Types Of Probation And Parole Essay Example for Free

Types Of Probation And Parole Essay Probation and parole are two different types of community amendment originally developed to tone down severe punishment for those who committed crimes or disobeyed the state’s rules and norms, though not visible in some countries or states. Probation is a procedure wherein the offender remains under the court’s supervision for certain period of time with a set of guidelines to avoid jail or prison, while parole is a time period after a person is released from jail or prison while under supervision. [1] The practice of the two community correction was the result of opposing beliefs of philosophers, classicalists, and positivists. Classicalists believe that when a person committed crime, he is responsible for his actions and therefore must be punished. On the other hand, positivists believe that the offenders have reasons that forced him to do such acts and deserve a chance to make himself better. Between 1841 and 1859, John Augustus insisted the practice of giving a temporary release for prisoners while serving the community as a lift in their sentence. The guiding philosophy of probation is rehabilitation. Augustus undoubtedly stated, It became pretty generally known that my labors were upon the ground of reform, that I confined my efforts mainly to those who were indicted for their first offence, and whose hearts were not wholly depraved, but gave promise of better things . . .[2]Augustus’ efforts were favored. A French word â€Å"parol† literally means â€Å"word of honor† as used by the prisoners of war when they take an oath of never to engage again in the warfare if released. In some states during 1938, parole, as a conditional pardon, was already practiced. The first recorded official practice of an early release of a convict was during the time of Samuel Howe. It was favored because of the problem in overcrowding in prison increased.[3] In Tennessee, a board of probation and parole, an independent State Commission composed of seven members appointed by the governor, decides whether the offender will be granted the privilege of a conditional release or if he will remain in prison[4]. The factors that parole board considers in granting parole are public safety, age, mental stability, marital status, educational background, repentance, time served, criminal records, level of severity of the offense, actions, rehabilitative efforts, and conduct while incarcerated.[5] A parole is a privilege and not a right, the possibility of denying a parole will happen when the parole board finds that: One, there is a great risk for the defendant to defy the conditions of the release program; secondly, if granting of the release will cause decrease in practicing of the crime that the offender is guilty of or it will promote disrespect for the law; next is if it will have an unpleasant effect on institutional discipline; and lastly, if the release will effective for the enhancement of the convict’s capacity to live a law-abiding life.[6] A prosecutor and a judge decide for probation requests. When under probation or parole the requirements include obey all laws of the society, report change of employment or address to probation officers, refrain from using drugs or alcohol, undergo random several drug tests, and limit traveling unless permitted by a probation officer.[7] States differ in the time span of probation and parole depending on the offense and behavior of the offender. Probation has a maximum of sixty months or five years while parole can be lifetime supervision if a person is paroled because of a murder case or given a penalty of a life sentence.[8] In California, there are two types of probation, the formal probation and the informal probation. In formal probation, the defendant is scheduled, usually once a month, to meet with the assigned probation officer for a regular report. In informal probation, scheduled meetings are not necessary but the defendant must complete the terms of sentence and should not be engaged in trouble. The defendant’s sentence may take account of different sanctions such as community service like cleaning public places, medical and educational mission programs of the government; counseling or rehabilitation, several unannounced drug testing, paying of required fines and penalties based on financial status of the offender and the intensity of the crime committed, reimbursement to the victim, and even house confinement under monitor or imprisonment. [9] Intensive supervised probation is a form of release wherein the offender undergoes a close monitoring and strict conditions. Individuals on ISP are those who have committed serious crimes like for an example murder. They are given excessive restrictions including regular meeting with the officers for reports because of the belief that these will discourage, or at least meddle, any possible criminal acts that is ongoing. Shock probation is another form in which the offender is initially sentenced with imprisonment.   After being brought before a judge after thirty, sixty or ninety days, his sentence is lifted into probation. In split sentence, the sentence of the offender includes imprisonment and probation. Appearing before a judge is also not required. The person will be jailed first, and then will undergo probation. Split sentence and shock probation are often used interchangeably.[10] If the convicted person violated his probation or parole, the possible sanctions are: increase in the level of supervision or imposing more strict regulations, house arrest with close monitoring, revocation of probation or parole, or jail confinement.[11] How can probation be violated? The most common violation includes the following situations: a person under probation or parole is required to pay fines and restitution as reimbursement to the victim, if he failed to do so a violation is committed; failure to complete required programs such as rehabilitation and community service; he is required to attend required court appearance for a progress report and not appearing is also a form of violation; defying of rules like when he is limited to visit some persons or travel into places but then he still insists; failure to attend on scheduled reports to a probation officer; changing his identity, employment, or other status conditions without reporting it to the officers; possession of illegal substances for instance drugs, alcohols or weapons; and lastly engaging in new crimes for he is required to stay out of trouble to avoid new offenses that may lead to revocation of the privilege. The judge and the prosecutor reflect on many factors in considering a probation violation. These includes: the nature and seriousness of the probation violation; the records of the offender in committing violations; the unlawful activity close to the probation violation; justifying conditions of violating the probation; the officer’s view of the violation whether he sees the violation as a big deal or something that can be dealt with; and the time when the violation is committed whether it happened in the beginning, middle or the end of the probation term or period.[12] In case of a serious violation, a parole violation hearing is required. It will be composed of the parolee, the probation officer and a board of selected individuals. Lawyers are excluded in the hearing. In a probation violation hearing, the defendant is allowed to seek help from his lawyer to represent him in the court. In case of a minor violation, sometimes, it can be dealt with the probation officer and no need to take the case in the court, which will just include some verbal warnings.[13] Probation and parole are just temporary release and if technical violations, like failure to follow the parole or probation conditions, or new offense, like performing another criminal act, are committed during the period of supervision, then the privilege can be revoked. Probation revocation is initiated by the probation officer. The defendant will be sent with a notification letter of the alleged violation, and then will undergo a preliminary hearing at which a legal authority will decide whether the evidence and claims are acceptable to pursue the hearing, if warranted; the revocation process will take place. During revocation trials, probationers are permitted to state under oath in their own behalf and have witnesses and lawyers at hand. The proofs that are presented in the revocation hearing are not as standard as of the usual criminal hearings, usually, simple evidence are enough. The possible decisions of the hearing, if found guilty, may include return to supervision, notice with re-establishment to supervision, or jail time. The revocation of parole is almost similar to probation; the difference is that probation is administrated by judicial decisions while the other is through administrative measures.   When arrest warrants are issued, the officers are empowered to take custody of the parolee with the maximum time of forty-eight hours. This happens when the offender is found to be a great threat to the community like when he is committing more severe crimes such as murder, rape, burglary and many others. However, when alleged of violation, a parolee has the right to receive a written notice before the revocation proceeding. He is also allowed to verify accusations of violating parole as well as the right to explain himself whether the evidences presented are correct and reliable that will prove that the violation actually happened. He may confront and interrogate petitioners. He should also receive a written explanation for the decisions concerning the revocation of the parole and what evidence was presented and considered in the outcome of the case. [14] Here are some statistical reports in probation and parole cases according to United States of America’s Department of Justice: At the end of the year 2005, over 4.9 million adults were under Federal, State, or local probation or parole authority; more or less 4.2 million on probation and eight hundred thousand on parole. There was a 0.06% increase in the population of probationers and parolees –an increase of thirty thousand during the year which is greater than a fifth of the average annual increase of 2.8% since 1995. There are twenty-three percent and twelve percent women in the nation’s population of probationers and parolees, respectively. Adults on probation are composed of fifty-five percent white, thirty percent black and thirteen percent Hispanic while those on parole have forty-one percent white, forty percent black, and eighteen percent Hispanic. Convicts released from prison because of parole board decision dropped to thirty-one percent from fifty percent in 2005, while compulsory discharge based on a constitutional prerequisite turn into fifty-one from a previous record of forty-five percent. Since 1995 to 2005, forty-five percent of the parolees completed their terms and conditions while thirty-eight percent were returned to jail, and eleven percent of them escaped. As of 2001, fifteen US states and the federal government had abolished parole programs[15]. Even with probation and parole programs, the number of offenders is still increasing. Law-breakers are everywhere and the governments of different states and countries never stop in seeking for the resolution for this problem. Aside from probation and parole, petitions for pardons and a death penalty charge has been passed to the government and is being implemented to some states and countries. But then, overcrowding in jail or prison is still the greatest challenge to the correctional institution.[16] Probation and parole are both implemented so that an offender may still have the chance to live in the community, though under supervision but at least free from the cold bars of jail, while still paying for the crime that he committed proving he is capable of obeying the law and abiding the society’s norms. As Augustus said, every person has the right for second chances. Not because an individual made a mistake once, he should be punished for the rest of his life. The driving force that pushed him to do such criminal acts should be changed and rehabilitated to prevent more serious crimes in the future.   But before a privilege is granted, everything must first undergo the legal process. References: Law Library-American Law and Legal information::Crime and Justice Vol.3 retrieved July 2, 2007 from http://law.jrank.org/pages/1817/Probation-Parole-History-Goals-Decision-Making-Origins-probation-parole.html Encyclopedia of Everyday Law retrieved July 3, 2007 from http://law.enotes.com/everyday-law-encyclopedia/probation-and-parole http://www2.state.tn.us/bopp/bopp_faq.htm http://www.legalmatch.com/law-library/article/parole-and-probation.html http://www.hmichaelsteinberg.com/probationparole.htm http://www.michigan.gov/corrections/0,1607,7-119-1435,00.html Stephen Rodriguez and Associates. http://www.probationviolationattorney.com/ U.S. Department of Justice  Ã‚ ·Ã‚  Office of Justice Programs Bureau of Justice Statistics http://www.ojp.usdoj.gov/bjs/pandp.htm [1] http://www.legalmatch.com/law-library/article/parole-and-probation.html [2] http://law.jrank.org/pages/1817/Probation-Parole-History-Goals-Decision-Making-Origins-probation-parole.html [3] http://law.enotes.com/everyday-law-encyclopedia/probation-and-parole [4] http://www2.state.tn.us/bopp/bopp_faq.htm [5] http://www.legalmatch.com/law-library/article/parole-and-probation.html [6] http://www.hmichaelsteinberg.com/probationparole.htm [7] http://www.legalmatch.com/law-library/article/parole-and-probation.html [8] http://www.hmichaelsteinberg.com/probationparole.htm [9] Law Library-American Law and Legal information::Crime and Justice Vol.3 retrieved July 2, 2007 from http://law.jrank.org/pages/1817/Probation-Parole-History-Goals-Decision-Making-Origins-probation-parole.html [10] http://law.enotes.com/everyday-law-encyclopedia/probation-and-parole [11] Encyclopedia of Everyday Law retrieved July 3, 2007 from http://law.enotes.com/everyday-law-encyclopedia/probation-and-parole [12] http://www.probationviolationattorney.com [13] http://www.probationviolationattorney.com [14] http://law.enotes.com/everyday-law-encyclopedia/probation-and-parole [15] http://www.ojp.usdoj.gov/bjs/pandp.htm [16] Encyclopedia of Everyday Law retrieved July 3, 2007 from http://law.enotes.com/everyday-law-encyclopedia/probation-and-parole

Andrew Llyod Webber BIO :: essays research papers

Andrew Lloyd Webber was born on March 22, 1948 to William & Jean Lloyd Webber. Even at a young age, Andrew loved to make his own music. Andrew also had a great interest in inspecting ancient monuments around England. It and history were what many thought he would choose to do for a career. However, his Aunt Vi introduced him to the theatre, and under her advice started writing music of his own. In 1956, Andrew went to Westminster and started composing music for the school's plays. In 1962, Andrew won a Challenge Scholarship that reduced his tuition at Westminster. Andrew won another scholarship in 1964 to transfer to Oxford. Tim Rice and Andrew met in 1965 and consequently, Andrew dropped out of Oxford to pursue music with Tim. The first musical Andrew wrote (The Likes of Us) was a failure, but soon afterwards Joseph was created. The first showing was at Colette Court in 1968. Jesus Christ Superstar came next. In 1971, Andrew married Sarah Jane Hugill. Andrew and Alan Ayckbourn, in 1975, started work on a new musical, Jeeves. Jeeves was not a success and Andrew went back to Tim. Together they wrote Evita in late 1975. The next musical, was Cats. It was an incredible hit and beat A Chorus Line for longest running musical and highest grossing musical! Cats made Andrew rich and famous and ready to start a musical about trains. Starlight Express was created in 1984, the most expensive musical created up to that point. The same year, Andrew divorced Sarah Hugill and married Sarah Brightman. Andrew's next work was Requiem. It isn't a musical, but serious music for a Mass. Sarah Brightman sang the female soprano part. Andrew's next work, Phantom of the Opera also included Sarah. One of Andrew's most famous works, Phantom was created in 1986. Aspects of Love, Andrew's next venture, opened in 1989. Its intimate setting and songs were critically praised. In 1991, Andrew and Sarah decided to call it quits and on February 15, 1991, Andrew got married yet again to Madeleine Gurdon.

Awareness Of Sensory Loss Essay

In centripetal loss ( touch. mobility. vision. hearing ) this can hold a negative impact to an person like for illustration in mobility an single can see hapless mobility. tilting to one side or trouble with their coordination. the person may hold trouble to feed or dress themselves. or may non be able to take part in an activity and in some fortunes an person may non be able to manage/maintain their personal day-to-day life. Another is eyesight or vision. an person who suffers from this disablement may hold a really difficult clip pass oning or even to show themselves to what they want to make and what their wants are without the aid of another individual. This instance is the same with an person who is deaf or have limited hearing. Sometimes when you suffer from these disablements. people easy judge you in a manner that they try to sequester you or belong you to hold a below mean intelligence and presume that you can non make or believe for yourself or believe the same as other people which may do farther unwellnesss for the person such as depression. anxiousness and isolation. There can besides be a positive impact of holding these disablements because aid is ever available. AIDSs and benefits are available to back up you. there are care systems in topographic point that an person may utilize to back up them with twenty-four hours to twenty-four hours life and promote the person to hold a positive mentality on life. assisting the single lead every bit much as an independent life as possible which in the long tally will guarantee the person is happy and secure. 1. 2 Some stairss that can be taken to get the better of the negative factors could be ; With an person with sight damage guarantee the person has their spectacless on if prescribed. guarantee the spectacless are clean and the person is able see through them. Guarantee the country is clear of any obstructions to forestall the person from stumbling over or knocking into things. if the environment remains the same and points are non moved the person may happen it easier to travel around as they will be familiar with where things are and will be able to avoid them. An person who has a hearing damage may happen it easier to hear you if they are taken in to a quiet and good illume environment to speak. besides guarantee the persons hearing AIDSs are in and working and the volume is turned up to their liking. Always make the single aware of different groups and administrations that can assist them. guarantee people include the person when they can alternatively of speaking over them or go forthing them out of activities as if they are non at that place. If this does go on so dispute any favoritism and explicate why it is incorrect. 1. 3 Peoples puting restrictions on an person with centripetal loss can be disenabling. for illustration. believing that a blind/poor sighted single can’t manage entirely or can’t see what others are making toward them or others. or that of a deaf/poor hearing single are amusing because of the manner they talk or are mocked for continually inquiring for a individual to reiterate themselves. These attitudes and beliefs can forestall the individual being including in society as an equal. This can so hold a negative consequence on the person which can do a concatenation reaction of mental unwellnesss such as depression. anxiousness and isolation. 1. 4 You can get the better of disenabling attitudes and beliefs in centripetal loss by disputing favoritism instantly and explicate why it’s wrong. theoretical account good pattern. You can besides acquire involved in societal activities that promote positive attitudes. Outcome2 2. 1 Sight loss – Always place yourself to the person and guarantee you make it clear that you are talking to them and non person else. they can’t read your organic structure linguistic communication so you need to be clear about your significances and waies etc. A noisy environment can do it hard for them to concentrate on your voice so it may be better to seek cut down background noise. Hearing loss – Be respectful to the person when seeking to acquire their attending e. g. use a light touch on the arm. flex down to the persons level so they can see your face. if they lip read they will necessitate to see your face to be able do out what you’re inquiring them. you need to talk clearly at a normal gait and tone. you may necessitate to be patient and repeat things. Deaf blind – some of the above plus you need to cognize the degrees of hearing loss and sightlessness and their preferable method of communicating. 2. 2 Persons with centripetal loss such as hearing or sight can profit from different types of effectual communicating. Persons with hearing loss may profit from utilizing gestural linguistic communication or images to pass on. Those with sight loss may profit most from vocal communicating and touch. 2. 3 Information can be provided in many different ways to an person with centripetal loss listed below are a few illustrations of ways information can be passed on to the person. Centripetal loss –braille. tape recordings hearing loss – British mark linguistic communication. Makaton. ocular AIDSs e. g. images. lip reading. Deaf/blindness – . Braille is a system of raised points which can be read by touch. The Moon alphabet consists of brocaded forms which can be read by touch. Objects of Reference are objects that have particular significances assigned to them. They stand for something in the same manner that words do. Result 33. 1 The chief cause of centripetal loss is aging. as we age our senses become less and less. Centripetal loss can besides be caused by an unwellness such as dementedness or by holding an accident and sustaining hurt. 3. 2 Congenital centripetal loss means the person was born with it. whereas acquired centripetal loss is when the centripetal loss has developed as is the consequence of ageing. serious hurt or unwellness with the person. 3. 3 The per centum of the general population holding centripetal loss is 45 % . harmonizing to hypertext transfer protocol: //www. sense. org. uk/content/research-deafblindness Sense estimates that there are around 250. 000 deafblind people in the UK. Outcome 4 4. 1These are a few of the many indexs and marks to place sight loss. hearing loss and deaf/blindness.Sight loss†¢Increased sensitiveness to visible radiation and blaze†¢difficulty distinguishing colorss†¢Clumsiness. knocking into things in familiar milieus†¢difficulty separating objects from one another†¢holding books/papers near to face†¢regular headaches/eyes aching†¢reduced dark vision†¢Trouble reading little print i. e. on medicines†¢difficulty recognizing faces of household and friends†¢squinting when watching the telecasting†¢loss of involvement in avocations such as needlecraftHearing loss†¢difficulty hearing clearly when in a group conversation or noisy room†¢Asking people to reiterate themselves all the clip†¢people looking to mutter when they are speaking usually†¢not hearing the telephone ring or the door bell†¢having to hold the volume on high on the telecasting or wireless†¢hearing bett er in one ear compared to the other†¢Adult voices easier to understand than children’†¢getting tired or stressed due to holding to concentrate harder when listening Deaf and Blindness†¢to response to sound or illume†¢sensitive to being touched†¢difficulty doing sense of milieus†¢Withdrawal and isolation†¢developmental hold†¢use of other senses. gustatory sensation. odor and touch. to derive information †¢personalised methods of communicating4. 2 When concerns are raised sing centripetal loss or alterations. the first class of action should be to reach their g. p. oculus specializers who after scrutiny may mention them to a specializer at the infirmary for farther hearing and vision trials. Result 5 If you are concerned about centripetal loss or you know person who is you can describe this to your carers. seniors. troughs if in a attention place scene. Sing persons populating in their ain place you can seek advice or describe the job to your local g. p. societal worker or speak to household members. There is a web site called sense you can look on for aid and support sing centripetal loss and you’d like advice and information about the support and services available. you can name Sense on 0300 330 9256 or e-mail: [ electronic mail protected ]/* */!function(t. e. r. n. c. a. p){try{t=document. currentScript||function(){for(t=document. getElementsByTagName('script'). e=t. length;e--;)if(t[e]. getAttribute('data-cfhash'))return t[e]}();if(t&&(c=t. previousSibling)){p=t. parentNode;if(a=c. getAttribute('data-cfemail')){for(e=''. r='0x'+a. substr(0. 2)|0. n=2;a. length-n;n+=2)e+='%'+('0'+('0x'+a. substr(n. 2)^r). toString(16)). slice(-2);p. replaceChild(document. createTextNod e(decodeURIComponent(e)). c)}p. removeChild(t)}}catch(u){}}()/* ]]>*/

What Causes the Change of Seasons on Earth

The change of seasons is one of those phenomena that people take for granted. They know it happens in most places, but dont always stop to think about why we have seasons. The answer lies in the realm of astronomy and planetary science. The biggest reason for the seasons is that Earths axis is tilted relative to its  orbital plane. Think of the orbital plane of the solar system as a flat plate. Most of the planets orbit around the Sun on the surface of the plate.  Rather than having their north and south poles point directly perpendicular to the plate, most planets have their poles at a slant. This is particularly true of Earth, whose poles are tilted 23.5 degrees. Earth may have a tilt because of a  large impact  in  our  planets  history that likely caused the  creation of our Moon. During that event, infant Earth was smacked pretty heavily by a Mars-sized impactor. That caused it to tip over on its side for a while until the system settled down.   The best theory about the formation of the Moon says that the infant Earth and a Mars-sized body called Theia collided early in the history of the solar system. The remnants were blasted to space and eventually coalesced to form the Moon. NASA/JPL-Caltech  Ã‚   Eventually,  the Moon formed and Earths tilt settled to the 23.5 degrees it is today. It means that during part of the year, half of the planet is tilted away from the Sun, while the other half is tilted toward it. Both hemispheres still get sunlight, but one gets it  more  directly when its tilted toward the Sun in summer, while the other gets it less directly during winter (when it is tilted away).   This diagram shows Earths axial tilt and how it affects the hemispheres that are tilted toward the Sun through different parts of the year.   NASA/CMGlee When the northern hemisphere is tilted toward the Sun, people in that part of the world experience summer. At the same  time,  the southern hemisphere gets less light, so winter occurs there. The solstices and equinoxes are used mostly in calendars to mark the beginning and end of seasons but are not themselves related to the causes of the seasons. Seasonal Changes Our year is divided up into four seasons: summer, fall, winter, spring. Unless someone lives at the equator, each season delivers different weather patterns. Generally, its warmer in spring and summer, and cooler in autumn and winter. Ask most people why it is cold in the winter and warm in the summer and theyll likely say that  Earth must be closer to the Sun in the summer and farther away in the winter. This seems to make common sense. After all, as someone gets close to a fire, they feel more heat. So  why wouldnt closeness to the Sun cause the warm summer season? While this is an interesting observation, it actually leads to the wrong conclusion. Heres why: Earth is farthest from the Sun in July each year and closest in December, so the closeness reason is wrong. Also,  when it is summer in the northern hemisphere, winter is happening in the southern hemisphere, and vice versa. If the reason for the seasons was solely due to our proximity to the Sun, then it should be warm in both the northern and southern hemispheres at the same time of year. That doesnt happen. Its really the tilt that is the main reason we have seasons. But, there is another factor to consider. All planets have an axial tilt, including the gas giants. The Uranus tilt is so severe it rolls around the Sun on it side. NASA It's Hotter at High Noon Too Earths tilt also means that the Sun will appear to rise and set in different parts of the sky during different times of the year. In the summertime the Sun peaks almost directly overhead, and generally speaking will be above the horizon (i.e. there will be daylight) during more of the day.  This means that the Sun will have more time to heat the surface of the Earth in the summer, making it even warmer. In the winter, theres less time to heat the surface, and things are a bit chillier. Observers can generally see this change of apparent sky positions for quite easily. Over the course of a year, its fairly easy to note the position of the Sun in the sky. In the summertime, it will be higher up and rise and set at different positions than it does in the wintertime. Its a great project for anyone to try, and all they need is a rough drawing or picture of the local horizon to the east and west. Observers can glance out at the sunrise or sunset each day, and mark the positions of sunrise and sunset each day to get the full idea. Back to Proximity So, does it matter how close Earth is to the Sun? Well, yes, in a sense, it does, just not the way people expect. Earths orbit around the Sun  is only slightly elliptical. The difference between its closest point to the Sun and the most distant is a little more than three percent. That isnt enough to cause huge temperature swings. It  translates to a difference of a few degrees Celsius on average. The temperature difference between summer and winter is a lot more than that. So, closeness doesnt make as much of a difference as the amount of sunlight the planet receives. Thats why just simply assuming that Earth is closer during one part of the year than another is wrong. The reasons for our seasons are easy to understand with a good mental image of our planets tilt and its orbit around the Sun. Key Takeways Earths axial tilt plays a large role in creating seasons on our planet.The hemisphere (north or south) tilted toward the Sun receives more heat during that time.Closeness to the Sun is NOT a reason for the seasons. Sources Earths Tilt Is the Reason for the Seasons!†Ã‚  Ice-Albedo Feedback: How Melting Ice Causes More Ice to Melt - Windows to the Universe, www.windows2universe.org/earth/climate/cli_seasons.html.Greicius, Tony. â€Å"NASA Study Solves Two Mysteries About Wobbling Earth.†Ã‚  NASA, NASA, 8 Apr. 2016, www.nasa.gov/feature/nasa-study-solves-two-mysteries-about-wobbling-earth.â€Å"In Depth | Earth – Solar System Exploration: NASA Science.†Ã‚  NASA, NASA, 9 Apr. 2018, solarsystem.nasa.gov/planets/earth/in-depth/. Edited by Carolyn Collins Petersen.