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The Sun
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48
Astronomy
Undergraduate 2
04/22/2010

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Term
500-428 BCE
Definition
Anaxagoras suggested sun was a hot glowing rock
Term
1600's
Definition
distance from sun to Earth is calculated
Term
Mid-1800's
Definition
sun's size and distance from earth becomes fairly well known
Term
Late-1800's
Definition
Gravitational contraction theory
Term
1905
Definition
Einstein publishes his paper titled E=mc^2
Term
1930's
Definition
discover sun's energy comes from nuclear fusion
Term
1930's
Definition
discover sun's energy comes from nuclear fusion
Term
Ideas from Mid-1800's
Definition
Sun must be creating a lot of energy from 150 million km aways; reasons why could include= cooling ember that had once been much hotter or chemical burning similar to coal or wood burning.
Term
Ideas from Late 1800's
Definition
New theory called gravitational contraction theory=shrinking gas cloud creates kinetic energy which heats up the core and creates a temperature increase.
Term
calculations from gravitational contraction theory
Definition
predicted sun to be 25 million years old,however Geologists said earth is much older than 25 million years b/c of carbon dating.
Term
Layers of the sun (from inner most to outer most)
Definition
Core...Radiative Zone...Convection Zone...Photosphere...Chromosphere...Corona
Term
List of Sun's layers from most dense to least dense
Definition
Core...Radiative Zone...Convection Zone...Photosphere...Chromosphere...Corona
Term
Temperature of interior layers from hottest to lowest temperature and what are their temps
Definition
Core (15 million K)...Radiative Zone (n/a)...Convection Zone (n/a)...Photosphere (5,800-6,000 K)
Term
Temperature of atmosphere layers from hottest to lowest temperature and what are their temps
Definition
Corona (millions of K)...Chromosphere (25,000-500,000 K)...Photosphere (5,800-6,000 K)
Term
How long does it take the Sun's equator to make a full revolution? How long does it take an area towards the northern tip of the sun to revolve?
Definition
25 days; 30 days
Term
What causes the magnetism in the sun?
Definition
A dynamo effect
Term
Who is known as Father of spectroscopy?
Definition
von Fraunhofer
Term
This element (2nd most abundant element in the universe) was discovered in the spectrum of the sun before it was discovered on Earth.
Definition
Helium
Term
The effect that shifts the wavelengths of spectral features in objects that are moving towards or away from the observer.
Definition
Doppler Effect
Term
Deep in the heart of the sun the battle between these two forces play out to hold it together
Definition
pressure and gravity
Term
Age of the sun?
Definition
4.6 billion years
Term
The overall result of the proton-proton chain is:
Definition
4h=1He+Energy
Term
The practice of making a planet more Earth-like is called:
Definition
Terraforming
Term
When the sun begins to exhaust its nuclear fuel, it will:
Definition
Swell up into a red giant
Term
The sun will eventually eject off its gaseous outer layer and expose its core called:
Definition
white dwarf
Term
The ejected layers are now ionized by the central white dwarf. These objects are called:
Definition
Planetary Nebula
Term
Planetary nebula usually last for how many years?
Definition
Thousands of years
Term
Once the central white dwarf star cools after a few million years, the star no longer radiates and becomes a:
Definition
black dwarf
Term
Which of these is ranked based on their temp from least to greatest?
Definition
Photosphere, Chromosphere, Corona
Term
Nearly all of the visible light we see from the sun is emitted from:
Definition
photosphere
Term
In the late 1800's, Kelvin and Helanholtz suggested that the sun stays hot due to...
Definition
gravitational contraction
Term
How does the Sun's mass compare to the Earth's mass
Definition
The sun's mass is 300,000 times the mass of the Earth's
Term
What are the appropriate units for the Sun's luminosity?
Definition
Watts
Term
Every second the Sun converts ~600 million tons of hydrogen into 576 million tons of Helium. The remaining 4 million tons of mass is...
Definition
Converted into pure energy through E=mc^2
Term
How can we measure the strength of magnetic fields on the Sun?
Definition
Looking for the splitting of spectral lines in the sun's spectrum (the zeeman effect)
Term
When we say the Sun is a ball of plasma, we mean that?
Definition
it consists of gas in which many or most of the atoms are ionized (missing electrons)
Term
What is the life cycle of a star?
Definition
1. (Protostar) A disturbance or shockwave triggers the gravitational collapse of a giant molecular cloud.
2. Collapsing gas releases gravitational potential energy which converts into heat.
3. (Star becomes alive when...)Core temp. reaches 10 million K, proton-proton chain reactions begin.
4. (Main Sequence/where our sun is today) Hydrostatic equilibrium is achieved between pressure and gravity.
5. (Red Giant) Helium core builds up, a thin layer of fusing hydrogen surrounding it causes the star to cool and expand.
6. (Planetary Nebula) Helium core ignites and reactions cause huge pulsations to give outer layers enough Kinetic Energy to be ejected.
7. (Planetary nebula/ white dwarf..Star dies) In the center of the nebula remains the core of the star, now made mostly of degenerate carbon and oxygen.
8. (Black dwarf) The core will cool to a dark cinder.
Term
3000 BCE
Definition
Egyptians came up with Sothis year, based on Sirius returning to same position in sky (365.25 days). Used for agricultural planting
Term
2000 BCE
Definition
Babylonia developed ideas of constellations from their myths and religion
Term
19th-16th century BCE
Definition
Old Babylonia created the Enuma anu Enlil that were ancient texts in cuneiform, written were omens and how celestial objects effected mundane life
Term
800 BCE Assyrian Astronomy
Definition
blended astronomy and astrology to study the stars in order to predict significant events on Earth as related to Kings
Term
600-45 BCE New Babylonia
Definition
could predict planetary motions and were the ones to implement the sexagesimal system
Term
500 BCE Greek Astronomy
Definition
great geometers and philosophers. began to explain the movements of the planets by assuming Earth was the center of the Universe
Term
624-547 BCE Thales
Definition
first to refuse to accept supernatural/mystical explanations for natural phenomena and successfully predicted a solar eclipse
Term
610-546 BCE Anaximander
Definition
first known to have written down his studies and was first to develop a mechanical model of the world (geocentric) believed earth was flat-topped cylinder.
Term
Order the greek spheres
Definition
Sphere of the stars-outer most
Saturn
Jupiter
Mars
Sun
Venus
Mercury
Moon
Earth
Term
570-495 BCE Pythagoras
Definition
mathematician
prime inspiration for Plato and Aristotle
Term
500-428 BCE Anaxagoras
Definition
brought philosophy to athens
attempted to scientifically account for eclipses, meteors, rainbows
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