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The Origin of Stars. From a power point modified by Christopher W. Ashcraft M.S., M.Ed. Cosmology. Origin of Stars Big Bang vs. Creation Solar System: Evidence of Design Age of the Cosmos. Are we being told all the evidence or just selected information to support a particular idea?.
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The Origin of Stars From a power point modified by Christopher W. Ashcraft M.S., M.Ed.
Cosmology Origin of Stars Big Bang vs. Creation Solar System: Evidence of Design Age of the Cosmos Are we being told all the evidence or just selected information to support a particular idea?
The Origin of Stars The Bible Earth created on day 1 The sun, moon, and stars on day 4 Evolution Stars evolved billions of years before the earth Theistic evolution Stars evolved billions of years before the earth
The Origin of Stars Hugh Ross (Astronomer), “Species Development: Natural Process or Divine Action,” Audiotape (Pasadena, CA: Reasons to Believe, 1990). “The entire process of stellar evolution is by natural process alone. We do not have to invoke Divine intervention at any stage in the history of the life-cycle of the stars that we observe.” Is this statement consistent with the Bible?
When I consider thy heavens, the work of thy fingers, the moon and the stars, which thou hast ordained; Psalms 8:3
The Origin of Stars • 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. (Genesis 1:16) • Lift up your eyes on high, and behold who hath created these things, that bringeth out their host by number:… (Isaiah 40:26)
The Origin of Stars • By the word of the Lord were the heavens made; and all the host of them. (Ps 33:6) • Praise him, sun and moon, praise him, all you shining stars….for he commanded and they were created. (Ps 148:3-5) • Thou, even thou, are Lord alone; thou hast made heaven, the heaven of heavens, with all their host… (Nehemiah 9:6)
Astronomy…stars • Astronomy is the study of the stars. • The brightness of the stars is referred to as its magnitude….the colour is determined by the temperature • Apparent magnitude- this is how bright a star appears to those on Earth • Dimmer stars have higher magnitudes • Brighter stars have lower or negative magnitudes
Apparent magnitude • It is actually measured on logarithmic scale • A one unit change –changes the brightness by a factor of 2.5…confused! Ask the maths teacher! • TWO factors determine a stars apparent magnitude: • How much light a star emits • The distance between the star and Earth • Greater the distance the dimmer the star appears-therefore the effect of distance must not be counted in the measurement.
Distances between stars! • Too hard to measure in km due to vast distances • Astronomers use light years- the distance taken for light to travel in a year= 9.5 trillion km • Sometimes they use parsec- this is equivalent to 3.26 light –years. • Do the activity pg 216
Parallax • The parsec is based on parallax- this is when you see different views of the same object • We can use parallax to measure the distance between the stars and the sun • As the earth moves around the sun our changing point of view means the position of the stars changes very slightly
Absolute Magnitude • This is how the actual brightness of a star is measured • This is how bright a star would appear if it was a distance of 10 parsecs from the earth • This way we can compare the brightness of stars from different galaxies-meaningfully.
Colour of stars • Stars emit different wavelengths of light • Some is in the visible spectrum or electromagnetic spectrum • When your eyes collect visible light your brain performs a very complex process to determine the colour of a star! • Scientists prefer to analyse the light by viewing it through coloured filters- it can then be precisely measured
Colour… • A stars spectrum is determined by the surface temperature • Cooler stars emit mainly infra-red and therefore are red in colour • Hotter stars are generally Blue • Medium stars are usually yellow, white or orange • Starlight is analysed using a spectrometer-this splits light into a spectrum to reveal its component colours.
Chemical elements stars • Sometimes lines appear in a stars spectrum- these relate to the elements present in a particular star • Certain elements emit colours of particular wavelengths- these can be measured to determine the elements in that star • Sometimes there are also dark lines or missing colours… • The lines are due to the light interacting with atoms in the outer layers of the stars
Contd: • The light energy gets absorbed by the electrons in the atoms in all the elements of the outer in the outer gas layers • Each electron will absorb different wavelength…and emit different colours • Scientists have created a classification system called spectral class which indicates the elements present, the temp and colour of a star…table pg 218 • It is nuclear fusion that keeps stars at such high temps
Nuclear Fusion • Stars are ¾ hydrogen • ¼ helium and iron and other heavy elements • Gravitational forces are said to be what heats up a star to such high temperaturesin the centre…at such temps the electrons cant stay bound to protons so the material takes on a “soupy” state of + ve charged ions and free electrons- Plasma • Read pg 219 or the photocopy of this page
Lifecycle of a Star • Early in the 20th century……Hertzsprung and Russel came up with plotting stars on a diagram….and noticed they fell into a number of clearly defined groups • Demonstrated the relationship between temp and brightness • Also showed stars went from one type to another- lifecycle of a star
Structure of stars • Star structure determined by the balance of opposing forces-gravity and radiation pressure • Gravity pulling material inwards and radiation forces generated by the heat of nuclear fusion • In most stars these forces are in equilibrium • They give a star , when balanced a constant radius and brightness- this last years until the hydrogen runs out
Red Giants • When the hydrogen of a medium star burns out-fusion stops- gravity makes it collapse inwards-outer layers fuse- the heat from the fusion produces radiation pressure-outer layers expand and cool • The outer layer fusion occurs at lower temperatures than normal stars so emits more light in the red spectrum- giving the star its distinct colour • These red giants last for about 100 million years-when this runs out the star collapses further- becomes a cloud of gas-planetry nebula
Nebula- and dwarfs! • Nebula will disperse to reveal hot dense carbon and hydrogen- the remains of a red giant- fades, becomes dense –white dwarf stars • Still very hot, but dimmer than the red giant from which it formed • No nuclear fusion occurs on a white dwarf- it fades, cools becomes a dark ball of inert matter- BLACK DWARF
SUPER GIANTS/SUPER NOVA • Stars 10 or more times larger than the sun • As so hot- generally known as blue super giants • Burn hydrogen at a very fast rate • Eventually use up all their fuel and become spectacular supernova • SUPERNOVA-all the fuel of the supergiant turns into iron/heavy elements through fusion-star cools-collapses in on itself-as it hits the core it rebounds in a massive explosion- supernova- most of the mass blown into space
He determines the number of the stars and calls them each by name. (Psalm 147:4)
Star Formation and Physics Nebula The popular theory is that stars form from vast clouds of gas and dust through gravitational contraction. Gas and dust clouds will expand NOT contract
Star Formation Don DeYoung (Ph.D. in Physics), Astronomy and the Bible, 2000, p. 84. “The complete birth of a star has never been observed. The principles of physics demand some special conditions for star formation and also for a long time period. A cloud of hydrogen gas must be compressed to a sufficiently small size so that gravity dominates. continued
Star Formation Fred Whipple, The Mystery of Comets, (Washington, D.C.: Smithsonian Institute Press, 1985), pp. 211, 213. “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.”
Star Formation Danny Faulkner, Ph.D. Astronomy “Most astronomers believe that the clouds gradually contract under their own weight to form stars. This process has never been observed, but if it did occur, it would take many human lifetimes. continued
It is known that clouds do not spontaneously collapse to form stars. The clouds possess considerable mass, but they are so large that their gravity is very feeble. Any decrease in size would be met by an increase in gas pressure that would cause a cloud to re-expand.”
Star Formation Hannes Alfven (Nobel prize winner), Gustaf Arrhenius, “Evolution of the Solar System”, NASA, 1976, p. 480. “There is general belief that stars are forming by gravitational collapse; in spite of vigorous efforts no one has yet found any observational indication of conformation. Thus the ‘generally accepted’ theory of stellar formation may be one of a hundred unsupported dogmas which constitute a large part of present-day astrophysics.”
Star Formation Charles Lada and Frank Shu (both astronomers), “The Formation of Sunlike Stars,” Science, 1990, p. 572. “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.”
Star Nurseries Do pictures confirm stars are forming? Eagle nebula
Star Nurseries Martin Rees (A leading researcher on cosmic evolution), Before the Beginning, 1998, p. 19. “Stars are still forming today. About 1500 light-years away lies the Orion Nebula: enough gas and dust to make millions of stars…. It even contains protostars that are still condensing …”
Star Formation and Nebula Images taken by the European Southern Observatory Very Large Telescope in January 2002 of the Horsehead Nebula in Orion verified that the structures are expanding.
Star Nurseries Ron Cowen, “Rethinking an Astronomical Icon: The Eagle’s EGG, Not So Fertile,” Science News, Vol. 161, 16 March 2002, pp. 171–172. “NASA’s claim in 1995 that these pictures showed hundreds to thousands of stars forming was based on the speculative ‘EGG-star formation theory.’ It has recently been tested independently with two infrared detectors that can see inside the dusty pillars. What did they find?
Few stars were there, and 85% of the pillars had too little dust and gas to support star formation. ‘The new findings also highlight how much astronomers still have to learn about star formation.’” No star nurseries
Star Formation and Time 100 Billion x 200 Billion 20 billion • 100 billion galaxies (1011) • 200 billion stars per galaxy (2x1011) • Universe 20 billion years old (2x1010) 1 trillion stars per year • 2.7 billion stars per day • 31,700 stars per second
Conclusion on Star Formation Abraham Loeb, (Harvard Center for Astrophysics), quoted by Marcus Chown, “Let there be Light”, New Scientist, Feb 7, 1998, “The truth is that we don’t understand star formation at a fundamental level.”
Our Sun: Mediocre? “Who are we? What are we? We find that we live on an insignificant planet of a humdrum star lost in a galaxy tucked away in some forgotten corner of a universe in which there are far more galaxies than people.” Carl Sagan
A Special Place Type G: only 9 percent of all stars. About 80 percent of all stars are Class M, which flare often and would kill us from radiation.
Designed Just for Us • If too massive: would be unstable. If not massive enough: Earth would have to be too close, would be tidally locked. • Its position in the galaxy is vital for life. Its galactic orbit is more nearly circular than about 80 percent of nearby stars.
Unusually Quiet and Gentle ‘Thank our lucky star’, New Scientist, 161(2168):15, 1999 • One recent 30-year study: photosphere is “constant in temperature” • “Sun-like stars normally produce a bright superflare about once a century…Why a superflare has not occurred on the Sun in recorded history is unclear. ‘I think a consensus is emerging that our Sun is extraordinarily stable’, suggests Galen Gisler, an astronomer at the Los Alamos National Laboratory in New Mexico.”
