• Save
Review#14 astronomy
Upcoming SlideShare
Loading in...5
×
 

Review#14 astronomy

on

  • 295 views

 

Statistics

Views

Total Views
295
Views on SlideShare
295
Embed Views
0

Actions

Likes
0
Downloads
0
Comments
0

0 Embeds 0

No embeds

Accessibility

Categories

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

Review#14 astronomy Review#14 astronomy Presentation Transcript

  • L.O: CELESTIALOBSERVATIONS, EARTH’S ROTATION& REVOLUTION, ELLIPTICAL ORBITSOF THE PLANETS, THE MOON, THESTARS & THE UNIVERSE.
  • Celestial means “of the sky”Celestial objects areall the objects in thesky.(the planets, stars,moon, sun etc)
  • All celestial objects appearto move across the sky ata rate of 150 per hour.
  • Viewed from the north polar, allconstellations appear to rotate aroundPolaris.Polaris, herein the center
  • EARTH HAS NIGHT ANDDAY BECAUSE IT ROTATESON ITS AXIS.
  • THE SIDE FACING THE SUNIS “DAY”. THE SIDE AWAYFROM THE SUN IS “NIGHT”
  • EARTHTAKES 24HOURSTOROTATE!
  • EARTHMOVE 15 0DEGREESEVERYHOUR.150 X 24=3600DEGREES
  • EVIDENCE THATEARTH ROTATES:
  • THE TWO MAIN EVIDENCE OFEARTH’S ROTATION ON ITS AXIS:•FOUCAULT’SPENDULUM•THE CORIOLISEFFECT.
  • For every hour, the Sun appears tomove 15 0 degrees per hour!
  • Night and day are caused byEarth rotating around the sun!!!!!
  • The seasons:
  • There are four important days thatyou must know. What are they?
  • There are four important days thatyou must know. What are they?
  • The parts that are “leaning” towards theSUN get the vertical (direct) rays haveSUMMER
  • The parts that are “leaning” away fromthe SUN get the vertical (direct) rayshave WINTER
  • What exact day is this? How do youknow?
  • JUNE 21st, the first day of summer in theNorthern hemisphere. Because the North isleaning towards SUN!
  • What day is this? How do youknow?
  • DECEMBER 21st, first day of winter innorth. Because north leans away fromsun.
  • THIS DIAGRAM SHOWS THESUN’S PATH IN NEW YORK STATE
  • The Heliocentricmodel
  • The Heliocentric model• The sun is thestationarycenter. All theplanets includingEarth revolvearound the sun.
  • The heliocentric model explainedretrograde motion: why planetsappear to wander backwards acrossthe sky.
  • The solar system(planets part 1)
  • The “solar system”: is theSun, the 8 planets, the “dwarf”planets, all the moons & every othercelestial object that revolves aroundSol.
  • Planets (pt 2):Our star systemhas 8 planets.
  • There are two classesof planets in our solarsystem: terrestrial andjovian.
  • Terrestrial planets:• The “earth-like” planets. “Terra” is anothername for Earth.• Mercury, Venus, Earth & Mars.• Terrestrial planets are small, “rocky”, highdensity & orbit close to the sun.• Someday, humanity may colonize the otherterrestrial planets for the benefit ofHumankind!
  • Mercury today
  • Venus earth’s “twin”
  • Earth: the“goldilocks” planet• Not too hot, nottoo cold.• The only planetthat can haveliquid water onits surface.• The only planetwe know thathas life.
  • Earth moves in two ways:Rotation:The Earth spinning onits north-south axis.The earth rotates at 150per hour. After 24hours, it has turned3600 (one full turn)
  • Earth moves in two ways:Revolution:The Earth’s slightly ellipticalorbit around the Sun.The Earth revolves about10 per day. After 365 1/4days, it has made a fullorbit around Sol.Rotation: earth rotates onits axis.
  • The 2 main evidence of earth’srotation:1.Foucaultspendulum2.The Coriolis effect
  • a Foucaults pendulum seems tochange directions is one proof ofEarth’s rotation.
  • The coriolis effect: the winds seem tocurve proof that earth rotates.
  • Jovian planets• The “Jupiter-like” planets. Jove was anothername for Jupiter.• Jupiter, Saturn, Uranus, Neptune.• They are very large, low density, madecompletely of gases such as Hydrogen, helium,methane & ammonia.• They used to all be called: “the gas giants”• Jupiter and Saturn are called the “gas giants”• Uranus and Neptune are the “ice giants”
  • Jupiter: a failed sun?
  • Saturn: very low density. Would float inwater!
  • Uranus
  • Neptune
  • Open to ESRT page 15
  • The sun• The sun is middle aged mainsequence star. 4.6 billion yearsold.• The sun is powered by nuclearfusion: Hydrogen atoms fusingtogether.
  • stars•All stars use nuclear fusionto “power” themselves.•Stars come in many colors:red, yellow (our sun), white,blue, (& probably brown)
  • stars•Stars have differentluminosity (brightness)•Stars have differenttemperatures
  • You are responsible for this page
  • Circles &****ellipses
  • ***The orbits of the planetsare not perfect circles!
  • a circle is a perfectly round shape withone central point called a focusThefocus
  • This is an ellipse: **an ellipse is a ovalshape with two foci (two “centers”)
  • ellipses are described as“eccentric”.Round but not a perfect circle.
  • ** ellipses have two axes, a **major axisand a minor axis.
  • the planets do NOT orbit the sun in perfect circles. Theplanets revolve around the sun in elliptical orbits(oval orbits), with sun being one of the foci.
  • This is a perfect circle!This is an ovalThis is an ovalWhich is more “oval”?
  • You are now responsible for thisformula.
  • On the performance part of the regents, youwill calculate the eccentricity of the orbit ofan asteroid….
  • Celestial objects orbital speed isfastest when close to the sun.
  • Gravity: the force ofattraction between bodies.
  • Larger mass objects have strongergravity than smaller mass objects.
  • Evidence of Earth’s revolvingaround the SUN:•Change in the Sun’sangular diameter.•The cyclical seasonalchange in the Zodiacconstellations.
  • 1.Angular diameter:proof Earth revolvesaround the Sun
  • the sun is very large but looks “tiny”because it is far away.
  • Proof #2: that Earthrevolves around thesun. The yearly changein the zodiac.
  • The constellations of the zodiacappear to move because Earth ismoving around the Sun!!!
  • Questions: name the two “R”ways Earth moves.Earth rotates and Earthrevolves.
  • Earth rotates(spins) on itsaxis.The earth rotatesat 150 per hour.After 24 hours, ithas turned 3600 .Rotation givesEarth night andday(one full turn)
  • Revolution:*Earth revolves around the Sun inslightly elliptical orbit.* Earth revolvesabout 10 perday. After 3651/4 days, it hasmade a full orbitaround Sol.
  • The moon:
  • The moon is Earth’sonly natural satellite.
  • The moon is a “satellite” of Earth because itrevolves around Earth.Similarly, Earth is satellite of the Sun, becauseEarth revolves around the SUN!
  • The moon takes 27 1/3 days tocomplete one revolution aroundEarth (sidereal month)
  • These are the Lunar phases:
  • the Sun’s light rays are always illuminatingone half of the Moon. That is why someparts look lit & some parts look dark.
  • As the Moon revolves around Earth,an Earth observer sees varyingamounts of the illuminated portion ofthe Moon.
  • The Moon takes 29 1/3 days tocomplete a phase cycle from one newmoon to the next new moon.(called asynodic or lunar month)
  • This is the Earth-Moon system viewedfrom space. what phase is A?
  • what phase is B?
  • what phase is C?
  • what phase is D?
  • what phase is E?
  • A tide is a rise in the Earth’s waterlevels caused by the Moon and Sun’sgravity.
  • We have tides because the Moon’sgravity and the Sun’s gravity are pullingon Earth’s oceans.
  • Both the Moon’ and the Sun’s gravityare pulling on Earth’s oceans ALL thetime…..
  • Spring tides andNeap tides:
  • Spring tides: the Sun and Moon’sgravity are pulling TOGETHER.
  • Spring tides happen at the FULL moonor the NEW moon, when the Sun andMoon pull together
  • What do you notice?
  • The tides are cyclical: a high tide tolow tide is ~ six hours.
  • *** a high tide to another high tide is~ 12.5 hours.
  • *** a high tide to another high tide is~ 12.5 hours.
  • A solar eclipse!
  • An “eclipse” is when theSun is blocked by theMoon or the Earth,causing a shadow to becasted.
  • solar eclipse: the moon blocksthe sun and casts a shadow onEarth.
  • solar eclipse: the moon blocksthe sun and casts a shadow onEarth.
  • Lunar eclipse:
  • Lunar eclipse: the Earth blocks thesunlight and casts a shadow on themoon.
  • Eclipses can only be seen overcertain parts of the earth
  • Eclipses can only be seen overcertain parts of the earth
  • Eclipses are rare because theMoon, Earth & Sun must be aligned.
  • The stars
  • Astronomers have learned that thereare many kinds of stars!.
  • stars with different colors, differentsizes, different luminosities (brightness)
  • This is the H-R diagram.
  • The H-R diagram is a graph that plotthe stars’ temperature against theirluminosity.
  • Open to ESRT page 15.
  • You are responsible for this page. Youmust know how to read it
  • Luminosity is “brightness”
  • Surface temperature of stars
  • As luminosity increases, temperatureincreases
  • color of stars
  • Mass (size) of stars
  • Earths place inthe universe:
  • During the scienctific revolution (therenaissance), Copernicus, Kepler, Galileo& Newton developed the heliocentricmodel: which showed that Earth is not thecenter of the universe; Earth revolvesaround the sun.
  • By the early 20th century, peoplerealized that our sun is only one ofbillions of other stars in the milky waygalaxy!
  • definition:Galaxy: A mass ofbillions of stars. Ourhome galaxy is called“the milky way”
  • A typical spiral galaxyThese arecalledspiralarms
  • The universe has countlessbillions of galaxies!
  • definition:The universe is :All ofexistence, all ofcreation, everything.
  • 3) The Milky Way Galaxy is in theUniverse
  • How space distances aremeasured:Space distances are sovast, new units of measurehad to be created to measurespace distances:1.The light-year2.Astronomical units (AU)
  • The big bang!
  • The universe is 13.7 billion years old. Itformed in an “explosion” called “the BigBang”. How do we know this?
  • The big bangtheory
  • Big bang theory• Developed by astronomers, who builtupon Hubble’s discoveries.• the Universe formed from a singleinfinitely dense particle called a“singularity” that “exploded” 13.7billion years ago.• This explosion is why the universe isexpanding.
  • Two evidence of the bigbang:1.***The “red shift” of light.2.The cosmic microwavebackground radiation.
  • ***The red shift oflight:
  • ** a celestial object moving away fromus, shows light waves that arestretched toward the red end of thevisible light spectrum: “red shifted”
  • red shifting is the may evidence thatthe universe is expanding. The furtheran object is from us, the redder it is.
  • Astronomers know that the universe isexpanding because the galaxies arered shifting.
  • beforeafter
  • The object is moving away from us
  • This celestial object has red shifted soit is moving away from us.
  • Which is the oldest? Which is theyoungest?