Earth from Mars Space Earth & Environmental Science
UNIVERSE
The universe is commonly defined as the totality of everything that exists, including planets, stars, galaxies, the contents of intergalactic space, and all matter and energy. According to the prevailing scientific model of the universe, known as the Big Bang, the universe expanded from an extremely hot, dense phase
The Beginning About 15 billion years ago a tremendous explosion started the expansion of the universe. This explosion is known as the Big Bang. At the point of this event all of the matter and energy of space was contained at one point. What existed prior to this event is completely unknown and is a matter of pure speculation. This occurrence was not a conventional explosion but rather an event filling all of space with all of the particles of the embryonic universe rushing away from each other. The Big Bang actually consisted of an explosion of space within itself unlike an explosion of a bomb where fragments are thrown outward. The galaxies were not all clumped together, but rather the Big Bang lay the foundations for the universe. The origin of the Big Bang theory can be credited to Edwin Hubble.
GALAXIES
Shapes
Our Galaxy: Milky Way The Milky Way galaxy is the spiral galaxy we call home, as do roughly 100 billion other stars. The Sun is far from the center of the Galaxy, halfway to the edge of the Galaxy along the Orion spiral arm. The center of the Milky Way As with most other galaxies, there is a super massive black hole there. Not only does it try to eat anything that goes near it, the area around it is a good place for new stars to form.
Our location
OUR SOLAR SYSTEM
Formation of the Solar System 1. Began to look like a solar system about 4.6 billion y.a. 2. Nebular Theory:The sun and the planets formed from a rotating disk of dust and gases. 3. Nebula:Cloud of dust and gas in space. (usually about 92* hydrogen, 7* helium, 1* other)
Formation of the Solar System 4. Remember!: any two objects in space attract each other- GRAVITATIONAL ATTRACTION 5. Accretion Disk:A rotating disk of gas and dust matter that may form around any of a variety of stars or other massive objects 6. The growth of planets began as solid bits of matterthat collided and clumped together through a process called accretion. 7. Planetesimals:Small irregular shaped body formed by colliding matter.
And then Planetesimals became protoplanets once their masses became great enough to possess an effective gravitational field. The sun initiates nuclear fusion. Solar wind and radiation swept out the remaining gaseous materials from the nebular disk. The inner planets became heated and melted. Their primordial atmospheres were lost. The Jovian planets (Jupiter, Saturn, Neptune and Uranus) because of their great masses retained their primeval atmospheres which are similar to the composition of the present-day sun.
The Sun The Sun is the star at the center of the Solar System. It weighs nearly 330,000 times as much as Earth!
Sun Facts Continued.. It is made up of mostly hydrogen and helium gases. It is 93 million miles from Earth. It takes 8 minutes and 19 seconds for light to travel from the Sun to the Earth.
Energy is produced by Fusion (joining of nuclei)
Because the sun is made of gas, no sharp boundaries exist between its various layers. Keeping this in mind, we can divide the sun into four parts: 1. solar interior 2. visible surface, or photosphere and two atmospheric layers, 3. chromosphere 4. corona.
The Sun Solar wind - stream of protons and electrons ejected at high speed from the solar corona. sunspot is a dark spot on the sun that is cool in contrast to the surrounding photosphere.. Sunspots appear dark because of their temperature, which is about TEMP = 1500 oc cooler less than that of the surrounding solar surface.
The Sun During their existence, solar flares release enormous amounts of energy, much of it in the form of ultraviolet, radio, and X-ray radiation. 9- Solar flares are brief outbursts that normally last about an hour and appear as a sudden brightening of the region above a sunspot cluster.
Aurora Borealis Auroras, the result of solar flares, are bright displays of ever-changing light caused by solar radiation interacting with the upper atmosphere in the region of the poles.
The Sun s Energy Electromagnetic Energy- type of energy radiated by the Sun in the form of waves. Waves- a way for energy to travel from one point to another. Long wavelength = Low energy. Short wavelength = High energy.
Wavelength and Visible Light
What happens to the energy once it reaches the Earth s atmosphere? -it is taken in as HEAT!
Heat Heat can be transferred by three methods: Radiation Convection Conduction
Radiation Radiation occurs when the Sun s energy is transferred to the Earth through waves. The Earth absorbs the energy as heat, warming the planet. Kitchen Example: Microwave
Convection Convection is the transfer of heat by the physical movement of the heated medium itself. It occurs in a cyclical motion: hot medium goes up, cold medium goes down. Occurs in liquids and gases only. Kitchen Example: - Oven or teapot
Conduction Conduction is heat transfer as a result of direct contact with heated medium without movement of the medium. Conduction occurs through TOUCH. Kitchen Example: Stovetop
Does the Sun s energy affect Earth? Photosynthesis- Plants use the Sun s energy to make food, which helps them grow.
Sun s energy uses continued Solar Power- We use the Sun s energy to power our homes through Solar Panels.
Why the sun makes life on earth possible
EARTH S MOVEMENTS
Kepler sthree Laws of Motion 1. Orbits of the planets are elliptical. An ellipseis an oval-shaped path. 2. Planet moves fastest when it is near perihelion and slowest when it is near aphelion Perihelion moment closest to sun Aphelion moment furthest from sun 3. planets more distant from the sun take longer to orbit the sun..
Sir Isaac Newton Although others had theorized the existence of gravitational force, Newton was the first to formulate and test the law of universal gravitation. Universal Gravitation 1. Gravitational force decreases with distance. 2. The greater the mass of an object, the greater is its gravitational force. Gravitational attraction keeps the planets in their orbits. Inertia keeps the planets moving along their orbits.
Who orbits what? Planets in the solar system orbit the Sun. Actually they orbit the center of mass Called the barycenter of the solar system Barycenter has smooth path through galaxy (but Sun/planets wiggle ) Earth/Moon system also has a barycenter
The revolution of the Earth around the sun Takes 365.25 days or one year. Leap year
Earth s Tilt The Earth's axis is tilted from perpendicular to the plane of the ecliptic by 23.45 This tilting is what gives us the four seasons of the year - spring, summer, autumn (fall) and winter. *Since the axis is tilted, different parts of the globe are oriented towards the Sun at different times of the year.
Seasons What two things cause the difference in the seasons? 1. The angle of the sun s rays 2. The length of the days There are two kinds of rays from the Sun: 1. Direct- occurs when Earth is tilted toward the Sun 2. Indirect-occurs when Earth is tilted away from the Sun In the Summer, we get the direct rays from the sun and the days are longer. (But we are farther away from the Sun) In the Winter, we get indirect rays from the Sun and the days are shorter. (But we are closer to the Sun)
The Earth Moon Sun System Everything is in motion The solar system speeds in the direction of the star Vega. The sun revolves around the galaxy. Earth is presently approaching one of its nearest galactic neighbors, the Great Galaxy of Andromeda. Sun is not stationary in our solar system. It actually moves as the planets tug on it, causing it to orbit the solar system's barycenter. The Sun never strays too far from the solar system barycenter
Earth's Precession Earth's polar axis precesses very slowly over a period of about 23,000 to 26,000 years. The term precession simply refers to a change in the direction of the axis of a rotating object. As this occurs, the pole of the Earth inscribes an arc in the heavens called the precessional arc. Earth's pole aligns with different pole stars throughout its precessional period. Polaris is Earth's current north-pole star. Earth's ~25,000-year precessional cycle is also referred to as "Earth's Great Year."
Precession The Earth's axis rotates (precesses) just as a spinning top does. Precession is caused by the gravitational pull of the Sun and the Moon on the Earth Therefore, the North Celestial Pole will not always be point towards the same starfield. Precession is the slow, top-like wobbling of the spinning Earth, with a period of about 26,000 years
Nutation Nutation is a small irregularity, or wobbling, in the precession of the equinoxes. This is a change in the angle ½ degree one way or the other. This occurs over an 18 year period and is due to the Moon exclusively. This would very slightly increase or decrease the amount of seasonal effects.
Nutation:(Latin nutare, "to nod") Nutation is, in astronomy, a small irregularity in the precession of the equinoxes Nutation superimposes a small oscillation, with a period of 18.6 years and an amplitude of 9.2 seconds of arc, upon this great slow movement. The cause of nutation lies chiefly in the fact that the plane of the Moon's orbit around the Earth is tilted by about 5 from the plane of the Earth's orbit around the Sun.
Rotation What does Rotation mean? Rotation occurs when something is spinning around an axis. What are some examples of things that rotate? Tops, Ballerinas, Figure skaters, cyclones, Tornadoes, a merry-goround, Earth How do we know that the Earth rotates? 1. Star trails- trails made with time exposure, circular paths that occur because the planet is moving and not stationary. 2. Winds curve because of the Earth s rotation. 3. Ocean currents curve clockwise in the northern hemisphere, and counterclockwise in the southern hemisphere. 4. The movement of a pendulum. It does not actually move, it is the Earth moving that causes the pendulum to appear to change the direction of its swing.
Night and Day What causes night and day? The rotation of the Earth The side of the Earth that is facing the sun has daylight, the side of the Earth away from the sun has night. It takes 23 hours 56 minutes and 4.1 seconds (24 hours) for the Earth to complete one rotation. The Earth is tilted on it s axis at a 23.5 degree angle. The Earth s tilt in the direction of the North Star. What is another name for the North Star? Polaris This tilt is what causes our days to get longer in the summer and shorter in the winter. Because of the Earth s rotation the sun appears to rise in the east and set in the west.
Summary What is the difference between rotation and revolution? Rotation occurs when an object spins around an axis. Revolution occurs when an object spins around another object. What type of movement causes night and day? The Earth s rotation What type of movement causes the change of seasons? The Earth s revolution- the angle of the sun, and the length of the day. How do we know that the Earth Rotates? Star trails, pendulum swings, ocean currents, wind currents
MOON
The moon revolves or orbits the Earth once every 29 days. We all ways see the same side of the moon because the moon rotates and revolves at about the same speed.
Tides As the moon travels around the earth and as they, together, travel around the sun, the combined gravitational forces cause the world s oceans to rise and fall, which is called tide.
Half of the Moon is always lit up by the sun. As the Moon orbits the Earth, we see different parts of the lighted area. http://www.nasm.si.edu/apollo30th/moontheater/phasepage2.html
The revolution of the Moon around the Earth makes the Moon look as if it is changing shape in the sky. http://btc.montana.edu/ceres/html/birthdayphases.htm
This is caused by the different angles from which we see the lighted part of the Moon's surface. These are called "phases" of the Moon. http://btc.montana.edu/ceres/html/birthdayphases.htm
http://www.niehs.nih.gov/kids/ lunar/why_phases.gif
The Moon passes through four major shapes during a cycle that repeats itself every 29.5 days. The phases always follow one another in the same order: New moon First quarter Third quarter Full moon