FINAL EXAM ESSAY 1 EARTH IN SPACE

A)Our knowledge of Earths location in the universe has been shaped by 400 years of telescopic observations, and has expanded radically in the last century. Initially, Earth was believed to be the center of the universe, which consisted only of those planets visible with the eye and an outlying sphere of stars. After the acceptance of the heliocentric mofdel in the 17th century observations by william h.and others showed that Earth's Sun lay within a vast, disc-shaped galaxy of stars, later revealed to be suns like our own. By the 20th century, observations of nebula revealed that our galaxy was only one of billions in an growing universe grouped into clusters and superclusters. By the 21 centuary the structure of the visible universe was becoming clearer. Superclusters, filaments and voids are likely the largest coherent structures that exist in the Universe. At still larger scales over 1000 megaparsecs the Universe becomes homogeneous meaning that all its parts have on average the same density, composition and structure.
Since there is believed to be no "center" or "edge" of the universe, there is no particular reference point with which to plot the overall location of the Earth in the universe. It is still undetermined whether the universe is infinate and there is speculation that our universe.
(1)http://en.wikipedia.org/wiki/Earth's_location_in_the_universe

 
 B) Motion. The galaxy is moving away from us, this is known as the Doppler effect. The same effect can be detected in sound. When a police car is speeding towards us the sound waves made by its siren are 'squashed' and the pitch sounds higher. As it passes us and starts to move away the sound waves are 'stretched' and the pitch sounds lower. In the 1920's Edwin Hubble observed that all galaxies (apart from a few local ones attracted towards our own and showing blueshift) show red shift. This indicates that the galaxies are all flying away from us, as in a Big Bang explosion. Expansion of the universe. Einstein's famous equations show that the universe should be expanding, not because the galaxies were moving through space, but because the 'empty' space between them (spacetime) is expanding. This cosmological redshift results because the light from the distant galaxies is stretched by the amount that space expands while the light is en route to us. This also reveals that the Earth is not at the centre of the universe with all the galaxies moving away from us, but that due to the expansion of the universe, all the galaxies are moving away from each other, like painted dots on a balloon moving apart as it is inflated. Gravity. This is also explained by Einstein's general theory. Light moving outwards from a star is moving 'uphill' in the star's gravitational field, and loses energy as a result. Because light cannot slow down - it always travels at the same speed - when it loses energy its wavelength increases, in other words, it is redshifted. It does however, require a very powerful gravitational field for this effect to be measurable, such as created by a white dwarf star.
(2) http://www.thekeyboard.org.uk/The%20Big%20Bang%20Theory.htm



C) Measurements by the WMPA satellite can help resolve this crisis. then the detailed structure of the cosmic microwaves will depend on the current density of the universe, the composition of the universe and its expansion rate. WMAP has been able to determine these parameterswith an accuracy of better than than 3% of the critical density. How does WMAP data enable us to determine the age of the universe is 13.7 billion years you may ask? with an uncertainty of 1% The key to this is that by knowing the composition of matter and energy density in the universe, we can use Einstein's General Relativity to compute how fast the universe has been expanding in the past. With that information, we can turn the clock back and determine when the universe had "zero" size, according to Einstein. The time between then and now is the age of the universe. There is one caveat to keep in mind that affects the certainty of the age determination: we assume that the universe is flat, which is well supported by WMAP and other data.

http://www.theresilientearth.com/files/images/cosmic_rays_hit_earth.jpg

(3) http://map.gsfc.nasa.gov/universe/uni_age.html

BIB
(1)
URL- http://en.wikipedia.org/wiki/Earth's_location_in_the_universe
Date updated- 10/16/10
Title-Earths location in the universe
Company- wikipedia

(2)
URL-http://www.thekeyboard.org.uk/The%20Big%20Bang%20Theory.htm
Date updated- 5/13/07
Title- The Big Bang Theory
Company-
(3)
URL- http://map.gsfc.nasa.gov/universe/uni_age.html
Date updated- 7/19/10
Title- WMAP
Company-  NASA 

FINAL EXAM ESSAY 2 THE SUN

THE SUN
A)Solar flares -Scientific research has shown that the phenomenon of magnetic reconnection is responsible for solar flares. Magnetic reconnection is the name given to the rearrangement of magnetic lines of force when two oppositely directed magnetic fields are brought together. This rearrangement is accompanied with a sudden release of energy stored in the original oppositely directed fields.
On the Sun, magnetic reconnection may happen on solar arcades – a series of closely occurring loops of magnetic lines of force. These lines of force quickly reconnect into a low arcade of loops leaving a helix of magnetic field unconnected to the rest of the arcade. The sudden release of energy in this reconnection causes the solar flare. The unconnected magnetic helical field and the material that it contains may violently expand outwards forming a coronal mass ejection.
This also explains why solar flares typically erupt from what are known as the active regions on the Sun where magnetic fields are much stronger on an average.
  http://dailypostal.com/wp-content/uploads/2010/08/solar-flare.jpg
B) Satellite solar outages occur because the Sun which is a powerful broadband microwave noise source passes directly behind the satellite when viewed from Earth and the receiver with the beam directed towards the satellite picks up both the satellite signal and the noise from the Sun.

The degree of interference caused by a satellite solar outage varies from slight signal degradation to complete loss of signal as the down link is swamped by the noise from the Sun. Parameters such as the antenna directivity can make large differences to the amount of time of the solar outage. Antennas with a very wide beamwidth could be affected for as much as half an hour, whereas antennas with higher gain and directivity levels as are more commonly used for satellite reception will be affected for much shorter periods of time. Typically only a few minutes.The effect of the solar noise causing the outage is very marked. Even at times of low solar activity, the effect is very noticeable and can result in noise levels of between 10 and 20 dB above the signals from transponders, dependent upon a host of factors.

 

(1) http://www.radio-electronics.com/info/satellite/solar-effects/sun-solar-outages-basics-tutorial.php

C)

Due to the large amounts of energy released in a supernova explosion, much higher temperatures are reached than stellar temperatures. These higher temperatures allow for an environment where elements up to the atomic mass of 254 are formed, californium being the heaviest known, though it is seen only as a synthetic element on earth. the maximum weight for an element fused is that of iron, reaching an isotope with an atomic mass of 56. Fusion of elements between silicon and iron occurs only in the largest of stars, which end as supernova explosions.

 

BIBS
(1)
URL-http://www.radio-electronics.com/info/satellite/solar-effects/sun-solar-outages-basics-tutorial.php
date updated-
Title- solar outrage
Company- radio electronics
(2)
URL-http://en.wikipedia.org/wiki/Supernova_nucleosynthesis
Date updated- 11/1/10
Title-Supernova
Company- wikipedia

Bad Astronomy Blog

Watching the movie I said that when the astronaut was blinded by the sun it was factual. After looking it up on the Bad Astronomy website I learned that Phil Plait disaggred with me becasue although he didn't know how close the comet actually was to the sun, he said that n.a.s.a. would have given them built in visors or built in a u.v. block to their visors. They did have sun visors the astonaut was just in panic so he couldn't get it over his face in time therefore I disagree wiht Phil. Phil also believes that it is wrong that the sun blinded him becasuse he was only loooking at it for a few seconds but I think it easily would have blinded him considering they seemed to be very close to the sun and he is looking directly into the sun. Also while watching the movie I believed that the comet would have caused a huge wave of water when it landed in the ocean. Phil agreed with me that it would have caused a big wave but he disagrees that the water would have compleatly receded from the beach to be drawn up into the wave. Also the water would have been traveling faster than sound so we wouldn't have heard the huge wave.
I believed that it was wrong for the commet to be making any sound and Phil agreed with me that you have to have a medium for sound to occur and space is a vacum, therefore there would be no sound.
Lastly while watching the movie I believed it was false that the commet weighed 500 billion tons and Phil agrred with me. He says that the commet woul have actually weighed about 1,000 trillion tons!

Misconceptions:
Bad Moon Rising - Can you see the moon during the day?
I think that the moon is ushually on the opisite side of the world when it is day time here wich would explain why we cant see it durning the day. but when its a new moon i think we can see it on our side of the earth because when its a new moon for us the moon is not up? so thats my connection to it.
after reading I was wrong. The moon is always up during the day you just have to know where to look to find it. so i guess its not just when there is a new moon.
The sky at Night - Do all starts look white?
when i look up at the sky i see white tints and orange tints. But when i squezz my eye shut and leave it cracked i can see diffrent colors. After reading I learned that all stars emit all of the colors of the rainbow. He says the best way to find out is to look at the stars in the summertime and look directly above at the brightest stars (Vega and Antares) which will clearly be blue and red orange.
A Step Farther Out - What's your sign? Astrology and the zodiac.
I know that my sign is scorpio because my birthday is in november. There are also 11 other sign for the other months. After reading I learned that there are more than just 11 constellations. There are between 13 and 24, because soom are for rare ecasions and what not, so feel special if u have one of thoose.