EARTHSPACE REVIEW Our Solar System Our complex solar

EARTH/SPACE REVIEW

Our Solar System Our complex solar system is made up of the sun, the moon, Earth, other planets and their moons, meteors, asteroids, comets, and unknown objects. Each of these bodies has its own unique characteristics and features. None of them are exactly the same.

Our Solar System Most scientists believe our solar system is about 4. 5 billion years old and that it began as a space cloud, called a nebula. The nebula was made up of bits of space dust, rocks, ice, and gas. After 100, 000 years or so, a tiny star, not yet ready to give light, began to form in the center of the nebula. This star was our Sun.

Our Solar System Scientists have organized space so we can understand how large space really is! Our Universe is everything that exists, including the Earth, the Solar System, and all the stars and galaxies. One of the most important things in the universe is gravity. It is the force that keeps the planets in motion around the sun. Gravity acts everywhere in the universe!

Our Solar System A Galaxy is a huge mass of stars, gas, and dust clouds that exist in one area of space held together by gravity. Scientists think there may be as many as 100 billion galaxies in the universe. Galaxies are larger than constellations and the solar system.

Our Solar System consists of the Sun and all the objects in space that orbit it, including the nine planets, and their moons, along with numerous comets, asteroids, and meteoroids.

The Earth and the Solar System are located in the Milky Way galaxy. The sun revolves around the Milky Way Galaxy once every 240 million years.

THE INNER AND OUTER PLANETS There are two groups of planets in our solar system, the inner planets and the outer planets.

The inner planets are closest to the Sun-Mercury, Venus, Earth, and Mars—have solid surface made of a mix of rocks, dirt, an minerals. Each of the inner planets are terrestrial, rocky, smaller, and have no rings.

The outer planets are farthest away from the Sun—Jupiter, Saturn, Uranus, and Neptune—don’t have a solid surface, they are made up mostly of gas, with a rocky core. They are all gaseous and have rings, they are also larger and known as the gas giants.

Of all the planets Saturn and Jupiter are the largest. Mercury is the closest to Earth and is the smallest.

As of 2006 Pluto was categorized as a dwarf planet. When it was first discovered in 1930, astronomers assumed Pluto was made of ice and gas because of its great distance from the Sun. However, scientists discovered Pluto was dense and has a rocky core, not gaseous as the other outer planets.

Pluto’s orbit is different from the orbits of the other planets. The larger planets travel around the Sun in an oval-shaped orbit. Pluto’s orbit is more of a stretched-out oblong. The other planet’s orbits are level with the Sun. Pluto’s is tilted. Pluto is not able to clear its orbit as the other planets so it is considered to be a dwarf planet.

ASTEROIDS Asteroids are like tiny planets, rocky or metallic objects, most of which orbit the Sun in the Asteroid Belt between Mars and Jupiter. There about 2, 000 of them! None of the asteroids have atmosphere.

Meteors, Meteorites, and Meteoroids So what is the difference between a meteor, meteorite, and a meteoroid? A meteoroid is a chunk of rock or dust in space. They usually come from comets or asteroids. When a meteoroid enters the Earth’s atmosphere it is then called a meteor. Meteors are also chunks of matter orbiting the sun in orbits that cross the planets. When meteors occasionally hit the Earth’s atmosphere, they vaporize and give off a steak of light. However, when the meteoroid passes through the atmosphere and hits the Earth’s surface it is now a meteorite.

COMETS A comet is a small, icy celestial body that orbits around the sun. It is made up of a nucleus (solid, frozen ice, gas and dust), a gaseous coma (water vapor, CO 2, and other gases) and a long tail (made of dust and ionized gases). The tail develops when the comet is near the Sun. Its long ion tail always points away from the sun, because of the force of the solar wind. The tail can be up to 250 million km long, and is most of what we see. Comets are only visible when they're near the sun in their highly eccentric orbits.

Earth is Unique

Earth is a unique rocky planet, covered with large oceans of water and has frozen ice caps in its polar regions. It has a protective atmosphere consisting of nitrogen and oxygen and has a magnetic field. The atmosphere and magnetic field help shield the earth’s surface from harmful sun radiation. Earth is the only known planet able to support life. Scientific evidence identifies that the earth is about 4. 5 billion years old!

Rotation or Revolution All of the planets revolve around the sun, and the moon revolves around the planets. Each of the planets rotates upon an axis. • The Earth completes one revolution (or orbit) around the sun every year (365 days). • The Earth completes one rotation on its axis every 24 hours.

WHAT REVOLVES AROUND WHAT?

NIGHT & DAY The earth is the 3 rd planet from the sun. It rotates on an imaginary axis and rotates once every 24 hours.

NIGHT & DAY As the earth rotates, different sides of it face toward or away from the sun. Depending on what side you are on, it is either day or night.

THE SEASONS Seasons are caused by the tilt of the earth on its axis. The angle that the sunlight strikes the earths surface creates Summer, Spring, Fall, and Winter.

EARTH’S REVOLUTION AND TILT The Earth moves around the sun in a regular curved path called an orbit. It takes 365 days or 1 year to revolve around the sun one time. The Earth is tilted on its axis. When Earth is tilted towards the sun we experience summer. The equator receives the most direct sunlight. Seasons occur because of the Earth’s tilt and revolution.

EARTH’S REVOLUTION AND TILT It is important to realize that warmer summer temperatures occur because the Sun’s rays are striking more directly, not because part of the Earth is closer to the Sun.

THE MOON PHASES Changes in the way the moon appears from Earth are called moon phases. We see the moon phases because of the sun’s light. When the moon appears to be getting larger, this is called waxing. When the moon appears to be getting smaller, this is called waning.

THE PHASES OF THE MOON

NEW MOON The new moon is the phase of the moon when the moon is not visible from Earth. This situation arises because the side of the moon that is facing us is not being lit by the sun.

WAXING CRESCENT MOON As the moon continues its orbit, a small part of it begins to reflect the sun’s light towards Earth. This sliver, or crescent, is called a waxing crescent moon. The waxing moon continues to grow larger each day until it becomes a full moon.

FIRST QUARTER MOON When the moon is half lit, it is called a first-quarter moon. This is because it is one quarter of the way through its orbit of the Earth.

WAXING GIBBOUS MOON A waxing gibbous moon occurs during days when the moon is more than half illuminated, but not fully in view. Gibbous means hump or humpback.

FULL MOON A full moon occurs when the Earth is between the moon and the sun and we can see the entire moon reflecting the sun’s light.

BLUE MOON When two full moons occur in a single month, the second full moon is called a "Blue Moon. " Another definition of the blue moon is the. BLUE third. MOON full moon that occurs in a seasontwo of the which hasinfour full moons (usually each When fullyear moons occur a single month, the second season hasisonly three full moons. ) full moon called a "Blue Moon. "

WANING GIBBOUS MOON As the moon become less full, it is called a waning gibbous moon. Waning means to get smaller. A waning gibbous moon is illuminated on the opposite side of a waxing gibbous moon.

THIRD QUARTER MOON OR LAST-QUARTER MOON After a few more days, the moon is once again half-lit. This time is is called a last quarter moon. It has gone through three-quarters of its orbit around the Earth.

WANING CRESCENT Soon, the moon is back to a crescent. This time it is called a waning crescent. Each day the sliver grows smaller and smaller until it cannot be seen at all.

NEW MOON We are now back to a new moon which again is the phase of the moon when the moon is not visible from Earth because the side of the moon that is facing us is not being lit by the sun.

LUNAR ECLIPSE The Earth is positioned between the moon and the sun, and Earth’s shadow falls on the moon because it is blocking sunlight.

SOLAR ECLIPSE The moon moves between the sun and Earth and blocks the sunlight from reaching Earth. There is only a small area on Earth that experiences a total block of sunlight during a solar eclipse.

THE SUN Our Sun is an average star. Like all stars, it is a large sphere of gas held together by gravity. When a medium- sized star like the sun used some of the gases in it’s center, it expands to become a supergiant. A stars’ color is a clue to its’ temperature. Red stars are the coolest, yellow stars are medium temperature, and whitish blue stars are the hottest.

Constellations are groups of stars that form patterns in the sky. The constellations are totally imaginary things that poets, farmers and astronomers have made up over the past 6, 000 years. The real purpose for the constellations is to help us tell which stars are which, nothing more. On a really dark night, you can see about 1000 to 1500 stars. Trying to tell which is hard. The constellations help by breaking up the sky into more manageable bits.

TIDES Tides are the periodic rising and falling of large bodies of water. Tides are caused by the gravitational interaction between the Earth and the Moon. The gravitational attraction of the moon causes the oceans to bulge out in the direction of the moon. Another bulge occurs on the opposite side, since the Earth is also being pulled toward the moon (and away from the water on the far side). Since the earth is rotating while this is happening, two high tides and low tides occur each day.

SPRING TIDES At certain times during the moon's revolution around the Earth, the direction of its gravitational attraction is aligned with the Sun's. During these times the two tide producing bodies act together to create the highest and lowest tides of the year. These spring tides occur every 14 -15 days during full and new moons.

NEAP TIDES When the gravitational pull of the moon and Sun are at right angles to each other, the daily tidal variations on the Earth are at their least. These events are called neap tides and they occur during the first and last quarter of the moon.

ASTRONOMICAL UNIT An astronomical unit, or AU, is equal to the mean (average) distance from the Earth to the Sun, which is about 92, 957, 000 miles (149, 600, 000 km).

LIGHT-YEAR A light-year is the distance that light can travel in one year in a vacuum, which is about 5, 880, 000, 000 miles or 63, 240 AU or 9. 46053 x 1012 kilometers.

ANCIENT ASTRONOMERS Copernicus Ptolemy Aristotle Galileo

ARISTOTLE Aristotle was a Greek philosopher born in 350 BC. He saw Earth’s curved shadow and concluded that Earth was round. Aristotle believed that the universe is spherical, finite, and centered around the Earth, (geocentric). Aristotle, like many others of his time, believed that the circle was the "perfect" shape, so the universe must be spherical, and all the orbits in it must also be circular. He also believed that celestial bodies were composed of either (in addition to the four other basic elements believed to exist at that time, earth, air, fire, water). Aristotle's ideas were adopted by the Church and were not tested for over a thousand years, until Galileo's experiments demonstrated errors in Aristotle's writings.

PTOLEMY Ptolemy (about 87 -150) was a Greek astronomer and mathematician who wrote about his belief that all celestial bodies revolved around the Earth, (geocentric). His writings influenced people's ideas about the universe for over a thousand years, until the Copernican System (with a heliocentric solar system) was accepted.

COPERNICUS Nicolaus Copernicus (1473 -1543) was an amateur Polish astronomer who developed the revolutionary Copernican system, a model of the solar system in which all the planets orbit the Sun, (heliocentric). His ideas overturned the old Ptolemaic System. Realizing that people are often afraid of new ideas, he shared his ideas with only a few friends. His seminal work was De Revolutionibus Orbium Coelestium ("On the Revolutions of the Celestial Orb"), published in 1543, the year he died.

GALILEO In 1609, Galileo was the first person to use a telescope to observe the skies. Galileo discovered the rings of Saturn (1610), was the first person to see the four major moons of Jupiter (1610), observed the phases of Venus, studied sunspots, and discovered many other important phenomena. In 1610, Galileo moved to Florence, Italy, where he pursued his research. After discussing and publishing the many discoveries he made using his telescope, including the confirmation that the Earth orbits the Sun, (this is called the Copernican system, heliocentric). After being warned not to discuss or publish his theory, Galileo disobeyed and published his book, "Dialogue Concerning the Two Chief World Systems. ” Galileo was put under house arrest, because he supported the view of a sun-centered universe.

ROBERT GODDARD Robert Goddard is the father of Modern Rocketry.

YURI GARGARIN The first man in space to orbit the Earth in 1961. He was Russian.

JOHN GLENN The first American to orbit the Earth in 1962.

VALENTINA TERESHKOVA First Russian Woman in Space in 1963.

NEIL ARMSTONG The first man to walk on the moon in 1969. He was American.

SALLY RIDE First American Woman in Space in 1983.

HISTORY OF SPACE EXPLORATION • Our understanding of the solar system has changed from an Earth-centered model (Aristotle and Ptolemy) to the sun-centered model (Copernicus and Galileo). • With the expansion of technology over the last half century, our knowledge of the solar system has increased substantially. • In 1958 the United States created a government agency to study space and create spin-offs to help human kind.

HISTORY OF SPACE EXPLORATION • SPUTNIK 1 - Modern space exploration began in 1957 with Soviet launch of this satellite.

HISTORY OF SPACE EXPLORATION • EXPLORER 1 -Launched in 1958, this was the first USA satellite. It discovered the Van Allen Radiation belt.

HISTORY OF SPACE EXPLORATION • MERCURY PROGRAM - Sent the first Americans into space in 1961.

HISTORY OF SPACE EXPLORATION • PROJECT APOLLO - Landed 12 humans on the moon between 1969 and 1972.

HISTORY OF SPACE EXPLORATION • Skylab-The first USA space station launched in 1973. It paved the way for the International Space Station.

HISTORY OF SPACE EXPLORATION • VOYAGER SPACE PROBES - Sent back pictures of Jupiter, Saturn, and Neptune. A space probe is a robot vehicle used to explore deep space.

HISTORY OF SPACE EXPLORATION • VIKING 1 AND 2 - Landed on Mars in 1976 and sent back data about the planet's soil and atmosphere.

HISTORY OF SPACE EXPLORATION • PIONEER PROBES - Used instruments to see through the thick clouds that cover Venus.

HISTORY OF SPACE EXPLORATION • SPACE SHUTTLES – Launched in 1981 and retired in 2011. A reusable space shuttle use to carry materials to space to create the International Space Station and launch the Hubble Telescope.

HISTORY OF SPACE EXPLORATION • HUBBLE SPACE TELESCOPE - Launched in 1990, it produces images five times as sharp as those from any telescope on Earth

HISTORY OF SPACE EXPLORATION CURIOSITY Mars Rover launched in 2011 to look for signs of life on Mars.

HISTORY OF SPACE EXPLORATION International Space Station Launched in 1998. A space station to create a research platform in space to advance our knowledge of space, to conduct experiments, and test new technologies.

CREDITS PICTURES ARE FROM THESE LINKS. . . • • • http: //www. 1 stclasswallpapers. com/computer_and_internet-mac_os_x_leopard_space_wallpaper. html http: //lopezotero 72. files. wordpress. com/2009/01/moon_phases 1. jpg http: //fc 05. deviantart. com/fs 26/f/2008/153/9/f/Day_And_Night_by_Ravenx. Corpse. jpg http: //fc 00. deviantart. net/fs 30/f/2008/090/2/a/4_seasons_by_vxside. jpg http: //www. success. co. il/knowledge/images/Pillar 4 -Space-and-Earth-Solar-System-Montage-NASA. jpg http: //files. myopera. com/phamlythanh/albums/637848/Space%20 Art%20 Wallpapers%2026. jpg • http: //www. google. com/imgres? imgurl=http: //www. free-widescreen-wallpaper. com • http: //www. dohosurf. org/images/earth. gif Good Luck on you Science SOL.