Jovian Planet Systems - Essay Example

?u05a1 Planetology Review Assignment Answer the following questions from your textbook, to continue to test your understanding of comparative planetology, including planetary atmospheres, gravitational pull, and masses. Provide additional information for your answers, as needed, to demonstrate your complete understanding and meet the criteria outlined in the Planetology Review Assignment Scoring Guide. Chapter 8, "Jovian Planet Systems," pages 254-55, review questions 2, 4, 6, 15, and 27. Chapter 9, "Asteroids, Comets, and Dwarf Planets," review questions 1, 3, 7, 20, and 33. Chapter 8, "Jovian Planet Systems," pages 254-55, review questions 2, 4, 6, 15, and 27. 2. Why is Jupiter so much more dense than Saturn? Could a planet be smaller in size than Jupiter but greater in mass? Explain. Ans: Jupiter is closer to sun and has over 3 times more than the mass of Saturn. Jupiter is denser than that of Saturn because of two factors. They are (i). Jupiter has relatively larger gravitation field because of its mass and rotational pressures. (ii). Jupiter has denser core of rocks and other minerals. Jupiter has heavy metals in its interior. Hence it is denser than that of Saturn. Yes. There could be a planet smaller in size but greater in mass than that of Jupiter. Because Jupiter is mainly made up of gas, hence any planet slightly smaller in size but made of solid material would have more mass than Jupiter. And also building a planet with Hydrogen and Helium is like assembling the fluffy pillows one over the other. As the pillows are stacked one above the other the pillows at the bottom are compressed and hence their mutual gravitational force increases. Hence it slightly increases in its height as and when the stack size is increased but gets denser. Therefore the extra mass increases the density of the planet but smaller change in mass. 4. Why does Jupiter have such a strong magnetic field? Describe a few features of Jupiter’s magnetosphere. Ans: Jupiter has a very strong magnetic field that is arises from electrical currents in the rapidly spinning metallic hydrogen interior. Jupiter’s magnetic field is 20,000 times stronger than that of Earth’s magnetic field. This strong magnetic field is generated because of the thick layer of metallic hydrogen. Jupiter’s magnetosphere traps far more charged particles than Earth’s magnetosphere. These particles contribute to auroras and also create belts of very intense radiation around Jupiter. This is so strong that it could damage the orbiting spacecraft. Jupiter’s magnetic field creates a magnetosphere that surrounds the planet as a shield which protects the planet from the solar wind. 6. Briefly describe Jupiter’s weather patterns and contrast them with those on the other jovian planets. What is the Great Red Spot? Ans: Jupiter’s atmosphere has several gases that condense to form clouds. Each of these gases condenses at a different temperature, leading to distinctive cloud layers at different altitudes. Jupiter has primarily three different cloud layers and Jupiter’s atmosphere is colder at higher altitudes. About 100 kilometers below the highest cloudtops, the temperatures are nearly earth-like And water can condense to form clouds. Higher up, the water clouds it is cold enough for a gas called ammonium hydrosulfide to condense into clouds which produces the dark colours of Jupiter. Higher still the temperature is so cold that ammonia condenses to make an upper layer of white clouds. Like the large hurricanes occasionally arise on Earth, Jupiter also has powerful storms. Spectroscopic observations (analysis of light) + calculations explains about the composition of clouds as follows: Ammonia (NH3) crystals in top layer. Ammonium hydrosulfide (NH4SH) crystals in middle layer. Water ice in lowest layer. The colors seem to be associated with temperature. White "zones" are higher and cooler. Dark "bands" are lower and warmer. Comparison with other atmosphere planets: Jupiter and Saturn have stripes of alternating color and wind direction. But Saturn's internal heat keeps temperatures same round the year and in the entire planet. Neptune's atmosphere is banded, and has a high-pressure storm, called the Great Dark Spot. Neptune has an axis tilt and it has relatively little seasonal change because of its internal heat. The heat created in Neptune's interior is released uniformly and keeps the temperature about the same year-round and planet-wide Because of large hurricanes Jupiter has powerful storms. Its storms are dwarf. There will also be the gigantic storms which are popularly known as great red spots. Surprising Discoveries? Suppose someone claimed to make the discoveries described below. (These are not real discoveries.) Decide whether each discovery should be considered reasonable or surprising. Explain clearly; not all these have definitive answers, so your explanation is more important than your chosen answer. 15. Neptune’s deep blue color is not due to methane, as previously thought, but instead is due to its surface being covered with an ocean of liquid water. Ans: This will not be a surprising discovery because Neptune is blue in color, with a few darker and lighter spots. The blue color is caused by atmospheric gases, including methane (CH4). The changing appearance of Neptune is due to its turbulent atmosphere. The winds on Neptune are stronger than on any other planet in the solar system, reaching speeds of 1,100 km/h (700 mi/h), close to the speed of sound. This extreme weather surprises, since the planet receives little energy from the Sun to power weather systems. Neptune is also one of the coldest places in the solar system. Temperatures at the top of the clouds are about –218°C (–360°F). Hence there is no chance of having the ocean of liquid water. Choose the best answer to each of the following. Explain your reasoning with one or more complete sentences. 27. Some jovian planets give off more energy than they receive because (a) fusion is taking place in their cores. (b) tidal heating is occurring. (c) they are still slowly contracting after formation. Ans: ( c ) : they are still slowly contracting after formation. Jupiter was almost twice the size of its current size, Jovian planets are contracting after formation. All the Jovian planets give off heat more than that they receive. Jupiter radiates its energy in the form of Infrared radiations, nearly twice as much as it receives from the sun. Saturn produces nearly twice the energy per unit mass. Hence we can conclude that Jovian planets give off more energy than they receive because they are slowly contracting after formation. Chapter 9, "Asteroids, Comets, and Dwarf Planets," review questions 1, 3, 7, 20, and 33. 1. Briefly explain why comets, asteroids, and meteorites are so useful in helping us understand the history of the solar system. A comet is a small solar system body that orbits the Sun. When close enough to the Sun, a comet exhibits a visible coma because of the effects of the solar radiation on the comet's nucleus. Comets nuclei are themselves the loose collections of ice, dust and small rocky particles. Asteroids are small system bodies in orbit around the sun; they are smaller than planets but larger than meteoroids. The distinction between asteroids and comets is made on visual appearance: Comets show a perceptible coma while asteroids do not. A meteorite is a natural object originating in outer space that survives an impact with the Earth's surface. While in space it is called a meteoroid. When it enters the atmosphere, impact pressure causes the body to heat up and emit light, thus forming a fireball, also known as a meteor or shooting star. The term bolide refers to either an extraterrestrial body that collides with the Earth, or to an exceptionally bright, fireball-like meteor regardless of whether it ultimately impacts the surface. These are left over debries from the early solar system, especially comets. They are made up of pre solar system material. Also, comets and astroids have not been acted upon by atmospheres that can change their chemical composition. Hence they will help us to know about the history of solar system. 3. Where is the asteroid belt located, and why? Briefly explain how orbital resonances with Jupiter have affected the asteroid belt. Ans: the asteroid belt is between Mars and Jupiter and majority of the asteroids are found in this place. During the birth of the solar system, planetesimals formed throughout the inner solar system. But the rocky planetesimals could survive only in the asteroid belt for billion years because the asteroids in the asteroid belt are clear of all the planets and therefore they can survive in their current orbit. Most of the asteroids tend to share a few particular orbital distances, leaving gaps between them and in those gaps only few asteroids will be present. The gaps in the asteroid belt are not random and they form nearly 12 year orbital period with Jupiter. The gaps occur in these places because of the orbital resonance of Jupiter. Whenever resonance arises the particles periodically line up with eachother and hence the gravity affects them. Hence the orbital period of those particles of Jupiter’s orbital period are affected by the strong Jupiter’s gravity. The repeated nudges from Jupiter pushes the asteroids out of their orbit. 7. What produces the coma and tails of a comet? What is the nucleus? Why do tails point away from the Sun? A comet is an icy small solar system body, when it is very close to the sun, displays a visible coma and sometimes a tail. Coma is a thin fuzzy, temporary atmosphere. These both phenomenons are due to the effects of solar radiation and solar wind upon the nucleus of the comet. Comet nucleus consists of loose collection of ice, dust and small rocky particles from a few hundred meters to tens of kilometers across. As a comet accelerates towards the sun, its surface temperature increases and ices gets converted into gas and easily escapes the comets weak gravity. Some of the escaping gas drags away the dust particles from the nucleus and this will create a large dusty atmosphere called coma. The coma grows as the comet continues into the inner solar system. The plasma tail consisting of the gas escaping from the coma gets ionized by the Ultraviolet rays from the sun and the solar wind carries this gas outward from the sun at very high speed. And hence the plasma tail almost directly away from the sun every time. The dust tail is made of dust particles are not affected by the solar wind and instead pushed away from the sun by much weaker pressure of sunlight itself. And therefore dust tail also points generally away from the sun. Surprising Discoveries? Consider the following hypothetical discoveries. (These are not real discoveries.) In light of what you’ve learned about the formation of our solar system, decide whether each discovery should be considered reasonable or surprising. Explain clearly; not all these have definitive answers, so your explanation is more important than your chosen answer. 20. A mission to Pluto finds that it has lakes of liquid water on its surface. In Pluto there would be lakes of liquid hydrocarbons, actually. Pluto is so cold that during its winter, the NITROGEN in its atmosphere freezes and falls to the ground as snow. Hence there might not be liquid water on the surface of Pluto. The other reason is its distance from sun. If there was water on Pluto that would mean it was receiving heat from another star or had some incredible internal heater. If it was liquid water, then Pluto must have some internal furnace. Water freezes at 32 deg. F. Pluto is like -253 degree F. Hence it is impossible to have liquid water on the surface of Pluto. Choose the best answer to each of the following. Explain your reasoning with one or more complete sentences. 33. About how often does a 1-kilometer object strike Earth? (a) every year (b) every million years (c) every billion years A meteorite with a 1km diameter will undoubtedly cause global damage. It is believed that a meterite a bit larger was responsible for the extinction of dinosaurs. Rocks this big only appears to hit Earth once every 100 million years. Celestial mechanics is the study of the motion of the celestial bodies on the basis of law of gravitation. Newton’s theory of universal gravitation resulted from experimental and observational facts. Present-day Celestial Mechanics can not be restricted to gravitational forces. There is panoply of non-gravitational forces acting on natural and artificial celestial bodies that perturb their motion in a significant way: gas drag, thermal emissions, interactions between radiation and matter, comet jets, tidal friction, etc. If the bodies have spatial extent then the gravitational force between them is calculated by summing the contributions of the notional point masses which constitute the bodies. In this way it can be shown that an object with a spherically-symmetric distribution of mass exerts the same gravitational attraction on external bodies as if all the object's mass were concentrated at point at its centre. The law of universal gravity states that Universal Gravitation’s Law (1687) – Bodies attract themselves mutually with a force proportional to their masses and inversely proportional to the square of the distance between them. Newton's law of universal gravitation states that every point mass in the universe attracts every other point mass with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. The accelerated fall of bodies to earth led Newton to assume that our planet attracted all the bodies that surround it towards its centre. Newton's genius lies in his ability to reach a general rule: the law of universal gravitation. An interesting point to remember is that, as the force of attraction between the two is mutual, both bodies move around their common centre of mass. However, when one of the astronomical objects is much greater than the other, the distance between the centre of mass and the centre of the large object is small. Eg: 1) Gravitational forces between two galaxies that are in the early stages of collision merging. Solving Newton’s laws for millions of stars and for the gas within these galaxies, we can actually make models for such phenomena that show how tidal forces are distorting these galaxies. 2) From the law of universal gravitation we can measure the weight of a planet. 3) With the advent of Newton’s theory of universal gravitation, the orbits of all the planets could be calculated to high precision and the tides can be understood. References The Essential Cosmic Perspective, 5th Edition. Addison-Wesley, 01/07/2009. Asteroids (2011) – science and technology - http://sci.esa.int/science-e/www/area/index.cfm?fareaid=13 Asteroids, Comets, and Meterorites: Their Intimate Relation with Life on Earth (2011) – by Stephen P. Broker – retrieved from http://www.yale.edu/ynhti/curriculum/units/1996/6/96.06.03.x.html - Jupiter and saturn (2011) – Wikepedia – retrieved from http://wiki.answers.com/Q/What_is_the_difference_between_Jupiter_and_Saturn#ixzz1MFr5doIT Jupiter denser than Saturn – retrieved from http://www.whycenter.com/why-is-jupiter-denser-than-saturn/ Magnetic field of Jupiter (2011) – retrieved from http://csep10.phys.utk.edu/astr161/lect/jupiter/magnetic.html Solar system magnetic field (2011) – retrieved from http://www.astronomynotes.com/solarsys/s7.htm Jupiter’s magnetic field ( 2011)- university today – retrieved from http://www.universetoday.com/15185/jupiters-magnetic-field/ Atmosphere of planets – ( 2011) Colorado education – retrieved from http://lasp.colorado.edu/education/outerplanets/giantplanets_atmospheres.php comet tail . (2011). In Encyclopedia britanica. Retrieved from http://www.britannica.com/EBchecked/topic/127558/comet-tail comets ( 2011)- retrieved from http://astrosun2.astro.cornell.edu/~pslii/astro1102/lib/chapterrev.pdf introduction to comets (2011)- retrieved from http://www.astrodrayer.com/intro-to-comets   Read More