Assignment 6

What is the Hubble Space Telescope?

Fig. 5 Hubbles Orbit [5]

Travelling at eight kilometres per second, five hundred and seventy kilometres above sea level [3], the legendary Hubble Space Telescope soars overhead once every hour and a half [1]. This one and a half billion dollar (at launch) scientific marvel was the first of its kind [3], a telescope mounted in the fabric of space, high above the ionosphere [1]. The uniqueness and placement of the Hubble Space Telescope are ultimately due to its base purpose, to see past the light distortions caused by Earth's atmosphere. These distortions consisted of too many variables to manually and individually address, from twinkling lights caused by shifting air pockets to the dampening of ultraviolet, gamma rays and X-rays as they passed through the atmosphere. Naturally, an easy solution to all of these problems was to place a telescope in space beyond Earth's protective veil [7].

The Hubble Space Telescope is a type of telescope known as a Cassegrain reflector [1]. Essentially, this means that it is fundamentally composed of 2 mirrors, a primary and a secondary. Light reflected off the primary mirror is funnelled by the secondary mirror, and focused through a doughnut hole in the primary mirror. This focusing of light causes an incredible increase in light collection and therefore exposure, creating a much clearer, brighter image [8]. Interestingly, the distortions caused by the atmosphere are so significant that even though Hubble's primary mirror was significantly downsized (due to budget issues) to two meters and forty centimetres, the images it produces outclass the competition by far. This is even more surprising in a relative sense, when considering that at its size, Hubble's primary mirror is only about twenty five percent the size of a mirror in a ground telescope [1].

Fig. 4 Hubble Inner Workings [4]

Not only is Hubble an imposing one of a kind telescope, it is also a high functioning space observatory. The hundred and twenty gigabytes of  data collected by Hubble per week [3] is analyzed by the treasure trove of scientific instruments it carries and is then transmitted via antennae to the Goddard Space Flight Centre. There the information is compiled and forwarded to the Space Telescope Science Institute to be consolidated, organized and then stored for safe keeping [1]. The brain of Hubble is controlled by two separate computers, and much like the left and right hemispheres of the human brain, they control separate functions. One computer controls the fundamental systems of the observatory including positioning the telescope; receiving satellite signals with instructions from Md. Engineers, while the other handles all of the scientific instruments [7]. 

Hubble History: 

Fig. 6 Hermann Obeth [6]

The first recorded instance of a proposal for a space telescope occurred over a half century before the launch of Hubble. In 1923,Hermann Obeth suggested in his book titled "Die Rakete Zu Den Planetraumen", that it would be possible to blast a telescope into space on a rocket. Due to technological restrictions this idea would be cast aside, not to be taken seriously again until just over two decades later [4]. Lyman Spitzer Jr. was the one who reignited the torch. He submitted a proposal for a space observatory in 1946, the space observatory that would eventually become known as Hubble. Over the next twenty three years Spitzer Jr. worked tirelessly, trying to convince NASA that the space telescope would be of insurmountable usefulness and finally, in 1969 the Large Space Telescope project was born [6].

Soon the intrigue of the Space Telescope spread to other nations and by 1975 the European Space Association began to collaborate with NASA on the Large Space Telescope. Not surprisingly, with the interest building, less than two years later Congress approved funding for the project [1]. With the project now in full swing there were many important decisions to be made. The Marshall and Goddard Space Flight Centres and Perkin-Elmer Corporation were chosen for their expertise to over see various tasks involved in Hubble's completion. As already mentioned, the Goddard Space Flight Centre was to deal with the transmission of Hubble's valuable data upon completion. Prior to launch they were also responsible for the design of the many scientific instruments aboard the observatory including the Wide Field and Planetary Camera, the High Speed Photometer, the Faint Object Spectrograph, the Faint Object Camera and the Goddard High Resolution Spectrograph. The design for the actual telescope however fell on the shoulders of Marshall Space Flight Centre  and their completed plans were sent to Perkin-Elmer Corporation for construction [6].

With construction underway, efforts were refocused on other preparations that needed to be made and by 1979, six years before the completion of the telescope, they began training astronauts for the upcoming missions [1]. In 1981 the primary mirror had been completed and four years later, Hubble was born [4]. Excitement soaring and tensions rising, Hubble was set to launch early 1986, all eyes were on the sky. Unfortunately, tragedy struck in the form of the Charger shuttle explosion; a space shuttle burst while lifting off causing a panic. All missions were to be grounded and the launch for Hubble was delayed [6]. Thankfully, order returned within just a few months and Hubble was carried into orbit by the shuttle Discovery before the years end [3]. 

Fig. 7 Charge Explosion [7]

The excitement of Hubble's successful launch would be short lived, for once the first photos returned by Hubble were collected they were found to be far too blurry; they were still an improvement over previous images, but were a far cry from expectations [1]. Through various calculations scientists realised that Hubble's primary mirror had a tiny, almost indiscernible flaw that was causing an unintentional bend in light, creating distortions in the images. In essence, the flaw in Hubble's main mirror was that it was too flat by roughly one fiftieth of a hair. Since the flaw in the mirror was so small, and an error in missing volume there was no good way to directly repair the mirror and replacing the entire mirror in space was infeasible. Instead, scientists calculated the placement of several smaller mirrors that would be placed inside Hubble to redirect the distorted light [2]. The next several years were dedicated to preparations for Hubble's first service mission; the parameters of which were extended to include upgrading the High Speed Photometer to the COSTAR as well as the Wide Field and Planetary Camera to the Wide Field and Planetary Camera 2 [1].

On December 2, 1993, after almost a year of harsh training,  an elite team was sent up to perform repairs on Hubble, its first service mission. This was one of the most important space missions of all time, for not only was it a very technical task on an incredibly expensive and fragile piece of equipment, but it was also the first real test of whether or not telescope repairs in space would be viable. The renovations on Hubble took place over the next seven days, over which the repairs and upgrades were completed in addition to some minor maintenance and replacing perishable parts [1]. Luckily, all of the tasks performed by the service team went without a hitch and all of Hubble's images thereafter were clear as a "crisp spring morning".

Over then next two decades Hubble would receive three more service missions as well as numerous operations extensions. In 1997 service mission two was launched, installing new instruments on board the observatory [4] as well as extending its life from 2005 to 2010 [2]. Service mission three was split into two trips, one in 1999 to fully overhaul Hubble's systems and one in 2002 simply to install instruments once again [4]. Hubble's fourth service mission was scheduled for 2006, but much like its launch, was delayed by another space shuttle explosion, the Columbia disaster [1] and would not occur for another three years. Finally, in 2009, Hubble was serviced for the last time, adding new instruments and performing final maintenance checkups [4]. This last mission maxed Hubble's lifetime to last until 2014 [1].

After two and a half decades of service, Hubble is reaching the end of its days. Its parts have slowly but surely degraded and aged, making them more difficult to and less worth replacing. Originally, Hubble had been planned to be retrieved, but now it will be left in orbit until it completely loses functionality and plummets back to Earth or is thrown into the dark depths of space [1]. Finally, once Hubble's usefulness is completely expired it will be replaced by the James Webb Space Telescope [9].

Achievements and Importance:

The ultimate power of Hubble's sight is not the images that it takes, but the vast expanse of accessable information it provides. Anyone can request time on the telescope and if approved by a comittee of proffessionals, have a year to collect and organise as much information as possible. Once a year is up the information is published to the public and becomes accessable to anyone [1]. Ironically, but not surprisingly time on the famed Space Telescope is hard to come by and only about twenty percent of proposals and selected [1].

Among the over ten thousand documents published based on Hubble information [1] some note worthy examples are:

• Discovering two moons of Pluto [5]
• discovered that gamma ray bursts were caused by incredibly massive stars collapsing in on themseleves when they no longer have the critical density to remain stable [1]. 
• increased the accuracy of the estimate for the age of the universe by a significant amount by measuring the pulsing of Cepheid variable stars [5]

Below are three of Hubble's most prominant images:

In Fig. 1 below is a massive galaxy, so massive in fact that many astronomers did not believe it could exist. They did not believe a galaxy could have formed so completely in such a short time. Not only is it incredibly massive, it is increidbly old as well, dating back to almost eleven billion years of age, brinking on the dawn of the universe. This "grand-design" spiral galaxy is the oldest galaxy ever discovered and would not have been seen without the Space Telescope. [12] 

Fig. 1 "Grand-Design" spiral galaxy [1]

Fig. 3 Hubble Deep Field Section [3

Fig. 2 Mixing Galaxies [2]

Depicted in Fig. 2 is a glimpse into our far future. Milllions of years from now the Milky Way and the Andromeda Galaxy will collide [10]. The swirling mass in the image below are the galaxies NGC 7714 and NGC7715. Passing close enough to eachother, their respective massive gravities began to affect eachotehr greatly. One day this glorious view will beam across our very own horizions and this may be the only real glimpse of it this generation will ever see [13].

In Fig. 3 is a portion of the famous Hubble Deep Field. This is one of the largest and most important images ever take by Hubble. In it, over a thousand five hundred galaxies can be seen, of densly various types. This has lend to a much greater understanding of the formation of galaxies through camparing the images of galaxies at different ages [14].

Works Cited:

1. http://hubblesite.org/the_telescope/hubble_essentials/ 
2. http://www.aerospaceguide.net/spacehistory/hubble-history.html
3. http://content.time.com/time/photogallery/0,29307,1897016,00.html
4. http://www.spacetelescope.org/about/history/
5. http://www.space.com/15892-hubble-space-telescope.html
6. http://www.nasa.gov/mission_pages/hubble/story/the_story.html
7. http://en.wikipedia.org/wiki/Hubble_Space_Telescope
8. http://www.britannica.com/EBchecked/topic/98119/Cassegrain-reflector
9. http://www.jwst.nasa.gov/
10. http://en.wikipedia.org/wiki/Andromeda%E2%80%93Milky_Way_collision
11. http://www.space.com/15947-milky-andromeda-galaxies-collision-simulated-video.html
12. http://io9.com/5927315/hubble-has-spotted-an-ancient-galaxy-that-shouldnt-exist
13. http://www.space.com/28583-galaxy-merger-hubble-telescope-photo.html
14. http://en.wikipedia.org/wiki/Hubble_Deep_Field#/media/File:HDF_extracts_showing_many_galaxies.jpg

Figures:

1. http://i.kinja-img.com/gawker-media/image/upload/s--n4NKplLg--/c_fit,fl_progressive,q_80,w_636/17tatwtoiu44djpg.jpg
2. https://blogger.googleusercontent.com/img/proxy/AVvXsEgwHTS3JW5Mnp1fveFMkZNqzX8tAcnrXHODC1tSKQmjMcCI5Xe6iJ49hfMmFQzlDYcAhdB2FUFtYkkhIwFqDPZnlTa_d2858iPu-xe4Z7wcL1Km1kvoVJx0b0C_BOoP9BCgRa8fN28dZFtTI-BEA3G4GlJbU7Hos9-1bd8b2gRCiXd5Ag=
3. http://upload.wikimedia.org/wikipedia/commons/0/03/HDF_extracts_showing_many_galaxies.jpg
4. https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEig-CZ89MpdLpXs43w5_pkcEPTG5QVoxMujMnqGEjnczuWPIUoZXkEgVQ7jDHs29b0WthWlZzK30KQBS9S4tInhl6zAoLi2UBA9iWQbaALZEY5fh-0s7TMEhZFtTSEv0B5NYi48BW0UBO1n/?imgmax=800
5. http://amazing-space.stsci.edu/news/archive/2008/03/graphics/hst_orbitposition.jpg
6. http://upload.wikimedia.org/wikipedia/commons/c/cc/Photo_of_Hermann_Oberth_-_GPN-2003-00099.jpg
7. http://vignette3.wikia.nocookie.net/ethics/images/f/fe/Challenger-disaster-myths-explosion_31734_600x450.jpg/revision/latest?cb=20130129201106

Assignment 5

Biography:

Fig.1 Alexander Friedmann

Alexander Alexandrovich Friedmann of Saint Petersburg, Russia   was born in the year 1888 [1]. Interestingly, Friedmann's date of birth, the 16th of June is often misstated as the 29th. This is due in part to Friedmann's incorrect conversion from an old Russian numbering style to a newer one, listing his birthday as the 17th. Furthermore, not knowing it had already been converted once, it was once again converted to the 29th [2]. Regardless of day, Friedmann was born to a family of performers; his father Alexander was a ballet dancer and his mother, Ludmila, a musician [1] He did not stay with them long however, as they divorced when Friedmann was only 9 years old and was taken into the custody of his soon to be remarried father [2].   

Following a relatively ordinary childhood, Friedmann enrolled in highschool at the Second St. Petersburg Gymnasium in 1897. There his brilliance would become apparent as he quickly blossomed from his shell of normality and it was not long before Friedmann was gunning for the top spot against his soon-to-be best friend Yakov Tamarkin. Then in 1905, astonishingly Friedmann and Tamarkin submitted a paper on Bernoulli numbers for publication. A year later the paper was published and  Friedmann and Tamarkin both began college life at the University of St. Petersburg [2]. By this point in time, Friedmann and Tamarkin were inseparable, working, studying and even striking together and eventually, upon meeting Paul Ehrenfest, they became the only two mathematicians to join Ehrenfest's Modern Physics Seminar group. There they discussed relativity, quantum theory and statistical analysis with Ehrenfest and a number of other younger physicists [1]. Throughout the course of his undergraduate studies in mathematics, Friedmann was heavily influenced by physicists such as Vladimir Steklov and Ehrenfest; this pushed him towards an interest in applied mathematics, particularly aeronautics. 

Fig. 2 Yakov Tamarkin, Vladimir Steklov and Paul Ehrenfest

After graduating in 1911, Friedmann immediately went on to attend graduate school for a masters in mathematics. This would prove to be a productive year for Friedmann; not only did he publish an article on the aeronautic contributions of Zhukovsky and Chaplygin, but he also joined an academic group, with Tamarkin, that studied the applied mathematics and analysis of mechanics [2]. Throughout the course of his masters degree, Friedmann continued to expand his areas of research, spreading from mathematics to aeronautics to the mechanics of fluids and meteorology [1] and as if he was not busy enough, he also lectured at the Mining Institute and Railway Engineering Institute [2]. Even with his varied research and massive workload, Friedmann concluded his masters degree in under two years and after graduating, was assigned a position with the Aerological Observatory in Pavlovsk. Surprisingly, given his more mathematical background, out of the topics he had researched at the university he was at the Observatory to study meteorology.

Fig. 3 Russian WWI Bomber

Later that same year, Friedmann joined the Russian air force predominantly for his mathematical prowess and physics knowledge, however he was also trained to be a bomber pilot [1]. Unfortunately war broke out all over Europe the following year, the first World War. Initially, Friedmann continued his efforts in meteorology, and sought out its most prominant mind, Vilhelm Bjerknes, but as the war stretched on with no end in sight, Friedmann decided to contribute directly to the war effort. Friedmann worked in the field, putting his mathematical skills and physics knowledge to the test. As a bomber, his goal was to mathematically model the trajectory a bomb would taken under variable conditions. He worked on his model furiously, writing letters to his cohort Steklov, from his days at the University of Saint Petersburg and was eventually successful in accurately modeling the bomber attack on the city of Przemysl [2]. At the end of 1915, Friedmann left field work and began instructing, he taught pilots about aerodynamics along with his discoveries in trajectory modeling. He was so successful with this that less than a year later he was promoted to head of the Central Aeronautical Station. Friedmann's time in this position was not to last though, for the Central Aeronautical Station was shutdown in 1917 post Russian Revolution [1].

After the end of the war in 1918, Friedmann accepted a professorship at Perm University, where he studied theoretical mechanics, but left abruptly two years later when civil war broke out [1]. He ended up taking a position at the Main Geophysical Observatory [2]. While working at the observatory, Friedmann crossed paths with Einstein's General Theory of Relativity and was instantly enthralled; another two years later he produced a solution to Einstein's equations that supported a dynamic universe [1]. This was groundbreaking, but also incredibly controversial, up to this point the vast majority of the physics community believed in the static unchanging universe. Einstein himself, even altered his equations in 1917 with a cosmological constant to force them to work with a static universe model [3]. Friedmann eagerly shared his finding with Einstein, who was naturally skeptical. At the first sight of Friedmann's idea, Einstein was off put, describing the work as "suspicious" and replied to Friedmann with his criticisms. Friedmann however, was not to be discouraged, he immediately sent Einstein a copy of all of his work on the matter urging him to look through it. After a careful half year long review Einstein admitted that the results were all correct, but was still an adamant believer in the static universe, stating that Friedmann's results were not descriptive of reality, similar to how Copernicus' model of the solar system was stated to be a tool [2]. Due to Einsteins critique as well as the fact that Friedmann only published in Russian, he received minimal recognition for his idea [3].

Friedmann completed his Master's dissertation on compressable fluids in 1922 and in 1924 he published a paper on his three Friedmann Models of the Universe, expanding models that fell in line with his solution to Einsteins equations [2]. He was unable to finish his work, for a year later Friedmann died from typhoid fever at the young age of 37 [1].

 Friedmann's Solutions to Einsteins Equations and the Friedmann Models of the Universe:

One of Friedmann's specialisations, and the topic of his Master's degree was the mechanics of fluids. As a natural extension to this, Friedmann viewed the whole universe much like a vast expansive fluid. He envisioned the universe as an even distribution of "universe-ness", that any two random pieces of the universe (at a large enough scale) should be basically indistinguishable. Under this belief and applying his mathematical knowledge of fluids, in conjunction with Einsteins equations, Friedmann was able to create the general form of a dynamic universe as a solution to said equations. Unfortunately, he was missing some vital information involving the properties of this so called "universe-ness", he could envision the universe as a fluid, but there was no way to determine the pressure or density of this mystery fluid [4]. With this lack of information, his general solution proposed three possible types of dynamic universe that fit the model. 

Fig. 4 Geometry of the Universe

1.  A Flat Universe: this is the most intuitive type of universe, and the type that most people probably envision when thinking about the universe. In this model, the curvature of space is nonexistent and its maximum expansion is infinite, however it's rate of expansion tends to zero [5]. In other words, this is a sheet-like universe that experiences constant, decelerating expansion. Eventually this model would be debunked, as it is known that the expansion is accelerating.
2.  A Closed Universe: this type of universe is akin to blowing up and deflating a balloon repeatedly. It has spherical (positive) curvature and expands out to a maximum and then shrinks back down to an infinitesimally small point [5]. This is also one of the current theories of the end of the universe, a cyclical universe that is continually destroyed and recreated. 
3. An Open Universe: this type of universe has hyperbolic (negative) curvature and is the hardest to imagines. It can be thought of as the shape of a hyperbolic saddle furthermore, all that is known about the expansion of this kind of universe if that it is always nonzero and will converge to some unknown constant [5]. 

George Gamow, Student of Friedmann:


George Gamow was a Russian physicist and cosmologist who was born in 1904. He was a student to Friedmann and would go on to help continue Friedmann's legacy by contributing to George Lemaitres Big Bang Theory, which was one of two competing theories spawned from Friedmann's ideas. He specialized in radioactive decay and would eventually defect from Russia to move to America [6].

His work with the Big Bang Theory was truly exceptional, beginning with his assumption of the "hot universe", that the universe in its youth was incredibly hot. From there, he applied Friedmann and Lemaitres theories of the expanding universe as well as his speciality in radiation to make groundbreaking discoveries in the formation of the universe [6]. 


Works Cited:

1. http://www.physicsoftheuniverse.com/scientists_friedmann.html
2. http://www-history.mcs.st-and.ac.uk/Biographies/Friedmann.html
3. http://www.decodedscience.com/alexander-friedmann-unsung-hero-of-modern-cosmology/19423
4. http://www.brighthub.com/science/space/articles/79590.aspx
5. http://www.einsteins-theory-of-relativity-4engineers.com/friedmann-equation.html
6. http://en.wikipedia.org/wiki/George_Gamow

Figures:

1. http://upload.wikimedia.org/wikipedia/commons/c/ca/Alexander_Friedman.png
2. http://apprendre-math.info/history/photos/Tamarkin.jpeg and http://upload.wikimedia.org/wikipedia/commons/thumb/b/b9/Steklov.jpg/220px-Steklov.jpg and http://upload.wikimedia.org/wikipedia/commons/8/8a/Paul_Ehrenfest.jpg
3. http://www.wio.ru/ww1a/gal/im_e.jpg
4. http://map.gsfc.nasa.gov/media/030639/030639_2_320.jpg

Assignment 4: The Changing Pluto

Pluto is a small celestial body known as a dwarf planet. Its diameter is roughly 20 percent of Earth's and its mass only 2 one thousandths [4]. Not only is Pluto small compared to the Earth, but it is also smaller than a number of moons in our Solar System, including Ganymede and Europa [8]. Given that its orbital distance is quite far relative to the solar system, at 39.3 AU and its general lack of atmosphere, Pluto is also incredibly cold. At minus 230 degrees Celsius, Pluto's surface temperature is only about 40 Kelvin above absolute zero, the coldest possible temperature [4].

Fig. 3: Interior of Pluto

Although Pluto usually does not have much of an atmosphere, it grows much more substantial as Pluto moves towards its perihelion [5], and across its path, it experiences changes in apparent brightness ranging from about 15-13.5 on the magnitude scale [6]. As far as composition goes, spectroscopy reveals that Pluto's icy surface is comprised predominantly of nitrogen, which freezes under the immense cold [7]. Underneath Pluto's frozen skin, lies its core of solid rock [5], furthermore, estimates involving Pluto's density place the ratio of rock to ice between 1:1 and 3:7. In other words the rocky components of Pluto contribute to over half of its mass; under the [reasonable] assumption that the majority of the rock is contained in the core. This suggests that Pluto has a substantially large rocky core, with a thinner icy surface [7]. Though it is the only dwarf planet to have ever been considered a planet, Pluto may not be the largest celestial object of its kind in our Solar System, Eris is a close contender, so close in fact that our current technologies cannot determine which is larger [4]. It is known however, that Eris is more massive than Pluto by almost 30 percent [9].

Fig. 4: Percival Lowell

The discovery of Pluto began with the discovery of Neptune. By observing the perturbations in the orbit of Uranus, an astronomer by the name of Urbain Le Verrier was able to mathematically predict the existence of Neptune; his prediction was incredibly accurate, placing Neptune within one degree of its exact location. Using his prediction, astronomers managed to finally observe the planet less than a year after Le Verrier's final prediction [10]. This idea of using perturbations to find a planet sparked a sudden interest in the astronomical community. Many individuals began searching for another planet who's gravity was acting on Neptune and Uranus, at the time, this mystery planet was dubbed "Planet-X" [11]. It was not until 1906 that any significant progress in this idea would be made, at which point a man named Percival Lowell initiated the search for "Planet-X" that would eventually lead to its discovery. Using a 23 cm telescope, Lowell managed to plot several probable locations for Pluto. Though he never managed to successfully identify it, a photograph containing Pluto was taken at his observatory nearly 15 years before it was observed by the man credited with its discovery [12]. 

Fig. 5: Tracking Perturbations in Orbits

Fig. 1: Clyde Tombaugh

The actual discovery of Pluto is credited to an avid stargazer by the name of Clyde Tombaugh. Born to a family of farmers in 1906, Illinois, Tombaugh grew up in relative poverty. Though unable to afford a formal higher education, Tombaugh studied rigorously on his own and used his finely honed knowledge of geometry to build his first telescope at the age of 20 [1]. Dissatisfied with his own initial handiwork, as well as the available telescopes on the market, Tombaugh continued to improve his designs. Eventually, his work with telescopes would bear him much fruit; notably, the 23 cm reflector telescope he built in 1928 got him his job at the Lowell Observatory [2]. He had based his design for the telescope on the details listed in an issue of Popular Astronomy, that

Fig. 2: Tombaugh's 1928 Telescope

being said, Tombaugh was not just hired for his design, he was hired for his observations with his telescopes. While working at the observatory, Tombaugh would accomplish much, his first major breakthrough being the discovery of Pluto. Using a telescope almost 50% larger than his design in 1928, he tracked the motion of celestial bodies [3], and in 1930, discovered the ex-ninth planet near one of the locations predicted by Lowell [12].  The next 5 years would be eventful for Tombaugh, during that time he began his formal university education in astronomy at the University of Kansas and married his wife Patricia Edson. By 1939, Tombaugh had graduated with both his bachelors and masters degrees in astronomy from UofK and had two children with Patricia, all the while working on and off with the observatory [2]. Tombaugh spent  nearly the next entire decade after his graduation noting down the motions of over 30,000 celestial bodies as his last contribution to the Lowell Observatory, after which he decided to travel to New Mexico [3]. Tombaugh spent the rest of his working days at the State University there, teaching lectures and raising funding for students, he died in the comfort of his own home after 9 decades of life [1].

At the time of its discovery, Pluto was believed to be a planet with mass approximately equivalent to that of Earth, however, this belief was founded solely on the perturbations of Neptune's and Uranus' orbit [13]. Once Charon, a moon of Pluto, was discovered by James Christy in 1978 [upon noticing a bulge towards one side of a photo of Pluto] [17], more precise measurements of Pluto's mass could be made by observing Charon's orbit [18].

Fig. 6: Discovery of Charon

Fig. 7: Orbit of Charon

These new calculations yielded a surprising result, that Pluto's mass was over 500 times smaller than astronomers initially believed [4]. This new discovery began to instigate doubt among many, as to whether Pluto should be considered a planet at all, and ensured that Pluto could not be the cause of the perturbations in Uranus' orbit [13]. Then, in 2006 Pluto was officially demoted from the rank of planet due to the fact that it failed to possess one of the three defining properties of planets as proposed by the International Astronomical Union; that every planet must orbit the sun, have enough mass to gain a spherical shape and have enough gravitational influence to absorb all competitive bodies in its vicinity. It is clear that Pluto satisfies the first two of these requirements, earning it the title of dwarf planet, as it is spherical and orbits the sun, however Pluto is not massive enough to gravitationally overpower its similarly sized neighbors and as such, cannot be considered a planet [14].


Among these similarly sized neighbors to Pluto, are the Plutinos, objects belonging to the Kuiper belt at a very specific location in space. All Plutinos have an orbital distance roughly equivalent to Pluto's, in addition to a whole number

Fig. 5: Kuiper Belt

resonance with Neptune [15], and are named as such because Pluto was the first Plutino. Some other notable Plutinos are Orcus and Ixion, as they rank among the brightest of currently known Plutinos [16]. Ultimately, Plutnios differ from Pluto and other Plutoids, bodies similar to Pluto, in orbital motion and size, with Pluto having a 3:2 resonance with Neptune while other Plutinos  have resonances ranging from 3:2 to 2:1 [19]. Furthermore, Plutoids (other than Pluto) tend to be smaller than Pluto by quite a bit and are even occasionally thrown out of resonance under the influence of Pluto's gravity [15].



Works Cited:

1. http://www.achievement.org/autodoc/page/tom0bio-1 
2. http://www.space.com/19824-clyde-tombaugh.html
3. http://www.britannica.com/EBchecked/topic/598927/Clyde-W-Tombaugh
4. http://space-facts.com/pluto/
5. http://solarsystem.nasa.gov/planets/profile.cfm?Object=Pluto
6. http://nssdc.gsfc.nasa.gov/planetary/factsheet/plutofact.html
7. http://www.space.com/43-pluto-the-ninth-planet-that-was-a-dwarf.html
8. http://www.mikebrownsplanets.com/2010/11/how-big-is-pluto-anyway.html 
9. http://en.wikipedia.org/wiki/Eris_%28dwarf_planet%29 
10. http://www.universetoday.com/21621/who-discovered-neptune/
11. http://en.wikipedia.org/wiki/Pluto#cite_note-Tombaugh1946-40 
12. http://en.wikipedia.org/wiki/Percival_Lowell#Pluto
13. http://en.wikipedia.org/wiki/Pluto#Demise_of_Planet_X
14. http://www.loc.gov/rr/scitech/mysteries/pluto.html
15. http://scienceworld.wolfram.com/astronomy/Plutino.html
16. http://en.wikipedia.org/wiki/Plutino
17. http://jameschristy.weebly.com/james-w-christy.html
18. http://lasp.colorado.edu/~bagenal/1010/SESSIONS/17.PlutoCharon.html
19. http://cseligman.com/text/planets/plutoid.htm

Figures: 

1. http://www.achievement.org/achievers/tom0/photos/tom0-006a.gif
2. http://upload.wikimedia.org/wikipedia/commons/4/43/ClydeTombaugh2.gif 
3. http://www2.astro.psu.edu/users/niel/astro1/slideshows/class39/035-pluto-interior.jpg 
4. http://media.web.britannica.com/eb-media/63/133163-004-13A32A74.jpg 
5. http://i.space.com/images/i/000/018/506/i02/kuiper-belt.jpg?1339696229
6. https://solarsystem.nasa.gov/multimedia/gallery/Charon_Disc.jpg
7. http://spaceplace.nasa.gov/review/ice-dwarf/pluto_orbit.en.gif