尼古拉·哥白尼Nicolaus Copernicus

尼古拉·哥白尼是这位著名天文学家名字的拉丁语版本，他在晚年选择了这个名字。他名字的原始形式是米科瓦伊·哥白尼或哥白尼·科佩尔尼格，但在本文中我们将始终使用哥白尼。他的父亲，也叫哥白尼·科佩尔尼格，在搬到托伦之前住在克拉科夫，在那里他做铜贸易生意。他还对地方政治感兴趣，成为托伦的公民领袖和地方法官。哥白尼·科佩尔尼格大约在1463年与芭芭拉·瓦岑罗德结婚，后者来自托伦一个富裕的家庭。他们搬进了托伦圣安妮街的一所房子，但他们在城外也有一个带葡萄园的夏季住所。哥白尼和芭芭拉·科佩尔尼格有四个孩子，两个儿子和两个女儿，其中哥白尼是最小的。

你可以在THIS LINK看到哥白尼出生房子的图片。

年轻的哥白尼十岁时父亲去世。他的舅舅爱德华·卢卡斯 Watzenrode是弗龙堡大教堂的教士，成为哥白尼和芭芭拉·科佩尼克的四个孩子的监护人。

你可以在THIS LINK看到卢卡斯 Watzenrode的图片。

哥白尼和他的兄弟安德烈亚斯留在托伦，在那里继续接受初等教育。1488年，哥白尼被舅舅送到弗沃茨瓦韦克的大教堂学校，在那里接受了良好的标准人文主义教育。在弗沃茨瓦韦克学习三年后，他进入克拉科夫大学（位于当时的波兰首都）。此时卢卡斯 Watzenrode已是埃尔姆兰主教，他为两个外甥都设想了教会生涯。哥白尼的兄弟安德烈亚斯同时进入克拉科夫大学，两人的名字都出现在1491-92年的入学登记册上。

哥白尼后来写道，在克拉科夫接受的大学教育是他后来取得一切成就的关键因素。在那里，他学习了拉丁语、数学、天文学、地理学和哲学。他从约翰尼斯·德·萨克罗博斯科于1220年所著的Tractatus de Sphaera中学习天文学。然而，不应认为哥白尼学习的天文学课程是现代意义上的科学课程。相反，它们是数学课程，介绍了亚里士多德和克劳狄乌斯·托勒密的宇宙观，以便学生能够理解历法、计算圣日的日期，并具备使那些从事更实用职业的人能够在海上航行的技能。作为天文学主要部分教授的还有我们今天称之为占星术的内容，教学生根据人们出生的确切时间计算他们的星盘。

在克拉科夫求学期间，哥白尼购买了1482年在威尼斯出版的欧几里得的Elements拉丁文译本，1492年在威尼斯印刷的Alfonsine Tables第二版（其中给出了行星理论和日食），以及1490年在奥格斯堡出版的约翰·缪勒的Tables of Directions（一部关于球面天文学的著作）。值得注意的是，哥白尼的这些著作的副本，由他签名，至今仍被保存。

正是在克拉科夫求学期间，哥白尼开始使用他名字的拉丁文版本，而不是Kopernik或Koppernigk。在克拉科夫学习四年后，他回到了托伦，但正如当时常见的那样，他没有正式毕业获得学位。他的叔叔卢卡斯 Watzenrode仍然决心让哥白尼在教会中有一份职业，这确实是一个能为想要追求学问的人提供保障的职业。为了获得必要的资格，哥白尼决定去博洛尼亚大学攻读教会法学位。1496年秋天，他前往意大利，于1496年10月19日进入博洛尼亚大学，开始三年的学习。作为母语为德语的人，他加入了“博洛尼亚大学德意志同乡会”。每个学生向“德意志同乡会”捐献他们能负担的金额，而哥白尼所捐的少量款项表明他当时经济状况不佳。

当他在那里时，他的叔叔提名他担任弗龙堡大教堂的教士职位。1497年10月20日，在博洛尼亚时，哥白尼收到了他被任命为教士的正式通知，以及他将获得的舒适收入，而无需返回履行任何职责。在博洛尼亚大学，哥白尼除了正式的教会法课程外，还学习了希腊语、数学和天文学。他在天文学教授Domenico Maria de 诺瓦拉的坎帕努斯的房子里租了房间，并开始与他一起进行研究，协助他进行观测。1497年3月9日，他观测到月亮遮掩了毕宿五星。

1500年，哥白尼访问了罗马，正如所有基督徒都被强烈鼓励前往庆祝大禧年那样，他在那里逗留了一年，向学者们讲授数学和天文学。在罗马期间，他观测了1500年11月6日发生的月食。1501年春，他回到弗龙堡（又称Frombork），并于7月27日正式就任埃尔姆兰教区教士。他尚未完成在博洛尼亚的教会法学位，因此请求舅舅允许他返回意大利，既攻读法律学位，又学习医学。哥白尼于1501年7月27日获准休假[13]：-

“……主要是因为哥白尼承诺学习医学，而作为一名有用的医生，有朝一日将为我们最可敬的主教以及教区成员提供建议。”

正如这段引文所示，主教座堂教士团喜欢他学习医学的提议，并提供了必要的资金。他再次启程前往意大利，这次前往帕多瓦。哥白尼返回意大利还有另一个几乎可以肯定他未曾透露的原因，那就是继续他的天文学研究。

帕多瓦以其医学院而闻名，当他在那里时，哥白尼既学习医学又学习天文学。当时天文学本质上是占星术，因此被认为与医学相关，因为医生使用占星术。1503年春天，他决定正式获得教会法博士学位，但他没有回到博洛尼亚，而是在费拉拉大学获得了学位。获得博士学位后，哥白尼在费拉拉待了几个月，然后回到帕多瓦继续他的医学研究。没有记录表明他从帕多瓦毕业。

当他回到祖国时，哥白尼再次从他在弗龙堡埃尔姆兰教区的教士职务中获准休假。这是为了让他能担任他舅舅卢卡斯 Watzenrode的医生，埃尔姆兰主教，但他为叔叔履行的职责远不止医疗，基本上成为了他的私人秘书和个人顾问。他担任这些职责大约五年，在此期间，他住在海尔斯堡城堡，距离弗龙堡几英里，这是埃尔姆兰主教的官邸。

1509年，哥白尼出版了一部经过正规印刷的著作，其中包含对鲜为人知的诗人忒奥菲拉克特斯·西莫卡忒斯的希腊诗歌的拉丁文翻译。在陪同叔父访问克拉科夫期间，他将这部诗作的手稿交给了当地的一位出版商朋友。卢卡斯于1512年去世，此后哥白尼恢复了他在弗龙堡的埃尔姆兰教士会中的教士职务。他现在比以往有更多时间致力于天文学研究，在他居住的城镇防御工事中一座塔楼的房间里设有一座天文台。

你可以在THIS LINK看到哥白尼在弗龙堡的天文台的照片。

大约在1514年，他分发了一本小书，不是印刷的而是手写的，给了几位朋友，他们知道作者是他，尽管扉页上没有署名。这本书通常被称为Little Commentary，阐述了哥白尼的宇宙理论，认为太阳位于中心。Little Commentary是一份引人入胜的文件。它包含七条公理，哥白尼给出这些公理，并非因为它们是不言自明的，而是因为他将把结论建立在这些公理上，而不依赖其他任何东西；见[79]。这些公理是什么？让我们陈述它们：

1. There is no one centre in the universe。
2. The Earth's centre is not the centre of the universe。
3. The centre of the universe is near the sun。
4. The distance from the Earth to the sun is imperceptible compared with the distance to the stars。
5. The rotation of the Earth accounts for the apparent daily rotation of the stars。
6. The apparent annual cycle of movements of the sun is caused by the Earth revolving round it。
7. The apparent retrograde motion of the planets is caused by the motion of the Earth from which one observes。

有人指出，2、4、5和7可以从3和6推导出来，但哥白尼的目的从来不是给出一个极小的公理集。这些公理中最引人注目的是7，因为尽管早期学者曾声称地球在运动，有些人声称它绕太阳旋转，但在哥白尼之前，似乎没有人正确解释过外行星的逆行运动。即使在他撰写Little Commentary时，哥白尼也计划写一部重要著作，因为他在其中写道（见[77]）：-

这里，为了简洁起见，我认为省略为我的更大著作准备的数学论证是可取的。

他很可能在1514年写了Little Commentary，并在次年开始了他的重要著作De revolutionibus Ⓣ（《论天球的旋转》）。

从哥白尼的性格来看，很明显他本希望在弗龙堡过一种安静的生活，认真履行他（相对较少的）职责，把所有业余时间用于观测、发展他的宇宙理论以及写作De revolutionibusⓉ（《论天球的旋转》）。同样明显的是，他作为天文学家的名声广为人知，因为当第五次拉特兰会议决定改进历法时——当时已知历法与季节脱节——教皇在1514年向专家征求意见，其中一位专家就是哥白尼。许多专家前往罗马为会议提供建议，但哥白尼选择以信件回复。他不希望为历法讨论贡献更多，因为他觉得天体的运动仍未以足够的精确度被理解。

然而，哥白尼所期望的和平在频繁战争的时期并不容易找到。构成哥白尼住所的弗龙堡防御工事是为了保护这座多年来被各种对立群体占领的城镇而建造的。1516年，哥白尼被赋予管理阿伦施泰因（也称为奥尔什丁）和梅尔萨克地区的任务。他在履行这些行政职责期间，在阿伦施泰因城堡住了四年。

你可以在THIS LINK看到哥白尼居住过的阿伦施泰因城堡的照片。

哥白尼总是热衷于进行观测，每当有理由参加会晤或与其他教士商议时，他都会回到位于弗龙堡的住所/天文台，并总是借此机会推进自己的研究。然而，当1519年末波兰与条顿骑士团之间爆发战争时，哥白尼已回到弗龙堡。经过一段时间的战争，哥白尼作为代表埃尔姆兰主教的两人代表团之一，被派往布劳恩斯贝格参加和平谈判。和平谈判失败，战争继续。弗龙堡遭到围攻，但即使在这绝望的时刻，哥白尼仍继续坚持观测。到1520年秋，哥白尼已回到阿伦施泰因城堡居住，并不得不组织防御以抵御进攻的军队。城堡抵御住了进攻，到1521年，一种不安定的和平得以恢复。

作为对其保卫阿伦施泰因的奖赏，哥白尼被任命为埃尔姆兰的专员，并受命在战后重建该地区。他的密友、教士团中的另一位教士Tiedemann Giese被指派协助他。

你可以在THIS LINK看到Tiedemann Giese的照片。

作为复兴计划的一部分，哥白尼提出了一项货币改革方案，并于1522年提交给格劳登茨议会。然而，尽管他出席了议会并为其合理的提议进行了强有力的辩论，这些提议却未被付诸实施。

哥白尼回到了弗龙堡，在那里他的生活变得不那么动荡，他获得了渴望的平静与安宁，得以进行观测并研究其日心说的细节。虽说他现在拥有了想要的平静，人们也应意识到，他是在孤立无援的情况下进行数学和天文学工作的，没有同事可以与之讨论问题。尽管哥白尼是一名教士，但他从未成为神父。事实上，1531年2月4日，他的主教威胁说，如果他不进入神职，就要剥夺他的收入，然而哥白尼仍然拒绝了。

哥白尼理论的完整阐述显然进展缓慢，直到他愿意看到它出版的状态，而这直到哥白尼生命的最后时刻才发生，当时他以De revolutionibus orbium coelestium Ⓣ（《论天球的旋转》）（纽伦堡，1543年）为标题出版了他毕生的工作。事实上，如果不是格奥尔格·约阿希姆·雷蒂库斯，维滕贝格大学一位年轻的数学和天文学教授，哥白尼的杰作可能永远不会出版。1539年5月，格奥尔格·约阿希姆·雷蒂库斯抵达弗龙堡，在那里他与哥白尼共度了大约两年。格奥尔格·约阿希姆·雷蒂库斯写到他的访问：-

我听闻哥白尼大师在北方诸地的声名，尽管维滕贝格大学已聘我为那些技艺的公共教授，然而，我认为除非通过那人的指导学到更多东西，否则我不会满足。我还要说，我不后悔经济上的花费，也不后悔漫长的旅程和其余的艰辛。然而，在我看来，这些麻烦带来了巨大的回报，那就是我这个相当大胆的年轻人，迫使这位可敬的人更早地与全世界分享他在这一学科中的想法。

我们应当注意，格奥尔格·约阿希姆·雷蒂库斯是新教徒，因此在宗教改革那个动荡时期，他访问天主教据点多少有些冒险。1539年9月，格奥尔格·约阿希姆·雷蒂库斯前往但泽，拜访了但泽市长，市长给了他一些经济援助，帮助出版Narratio PrimaⓉ（第一报告），或者给出其全名First report to Johann Schöner on the Books of the Revolutions of the learned gentleman and distinguished mathematician, the Reverend Doctor Nicolaus Copernicus of Toruń, Canon of Warmia, by a certain youth devoted to mathematics。这部作品的出版鼓励哥白尼发表他27年前承诺的其理论的完整数学细节。Swerdlow写道：-

哥白尼不可能要求对其新天文学向良好文学界作出更博学、优雅和热情的介绍了；事实上，时至今日，“第一报告”仍然是介绍哥白尼工作的最佳入门。

在他的First Report中，格奥尔格·约阿希姆·雷蒂库斯写到了哥白尼的工作方式（见[80]）：-

……我的老师眼前总是有各个时代的观测以及他自己的观测，按目录顺序汇编；然后，当必须得出某个结论或对科学及其原理作出贡献时，他从最早的观测进展到他自己的观测，寻求使它们全部协调一致的相互关系；在乌拉尼亚的指导下，通过正确推理得到的结果，他随后与克劳狄乌斯·托勒密和古人的假设进行比较；在对这些假设进行了最仔细的检查后，他发现天文学证明要求拒绝它们；他假定新的假设，确实并非没有神圣的灵感和众神的恩惠；通过应用数学，他以几何方式确立了可以通过正确推理从中得出的结论；然后，他将古代观测和他自己的观测与他所采用的假设协调起来；在完成所有这些操作后，他最终写下了天文学定律……

在与哥白尼同住期间，格奥尔格·约阿希姆·雷蒂库斯写信给几个人，报告哥白尼正在取得的进展。例如，1541年6月2日，格奥尔格·约阿希姆·雷蒂库斯写道，哥白尼[80]：-

……身体相当健康，并且写作甚多……

而他在6月9日写道哥白尼[80]：-

……终于克服了他长期不愿将书稿付印的犹豫。

到8月29日De revolutionibus orbium coelestiumⓉ（《天体运行论》）已准备付印。格奥尔格·约阿希姆·雷蒂库斯在返回维滕贝格履行教学职责时带走了手稿，并将其交给纽伦堡的印刷商Johann Petreius。纽伦堡是当时主要的印刷中心，而Petreius是城里最好的印刷商。然而，由于他无法留下监督印刷，便请安德烈亚斯·奥西安德尔（Andreas Osiander）承担此项工作。奥西安德尔是一位路德宗神学家，在印刷数学文本方面颇有经验。奥西安德尔所做的，是写了一封致读者的信，插在扉页之后，取代哥白尼原来的序言。他在信中声称，书中的结果并非意在作为真理，而只是提供一种更简便的方法来计算天体的位置。这封信没有署名，其真正作者直到50年后由约翰内斯·开普勒公开才为人所知。奥西安德尔还巧妙地改动了标题，使其看起来不那么像是对真实世界的断言。有些人对奥西安德尔这一巨大的欺骗行为感到震惊，正如当时的格奥尔格·约阿希姆·雷蒂库斯一样；另一些人则认为，正是因为奥西安德尔的序言，哥白尼的著作才得以被人阅读，而没有立即遭到谴责。

在De revolutionibusⓉ（《天体运行论》）中，哥白尼陈述了若干理由，说明太阳位于宇宙中心是合乎逻辑的：-

万物之中，太阳居于中央。作为这盏明灯在这宇宙——这最美丽的殿堂——中的位置，难道还能有别的或更好的地方比中心更合适吗？从中心，它能同时照亮一切。因此，有人不无恰当地称太阳为宇宙之灯，有人称其为宇宙之心，还有人称之为宇宙之主。

哥白尼的宇宙论把静止的太阳放在宇宙的中心附近，而不是正中心，并且还让地球具有几种不同的运动。哥白尼面临的问题是他假设一切运动都是圆周运动，因此像克劳狄乌斯·托勒密一样，被迫使用本轮（例如见[78]）。因此，他的大多数同时代人，以及直到十七世纪中叶的大多数天文学家和自然哲学家，都认为这不可信。在De revolutionibus orbium coelestiumⓉ（《天体运行论》）原定的序言中，哥白尼表明他完全清楚自己的工作会招致的批评：-

也许会有一些喋喋不休的人，虽然对数学完全无知，却擅自对数学问题作出判断，并且为了他们的目的而肆意曲解《圣经》的某些段落，竟敢对我的事业吹毛求疵并加以指责。我无视他们，甚至鄙视他们的批评为毫无根据。

其著名的捍卫者包括约翰内斯·开普勒和伽利略，而哥白尼理论的理论证据则在大约150年后由艾萨克·牛顿的万有引力理论提供。

据说哥白尼在临终时第一次收到这本印刷书，全书约200页，用拉丁文写成。他死于脑溢血。

第谷·布拉赫不接受哥白尼关于地球绕太阳运动的说法，尽管如此，他写道：-

通过自己所作的观测，他[哥白尼]发现了克劳狄乌斯·托勒密中的某些缺陷，并得出结论：克劳狄乌斯·托勒密所建立的假设承认某些不适当的东西，违反了数学的公理。此外，他发现阿方索星表的计算与天体的运动不一致。因此，他以惊人的智力敏锐性建立了不同的假设。他重建了天体运动科学，以至于在他之前没有人对天体的运动有更准确的认识。

Rudnicki [13]对哥白尼作出如下评价：-

他确实富有创造力。他的科学方法虽然受限于当时的知识与信仰视野，却仍堪称理想的客观。在伦理上，他一生的行为见证了最高标准。他行善。他赢得了同时代人的普遍尊重与荣誉。多年来，他自我牺牲地服务于祖国的事业。但他不懂得私人的、家庭的欢乐。

Nicolaus Copernicus is the Latin version of the famous astronomer's name which he chose later in his life. The original form of his name was Mikolaj Kopernik or Nicolaus Koppernigk but we shall use Copernicus throughout this article. His father, also called Nicolaus Koppernigk, had lived in Kraków before moving to Toruń where he set up a business trading in copper. He was also interested in local politics and became a civic leader in Toruń and a magistrate. Nicolaus Koppernigk married Barbara Watzenrode, who came from a well off family from Toruń, in about 1463. They moved into a house in St Anne's Street in Toruń, but they also had a summer residence with vineyards out of town. Nicolaus and Barbara Koppernigk had four children, two sons and two daughters, of whom Nicolaus Copernicus was the youngest.

You can see a picture of the house in which Copernicus was born at THIS LINK.

When young Nicolaus was ten years old his father died. His uncle Lucas Watzenrode, who was a canon at Frauenburg Cathedral, became guardian to Nicolaus and Barbara Koppernigk's four children.

You can see a picture of Lucas Watzenrode at THIS LINK.

Nicolaus and his brother Andreas remained in Toruń, continuing their elementary education there. In 1488 Nicolaus was sent by his uncle to the cathedral school of Włocławek where he received a good standard humanist education. After three years of study at Włocławek he entered the University of Kraków (situated in what was then the capital of Poland). By this time Lucas Watzenrode was Bishop of Ermland and he envisaged a church career for both of his nephews. Andreas, Nicolaus's brother, entered the University of Kraków at the same time, and both their names appear on the matriculation records of 1491-92.

University education at Kraków was, Copernicus later wrote, a vital factor in everything that he went on to achieve. There he studied Latin, mathematics, astronomy, geography and philosophy. He learnt his astronomy from Tractatus de Sphaera by Johannes de Sacrobosco written in 1220. One should not think, however, that the astronomy courses which Copernicus studied were scientific courses in the modern sense. Rather they were mathematics courses which introduced Aristotle and Ptolemy's view of the universe so that students could understand the calendar, calculate the dates of holy days, and also have skills that would enable those who would follow a more practical profession to navigate at sea. Also taught as a major part of astronomy was what today we would call astrology, teaching students to calculate horoscopes of people from the exact time of their birth.

While a student in Kraków, Copernicus purchased a copy of the Latin translation of Euclid's Elements published in Venice in 1482, a copy of the second edition of the Alfonsine Tables (which gives planetary theory and eclipses) printed in Venice in 1492, and Regiomontanus's Tables of Directions (a work on spherical astronomy) published in Augsburg in 1490. Remarkably Copernicus's copies of these works, signed by him, are still preserved.

It was while he was a student at Kraków that Copernicus began to use this Latin version of his name rather than Kopernik or Koppernigk. He returned to Toruń after four years of study at Kraków but, as was common at the time, did not formally graduate with a degree. His uncle Lucas Watzenrode was still determined that Copernicus should have a career in the Church and indeed this was a profession which would allow security for someone wanting to pursue leaning. So that he might have the necessary qualifications Copernicus decided to go to the University of Bologna to take a degree in canon law. In the autumn of 1496 he travelled to Italy, entering the University of Bologna on 19 October 1496, to start three years of study. As a native German speaker he joined the "German Nation of Bologna University". Each student contributed to the "German Nation" an amount they could afford and the small contribution that Copernicus made indicates his poor financial position at that time.

While he was there his uncle put his name forward for the position of canon at Frauenburg Cathedral. On 20 October 1497, while in Bologna, Copernicus received official notification of his appointment as a canon and of the comfortable income he would receive without having to return to carry out any duties. At Bologna University Copernicus studied Greek, mathematics and astronomy in addition to his official course of canon law. He rented rooms at the house of the astronomy professor Domenico Maria de Novara and began to undertake research with him, assisting him in making observations. On 9 March 1497 he observed the Moon eclipse the star Aldebaran.

In 1500 Copernicus visited Rome, as all Christians were strongly encouraged to do to celebrate the great jubilee, and he stayed there for a year lecturing to scholars on mathematics and astronomy. While in Rome he observed an eclipse of the Moon which took place on 6 November 1500. He returned to Frauenburg (also known as Frombork) in the spring of 1501 and was officially installed as a canon of the Ermland Chapter on 27 July. He had not completed his degree in canon law at Bologna so he requested his uncle that he be allowed to return to Italy both to take a law degree and to study medicine. Copernicus was granted leave on 27 July 1501 [13]:-

... principally because Nicolaus promised to study medicine, and as a helpful physician would some day advise our most reverend bishop and also the members of the Chapter.

As this quotation indicates, the Cathedral Chapter liked his proposal to study medicine and provided the necessary funds. He set off again for Italy, his time going to Padua. Copernicus had another reason to return to Italy, which he almost certainly did not disclose, and that was to continue his studies of astronomy.

Padua was famous for its medical school and while he was there Copernicus studied both medicine and astronomy. At that time astronomy was essentially astrology and, as such, considered relevant to medicine since physicians made use of astrology. In the spring of 1503 he decided formally to obtain his doctorate in Canon Law, but he did not return to Bologna but rather took the degree at the University of Ferrara. After receiving his doctorate, Copernicus stayed in Ferrara for a few months before returning to Padua to continue his studies of medicine. There is no record that he ever graduated from Padua.

When he returned to his native land, Copernicus was again granted leave from his official duties as a canon in the Ermland Chapter at Frauenburg. This was allow him to be physician to his maternal uncle Lucas Watzenrode, the Bishop of Ermland, but he carried out far more duties for his uncle than medical ones becoming essentially his private secretary and personal advisor. For about five years he undertook these duties and during this period he lived at Heilsberg Castle, a few miles from Frauenburg, the official residence of the Bishop of Ermland.

In 1509 Copernicus published a work, which was properly printed, giving Latin translations of Greek poetry by the obscure poet Theophylactus Simocattes. While accompanying his uncle on a visit to Kraków, he gave a manuscript of the poetry book to a publisher friend there. Lucas Watzenrode died in 1512 and following this Copernicus resumed his duties as canon in the Ermland Chapter at Frauenburg. He now had more time than before to devote to his study of astronomy, having an observatory in the rooms in which he lived in one of the towers in the town's fortifications.

You can see a picture of Copernicus's observatory in Frauenburg at THIS LINK.

Around 1514 he distributed a little book, not printed but hand written, to a few of his friends who knew that he was the author even though no author is named on the title page. This book, usually called the Little Commentary, set out Copernicus's theory of a universe with the sun at its centre. The Little Commentary is a fascinating document. It contains seven axioms which Copernicus gives, not in the sense that they are self evident, but in the sense that he will base his conclusions on these axioms and nothing else; see [79]. What are the axioms? Let us state them:

1. There is no one centre in the universe.
2. The Earth's centre is not the centre of the universe.
3. The centre of the universe is near the sun.
4. The distance from the Earth to the sun is imperceptible compared with the distance to the stars.
5. The rotation of the Earth accounts for the apparent daily rotation of the stars.
6. The apparent annual cycle of movements of the sun is caused by the Earth revolving round it.
7. The apparent retrograde motion of the planets is caused by the motion of the Earth from which one observes.

Some have noted that 2, 4, 5, and 7 can be deduced from 3 and 6 but it was never Copernicus's aim to give a minimal set of axioms. The most remarkable of the axioms is 7, for although earlier scholars had claimed that the Earth moved, some claiming that it revolved round the sun, nobody before Copernicus appears to have correctly explained the retrograde motion of the outer planets. Even when he wrote his Little Commentary Copernicus was planning to write a major work, for he wrote in it (see [77]):-

Here, for the sake of brevity, I have thought it desirable to omit the mathematical demonstrations intended for my larger work.

It is likely that he wrote the Little Commentary in 1514 and began writing his major work De revolutionibus Ⓣ in the following year.

Given Copernicus's nature it is clear that he would have liked to have lived a quiet life at Frauenburg, carrying out his (relatively few) duties conscientiously and devoting all his spare time to observing, developing his theories of the universe, and writing De revolutionibus Ⓣ. It is equally clear that his fame as an astronomer was well known for when the Fifth Lateran Council decided to improve the calendar, which was known to be out of phase with the seasons, the Pope appealed to experts for advice in 1514, one of these experts was Copernicus. Many experts went to Rome to advise the Council, but Copernicus chose to respond by letter. He did not wish to contribute more to the discussions on the calendar since he felt that the motions of the heavenly bodies was still not understood with sufficient precision.

The peace which Copernicus wished, however, was not easy to find in a period of frequent wars. The fortifications of Frauenburg that formed Copernicus's home had been built to protect the town which had been captured by various opposing groups over the years. In 1516 Copernicus was given the task of administering the districts of Allenstein (also known as Olsztyn) and Mehlsack. He lived for four years in Allenstein Castle while carrying out these administrative duties.

You can see a picture of Allenstein Castle where Copernicus lived at THIS LINK.

Always keen to make observations, Copernicus returned to his home/observatory in Frauenburg whenever there was a reason to attend a meeting or consult with the other canons, always taking the opportunity to further his researches. However when war broke out between Poland and the Teutonic Knights towards the end of 1519 Copernicus was back in Frauenburg. After a period of war, Copernicus was sent to participate in peace talks in Braunsberg as one of a two man delegation representing the Bishop of Ermland. The peace talks failed and the war continued. Frauenburg came under siege but Copernicus continued making his observations even at this desperate time. By the autumn of 1520 Copernicus was back living in Allenstein Castle and had to organise its defence against attacking forces. The castle resisted the attack and by 1521 an uneasy peace had returned.

As a reward for his defence of Allenstein, Copernicus was appointed Commissar of Ermland and given the task of rebuilding the district after the war. His close friend, Tiedemann Giese, another canon in the Chapter, was given the task of assisting him.

You can see a picture of Tiedemann Giese at THIS LINK.

As part of the recovery plan, Copernicus put forward a scheme for the reform of the currency which he presented to the Diet of Graudenz in 1522. However, despite attending the Diet and arguing strongly for his sensible proposals, they were not acted on.

Copernicus returned to Frauenburg where his life became less eventful and he had the peace and quiet that he longed for to allow him to make observations and to work on details of his heliocentric theory. Having said that he now had the peace he wanted, one should also realise that he was undertaking his mathematical and astronomical work in isolation with no colleagues with whom to discuss matters. Although Copernicus was a canon, he had never become a priest. In fact on 4 February 1531 his bishop threatened to take away his income if he did not enter the priesthood, yet Copernicus still refused.

A full account of Copernicus's theory was apparently slow to reach a state in which he wished to see it published, and this did not happen until the very end of Copernicus's life when he published his life's work under the title De revolutionibus orbium coelestium Ⓣ (Nuremberg, 1543). In fact had it not been for Georg Joachim Rheticus, a young professor of mathematics and astronomy at the University of Wittenberg, Copernicus's masterpiece might never have been published. In May 1539 Rheticus arrived at Frauenburg where he spent about two years with Copernicus. Rheticus wrote of his visit:-

I heard of the fame of Master Nicolaus Copernicus in the northern lands, and although the University of Wittenberg had made me a Public Professor in those arts, nonetheless, I did not think that I should be content until I had learned something more through the instruction of that man. And I also say that I regret neither the financial expenses nor the long journey nor the remaining hardships. Yet, it seems to me that there came a great reward for these troubles, namely that I, a rather daring young man, compelled this venerable man to share his ideas sooner in this discipline with the whole world.

We should note that Rheticus was a Protestant, so in those troubled times of the Reformation he took somewhat of a risk visiting a Catholic stronghold. In September 1539 Rheticus went to Danzig, visiting the mayor of Danzig, who gave him some financial assistance to help publish the Narratio Prima Ⓣ or, to give it its full title First report to Johann Schöner on the Books of the Revolutions of the learned gentleman and distinguished mathematician, the Reverend Doctor Nicolaus Copernicus of Toruń, Canon of Warmia, by a certain youth devoted to mathematics. The publication of this work encouraged Copernicus to publish the full mathematical details of his theory which he had promised 27 years earlier. Swerdlow writes:-

Copernicus could not have asked for a more erudite, elegant, and enthusiastic introduction of his new astronomy to the world of good letters; indeed to this day the "Narratio Prima" remains the best introduction to Copernicus's work.

In his First Report Rheticus wrote about Copernicus's way of working (see [80]):-

... my teacher always had before his eyes the observations of all ages together with his own, assembled in order as in catalogues; then when some conclusion must be drawn or contribution made to the science and its principles, he proceeds from the earliest observations to his own, seeking the mutual relationship which harmonizes them all; the results thus obtained by correct inference under the guidance of Urania he then compares with the hypothesis of Ptolemy and the ancients; and having made a most careful examination of these hypotheses, he finds that astronomical proof requires their rejection; he assumes new hypotheses, not indeed without divine inspiration and the favour of the gods; by applying mathematics, he geometrically establishes the conclusions which can be drawn from them by correct inference; he then harmonizes the ancient observations and his own with the hypotheses which he has adopted; and after performing all these operations he finally writes down the laws of astronomy ...

While living with Copernicus, Rheticus wrote to several people reporting on the progress Copernicus was making. For example on 2 June 1541 Rheticus wrote that Copernicus [80]:-

... is enjoying quite good health and is writing a great deal ...

while he wrote that on 9 June Copernicus [80]:-

... had finally overcome his prolonged reluctance to release his volume for publication.

By 29 August De revolutionibus orbium coelestium Ⓣ was ready for the printer. Rheticus took the manuscript with him when he returned to his teaching duties at Wittenberg, and gave it the printer Johann Petreius in Nürnberg. This was a leading centre for printing and Petreius was the best printer in town. However, since he was unable to stay to supervise the printing he asked Andreas Osiander, a Lutheran theologian with considerable experience of printing mathematical texts, to undertake the task. What Osiander did was to write a letter to the reader, inserted in place of Copernicus's original Preface following the title page, in which he claimed that the results of the book were not intended as the truth, rather that they merely presented a simpler way to calculate the positions of the heavenly bodies. The letter was unsigned and the true author of the letter was not revealed publicly until Kepler did so 50 years later. Osiander also subtly changed the title to make it appear less like a claim of the real world. Some are appalled at this gigantic piece of deception by Osiander, as Rheticus was at the time, others feel that it was only because of Osiander's Preface that Copernicus's work was read and not immediately condemned.

In De revolutionibus Ⓣ Copernicus states several reasons why it is logical that the sun would be at the centre of the universe:-

At the middle of all things lies the sun. As the location of this luminary in the cosmos, that most beautiful temple, would there be any other place or any better place than the centre, from which it can light up everything at the same time? Hence the sun is not inappropriately called by some the lamp of the universe, by others its mind, and by others its ruler.

Copernicus's cosmology placed a motionless sun not at the centre of the universe, but close to the centre, and also involved giving several distinct motions to the Earth. The problem that Copernicus faced was that he assumed all motion was circular so, like Ptolemy, was forced into using epicycles (see for example [78]). It was consequently considered implausible by the most of his contemporaries, and by most astronomers and natural philosophers until the middle of the seventeenth century. In the intended Preface of De revolutionibus orbium coelestium Ⓣ Copernicus showed that he was fully aware of the criticisms that his work would attract:-

Perhaps there will be babblers who, although completely ignorant of mathematics, nevertheless take it upon themselves to pass judgement on mathematical questions and, badly distorting some passages of Scripture to their purpose, will dare find fault with my undertaking and censure it. I disregard them even to the extent as despising their criticism as unfounded.

Its notable defenders included Kepler and Galileo while theoretical evidence for the Copernican theory was provided by Newton's theory of universal gravitation around 150 years later.

Copernicus is said to have received a copy of the printed book, consisting of about 200 pages written in Latin, for the first time on his deathbed. He died of a cerebral haemorrhage.

Brahe, who did not accept Copernicus's claim that the Earth moved round the sun, nevertheless wrote:-

Through observations made by himself [Copernicus] discovered certain gaps in Ptolemy, and he concluded that the hypotheses established by Ptolemy admit something unsuitable in violation of the axioms of mathematics. Moreover, he found the Alfonsine computations in disagreement with the motions of the heavens. Therefore, with wonderful intellectual acumen he established different hypotheses. He restored the science of the heavenly motions in such a way that nobody before him had a more accurate knowledge of the movements of the heavenly bodies.

Rudnicki [13] gives this appreciation of Copernicus:-

He was truly creative. His scientific method, though determined by the horizons of contemporary knowledge and belief, was yet ideally objective. Ethically, his actions throughout his life bear witness to the highest standards. He did good. He earned the general respect and honour of his contemporaries. For many years he served self-sacrificingly the cause of his native country. But he knew no private, domestic joys.