Reason The Planets Orbit The Sun example essay topic

Physical data of planets in the solar system Types of orbit of artificial satellites around Earth Movements and orbits of planets and moons are determined by gravitational forces How the solar system was formed About meteors and meteorites Physical data of the planets in the Solar System Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Pluto mean distance from Sun (Earth = 1) 0.387 0.723 1 1.524 5.203 9.539 19.19 30.061 39.529 time taken to orbit Sun (years) 0.24 0.62 1 1.88 11.86 29.46 84.01 164.79 248.54 equatorial radius (km) 2439 6052 6378 3397 71490 60268 25559 25269 1160 mass of planet (Earth = 1) 0.06 0.82 1 0.11 317.89 95.18 14.53 17.14 0.002 number of observed satellites 0 0 1 2 16 18 15 8 1 There are different types of orbit of satellites around Earth The moon orbits Earth in the same way that the nine planets orbit the Sun. When space engineers make artificial satellites, they can decide on which type of orbit the satellite will need to do it's job. They can pick an orbit that goes around Earth's equator, or one that goes over Earth's North and South Poles... or anything in between. They can pick a low-altitude orbit of just a few hundred miles above Earth's surface or one that is thousands of miles out in space.

The two Geostationary Operational Environmental Satellite weather satellite, have the job of keeping an eye on the weather over North America. They need to "never take their eyes off" any developing situation, such as tropical storms brewing in the Atlantic Ocean, or storm fronts moving across the Pacific Ocean toward the west coast of America. Therefore, they are "parked" in what is called a geostationary orbit. They orbit exactly over Earth's equator and make one orbit per day.

Thus, since Earth rotates once on its axis per day, the satellite seems to hover over the same spot on Earth all the time. On the other hand, satellites whose job is to make maps or study all different parts of Earth's surface need an orbit that comes as close to passing over the North and South Poles as possible. This way, Earth turns under the satellite's orbit and Earth does most of the work of travelling! Also, the satellite should be close to Earth's surface (a few hundred miles up) to get a good view with its imaging and measuring instruments. The lower the satellite's orbit, the less time it takes to make one trip around Earth, and the faster it must go.

That's why a geostationary orbit must be so high. It has to go out far enough so that it can travel slowly enough to go around Earth only once per day. At the equator, Earth itself is rotating from west to east at 1041 miles per hour. If the satellite is launched in the same direction as Earth is rotating, it gets quite a boost. If it is launched toward the north or south, it doesn't get to take advantage of this boost. Or, if the satellite is launched toward the east, it takes a lot of fuel in the spacecraft's thrusters to change the inclination, or tilt, of its orbit.

A polar orbit has a high inclination. The movements and orbits of planets and moons are determined by gravitational forces All planets in the Solar System orbit the Sun. A planet orbiting the Sun is like the moon or a NASA satellite orbiting Earth. The lighter object always orbits the heavier one, and the Sun is by far the heaviest object in the solar system.

The Sun is 1000 times heavier than the largest planet, Jupiter and it is more than 300,000 times heavier than Earth. Issac Newton realized that the reason the planets orbit the Sun is related to why objects fall to Earth when we drop them. The Sun's gravity pulls on the planets, just as Earth's gravity pulls down anything that is not held up by some other force and keeps you and me on the ground. Heavier objects produce a bigger gravitational pull than lighter ones, so as the heavyweight in our solar system, the Sun exerts the strongest gravitational pull.

The Solar System was formed around 4.6 billion years ago Scientists believe that the solar system was formed when a cloud of gas and dust in space was disturbed, maybe by the explosion of a nearby star (a supernova). This explosion made waves in space, which squeezed the cloud of gas and dust. This squeezing made the cloud start to collapse and as gravity pulled the gas and dust together it formed a solar nebula. The cloud began to spin as it collapsed. Eventually, the cloud grew hotter and denser in the centre, with a disk of gas and dust surrounding it that was hot in the centre but cool at the edges. As the disk got thinner and thinner, particles began to stick together and form clumps.

Some clumps got bigger as particles and small clumps stuck to them, eventually forming planets or moons. Near the centre of the cloud, where planets like Earth formed, only rocky material could stand the great heat. Icy matter settled in the outer regions of the disk along with rocky material, where the giant planets like Jupiter formed. As the cloud continued to fall in, the centre eventually got so hot that it became a star, the Sun, and blew most of the gas and dust of the new solar system with a strong stellar wind. By studying meteorites, which are thought to be left over from this early phase of the solar system, scientists have found that the solar system is about 4,600 million years old! About meteors and meteorites A meteor is a bright streak of light in the sky (a "shooting star" or a "falling star") produced by the entry of a small meteoroid into the Earth's atmosphere.

On a clear night you can see around three per hour. Meteorites are bits of the solar system that have fallen to the Earth. Most of these meteorites come from asteroids. A very large number of meteoroids enter the Earth's atmosphere each day amounting to more than a hundred tons of material. But they are almost all very small, just a few milligrams each. Meteoroids larger than a few hundred tons can make craters in the Earth's surface.