Earths Role as a Body in Space
Ch 28-31 Earths Role as a Body in Space Earths Motion through Space
How is Earths motion related to the origin of the galaxy and its solar system? The Origin of Our Expanding Universe
The Big Bang Theory universe began as a point & has been expanding ever since en.wikipedia.org The Origin of the Milky Way
Astronomers hypothesize that the galaxy began as A rotating, spherical cloud in space Our solar system continues to orbit the center of the Milky Way because it developed in the plane of the disk that orbited the central nuclear bulge of stars The Origin of the Solar System
Our solar system began when a rotating, interstellar cloud of gases (nebula)collapsed (due to gravity) & formed a sun & orbiting planets Earth orbits the Sun because it was located outside the center of the spinning nebula Earths Position in Space
What is Earths position within the hierarchy of the universe? A. Earths Position in the Universe
Solar System (3rd planet from Sun) Milky Way Galaxy (the Orion Arm) Local Group (about 40 galaxies) Supercluster (Virgo) Universe! How do Keplers laws describe Earths orbit?
Focus Question How do Keplers laws describe Earths orbit? 1. Keplers First Law The Law of Orbits: All planets move in elliptical orbits, with the sun at 1 focus. An ellipse is oval shape centered on 2 points instead of 1 point. The orbital period of a planet is how long it takes for it to travel a complete orbit around the Sun. We call this a year! 2. Keplers Second Law The Law of Areas: A line that connects a planet to the Sun sweeps out equal (=) areas in equal (=) times. Earth sweeps out a longer path when it is closer to the Sun. Earth moves fastest when it is closest to the Sun. 3. Keplers Third Law The Law of Periods: The square of the orbital period of any planet is proportional to the cube of the semi major axis of its orbit. P = a (P = orbital period = unit of time in Earth yrs, a = length of the semi major axis) If you know the distance of a planet to the Sun, you would be able to figure out its orbital period. Basically The closer a planet is to the Sun, the shorter its orbital period is. Barycenter and Earths Orbit
Barycenter is the center of mass between a planet and the Sun. The law of universal gravitation states that every pair of bodies in the universe attracts each other with a force related to mass (the more mass they have, the stronger the pull) AND distance (the farther apart they are, the weaker the pull) Focus Questions What causes the day and night cycle? What motion and force causes Earths slightly squished shape? 13 Earths Rotation Causes Day and Night
Earths axis is the imaginary line that goes through the N & S poles. Day and night are caused by the rotation of Earth on its axis - spinning towards & away from the Sun. ( hrs) Earths Rotation Causes Its Slightly-squished Shape
What motion causes Earth to take the shape of an oblate spheroid? Earths rotation What force causes the Earths mass to move outward from its center at the equator as Earth rotates? centrifugal force Focus Question (and Answer!)
What causes the seasons? The tilt of the Earth on its axis as it revolves around (orbits) the Sun. Earths Orbit and the Seasons!
What causes summer in the northern and southern hemispheres? when the hemisphere is tilted toward the Sun during Earths orbit Earths Orbit and the Seasons!
Fall occurs when a hemisphere is starting to tilt away from the Sun. Earths Orbit and the Seasons! Fall occurs when a hemisphere is starting to tilt away from the Sun. Earths Orbit and the Seasons!
What causes winter in the northern and southern hemispheres? when the hemisphere is tilted away from the Sun during Earths orbit An Owl in Springtime!Spring occurs when the hemisphere is starting to tilt towards the Sun. Earths Orbit and Seasons
The seasons in the northern and southern hemispheres are opposite each other because When 1 hemisphere is tilted towards the Sun, the other is tilted away from it Think About It What would happen to the average temperatures during our winter if Earth was tilted MORE on its axis ? What circumstances can bring about a long term change in the seasons?
Focus Question What circumstances can bring about a long term change in the seasons? Precession Precession is the wobble in Earths rotational axis.
One full cycle of precession takes 26,000 years! The force that causes precession is the sideways pull of the Moon & Sun on the Earths bulging equator. Nutation Nutation is a change in the angle of tilt of Earths axis
Nutation Nutation is a change in the angle of tilt of Earths axis Present tilt of Earths axis is 23.5. The tilt can vary from 22.1 to 24.5 . http://www. cgrer. uiowa
Nutation If the angle of tilt decreased to 22.1 there would be less of a temperature difference b/tw seasons. If the angle of the tilt ofEarths axis increased to 24.5 there would be more of a temperature difference b/tw seasons. What forces and heavenly bodies cause the tides?
Focus Question What forces and heavenly bodies cause the tides? the gravitational attraction among Earth, the Moon, and the Sun.
Tides Tides are caused by the gravitational attraction among Earth, the Moon, and the Sun. What forces & heavenly bodies cause the tides?
gravitational pull of Moonon oceans facing it causes high tide centrifugal swishoceans facing away from Moon experience less of a pull (high tide) The sides of Earth NOT directly facing toward or away from the Moon experience low tide. The Cause of Tides The Cause of Tides What motion causes tides at location tochange every 6 hours? Earths rotation on its axis Spring Tide Twice a month, the Earth, Moon, & Sun align (line up) causes the Moon & Sun to pull together on Earths oceans. Higher high tides / lower low tides Neap Tide Twice a month, the Earth, Moon, & Sun will form a right angle which causes the Moon & Sun to pull from different directions on Earths oceans. Evens the tides Fusion Fusion is the fusing of smaller, lighter hydrogen atoms to form a larger, heavier helium atom (which releases energy) Fusion Fusion occurs in the stars! (our Sun) Or in Iron Mans chest
Fission Fission is splitting of bigger, heavy atoms (like uranium or plutonium) into smaller, lighter atoms 35 Fission Differs From Fusion
Fission differs from fusion in that Fission is SPLITTING atoms, not FUSING atoms. The Radioactive Boy Scout is a warning about investigating fission in your backyard shed! Fission Fission is used on Earth
in nuclear power plants & submarines (to generate electricity) 37 Fusion and Fission: Nuclear Reactions
Fusion and fission are nuclear reactions because the nuclei of atoms are fusing (in fusion) OR splitting (in fission). (Remember Thats the center part of the atom where protons and neutrons are located) New atoms are made in both types of reactions. Combustion Combustion is burning of a fuel in presence of O2 (oxygen) to produce energy (heat & light) a. It is a chemical reaction which recombines atoms. (FUEL) Methane 39 Power Plants (Belews Creek)
Combustion used in Vehicles Power Plants (Belews Creek) Fireplaces Think About It How does the Sun harm living things?
(What types of energy from the Sun are harmful?) Focus Question How are the harmful forms of radiation from the Sun deflected away or filtered so that they dont reach living things? The Suns Energy 1. Electromagnetic radiation consists of
electric & magnetic disturbances that travel through space as waves. 2. The electromagnetic spectrum organizes forms of EM energy by wavelength 3. The Sun produces electromagnetic radiation across the spectrum radio waves, microwaves, infrared energy (heat), visible light, ultraviolet radiation, x-rays, & gamma rays The Electromagnetic Spectrum
4. The shorter the wavelength, the more harmful the energy! The Ozone Layer Ozone (O3)
5. Which gas blocks ultraviolet radiation from the Sun? Ozone (O3) It is found in the stratosphere. Chlorofluorocarbons (CFCs) damage O3. These are found in aerosols, coolants, & cleaners. Solar Wind and Earths Magnetic Field
1.Solar wind is a supersonic plasma (Remember, thats charged particles or ions) that flows outward from Sun at high speeds & bathes planets in a flood of high-energy particles.(Which isnt very good for us!) Solar Wind and Earths Magnetic Field
2. Earths magnetic field protects us from the solar wind by deflecting these particles and trapping them in two huge rings (Van Allen belts) How does the Suns energy warm Earths surface and atmosphere?
Focus Question How does the Suns energy warm Earths surface and atmosphere? 48 Energy For Earth 1. Radiation is
transfer of energy through space by EM waves (visible light, ultraviolet radiation, & other) Energy For Earth 1a.The Suns energy reaches Earth by the process of radiation. 1b.About 50 % of the Suns energy is absorbed by Earths surface. 1c. Remember ozone blocks most of the UV radiation. Differential Heating
1d. Which heats up and cools down more slowly water or land? This is called differential heating. This is what moderates the climate incoastal areas. In winter, the ocean acts like a giant heater and in summer, the ocean acts like a giant air conditioner. Differential Heating and North Carolina
Our moderate coast The Outer Banks! Energy for Earth 2. Conduction is the transfer of energy that occurs when molecules collide Air molecules just above Earths surface are warmed by conduction. Energy moves from your hand to your desk.Why? Heat waves over hot sand! 53 Energy for Earth 3. Convection is the transfer of energy by the flow of a heated substance Warm air will rise. When the warm air gets high enough, it cools and sinks. This creates a convection current. 54 Energy for Photosynthesis
During photosynthesis, solar energy is transformed into chemical energy (food). This occurs in plants, algae & some bacteria. For this to occur, there must be water, CO2, Energy source: sunlight. In plants, this occurs in chloroplasts.