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The Universe Chapter 1 Why was Astronomy important to the ancients? Natural Clocks •Motion of the sun, moon, planets and stars –plant crops, harvest crops Location, Location, Location •Sailors relied on the astronomy –―Astronomy is the handmaiden to the sailor‖ ________________ (2000 B.C.) • ________ ___________ –Year •12 months –7 days a week – _______ _______ a year –Day •24 hours •60 minutes / hour •60 seconds / minute •Stonehenge _____________ Universe (_________ ____________) •The use of Stonehenge as an astronomical observatory Apparent Path of the Sun ____________ •The ____________ ____________ __________ ___________ across the sky in the course of a year –Plane of earth‘s orbit around the sun ________________ •____________ ___________ of ____________ •____________(―circle of animals‖) –12 equal divisions –________ _______ ________ one ―_______‖ each month Sun‘s movement through Zodiac Planets (―wanderers‖) •______________ motion – the ___________ __________ __________ ___________ that a planet makes in its orbit about the sun Celestial Location •__________ ___________ –A ____________ used by astronomers to __________ ____________ in _______________ •Right ascension – analogous to longitude •Declination – analogous to latitude Finding the North Celestial Pole ___________ – the North Star Celestial Distance Circle Circle Circle ___________ ___________ •Angular size of an object determined by: –_____________ –_______ ________ Parallax •__________________ – the _________ __________ in _____________ of an object ________________a ____________ of other objects The Parallax Angle Parsec ___________ The _____________ _____________ __________ of astronomers Two Beliefs on the Existence of Stars Explanation for the Existence of Stars What evolutionists believe Sun •Ordinary star •Average brightness •Massive, dense ball of gases •Nuclear fusion reaction Origin of Stars •Starts as a ____________ –________________ _______________ of ______________ gas •Gravity –forms protostar Large Magellanic Cloud Protostar •Begins as a cloud –an accumulation of gases that will become a star –Diameter •Trillions of miles –requires 1 x 1057 atoms Protostar •Gravitational attraction –atoms accelerate toward center –temperature increases –Forms a dense sphere •diameter –1.5 million miles Stable star •Gravitational attraction –nuclear fusion begins –1.5 million miles –begins stable life span Star Interior •___________ –_________ ___________ –15 million degrees °C –Intense pressure •300 billion atmospheres –Density •12x solid lead –1/3 mass of star Star Interior •____________ _____ –Density of water •____________ _____ –1/10 density of water –surface emits visible light, UV radiation, and infrared –5,500 °C Life Span of Stars •Sun –Converts 1.4 x 1017 kg of matter to energy every year •has enough hydrogen for 5 billion more years Brightness of Stars •_____________ ___________ –_____________ ____________ for different _________ of ____________ of objects as __________ _______ ________ Brightness of Stars •_____________ ___________ –A _____________ _____________ to _________________ for the _______________ ___________ to the stars –Standard distance •10 parsecs = 32.6 light years Brightness of Stars •Absolute Magnitude –Sun •Apparent magnitude = – 26.7 •Absolute magnitude = + 4.8 Distribution of Radiant Energy from Sun •Not all energy from a star goes into visible light (KNOW) Star Temperature •Star _________ _______________ _____ the ______________ of the star •Hot = ________ •Moderate = white/yellow •Cool = ______ •Stellar Types and Temperatures –O B A F G K M Classification of Stars Star Types •Classification based on: –_______________ –_______________ •Henry Russell (United States) 1910 •Ejnar Hertzsprung (Denmark) 1910 Hertzsprung-Russell Diagrams Examples Hertzsprung-Russell diagram Hertzsprung-Russell diagram H-R Diagram Hertzsprung-Russell diagram •__________ _________ __________ –average size, ______________ stars –_________ __________ brightness, temperature, and ____________ ____ _________ Hertzsprung-Russell diagram •______ ________ –___________ •Lots of surface area giving off light –_____temperature –Low density giants •100x bigger than sun but with same mass Hertzsprung-Russell diagram •__________ ________ stars –________ •small (2x earth size) –________ _______ –Very dense •mass sun Hertzsprung-Russell diagram •Life Stages –Evolutionary theory •Sun –Nebula –main sequence –red giant –white dwarf –Cold lump of carbon (black dwarf) Hertzsprung-Russell diagram •_________ __________ –stars that ________ _______ ___________ over a period of time –magnitude •.001X •period 20x change –seconds to years –30,000 identified Hertzsprung-Russell diagram •Cepheid Variable Stars –Bright variable stars used to calibrate brightness with distance •Measure distances to other galaxies Relative Sizes of Stars The Life of a Star Evolutionary Theory Main Sequence Life Cycle •Stable Star –Nuclear Fusion •_________ ___________ to ____________ Main Sequence Life Cycle •Low on hydrogen fuel •Star contracts –expansion reduced Main Sequence Life Cycle •Collapse heats helium and remaining hydrogen •Hydrogen fuses and layers expand •Red Giant produced Main Sequence Life Cycle •Red Giant –surface temperature •4,000 °K –1000x larger than main sequence Main Sequence Life Cycle •Red Giant –After many years helium fusion begins in core •100 million degrees required –________ _________ into _________ in core –red giant decreases in size (main sequence) Main Sequence Life Cycle •Helium core transformed into carbon core –helium fusion begins in second shell –expands to red giant again Main Sequence Life Cycle •Outer layers begin to pulsate from constant cycle of contraction and expansion •violent explosion blows off outer layers leaving hot core Planetary Nebula •Blown-off outer layers of star •_________ ___________ •adds dust and gas between stars • Planetary Nebula Main Sequence Life Cycle •Carbon core and helium fusion shell gravitationally contract to form a small dense white dwarf star Main Sequence Life Cycle •White dwarf star –cools from white, to red, then to a black lump of carbon in space Life Cycle of Star High Mass Main Sequence •After blowing off outer shells –core contracts –carbon fusion begins •600 million degrees Kelvin High Mass Main Sequence •_________ ____________ continues (plus other fusion reactions) until _________ is produced •Iron fusion produces no energy –star out of fuel High Mass Main Sequence •Star collapses and then violently explodes into a _____________ –produces brilliant light in sky lasting for months •Elements from Iron to Uranium formed in explosion 1987A Supernova (Before and After) High Mass Main Sequence •Remains of compressed core after supernova –> 1.4 solar masses •_________ ________ - small, very dense with center core of _______ __________ –> 3 solar masses •black hole Neutron Stars •Gravitational force collapses nuclei forcing protons and electrons together into neutrons •super dense –1011 kg/cm3 •super small –10-20 km •___________--___________ neutron star that emits _____ ___________. __________ _____________ •___________ _____________ _____________ the repulsive force of all subatomic particles •super super dense –__________ ____________ _____________ •super super small –0 radius Explanation for the Existence of Stars What creationists believe Genesis 1:16 •And God made two great lights; the greater light to rule the day, and the lesser light to rule the night: he made the stars also. Problems with Star Birth •It is very difficult to get a gas cloud (nebula) to contract because gases naturally expand –The catch is that the conditions required to compress the gas to that point seem to require the shock waves from the explosion of a previously existing star •Chicken/egg dilemma Problems with Star Birth •Almost every nebula is hundreds of times bigger than the critical size needed to form a stable star –―Precisely how a section of an interstellar cloud collapses gravitationally into a star…is still a challenging theoretical problem…Astronomers have yet to find an interstellar cloud in the actual process of collapse‖ Fred Whipple, The Mystery of Comets, 1985 Problems with Star Birth If a nebula were to begin contracting it would spin and that would be a serious detriment to collapse because of the outward centrifugal force The spin would produce a powerful magnetic field that tend to stop the collapse before a star could form The birth of a star has never been observed (KNOW) ―Despite numerous efforts we have yet to directly observe the process of stellar formation…The origin of stars represents one of the fundamental unsolved problems of contemporary astrophysics.‖ Charles Lada and Frank Shu, ― The Formation of Sunlike Stars‖, Science, 1990 •When dark nebula (mostly dust) collide with emission nebula (fluorescent regions of gas) images like the Eagle Nebula form. The result is whitish areas appearing at the edges of the dark fingers of dust. Gases at such high temperatures will quickly disperse. Star death has been observed (KNOW) Supernovas •A ______________, or ___________ ____________ ____________, is one of the most brilliant and powerful objects in the cosmos. –Our galaxy, The Milky Way, should produce one supernova every 25 years. –Supernovas cause a huge expanding cloud of debris Supernova Remnants and the age of the Universe How Evolutionists Respond •As the evolutionist astronomers Clark and Caswell say, ‗Why have the large number of expected remnants not been detected?‘ and these authors refer to ‗The mystery of the missing remnants‘. Clark and Caswell, 1976. Monthly Notices of the Royal Astronomical Society, 174:267; cited in Ref. 1. How Creationists Respond •There should be no mystery — Psalm 19:1 says: ‗The heavens declare the glory of God; and the firmament shows his handiwork.‘ •Supernovas declare His mighty power, but are still only finite expressions. The low number of their remnants is a pointer to God‘s recent creation of the heavens and earth. Star Degeneration •Space _____________ _____________ universal trend of ________ ____________, not star formation –Novas and supernovas •Conclusion: the universe of created stars is slowly aging –If black holes exist, they support this conclusion. Facts about our Sun •Ideal size to support life on earth •The sun is in an ideal environment –A single star –Position in Milky Way Galaxy –Fairly circular orbit –Distance from Milky Way center •Exceptionally stable –Solar flares Galaxies _____________ •_________ of ____________ and billions of stars that _______ the _________ ____________ of the ____________ •________ __________ Galaxy –200 billion stars –________galaxy •Billions of galaxies –100 billion counted Galaxy •Clusters of galaxies •Superclusters of galaxies Cluster of Galaxies (Virgo) Milky Way Galaxy •Galactic ___________ •Galactic ________ –Location of ______ •Galactic ________ Milky Way Galaxy •How close is the sun to the center of the Milky Way? Milky Way Galaxy •The Sun is _________ _______ _______ from center of the galaxy Milky Way Galaxy •How big is the Milky Way? Milky Way Galaxy •____________ __________ ___________ in diameter Milky Way Galaxy •How long does it take the Sun to revolve around the nucleus? Milky Way Galaxy •Sun would complete one revolution every 200 million years Milky Way Galaxy •What is the Milky Way composed of? Milky Way Galaxy •__________ ____________ _________ •Thin concentration of gas, dust, and chemical compounds –____________ –Iron –Carbon compounds –Silicon compounds Milky Way Galaxy •What is in the nucleus? –red stars •Little dust or gas •5,000 light year radius –_________ __________ __________ •1-2 light year radius Milky Way Galaxy •What is in the halo? –Groups of massive red stars in clusters Milky Way Galaxy •What is in the disk? –galactic clusters of stars Other Galaxies •Nearest neighbor –dwarf spherical galaxy •only 1,000 light years across –80,000 light years away –Milky Way has 11 satellite galaxies Other Galaxies •________________ Galaxy –2 million light years away –___________ in ________ and __________ to the Milky Way –100 billion stars Other Galaxies •What is the farthest galaxy from Earth? Other Galaxies •Galaxy 4C41.17 •15 billion light years away Other Galaxies •What is the largest galaxy? Other Galaxies •Abell 2029 –60x size of the Milky Way •100 trillion stars •diameter of 6 million light years Classification of Galaxies •Edwin Hubble (1926) –Elliptical galaxies (20%) –___________ galaxies (50%) –Barred galaxies (30%) –Irregular galaxies Bell Telephone Labs •1920‘s –Wanted to set up a radio-telephone communication system across the Atlantic –Sun‘s rays caused unwanted natural radio interference –Set up research to study the problem Radio Astronomy •The first radio astronomy observations were made in 1932 by the Bell Labs physicist Karl Jansky who detected cosmic radio noise from the center of the Milky Way Galaxy while investigating radio disturbances interfering with transoceanic telephone service. Radio Astronomy Born •1933 –__________ __________ also come from __________ ___________