After School Review Commack High School Astronomy After School Review Commack High School

Orbit around an object Spinning on its Axis 365.26 days 15º per hour Solar System Motions Rotation Revolution Spinning on its Axis 15º per hour (days) Orbit around an object 365.26 days (years) Proof: Viewed constellations differ each season Proofs: Focault pendulum Coriolis effect K. Corbisiero 2010

Seasons Fall - Sept. 23 – Parallel to Sun Winter Summer Dec. 21 Direct Rays on Equator 12 hours of day and night Winter Dec. 21 Tilted Away Direct Rays on Tropic of Capricorn 9 hours of daylight Summer Jun. 21 Tilted Toward Direct Rays on Tropic of Cancer 15 hours of daylight Spring – March 21 – Parallel to Sun Direct Rays on Equator 12 hours of day and night K. Corbisiero 2010

Tilt with respect to the Sun Reasons for the Seasons: ___________________________________ 2. ___________________________________ Tilt with respect to the Sun Revolution around the Sun Distance from the Sun is NOT a reason! We are actually closer to the Sun in the Winter! K. Corbisiero 2010

Sun Centered Earth Centered (Geo = Earth) Heliocentric Model Geocentric Model Sun Centered (Heli = Helium which the Sun is partially made up of) Earth Centered (Geo = Earth) K. Corbisiero 2010

Note that the paths are ALWAYS 23.5° apart! Path of the Sun June 21 Direct Rays on Tropic of Cancer Rises North of East Sets North of West Equinox rises due East at 6:00 AM Equinox sets due West at 6:00 PM March 21 & Sept 23 Direct Rays on Equator Polaris at 41º Sets South of West Rises South of East Dec 21 Direct Rays on Tropic of Capricorn Note that the paths are ALWAYS 23.5° apart! K. Corbisiero 2010

Daylight Length with Respect to Seasons Winter Look at the Full Amount of Day & Night to determine the portion of Day and the portion of night in 24 hours. Season is ______________ in N.H. Earth is tilted AWAY from Sun Equator gets 12 hrs day & night North Pole gets 6 months night Summer Season is ______________ in N.H. Earth is tilted TOWARD Sun Equator gets 12 hrs day & night North Pole gets 6 months day K. Corbisiero 2010

What time is it at point X? It would be Noon here since the Sun would be highest in the sky for people on Earth It would be Midnight here 6:00 PM (Sunset) 6:00 AM (Sunrise) It is closest to 6:00 PM since the Earth is just entering into darkness at that point. You MUST look at where the Sun is in relation to the Earths rotation. K. Corbisiero 2010

Changes based on the height of the sun in the sky Shadows S Our shadow is to the North because the Sun is always in the South! N Seasonal Changes Longest shadows in the winter Shortest shadows in the summer Daily Changes Longest shadows near sunrise and sunset Shortest shadows at Noon Changes based on the height of the sun in the sky K. Corbisiero 2010

Eccentricity of an Ellipse Calculation: Formula ESRT’s pg 1 Note: there are NO units The value must be between 0 and 1 0 is a perfect circle(least elliptical) 1 is a straight line (most elliptical) Increasing Eccentricity More eccentric is more elliptical! K. Corbisiero 2010

Eccentricity of an Ellipse Drawing an Ellipse K. Corbisiero 2010

Calculate the Eccentricity of the Ellipse Distance between Foci Eccentricity = Length of major axis 1.1 cm 4.3 cm = = 0.256 NOTES: Measure VERY Accurately! Answer must be to thousandths place There are NO units! K. Corbisiero 2010

More: Farthest = Least Closest = Greatest Gravity Gravity Velocity Apparent Diameter Closest = Greatest Gravity Velocity Apparent Diameter K. Corbisiero 2010

Solar System Data Table – page 15 ESRT’s Use to: Order of the planets Compare sizes of planets Determine distances between planets and the Sun Days and Years of all the planets Eccentricities of planets Density and Mass of planets NOTE: Asteroid belt is between Mars & Jupiter Years Days K. Corbisiero 2010

A C E G A Phases of the Moon Full Moon Position Lunar Eclipse May Occur New Moon Position Solar Eclipse May Occur Identify which letter shows the position of the moon that each phase would be viewed from Earth: A C E G A K. Corbisiero 2010

Tides NeapTides Spring Tides They occur due to the gravitational attraction of the Moon and Earth. High Tides will occur on the side of the Earth where the Moon is (and on the opposite side too). Spring Tides NeapTides Highest Highs, and the lowest Lows Occurs during full and new moon phases only because the gravity of the Sun and the Moon work together More gravity = higher tides Lowest Highs and Highest Lows Occurs during quarter Moons when the Suns and the Moons gravity work against each other H = High Tide L = Low Tide H = High Tide L = Low Tide Sun Gravity + Moon Gravity Extra High tides, and Extra Low Tides Moon Gravity – Sun Gravity NOTE: The Moons gravity has more effect than the Suns only because it is closer! K. Corbisiero 2010

Solar & Lunar Eclipses They do not occur every month because the moons orbit is tilted. Solar Eclipse Lunar Eclipse Earths Shadow darkens the Moon The Moon blocks the Sun from the Earth May occur only during a Full Moon May occur only during a New Moon K. Corbisiero 2010

Did you know: We only ever see ONE side of the moon!! Why? Because the moons rotation is equal to its revolution!

Stars Hottest Coolest Giants Dwarfs Hottest Coolest Characteristics - Page 15 ESRT’s Use to: Determine how hot a star is by its color Blue is __________, Red is ___________ Determine the stage of a star in its life Early = ________________ Intermediate = _______________ Late = ________________ Luminosity is how bright the star is compared to the Sun. If it is higher than the Sun on the chart, it is brighter and emits more energy If it is lower than the Sun on the chart, it is duller and emits less energy Hottest Coolest Main Sequence Giants Dwarfs Hottest Coolest K. Corbisiero 2010

Star Trails Polaris is in the center! This is what the stars would look like IF the Earth DID NOT Rotate! Pictures of stars taken with time lapse photography. The pictures are superimposed onto one picture to see how the star appears to move in the sky over time. The length of time can be determined because every 15 equals 1 hour. This is how star trails appear in the New York. Polaris is in the center of the star trails and all stars appear to move around Polaris. How long was the sky to the right photographed? Looking at star trail 1, 90° - 30° = 60/15° per hour = 4 hours! K. Corbisiero 2010

Our Galaxy The Milky Way A Spiral Galaxy Our Solar System is one of Billions of Solar Systems in our Galaxy Our Galaxy is one of Billions of Galaxies in our Universe Our Solar System is Here Side View Top View K. Corbisiero 2010

Universe Galaxies LARGE The Universe The Universe is made up of Billions of Galaxies Galaxies Solar Systems Draw one symbol inside the other starting with the part of our Universe that is the largest. Each shape should be inside of another shape. Planets Moons small K. Corbisiero 2010

The Big Bang Theory The Big Bang Occurred about 15 billion years ago (note our Solar System is only 4.6 billion years old) Proof the Universe is Expanding: 1. Cosmic Background Radiation 2. The Red Shift Effect K. Corbisiero 2010

Red & Blue Shift Blue End Red End Red Run Away, Blue Come’n Play Every Element has its own spectral line ‘signature’ here on Earth (standard) – no two elements have the same one. When we look at distant galaxies, the spectral lines are shifted toward the red end of the visible spectrum because they are moving away from us. If something is shifted toward the blue end, it is coming towards us. Blue End Red End K. Corbisiero 2010

RED RUN AWAY BLUE COME’N PLAY All Galaxies are MOVING AWAY from each other in all directions outward from the center of the Universe! RED RUN AWAY BLUE COME’N PLAY If see a red shift, object is longer wavelength and moving away from us If see a blue shift, object is shorter wavelength and moving toward us K. Corbisiero 2010

The End