History
Long ago Greeks thought everything revolved around the Earth. But in 1543 Copernicus said we orbit the sun. (Asimov, 2005)
Gallileo first used a telescope in 1609. (Silverstein, et al., 2003)
And then there was the space race between the US and the Soviet Union.
The USSR (the Russsians) sent Sputnik. They also sent Yuri Gagarin to orbit the Earth. Then a year later John Glenn was the first American to orbit the earth. On July 20th, 1969, Neil Armstrong stepped on the moon. (Silverstein, et al., 2003). The last time we were on the moon was December 1972 (Arnett, 2005 )
Since then NASA has sent many probes and to explore other planets and sectors of the universe. We also now have an International Space Station orbiting the earth as well as the Hubble Telescope. Since the telescope is orbiting the earth and there is no atmosphere in the way, the Hubble can take amazing pictures of space.
Moon
“The asymmetric nature of this gravitational interaction is also responsible for the fact that the Moon rotates synchronously, i.e. it is locked in phase with its orbit so that the same side is always facing toward the Earth.” (Arnett, 2005 para. 7)
Seasons, diff in N and S
Gravitational mass
Everything has a gravitational pull. Larger objects have more pull. (Silverstein, et al., 2003)This means that the sun pulls the planets (including earth) and planets pull objects like t he moon and asteroids. When an object is caught in the pull of an object it often goes into orbit.
Telescopes
Compare sizes
The sun is HUGE! Its mass is “745 times greater than that of all the planets in the solar system combined” (Silverstein, et al., 2003 p. 14).
Planets: (Silverstein, et al., 2003)
inner=Mercury, Venus, Earth, Mars, outer=Jupiter, Saturn, Uranus, Neptune….and Pluto is no longer a planet.
Mercury has no atmostphere to trap rays and heat so sky is always dark
Venus is very bright because the sun’s rays reflect off its thick clouds
Earth only one that can support life because of oxygen in atmosphere. Only planet where water can be both liquid and solid.
Moon. The sun’s rays refledt off the moon. The moon also has gravitational pull, it pulls back and the water goes back and forth, tides.
Mars. Red. A lot like Earth with valleys and mountains
Jupiter is also huge. 1,000+ earths could fit inside it. Very gaseous. It even used to be bitter. It keeps shrinking. Jupiter has four moons. Called Galilean moons because Gallilleo discovered them. One named Io and Europa. (Silverstein, et al., 2003)
Saturn has visible rings with a telescope, 30 moons, gas surface. Spin very fast, like Jupiter. Saturn is really light. It would float on water. (Silverstein, et al., 2003)
Uranus was discovered by Herschel in 1781 with a telescope he made himself (Silverstein, et al., 2003). It has methane gas. It spins differently. It spins on its side
Neptune is windy! Very cold. Moon called Triton is covered with ice. -391 degrees Fahrenheit
Pluto is smaller than earth’s moon. It has a moon named Charon. Pluto is not really a planet.
Rotation=day. Different for everyplanet. Earth 24 hours. Jpiter takes 10 hours. Venus takes 243 Earth days.
Compare distances
Space is so big that we measure distances in light-years. A light-year is the time it takes for light to travel there in a year. Light travesl at 186,000 miles per second and in a year almost six million million miles. In numbers this would read 6,000,000,000,000 miles. (Rey, 1982 p. 14)”
Solar systems, galaxies, universe
Our solar system is in a galaxy called the Milky Way. There are several stars and solar systems in a galaxy and several galaxies in the universe. (Silverstein, et al., 2003) The closest large galaxy to us is the Andromeda Galaxyit is 3 million light years away from us. (Asimov, 2005).
The universe is expanding
Constellations
There are pictures in the sky made out of stars. They are called constellations. Some constellations are circumpolar: that means they stick around the North or South poles. For example the big dipper is circumpolar. It is always near Pollaris. Other constellations like Scorpious and Capricorn are part of the Zodiac. This means they change with the seasons instead of circling the poles.
Navigation and calendar
Asteroids: rocks going around the asteroid belt. Our atmostphere acts like a shield to asteroids and they burn up.
Meteroroids Objects before they reach Earth’s atmosphere.
Metoers if they burn up in the atmosphere
Metoritesif they reach the surface of earth (Silverstein, et al., 2003)
Comets are not rock. They are ice and dust and snow. They heat up and the ice turnsinto a hot gas and this makes the tail (Silverstein, et al., 2003)
Stars
Thanks to Doppler, we learned that stars that are comeing toward us appear more blue while stars going away appear more red. (Asimov, 2005)
Stars are born in nebulas. Nebulas are huge clouds of dust and gas. A lot of this is pulled together by gravity and then the hydrogens smash together. A star then must keep burning the hydrogen. The hydrogen supply eventually gets low and runs out and during this time the star expands to be a red giant. Red giants are cooler on the outside and a lot hotter on the inside. Then the star’s core is so hot it starts burning helium. Slowly the outer layer of the star fades away and the core shrinks own to a white dwarf. After time the wite dwarf becomes a black dwarf, which no longer gives light. (Silverstein, et al., 2003)
There are certain stars that are so big they are called supergiants They burn carbon and oxygen and burn everything until they have a very heavy core of mostly iron. The gravity is so strong in the core that the star collapses on it’s self. This triggers a massive explosion and then a supernova is produced. (Silverstein, et al., 2003)
If the supernova is relatively small it forms a pulsar. This is also called a neutron star. It spins fast and sends out pulses of radio waves. If the supernova is relatively large, the core collapses and it forms a black hole. (Silverstein, et al., 2003)
Arnett, Bill. 2005 . Nine Planets. The Moon. [Online] Apr 20, 2005 . [Cited: Nov 20, 2008.]
Asimov, Isaac. 2005.The Birth of Our Universe. Milwaukee, WI: Gareth Stevens Publishing, 2005.
Rey, H. A. 1982.Find the Constellations. New York: Houghton Mifflin Company, 1982.
Silverstein, Alvin, Silverstein, Virginia and Silverstein Nunn, Laura. 2003.The Universe. Brookfield, Connecticut: Twenty-first Century Books, 2003.