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The Solar System Unit 4. Unit 4 Vocabulary 1. Rotation 2. Revolution 3. Axis of rotation 4. Summer...

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The Solar System Unit 4
Transcript

Unit 5 -

The Solar SystemUnit 4

1Unit 4 VocabularyRotationRevolutionAxis of rotationSummer solsticeWinter solsticeAutumn equinoxVernal equinoxOblate sphereGeodesySolar eclipseLunar eclipseEcliptic planeSpecific heatSpring tideNeap tideFoucaults pendulumCoriolis effectLatitudeUnit 4 vocabularyLongitudeConductionConvectionRadiation Big bang theorySteady-state theoryInflationary universe modelDoppler effectPrecession

BarycenterNutationEccentricity

Chapters:11.128-31The Sun-Earth-Moon SystemThe relationships between the Sun, Moon, and Earth are important to us in many ways. The Sun provides light and warmth and an energy source. The Moon raises tides in our oceans and illuminates our sky with its monthly cycle of phases. Both are used for the calendar and timekeeping systems.The Sun-Earth-Moon SystemOur view of the Suns position changes throughout the year as Earth moves in its orbit about the Sun. Seasons occur on Earth because Earths axis is tilted.The Moon goes through a cycle of phases each lunar month that correspond to our changing view from Earth of the sunlit side of the Moon.Seasons, moon phases, tides and eclipses.The Sun-Earth-Moon SystemTides are caused by the gravitational attraction of the Moon, and to a lesser extent, the gravitational attraction of the Sun.A solar eclipse occurs when the Moon lies directly between Earth and the Sun. A lunar eclipse occurs when the Moon passes through Earths shadow.

Seasons, moon phases, tides and eclipses.- Half the Moon is always lit by Sun- As the Moon orbits the Earth, we see different parts of the lighted half.

http://www.nasm.si.edu/apollo30th/moontheater/phasepage2.html Moon PhasesRevolution of Moon around Earth makes us have different angles of MoonLooks like its changing shapeThese are "phases" of the Moonhttp://btc.montana.edu/ceres/html/birthdayphases.htm

Waxing: increasing, growing larger

"Waning: decreasing, growing smaller

9

Waxing: increase illuminated portion

Waning: decrease illuminated portion

Eight phases

Daily MotionsEarths RotationThere are two relatively simple ways to demonstrate that Earth is rotating. 1.A Foucault pendulum, which has a long wire, a heavy weight, and will swing in a constant direction, appears from our point of view to shift its orientation. 2.Flowing air and water on Earth are diverted from a north-south direction to an east-west direction as a result of Earths rotation in what is known as the Coriolis effect.Daily changes to EarthDue to rotation-Rotation Earth spinning around its axis. Earth rotates towards the east (counter-clockwise from the north star)Causes the sun to rise, set and rise again in a 24 hour period.

Daily changes to EarthSeasonal changes due to tilt and revolutionCaused because Earth is tilted on its axis and moves around the sunSummer = the hemisphere tilted toward the sunWinter = the hemisphere tilted away from the sun

Daily changes to EarthTidal impact due to the moon and sun.High tide and low tides are caused by gravitational attraction with the moon (mostly) and the sun.

Solar EclipseThe moon passes directly between the sun and Earth.Umbra area = total eclipsePenumbra area = partial eclipse

Lunar EclipseWhen the moon passes through Earths shadow.Can happen only at the time of a full moon and the moon is the opposite direction from the sun.

Shape of the EarthBecause Earth rotates, the sphere is distorted by the centrifugal force. This is the force that causes objects to move outward away from the center of gravity.Earth's circumference and diameter differ because its shape is classified as an oblate spheroid or ellipsoid, instead of a true sphere.

Shape of the EarthThe equatorial bulge at Earth's equator is measured at 26.5 miles (42.72 km) and is caused by the planet's rotation and gravityThis means that instead of being of equal circumference in all areas, the poles are squished and a larger circumference and diameter at the equator.

Shape of the EarthThe Earth's gravitational pull is slightly weaker at the Equator due to its equatorial bulge.

The slightly weaker gravitational pull and momentum of the spinning Earth makes equatorial regions ideal places for space launches. It takes an enormous amount of energy to launch a satellite or other spacecraft out of the Earth's atmosphere.

Ultimately, energy from the Sun is the driving force behind weather and climate, and life on earth.

Did you know that the Sun blasts more than a billion tons of matter out into space at millions of kilometers per hour?

How does energy flow from the sun to the Earth?The transfer of energy from the Sun occurs primarily by radiation. Once the Suns energy reaches Earth, it is intercepted first by the atmosphere. A small part of the Suns energy is directly absorbed, particularly by certain gases such as ozone and water vapor.Some of the Suns energy is reflected back to space by clouds and Earths surface.How does energy flow from the sun to Earth?The Sun warms the planet, drives the hydrologic cycle, and makes life on Earth possible. The amount of sunlight received on Earths surface is affected by the reflectivity of the surface, the angle of the Sun, the output of the Sun, and the cyclic variations of the Earths orbit around the Sun.

Specific HeatWhy, on the same day, are the temperatures of water, sand, and asphalt so different? Specific heat is the key. Specific heat is how much heat energy is needed ro raise the temperature of a substance. Specific HeatWater has a very high specific heat. That means it needs to absorb a lot of energy before its temperature changes. Sand and asphalt, on the other hand, have lower specific heats. This means that their temperatures change more quickly. When the summer sun shines down on them, they quickly become hot.Transferring Heat EnergyHere are three easy things to know about the way heat flows:

1)There has to be a temperature difference. Energy only flows as heat if there is a temperature difference.

2) Energy as heat flows from a higher temperature to a lower temperature.

3) The greater or larger the difference in temperature, the faster the energy flows.RadiationA type of energy that can travel through space. It doesn't need matter to conduct it from place to place. It can travel through air or through a vacuum.Ex: When you stand near hot molten lava, the heat you feel on your skin is mostly radiant heat. This type of heat doesn't need air to travel through. Even if you were standing in a vacuum (no air) you would feel the heat.ConductionA type of heat flow that results when things are actually touching. Energy traveling as heat by conduction needs matter to flow through. Conduction cannot travel through a vacuum because in a vacuum there are no atoms or moleculessomething made of atoms or molecules has to touch something else made of atoms or molecules in order for there to be conduction.

Ex: If you touch a hot object the heat is conducted by physical contact with your skin.ConvectionA type of heat transfer in which the motion is not generated by an external source but only by density differences.Can occur in fluid or airEx: Ocean currents and winds

Combustion and nuclear reactions Combustion: a chemical reaction (sharing, transfer, loss, gain of electrons; burning with the presence of oxygen.Nuclear reactions: Fission: Process in which heavy atomic nuclei split into smaller, lighter nuclei.Fusion: Process in which light hydrogen nuclei combine into heavier helium nuclei.The Sun emits many forms of electromagnetic radiation in varying quantities. As shown in the diagram:about 43% is in the visible parts of the spectrumabout 49% in the near-infrared7% ultravioletless than 1 percent of solar radiation is emitted as x-rays, gamma waves, and radio waves.

Earths Magnetic FieldThe Earth has a substantial magnetic field. It protects us from harmful solar wind from the sun.Charged particles given off by the Sun are deflected by the Earths magnetic field.These particles interact with our atmosphere and create the auroras.

Earths Magnetic FieldThe origin of the Earth's magnetic field is not completely understood, but is thought to be associated with electrical currents produced by the coupling of convective effects and rotation in the spinning liquid metallic outer core of iron and nickel.

Earths Magnetic FieldSolar wind is first deflected by the bow shock. The corresponding region of space sitting behind the bow shock and surrounding the Earth is termed the magnetosphere; it represents a region of space dominated by the Earth's magnetic field in the sense that it largely prevents the solar wind from entering.

How our universe beganThere are three theories we will discuss about the origin of the universe:The steady state theory says that new matter is created as the universe expands so that the overall density of the universe stays the same.The inflation theory says that a period of extremely rapid expansion of the universe happened prior to the Big Bang and was dominated by a type of vacuum energy that later produced the matter that fills the universe today.The big bang theory says that the universe began about 13.7 billions years ago as a single point and has been expanding ever since.Steady-state Theory

Inflation Theory

Big Bang Theory

Organization of the universeUniverseGalaxiesSolar systems (planetary systems)StarsSatellite planets around a star ex: Earth is a satellite planet to our sun

The universe is expandingAstronomers in the early 20th Century got the shocks of their lives when they discovered that galaxies appeared to be rushing away from us. They did this by taking spectra of the galaxies, and then measuring the shift in their spectrum due to their motion.

This phenomenon is called the Doppler Shift . With light, an object approaching you has its light waves compressed, or shortened. This is called a blue shift (since in visible light the shorter wavelengths are blue). If the object is moving away, the wavelengths are stretched, resulting in a red shift of the spectrum.

The universe is expandingAs objects move they emit a lightRed shift- objects are moving away Blue shift- objects are moving closer

All planets and galaxies are showing a red shift What does this mean?

Movement through spaceMovement of our solar system through the Milky Way Galaxy.It takes the sun over 200 million years to revolve around the galaxy.The last time we were in the same place dinosaurs were just starting to appear.

Motion of the EarthHow does the Earth move within our solar system?Orbital motion The Earth orbits (revolves) around the sun once per year.Change in seasons dependent on the tilt of the EarthRotation around the axis Earth rotates around the axis once per day.Causes day and nightHow does the solar system move in the galaxy?Our solar system follows the path of the sun around the galaxy center.Takes over 200 million years for our solar system to orbit the center of the Milky Way galaxy

Motion of the Earth1. Precession - A slight movement in the direction of the earths axis, but without any change in tilt. This changes the stars near (or not near) the Pole but does not affect the seasons as long as the angle stays the same.Happens over a period of 26,000 years. Right now our axis points at Polaris. In the year 14,000 it will point at Vega.

Motion of the Earth2. Nutation - a wobbling, or swaying motion around the axisCauses a change in the angle degree over an 18 year period due to the moon exclusivelyWill slightly increase or decrease the amount of seasonal effects

Motion of the Earth3. Barycenter the point between 2 objects where they balance each other.Our sun actually orbits the barycenter of the solar system as it moves through the galaxy because of the tug from the planets.

Models of the solar system492000 years ago, many philosophers developed ideas about the universe based on what they saw.

One of these was Aristotle , a Greek philosopher who lived from 385 to 322 B.C.

He promoted an Earth-centered (Geocentric) universe model.7

50Heliocentric ModelCopernicus came up with the model we use today the sun-centered or Heliocentric model.When Copernicus first developed his model it was quite controversial and was not accepted until after his death in 1543.

Each planet revolved around the sun in the same direction but at different speeds.Both the geocentric and heliocentric models first had the planets orbits as perfect circles.When Copernicus first developed his Heliocentric model it was quite controversial and was not accepted until after his death Both the geocentric and heliocentric models first had the planets orbits as perfect circlesHeliocentric ModelSun-centered model

52When Copernicus first developed his Heliocentric model it was quite controversial and was not accepted until after his death Both the geocentric and heliocentric models first had the planets orbits as perfect circlesHeliocentric Model53A Danish astronomer named Tycho Brache devoted his life to making detailed observations of the positions of the stars and planets.

He hired a German assistant name Johannes Kepler.12Kepler was able to explain Braches observation in mathematical terms.

In the early 1600s Kepler developed 3 laws that explained most aspects to planetary motion.Keplers Laws54Keplers 1st Law - law of ellipsesKeplers 2nd Law - law of equal areasKeplers 3rd Law - law of periods14Keplers 1st Law, the law of ellipses55Each planet orbits the sun in a path called an ellipse.An ellipse is an oval whose shape is determined by 2 points with the figure.Each of these points are called a foci.The sun is one foci point for our planets.Some ellipses look like circles - This happens when there is only one foci point.15

Keplers 1st Law, the law of ellipses56Because the planets do not travel in a perfect circle, they are not always the same distance from the sun.The point where the orbit is the closest is called perihelion.The point furthest away from the sun is called aphelion.17Eccentricity - how flattened the ellipse is, more flattened, the more eccentric (measurements always between 0 and 1 with 1 equaling a flat line and 0 equaling a perfect circle) Properties of Ellipses

Keplers 2nd Law - law of Equal Areas58Describes the speed at which any given planet will move while orbiting the sun. The speed at which any planet moves through space is constantly changing. A planet moves fastest when it is closest to the sun and slowest when it is furthest from the sun.58

Keplers 3rd Law - Law of periodsKepler found a mathematical relationship between the size of a planets ellipse and its orbital period. He found that the ratio of a planets ellipse to its orbital period is nearly the same for all of the planetsThe orbital period (p) in Earth years and distance from the sun (a) in A.U.s gives the ratio of p/a=1

Mercury, the closest planet to the sun, takes 88 days to orbit the sun. While the dwarf planet Pluto requires 248 years to do the same.Used to find the distance from the sun or the period of the planets revolution if one or ther other is available The average speed of Earth is about 30 km/sec and Pluto the furthest planet from the sun is traveling at a rate of about 5 km/sec. Mercury is traveling about 49 km/secFundamentalsSunlight reaching the Earth can heat the land, ocean, and atmosphere. Some of that sunlight is reflected back to space by the surface, clouds, or ice. Much of the sunlight that reaches Earth is absorbed and warms the planet.When Earth emits the same amount of energy as it absorbs, its energy budget is in balance, and its average temperature remains stable.The tilt of Earths axis relative to its orbit around the Sun results in predictable changes in the duration of daylight and the amount of sunlight received at any latitude throughout a year. These changes cause the annual cycle of seasons and associated temperature changesGradual changes in Earths rotation and orbit around the Sun change the intensity of sunlight received in our planets polar and equatorial regions. For at least the last 1 million years, these changes occurred in 100,000-year cycles that produced ice ages and the shorter warm periods between them.A significant increase or decrease in the Suns energy output would cause Earth to warm or cool. Satellite measurements taken over the past 30 years show that the Suns energy output has changed only slightly and in both directions. These changes in the Suns energy are thought to be too small to be the cause of the recent warming observed on EarthTest ReviewDraw and label the different moon phasesWhat causes our seasons?Draw a lunar eclipse.Draw a solar eclipse.What is the penumbra? Umbra?Identify each season and which latitude the sun is directly over?What is the Foucault pendulum prove? And how does it prove it?What is rotation? How long does it take?What is revolution? How long does it take?What are 2 pieces of evidence that our Earth is rotating? Explain each.How many degrees is the Earth tilted?What causes the bulge around the equator?What is the shape of Earth? And why?Name, describe and give an example of the 3 ways heat is transferred on Earth.Explain differential heating of our Earth. (water vs. land)Why is Earths magnetic field important?

Test ReviewWho came up with the Geocentric universe model? Who came up with the Heliocentric universe model? What do each of them mean?Know what all of Keplers laws state.What is Earths focus point?How is eccentricity measured?Do planets closer to the sun or further from the sun have faster revolutions?Know the organization of the universe.What is the evidence for the universe expanding?Know the definitions of precession, nutation and barycenterBe able to label foci, major axis, semi-major axis, perihelion, aphelion


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