Transcript red storm
Intro Questions • How do the Sun and the Earth interact with one another? • Why does the Earth rotate around the Sun? (More to it than you think) • Why do other planets take longer to revolve around the Sun? Gravity and Newton • Newton’s apple theory • Same force that drops the apple, keeps all the planets in orbit around the Sun - gravity. 1 3 - The attraction between two masses The Earth The Moon The Sun The bigger an object’s mass, the greater the effect of gravity The closer an object is to another object, the greater the effect of gravity Gravity • Anything that moves with circular motion requires a centripetal force to keep it accelerating. The force acts to the centre of the circular motion • The force of gravity is the centripetal force between two large masses • The larger the mass, the larger the force of gravity and the further the masses move apart, the smaller the force of gravity Mars Sun Earth Mars Less gravity Sun Force of gravity Earth The bigger an object’s mass, the greater the effect of gravity The Moon is 1/80th the mass of the Earth and has a gravitational pull of 1/6th of the Earth Day & Night SUNLIGHT Anti-clockwise The Earth spins on its axis once every 24 hours. The Earth & Beyond : The Seasons (The Northern Hemisphere) Tilted away from the Sun- Sun is low in the sky Long nights When it is Summer in the Northern Hemisphere, it is Winter in the Southern Hemisphere Day and night the same length Tilted towards the Sun- Sun is high in the sky Long days Day and night the same length Sunlight rays are slanted across the land Sunlight rays are almost directly on the land Why do countries close the equator not experience much change in climate from season to season? The Earth’s surface gains most heat when the Sun is above the horizon for the most hours, and when it reaches the highest angle in the sky. This happens around JUNE 21ST in the Northern hemisphere and DECEMEBER 21ST in the Southern hemisphere. This midsummer day is called the SUMMER SOLSTICE. The WINTER SOLSTICE is when the Sun is at its lowest angle above the horizon and stays above the horizon for the fewest hours. Between the solstices there are two EQUINOX when the day length is equal to the night length. Choose the correct words from the box below to complete the diagram- June 21st March 21st and September 21st Northern Hemisphere December 21st EastSunrise West- Sunset December 21st March 21st East Sunrise September 21st Sunset Northern West June 21st Intro Questions • What happens during a solar eclipse? • Why doesn’t a solar eclipse happen every month when there’s a full moon? Eclipses 1. A solar eclipse: 2. A lunar eclipse: Your Weight on Mars • Calculate what your weight would be on Mars. • 1) Multiply your weight times 0.225 • 2) Multiply that number by 0.38 • For extra help, read pg 439 Our Solar System The Solar System is made up of… - Eight Planets - Moons orbiting planets - A large band of asteroids - Comets - The Sun (a star) Jupiter’s Red Storm Cryovolcano on Titan Acid Rain on Venus Exploration Questions • What do you think was the purpose of landing a rover on Mars? • Even if we can’t land on them, how can we get information about the outer planets? • Do you think humans will ever be able to live on another planet? Explain. Stars Formation • 1) Hydrogen atoms collide in a nebula from gravitational pull • 2) Reaction produces heat, helium atoms are formed at 18 million degrees • 3) Star expands as it heats, turning red. Helium turns into carbon atoms • 4) As it cools and releases helium, star turns white and shrinks. Vocabulary • Supernova: the bursting of a star when it is dying out • Black Hole: an intense pull of gravity from a very dense object in space • Constellation: stars that make up a pattern • Lightyear: the amount of distance light travels one full year Do Now • Read pgs 462-463 and answer the Quick Check Questions on page 463 • Work by yourself How did it all start? 29 Premise • Our universe sprang into existence as singularity around 13.7 billion years ago. • A singularity is a point where the predictable nature of physics breaks down • They are thought to exist at the core of black holes. 30 Expansion of the Universe • Observations of distant galaxies show that the light emitted from them has been shifted to longer wavelengths over time • These shifts are uniformly isotropic, distributed evenly among the observed objects in all directions. 31 Expansion of the Universe • On the left is a spectrum of the transmitted frequency of light from a star. • The right spectrum is the observed frequency of the star from Earth. • The spectral lines are observed to be shifted towards the red end. • This shows that the star is moving away from us 32 Misconceptions • A Giant Explosion/fireball • Some experts say that there was no explosion; there was (and continues to be) an expansion. • Imagine a balloon expanding: an infinitely small balloon expanding to the size of our current universe over billions of years. Balloon Expansion • According to the many experts, space didn't exist prior to the Big Bang. • The singularity didn't appear in space; rather, space began inside of the singularity. • Prior to the singularity, nothing existed, not space, time, matter, or energy - nothing. Steady State Theory According to this theory, the Universe has always existed; it had no beginning and will continue forever. Although the universe is expanding, it maintains its average density – steady-state – through the continuous creation of new matter. Most cosmologists now reject the theory because it cannot explain background radiation or the observation that the appearance of the universe changes with time. Where’s the Evidence? • The Red Shift - Galaxies far away from our home galaxy, the Milky Way appear to be ‘red shifted’. This suggests the Universe is expanding. 37