1 parsec = 3.26 ly = 3.26 ly = 30 million million km= 30 million million km

2. Magnitude2. Magnitude

It refes to the brightness of the stars.It refes to the brightness of the stars. Two ways of describing the brightness of Two ways of describing the brightness of

the starsthe stars 1. 1. Apparent MagnitudeApparent Magnitude – the brightness as it – the brightness as it

appears to the observer. (Hipparchus)appears to the observer. (Hipparchus) 2. 2. Absolute MagnitudeAbsolute Magnitude – – the brightness the the brightness the

star would have if it were viewed at equal star would have if it were viewed at equal distance with the other starsdistance with the other stars

3. SIZE3. SIZE

Although these term describe the size of stars, Although these term describe the size of stars, they do not actually refer to size but rather to the they do not actually refer to size but rather to the brightness of the starsbrightness of the stars

Stars with absolute magnitude brighter than 1 are Stars with absolute magnitude brighter than 1 are called giants.called giants.

Those with absolute magnitude less than 1 are Those with absolute magnitude less than 1 are called dwarfscalled dwarfs

Those that are brighter than giants are Those that are brighter than giants are supergiants, although some giants are bigger than supergiants, although some giants are bigger than supergiants.supergiants.

The absolute magnitude of the stars The absolute magnitude of the stars depends on two things:depends on two things:

1. Size 1. Size 2. Temperature2. Temperature

4. Color and Temperature4. Color and Temperature

COLORCOLOR TEMPTEMP EXAMPLEEXAMPLE

REDRED 1500-35001500-3500 BetelgeuseBetelgeuse

ORANGEORANGE 50005000 Antares, Antares, ArcturusArcturus

YELLOWYELLOW 60006000 Canopus, SunCanopus, Sun

WHITEWHITE 7500-11,0007500-11,000 VegaVega

BLUISH WHITEBLUISH WHITE Over 25000Over 25000 RigelRigel

5. COMPOSITION5. COMPOSITION

A method of classifying stars according to A method of classifying stars according to composition using colors of spectrum was composition using colors of spectrum was introduced by introduced by Fr. Angelo SecchiFr. Angelo Secchi

6. Mass6. Mass

Stars vary in mass.Stars vary in mass. It pertains to the amount of matter present in It pertains to the amount of matter present in

a given body.a given body.

THE LIFE CYCLE OF STARSTHE LIFE CYCLE OF STARS

1. 1. BirthBirth – beginning star is called a protostar. – beginning star is called a protostar. 2. 2. InfancyInfancy – protostar at this stage is now called – protostar at this stage is now called

star.star. 3. 3. MaturityMaturity – Stable stage. – Stable stage. 44. Later year. Later year – stage wherein most of the H2 – stage wherein most of the H2

atoms have been converted to helium.atoms have been converted to helium. 5. 5. Last stageLast stage – stars now have helium core and – stars now have helium core and

the outer envelop composed of hydrogen. the outer envelop composed of hydrogen.

Star ClassesStar Classes

Binary starBinary star – stars of unequal magnitude – stars of unequal magnitude bound together by mutual gravitational bound together by mutual gravitational force. One revolves around the other.force. One revolves around the other.

Variable starsVariable stars – whose brightness vary – whose brightness vary periodically. periodically. – Cepheid variableCepheid variable – pulsating star whose – pulsating star whose

brightness & temperature vary accd’g to regular brightness & temperature vary accd’g to regular pattern. As it expands it becomes cooler and pattern. As it expands it becomes cooler and dimmer and when it contracts, it becomes hotter dimmer and when it contracts, it becomes hotter & brighter. The brightness may last for a week.& brighter. The brightness may last for a week.

– Long period variablesLong period variables – star whose bright and – star whose bright and dim period last for 150 days or more. dim period last for 150 days or more.

– Nova or supernovaNova or supernova – stars which suddenly – stars which suddenly becomes very bright and eventually explodes.becomes very bright and eventually explodes. Tycho BraheTycho Brahe – observed the first supernova in 1572 – observed the first supernova in 1572

CONSTELLATIONCONSTELLATION

Group of stars that forms a pattern like Group of stars that forms a pattern like heroes, animals and objects that were heroes, animals and objects that were famous in their mythology.famous in their mythology.

Johannes BayerJohannes Bayer – assigned Greek letters in – assigned Greek letters in alphabetical order to the star in each alphabetical order to the star in each constellation to designate their brightnessconstellation to designate their brightness

Zodiacal ConstellationZodiacal Constellation

AriesAries – the ram – the ram TaurusTaurus – the bull – the bull GeminiGemini – the twin – the twin CancerCancer – the crab – the crab VirgoVirgo – the virgin – the virgin LibraLibra – the scale – the scale

ScorpioScorpio - the scorpion - the scorpion SagittariusSagittarius – the archer – the archer CapricornCapricorn – the sea goat – the sea goat AquariusAquarius - the water carrier - the water carrier PiscesPisces – the fish – the fish LeoLeo – the lion – the lion