Pluto: A Planet?
Many issues have arisen from the debate whether or not Pluto is a planet. Some astronomers say that Pluto should be classified as a “minor planet” due to its size, physical characteristics, and other factors. On the other hand, some astronomers defend Pluto’s planet status, citing several key features.
Indeed, most of the problem is that there is no formal definition of a planet. Furthermore, it is very difficult to invent one that would allow the solar system to contain all nine planets. I suggest that for an object to be classified as a planet, it must embody three characteristics. It must be in orbit around a star (thus removing the larger satellites from contention), it must be too small to generate heat by nuclear fusion (so dwarf stars are excluded) and it must be massive enough to have collapsed to a more or less spherical shape (which excludes comets, and most of the asteroids). These criteria would admit a few of the larger asteroids and probably some of the Kuiper belt objects as well, but adding a requirement for a planet to have a minimum diameter of 1,000 km would remove the larger asteroids from contention while retaining Pluto.
Below are some brief reasons as to why Pluto may not be considered a planet with my rebuttal.
Pluto is small compared to the other planets.
Pluto is about half the size of the next smallest planet, Mercury. However, there is no scientific reason whatsoever to pick the size of Mercury as being the size of the smallest object to be called a planet. Mercury itself is less than half the size of Mars, and Mars is only about half the size of Earth or Venus. Earth and Venus are only about one-seventh the size of Jupiter. Why not pick one-tenth the size of Jupiter as the size of the smallest planet, if the cutoff is going to be chosen arbitrarily? In that case, Mars, Mercury and Pluto would all have to be classified as asteroids. If the size-cutoff between asteroids and planets is going to be randomly chosen, the cutoff value should be agreed upon in open debate among interested scientists.
Pluto is smaller than 7 moons in the solar system.
Pluto is smaller than Earth's Moon, Jupiter's moons Io, Europa, Ganymede, and Callisto, Saturn's moon Titan, and Neptune's moon Triton. On the other hand, Pluto is larger than the other 40 known moons in the solar system. There is no scientific reason to arbitrarily dis...
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...Willem J. Luyten
Science, New Series, Vol. 123, No. 3203. (May 18, 1956), pp. 896-897.
Stable URL: http://links.jstor.org/sici?sici=0036-8075%2819560817%293%3A124%3A3216%3C322%3ATPP%3E2.0.CO%3B2-L
This site is very reliable. It is the Scholarly Journal Archive.
2. Letters
The Planet Pluto
Gerard P. Kuiper
Science, New Series, Vol. 124, No. 3216. (Aug. 17, 1956), p. 322.
Stable URL: http://links.jstor.org/sici?sici=0036-8075%2819560817%293%3A124%3A3216%3C322%3ATPP%3E2.0.CO%3B2-L
This site is very reliable. It is the Scholarly Journal Archive.
3. Research News
Planetary Scientists are Seeing the Unseeable
Richard A. Kerr
Science, New Series, Vol. 235, No. 4784. (Jan. 2, 1987), pp. 29-31.
Stable URL: http://links.jstor.org/sici?sici=0036-8075%2819870102%293%3A235%3A4784%3C29%3APSASTU%3E2.0.CO%3B2-L
This site is very reliable. It is the Scholarly Journal Archive.
4. This is a site about Pluto. http://dosxx.colorado.edu/plutohome.html It is reliable since it is a part of an established academic institution.
5. This is the NASA page for Pluto. http://pds.jpl.nasa.gov/planets/welcome/pluto.htm
6. Another site from NASA. http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/pluto.html
It was at first thought to be bigger than Pluto later it ended up being somewhat smaller than Pluto. Eris finishes one rotation around the Sun in 580 years. Eris is the reason why Pluto’s planetary status was changed to being a dwarf planet. The Kuiper Belt has a section called Classic Kuiper Belt. This is the busiest area of this belt and is situated at a distance of around 42 to 48 AU. In the beginning, when the solar system was created gas, dust and rocks, came together to form planets. Most of the debris was swept away by gravitational pull for those planets, but some debris survived because they were far enough away to not be affected by the gravitational pull for those planets. Finding the Kuiper Belt gave us more insight into the mystery of the objects located in the Kuiper belt. Most KBO’s are so far away that their measurements cannot be concretely calculated. By using the data collected by the Spitzer space Telescope most of the KBO’s have known sizes. In 2015 the New Horizon Spacecraft flew past Pluto for an up close exploration of the Kuiper Belt Objects. The primary real expectation of the Kuiper belt's presence, most planetary researchers now agree, originated from Uruguayan cosmologist Julio
The majority of people have a very basic understanding of Earth, the planet we reside in, let alone the seven other planets in our solar system. The eight planets surrounding our star, the Sun, are separated into two very simple categories: Jovian and Terrestrial Planets. Throughout this paper, I will be explaining the basic structure and properties of the eight planets in our solar system, along with a brief history on the discovery of our solar system and what’s to come in the future. I will also go in depth into the difference between the Jovian Planets and the Terrestrial Planets, from the basic differences to the different structures and properties.
Saturn, one of the four gas planets in the solar system, is no doubt the most mysterious. The puzzling questions about this extraordinary planet has had scientists wondering and researching since it was first discovered. Now that NASA has sent missions to Saturn, we are starting to understand more and more. Saturn is a unique planet because of its magnificent size, its rare atmosphere, and several rings unlike any other planet.
To date Uranus has been found to have 21 satellites four of which have yet to be named and 11 rings.
Zimmerman, Kim. "Callisto: Facts about Jupiter's Dead Moon." Space.com. N.p., 5 July 2013. Web. 24 Feb. 2014
Now that Pluto is no longer included, how many planets are there left in the Solar System?
Although Pluto was discovered in 1930, limited information on the distant planet delayed a realistic understanding of its characteristics. Today Pluto remains the only planet that has not been visited by a spacecraft, yet an increasing amount of information is unfolding about this peculiar planet. The uniqueness of Pluto's orbit, rotational relationship with its satellite, spin axis, and light variations all give the planet a certain appeal.
Uranus is so far away that scientists knew comparatively little about it before NASA's Voyager 2 undertook its historic first encounter with the planet. The spacecraft flew closely past distant Uranus, and came within 81,500 kilometers (50,600 miles) of Uranus's cloudtops on Jan. 24, 1986. Voyager 2 radioed thousands of images and mass amounts of other scientific data about Uranus, its moons, rings, atmosphere, interior and magnetic environment. However, while Voyager has revealed much about the gas giant, many questions remain to be answered.
When I was a child, I vividly remembered an anime series called Sailor Moon. The plot revolved around nine superheroes who were named after the nine planets of the solar system. As a child, I could recall the theme song of the series, which begins with “She is the one named Sailor, Sailor Venus, Sailor Mercury, Sailor Mars, Sailor Jupiter,...She is the one named Sailor Moon.” One day, my sister came up to me and told me that Pluto was no longer a planet. When she told me I could not believe my ears, they took out Pluto from the solar system. Recalling the moment that Pluto was removed as planet, I questioned what criteria decided the removal of it from the solar system. At the same time, these changes are made by scientists who believe it does
The quest for classification of Pluto carried on as Neil deGrasse Tyson collaborated with various other leading figures who debated the validity of classifying Pluto as a planet. “The Pluto Files” documented Tyson’s trip across the country to meet with correspondents who both agreed in denouncing Pluto as a planet and those who quite strongly opposed. It all started in the planetary museum in which the model of the solar system did not include Pluto. Instead, it took a trip downstairs to find the model of the Kuiper Belt where Pluto is categorized and shown as a small dot amongst a sprinkling of others. This lack of Pluto caused an uproar of which Tyson was not expecting, and which he willingly chose to speak out against. His meeting with other
There are many interesting facts about the planets. They are classified in two different categories, which is either a Terrestrial Planet or a Gas Giant. Take Mercury for example, it is one of the terrestrial planets in the Solar System. Also, Mercury may contain ice, it slowly rotates around the Sun so it exposes all of it sides to the Sun’s strong rays, so it’s hard to visualize whether the ice remains solid. Mars has various aspects of its own; some scientists discovered that this planet has water upon its surface. This discovery was encountered by the NASA’s spacecraft Odyssey.
Perhaps one of the most interesting features of our fathomless universe are the planets that are classified as gas giants. Huge, turbulent, and distant, the gas giants are some of the most enigmatic features in our Solar System. I have a personal interest to the gas giants and celestial bodies in general. When I was a child, I was fascinated by our Solar System. I read innumerable books about space, and my interests of outer space had been piqued further by other forms of media. Although I held this interest of space, growing up left me with little time to learn about space, and I lost interest for a while. Taking Earth Science in Milpitas High re-invigorated my interests in the celestial bodies. Using this class, I’m now able to focus on learning more about our colossal universe, in particular, the outer planets.
"The Sun L Sun Facts and Images." The Nine Planets Solar System Tour. Web. 28 Nov. 2011.
Our solar system has eight planets, their moons and satellites, and they are all orbiting the Sun. The eight planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Pluto used to be the ninth planet but IAU changed the definition of planet and Pluto did not meet the standards so it is now a Dwarf planet.
Pluto has a radius of 1184km while Mercury, the smallest current planet, has a radius of 2440km. This appears to be a huge difference, but they are quite close in size when it is taken into consideration that Jupiter has a radius of 64911km. [3] The fact that Mercury is considered to be a planet, but Pluto is considered to small is a result of the fact that planets are generally thought to be large objects, but no official size requirement has ever been defined. The fact is that any definition based on size will be arbitrary, so the problem exists of picking a cutoff. Tim DeBenedictis proposes a very reasonable solution to this problem. He proposes that we set the cutoff for planetary size at 1000km. [3] This is as arbitrary as any other number, but picking 1000km has benefits. Firstly, this fits well with the fact that we use base 10 in mathematics. This also makes the number of planets 10 with Pluto and Eris being added to the eight that we currently have. This results in a reasonable and concrete limit on the size of