The Law of Universal Gravitation is vital because it mathematically proves Kepler's Three Laws of Planetary Motion. The Planets follow the same laws of motion as objects on the surface of the earth. (B) Newton discovered other types of orbits that have circular of elliptical paths. However, if the velocity of an orbiting body were increased, its orbital path would change to a parabola or hyperbola and it would escape the gravitational pull of the sun. It would then leave the solar system. Parabolas are the orbital paths of objects in the form of an open curve. If one cuts out an angle in a circular cone, it would follow this path p

3) The photon energy equals the energy difference between the orbits.

Unwanted Refraction: pouring molten glass into a mold makes lenses. Air bubbles form in the lens as the liquid gas cools. The air bubbles cause, distorted images due to extra refractions.

There are five main problems with the refracting telescope:

The reflecting telescope was helpful in solving some of these problems because they use mirrors with top coated surfaces which light does not enter. Mirrors don't sag because they can easily be supported unlike heavy lenses. Since light doesn't enter the mirror, the problems of different wavelengths, chromatic aberration and opaque do not occur. However, spherical aberration can still occur because when light enters a telescope with a spherical mirror at different distances from the mirror's center, the light comes into focus at different focal lengths. One other main problem with reflecting telescopes is that they block out about ten percent of light attracted by the primary mirror. They are still the preferred telescopes to use. (B) I would build a reflecting telescope. I would want the mirror to be F/15, 800" at the most. Anything larger would not useless. I would ground, polish, shape and coat the mirror with aluminum coating. I would make the mirror concave in order to collect light to a point and then reflect it to a secondary mirror. I would turn the secondary mirror to a 45-degree angle and would build the eyepiece onto the side so that the light will come out the side.

(B) Four scientifically important parameters that can be sensed by spectroscopes attached to observational telescopes are: 1) Physical conditions of an object. 2) The chemical composition of an object. 3) Velocities of an object. 4) The lines in the spectrum of the light coming off an object can be measured.

Reflecting telescopes: Reflection refers to the use of a primary mirror to reflect the light back to a focus instead of refracting it. These telescopes use a concave (curved similar to a bowl) mirror instead of a lens. This mirror is called a primary mirror. The mirror is concave so that any line across the center of the mirror is a parabola. A parabola is an open curve formed by an object traveling a path. If a mirror has this shape, it is called a parabolic mirror, which reflects light rays to a sharp focus in front of itself. Then a second mirror reflects the rays to an eyepiece.

3 #) Four telescopic discoveries made by Galileo were: 1) Venus goes through phases similar to those of the moon. This is significant because it proved that Venus goes around the sun, supporting the heliocentric cosmogony theory. 2) Galileo discovered four moons near Jupiter, which orbit Jupiter because they move back and forth from one side of the planet to the other. These moons are significant because they prove Kepler's third law. The square of a moon's orbital period about Jupiter is proportional to the cube of its average distance from the planet. These moons are called the Galilean Moons. 3) He saw mountains on the moon, so for the first time people could have and idea of the surface of the moon. 4) He also was the first to see sunspots on the sun. This discovery proved that the sun was not perfect, contrary to popular belief at that time. It was somewhat defected by these sunspots since it was considered by many as symbol of perfection.

Some common words found in the essay are:
Doppler Effect, Unwanted Refraction, Ursae Majoris, Metius Galileo, Bohr Orbits, Galilean Moons, Motion Planets, Mons Venus, Paschen Series, Mars Mars, solar system, magnetic field, spectral lines, reflecting telescope, primary mirror, refracting telescope, reflecting telescopes, velocity star, lines called, hydrogen atom, reflecting telescope mirror, star 70 virginis, called emission spectrum, focus focal lengths, light focus focal,
Approximate Word count = 3032
Approximate Pages = 12 (250 words per page double spaced)