Astronomy Earth Science R
I. What is Astronomy? Astronomy is the study of the Universe.
A. Astronomical Measures • Long distances exist in space and are measured in Light Years. • A light year is the distance that light travels in one year at a velocity of 186,000 mps or 669,600,000 mph. That’s 5,865,696,000,000 miles in one year. • One Light Year = 1 Astronomical Unit (AU)
B. Galaxies • A galaxy is a system of stars (billions). • There are three types.
The Milky Way from Earth http://zebu.uoregon.edu/~imamura/209/mar31/milkyway.gif
Our position in the Milky Way http://www.ncsu.edu/project/agronauts/images/milky_way.jpg
Our nearest neighbor… The Andromeda Galaxy http://en.wikipedia.org/wiki/Image:M31_Lanoue.png
b. Elliptical Galaxies http://www.glyphweb.com/esky/_images/illustrations/galaxy.gif
c. Irregular Galaxies http://www.godandscience.org/images/irregulargalaxyngc1705.jpg
C. The Sun – Our Closest Star • Energy from the Sun drives all weather and water processes on Earth • Temperature ranges from 6000 K at the surface to 12,000,000 K at the center. • The sun is composed of H & He. • Age is about 5 by and is expected to last another 5 by.
6. Sunspots • Cooler gases result in dark spots called sunspots. • Indicate that the sun does not rotate uniformly. • Occur in 11 year cycles. • Can alter Earth’s climate. • Are actually areas of cooler gases.
Checkpoint • What is the fuel of the Sun? HYDROGEN
Sample Questions What type of star is Polaris? RED GIANT Two stars of the same color are plotted on an H-R diagram. Star A is more luminous than Star B. Correctly explain the reason for this difference. Star A is larger than Star B
More Sample Questions Name a star that is cooler and many times larger than Earth’s Sun. Betelguese Compared to other groups of stars, the group that has low luminosity and low temperatures are the Red Dwarfs
Checkpoint What does a shift in wavelength toward the red-light end of the visible spectrum tell us about the universe? It is expanding Name a star whose surface temperature is closest to the temperature of the boundary between Earth’s mantle and Core. The Sun
Checkpoint Which type of electromagnetic energy is more intense? ULTRAVIOLET or INFRARED
II. The Solar System • How did the planets form? Planets’ characteristics are based on their distances from the Sun. Terrestrial Planets are mostly rock where heat drove off ice & gases. Jovian Planets are cooler and farther from the Sun therefore are mostly gas
A. Terrestrial Planets • MERCURY No Moons. Period of Revolution = 88 days Period of Rotation = 59 days Temps = -180 to 430ºC No atmosphere. Difficult for us to see it being so close to the sun. The surface is “Frozen in time” like our Moon and Mars.
Terrestrial Planets 2. VENUS No Moons. Period of Revolution = 224.7 days Period of Rotation = 243 days Temps = consistently >400ºC The thickest atmosphere; mostly CO2 and the air pressure is 90x that of Earth: Greenhouse Effect Surface of great mystery. Extensive Volcanism. Day is longer than a year. Retrograde Motion
Terrestrial Planets 3. EARTH One Moon. Period of Revolution = 365.26 days Period of Rotation = ~24 hours LIFE is supported in the Ecosphere region around the Sun (from Venus to Mars) Oceans served as the breeding ground for life. Oceans allow us to live comfortably in moderation
Terrestrial Planets 4. MARS Two Moons. Period of Revolution = 687 days Period of Rotation = ~25 hours Temps reach 27 C LIFE?? Polar Ice Caps
B. Jovian Planets 5. JUPITER Sixteen Moons. Period of Revolution = 11.86 yrs Period of Rotation = 9 hr, 50 min A spinning top Great Red Spot
Jovian Planets 6. SATURN Eighteen Moons. Period of Revolution = 29.46 yrs Period of Rotation = 10 hr, 14 min Rings of Ice
Jovian Planets 7. URANUS Twenty-one Moons. Period of Revolution = 84 yrs Period of Rotation = 17 hr, 14 min Rotating on it’s side in Retrograde Motion.
Jovian Planets 8. NEPTUNE Eight Moons. Period of Revolution = 164.8 yrs Period of Rotation = 16 hours Temps as low as -210 C Outermost planet in our solar system. Faint rings. Low energy from the sun leads to high winds.
Dwarf Planets xx. PLUTO & CO. Pluto itself has 2 moons. Period of Revolution = 247.7 yrs Period of Rotation = 6 days, 9 hrs Oblong orbit disqualifies it as a planet There are now eight similar objects beyond Neptune
Checkpoint • Which planets if placed in water would float? SATURN Correctly compare the size, density and composition of Neptune to Earth. Neptune is larger, more gaseous and less dense
Checkpoint A major belt of asteroids is located between Mars and Jupiter. What is the average distance from the Sun to the Asteroids? 390 million km
Space Travel the most significant advance in our study of Astronomy PLAY VIDEO
III. Space Objects • Asteroids – Left over debris An asteroid belt comprised of thousands of small rocks circles the sun between Mars and Jupiter. The asteroid Hermes nearly hit Earth in 1936. It could happen…
B. Comets • Large chunks of Ice moving at high velocities. • Have orbits of High Eccentricity. See p 42. http://images.google.com/imgres?imgurl=http://starryskies.com/The_sky/events/meteors/comet.orbit.jpg&imgrefurl=http://starryskies.com/The_sky/events/meteors/origin.html&h=345&w=410&sz=12&hl=en&start=1&tbnid=Zcg5lacDm8BjnM:&tbnh=105&tbnw=125&prev=/images%3Fq%3DComet%2Borbit%26svnum%3D10%26hl%3Den%26lr%3D
C. Impact Events • Craters are the result of impacts from extra-terrestrial objects.
IV. Deep Space Phenomena • Scientists believe the universe started with the big bang, 15 to 20 million years ago. Clouds of H & He became galaxies and stars.
A. Life of a Star • Nebula – gas and dust cloud • Nuclear Fusion begins • As the star ages, it becomes a red giant • After the red giant collapses, it becomes a white dwarf. • Increased gravity results in a neutron star. • A neutron star may explode, resulting in a supernova. • A new star called a pulsar may form briefly and the increased gravity causes it to collapse forming a black hole.