373:. This book restored and updated the old idea of Aristarchus that Earth spins around the sun. The new version was written with so much mathematical detail that it could contest the Ptolemaic model. By this time, scientists noticed several inaccuracies in the Ptolemaic model. They were more open to revising it, but largely kept using it because of the huge work involved in changing the tables. Copernicus thought that Earth spinning around the sun could provide a simpler explanation for the retrograde motion of the planets, and calculated the distance of the planets to the Sun. However, he kept the idea of circular orbits, and added several composite orbits to explain the errors caused by it. Although he correctly displaced the center of the Solar System, this first model turned out to be as inaccurate and as complex as the Ptolematic one, and did not get much supporters in the first decades.
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universe and fire to rise away from it, under that logic the existence of other worlds would not be possible. He also thought that Aether moves in circles, and for that reason the universe could not be spatially infinite. Aristotle also rejected the plurality of universes, or heavens, arguing that the universe has a Prime Mover that started it all. If there were more than one universe then there would be more than one Prime Mover, and he considered that idea to be impossible. This idea may be influenced by his theological views, as well as his views about physics and cosmology. He concluded that "The world must be unique... There cannot be several worlds".
505:
worlds were just like Earth. However, the only fact about this that was found at this time was that the stars and the classical planets are not lights but celestial objects analogous to Earth, and that life in them may be plausible, if still unknown. The idea of extraterrestrial life, which was once a radical notion held by limited and specific people, became an accepted idea discussed in college classrooms. The change was also possible because of the changes in religious and philosophical thinking that took place at the time.
346:
64:
258:. Many Islamic scholars studied at the Library and cited or translated the work of the Greek authors, which did not get completely lost. They were also in contact with Hindu scholars from India, who were in turn influenced by the Chinese works and discoveries. Thus, Baghdad created a synthesis of the combined works of Ancient Greece, India, China, and their own scholars. This knowledge spread across the
320:: they considered that God was being analyzed in a very rational way, and that they were close to suggesting that God could not do certain things, such as creating infinite worlds. In the following years several scholars discussed the plurality of worlds and maintained that it was not a theological impossibility, even if they rejected it for other reasons.
306:"the world was made by Him", with "world" in singular, which would mean only one. A single world would also mean order, in contrast with the plurality of words held by atomists, who would believe in chance rather than in an "ordaining wisdom" creating it all. He cited the Aristotlean thought in his support;
557:
Most knowledge of astronomy is relevant in some way for the discussion of extraterrestrial life, but there are three main tenets. One, that the universe is incredibly vast and old. Second, the elements that make up life on Earth are plentiful. Third, that the laws that rule matter are the same across
98:
sought to explain the nature of the universe without relying on supernatural explanations, and reasoned that Earth was a flat disk floating on an ocean of water. The idea was not widely accepted even then, but it established the underlying idea that the universe is intrinsically understandable. Greek
410:
However, some scientists had concerns over the new model. Aristotle had once stated that Earth could not move because, if it did so, birds, clouds, and falling objects would be left behind. Orbits had to be circular because the heavens had to be perfect and unchanging. And if Earth moved, the stars
330:
in the context of the plurality of worlds. He reasoned that if there were people on other worlds they would not be living in sin, because they would not descend from Adam and Eve, but they would still live by virtue of God. He assumed that the death of Christ would surely redeem the people of other
504:
Although the dispute was not specifically about extraterrestrial life, the outcome kickstarted it. As there was a conflict between atomists and
Aristotelians back in ancient Greece, and the Aristotelians were proved to be wrong, many assumed that this meant that atomists were right and that other
44:
radically altered mankind's image of the architecture of the cosmos by removing Earth from the center of the universe, which made the concept of extraterrestrial life more plausible. Today we have no conclusive evidence of extraterrestrial life, but experts in many different disciplines gather to
491:
The
Copernican revolution, the time between Copernicus and Newton, was almost 150 years and changed science forever. It changed the view of the universe and the place of Earth and humankind in it, shifting from a central position to just a world like many others. It also changed the way science
384:
to make sense of his observations, so that did not feel like he lived in vain. Kepler initially kept the circular orbits, and eventually found a system that would explain all the data, except for a mistake of 8 arcminutes on the position of Mars. However, Kepler trusted the accuracy of Tycho's
212:
opposed the idea of a plurality of worlds. Plato reasoned that there could be a single heaven, and that if there were several worlds the universe would be composite, eventually falling into dissolution and decay. Aristotle thought that the earth element would tend to fall to the center of the
524:
The study of astronomy continued after Newton, and later technological devices and math models allowed to study objects that were undreamt of at the time. Although no actual extraterrestrial life has been found, either in the Solar System or elsewhere, science currently has a far greater
103:
but based their ideas on pure thought instead. However, their discussions laid some principles that would eventually lead to it, such as the rejection of supernatural explanations and that ideas would not be valid if they were contradicted by observable facts. They also developed
447:. The existence of the Galilean moons refuted the common argument that the Moon would not stay with a moving Earth. As for the stellar parallax, Galileo could not prove that the stars were more distant than estimated, but got strong evidence suggesting it: a closer look at the
175:
The Greeks discussed as well the possible existence of other worlds, but did not consider the planets as such. In their view, the celestial sphere was a part of Earth and other potential worlds would have their own ones. There was consensus that the world was made of the four
459:. However, the idea generated such controversy that Galileo was summoned by the Inquisition and forced to recant his findings. Galileo, who was 70 at the time and probably fearing that his life would be at stake, did as ordered. It is said that Galileo muttered "
454:
Although those discoveries proved that Earth was not located at the center of everything, they did not completely prove that it spins around the Sun; this fact was fully confirmed when the stellar parallax was measured in detail and with
488:, and explains all motions in the universe. It also uses maths to explain that Kepler's laws of planetary motion are a natural consequence of the laws of gravitation and motion. With this, the geocentric model was completely discarded.
83:
were explained as the actions of mythological deities. However, it soon became evident that celestial objects move and behave in regular and predictable patterns, which helped in keeping track of time, tides, and seasons, crucial for
288:, who did not believe in many worlds existing at the same time, but rather in worlds that may exist before and after Earth. He developed this idea to explain God's apparent lack of purpose and activities before creating the world.
204:
said in his "Letter to
Herodotus" that "There are infinite worlds both like and unlike this world of ours... we must believe that in all worlds there are living creatures and plants and other things we see in this world".
144:
proposed instead that it is Earth that spins around the sun, which makes it easier to explain the retrograde motion of the classical planets, but this was rejected by other Greeks. They pointed out that if Earth moves a
23:
is a scientific idea that has been debated for centuries. Initially, the question was purely speculative; in modern times a limited amount of scientific evidence provides some answers. The idea was first proposed in
127:
that Earth was a perfect sphere, as they associated circles and spheres with mathematical perfection. The model of the celestial sphere works for distant stars, which seem to be at fixed locations in the sky to the
500:
it works that way and not another. Mere guesses like atomism or aesthetic preferences like heavenly perfection would not fly anymore. Any explanation and assumption was required to be proved before being accepted.
192:. The atomist view would allow the existence of other worlds, as the processes that created Earth may happen elsewhere as well. Although very few of their writings were preserved, it is known that early atomists
492:
works. Previous academics were willing to give leeway to mistakes and errors of measurement, which were strictly less tolerated by the new generations. There was also a stronger emphasis to understand not only
549:
in particular help to understand the conditions at places other than Earth and how they can be more beneficial or harmful for life. All those sciences are collectively studied under the umbrella science of
439:
such as craters and mountain ranges. If the heavens were not as perfect as originally considered, then the idea that orbits are not perfect circles was not so questionable. Galileo also discovered the
149:
would change the location of stars in the sky during the year. Although stellar parallax does exist, stars are too far away from Earth, more than Greeks considered, to be noticeable by the naked eye.
280:
The views of the atomists fell under religious scrutiny when
Christianity became a prominent religion. All Church Fathers who made mention of the idea of the plurality of worlds dismissed it as a
466:
Despite the trial, by 1630 the model of Kepler and the clarifications of
Galileo were unanimously accepted. However, although it was accepted that planets moved in ellipses, it was not clear
292:
rejected this idea, proposing that time only manifests in the motion of the material, which means that there was no time "before" the creation because time itself started with it.
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instead. He also noticed evidences of the curved surface of the world and proposed that the Earth was shaped like a cylinder. Most other Greeks, however, preferred the proposal of
316:
a few years before. He also considered that, as God was only one, he would create only one world to mirror his own perfection. However, the ideas of
Aquinas were banned by the
389:
he could explain the recorded motion of all the planets, including Mars' retrograde motion, without using composite circles to do so. He compiled his final results as the
376:
A recurring problem for both models was the lack of quality data, as the telescope had not been invented yet and naked eye observations are highly inaccurate. The Danish
36:. The debate continued during the Middle Ages, when the discussion centered upon whether the notion of extraterrestrial life was compatible with the doctrines of
1925:
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with seas. Kepler said that the Moon has an atmosphere and intelligent inhabitants, even writing a science fiction story about them. Dominican philosopher
1305:
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observations, and so refused his provisional results. Instead, he challenged the circular orbits and tried with other shapes. With orbits shaped as
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accepted the existence of extraterrestrial life, which became one of the charges leveled against him at the
Inquisition, leading to his execution.
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1597:
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follow complex paths and vary in their brightness. This was explained by adding other layers to the celestial sphere. This was detailed in the
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the universe. As a result, it can be reasoned that there is nothing special about Earth, and that life on other worlds should be plausible.
1215:
415:. First, he explained that an object in motion stays in motion unless a force stops it; a principle nowadays included in the first of
463:" (Italian for "And yet it moves"), but most historians doubt it, given the possible consequences Galileo would have faced if heard.
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worlds just as it did for humans on Earth, and did not consider fitting that God would repeatedly manifest at each different world.
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88:. Most ancient civilizations had great knowledge of astronomy but only used it for religious and practical needs.
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sought to gather such data, by creating huge naked-eye observatories. On his deathbed, he asked his assistant
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541:, the process by which life can be generated by non-living things, which is not yet completely understood.
419:. The idea of heavenly perfection was already being challenged by Tycho's observations. Tycho had observed
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thought that the four elements were exclusive to Earth and that the universe was made of a fifth one, the
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thought that all existence was composed by atoms, small and indivisible pieces of the four elements, and
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The Greek ideas and debates expanded across the ancient world, beyond Greece.
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thought that atoms should create other worlds the same way Earth was created.
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also revealed "imperfections" in celestial bodies: the sun was shown with
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180:, earth, water, fire and air. From there, they had two opposite ideas:
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the way it works. Chemistry and biochemistry also help to understand
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262:, and finally returned to Europe when many scholars escaped from the
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sought to go beyond that and explain the architecture of the cosmos.
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should leave a stellar parallax. Those concerns were addressed by
132:, but the Sun and the Moon move at different speeds and the other
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The extraterrestrial life debate antiquity to 1915: A source book
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432:
420:
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181:
71:
proposed that other worlds may have their own animals and plants.
29:
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covered by a celestial dome was soon discarded. Thales' student
1905:
1417:
1325:
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Besides that, there was much speculation. Galileo confused the
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281:
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of
Jupiter, celestial bodies orbiting another planet, and the
209:
156:
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made a series of military campaigns that expanded the Greek
1187:
525:
understanding of the context of such life or lack thereof.
1926:
Potential cultural impact of extraterrestrial contact
470:
they did so. The reason was finally explained by Sir
1306:Habitability of F-type main-sequence star systems
1296:Habitability of K-type main-sequence star systems
1963:
1593:Communication with extraterrestrial intelligence
45:study the idea under the scientific umbrella of
451:revealed that it is composed of several stars.
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254:became a hub of learning and trade during the
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171:) opposed the idea of a plurality of worlds.
16:Historical views about extraterrestrial life
1901:History of the extraterrestrial life debate
1598:Gauss's Pythagorean right triangle proposal
849:
847:
477:Philosophiæ Naturalis Principia Mathematica
326:was likely the first author to discuss the
1216:Planetary habitability in the Solar System
1005:
991:
423:, which proved that sometimes the heavens
1012:
871:
574:Not to be confused with Kepler's laws of
242:to the Middle East, founding the city of
1643:Search for extraterrestrial intelligence
1311:List of potentially habitable exoplanets
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1448:Living Interplanetary Flight Experiment
1964:
1349:Biological Oxidant and Life Detection
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1301:Habitability of yellow dwarf systems
1286:Habitability of neutron star systems
1046:Viking lander biological experiments
1276:Habitability of binary star systems
1251:Catalog of Nearby Habitable Systems
366:De revolutionibus orbium coelestium
276:European science in the Middle Ages
13:
1911:Nexus for Exoplanet System Science
1754:Hypothetical types of biochemistry
1281:Habitability of natural satellites
14:
2003:
1291:Habitability of red dwarf systems
391:Kepler's laws of planetary motion
52:
1443:Life Investigation For Enceladus
529:studies the nature of life, and
484:. This book also introduced the
328:death and resurrection of Christ
312:had been translated to Latin by
250:which was eventually destroyed.
246:in Egypt, which would house the
99:philosophers did not follow the
960:Crowe, Michael J., ed. (2008).
941:(4th ed.). United States:
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1433:Journey to Enceladus and Titan
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401:Galileo before the Holy Office
1:
1566:Berkeley SETI Research Center
1266:Extraterrestrial liquid water
585:
403:, a 19th-century painting by
75:During the early days of the
1982:Obsolete scientific theories
1886:Extraterrestrials in fiction
1759:Interplanetary contamination
1256:Circumstellar habitable zone
1140:(unusual light fluctuations)
1132:(unusual light fluctuations)
1124:(unusual light fluctuations)
486:law of universal gravitation
480:, which described the three
405:Joseph-Nicolas Robert-Fleury
28:, where it was supported by
7:
1744:Extraterrestrial hypothesis
427:change. The newly invented
10:
2008:
1458:Mars sample-return mission
917:Bennett & Shostak 2016
905:Bennett & Shostak 2016
881:Bennett & Shostak 2016
866:Bennett & Shostak 2016
854:Bennett & Shostak 2016
839:Bennett & Shostak 2016
827:Bennett & Shostak 2016
803:Bennett & Shostak 2016
731:Bennett & Shostak 2016
707:Bennett & Shostak 2016
647:Bennett & Shostak 2016
623:Bennett & Shostak 2016
611:Bennett & Shostak 2016
599:Bennett & Shostak 2016
369:in 1543, kickstarting the
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273:
224:, with proponents such as
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1992:Theological controversies
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1334:
1239:
1211:Earliest known life forms
1203:
1156:
1113:
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578:motion, mentioned earlier
284:. The only exception was
1576:Breakthrough Initiatives
966:University of Notre Dame
561:
1680:extraterrestrial beings
1271:Galactic habitable zone
964:. Notre Dame, Indiana:
496:nature works, but also
417:Newton's laws of motion
90:Ancient Greek astronomy
79:the things seen in the
59:Ancient Greek astronomy
1828:Planetarium hypothesis
1818:Hart–Tipler conjecture
1803:Dark forest hypothesis
1793:Aestivation hypothesis
1512:Venus In Situ Explorer
1316:Planetary habitability
1105:(misidentified quasar)
1097:(misidentified pulsar)
407:
357:
264:fall of Constantinople
172:
111:The initial idea of a
72:
1972:Extraterrestrial life
1931:Post-detection policy
1833:Rare Earth hypothesis
1658:Voyager Golden Record
1551:Allen Telescope Array
1386:Enceladus Life Finder
1321:Superhabitable planet
1014:Extraterrestrial life
933:Bennett, Jeffrey O.;
399:
371:Copernican Revolution
348:
341:Copernican Revolution
335:Copernican revolution
248:Library of Alexandria
155:
66:
42:Copernican Revolution
21:extraterrestrial life
1987:Religion and science
1977:History of astronomy
1921:Planetary protection
1808:Firstborn hypothesis
1798:Berserker hypothesis
1769:Mediocrity principle
1586:Breakthrough Message
1204:Life in the Universe
939:Life in the universe
318:Condemnation of 1277
296:discussed it in his
142:Aristarchus of Samos
77:history of astronomy
1734:Directed panspermia
1713:Reptilian humanoids
1581:Breakthrough Listen
1561:Arecibo Observatory
1507:Titan Mare Explorer
1080:Signals of interest
1040:Murchison meteorite
1028:Shergotty meteorite
435:, and the Moon has
361:Nicolaus Copernicus
236:Alexander the Great
86:ancient agriculture
1856:Ancient astronauts
1453:Mars Geyser Hopper
1381:Enceladus Explorer
1021:Events and objects
457:stellar aberration
408:
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290:Augustine of Hippo
256:Islamic Golden Age
220:spread across the
178:classical elements
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73:
1959:
1958:
1489:SpaceX Red Dragon
1404:Rosalind Franklin
1199:
1198:
1058:Allan Hills 84001
1052:Allan Hills 77005
975:978-0-268-02368-3
952:978-0-13-408908-9
547:planetary science
314:Gerard of Cremona
240:Macedonian Empire
134:classical planets
101:scientific method
96:Thales of Miletus
19:The existence of
1999:
1936:San Marino Scale
1876:Brookings Report
1823:Neocatastrophism
1729:Cosmic pluralism
1703:Little green men
1678:Types of alleged
1603:Astrolinguistics
1192:
1184:
1183:(unknown origin)
1180:Fast radio burst
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1148:(unknown origin)
1145:HD 164595 signal
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1034:Nakhla meteorite
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324:William Vorilong
299:Summa Theologica
260:Byzantine Empire
147:stellar parallax
121:celestial sphere
119:proposed a full
32:and rejected by
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1941:Technosignature
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1668:Xenolinguistics
1633:Project Phoenix
1623:Project Cyclops
1608:Lincos language
1571:Bracewell probe
1556:Arecibo message
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1428:Icebreaker Life
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413:Galileo Galilei
382:Johannes Kepler
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302:: according to
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231:De rerum natura
138:Ptolemaic model
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1838:Zoo hypothesis
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1795:
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1780:
1779:
1777:
1776:
1771:
1766:
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1756:
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1739:Drake equation
1736:
1731:
1725:
1723:
1719:
1718:
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1695:
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1670:
1665:
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1655:
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1640:
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1630:
1625:
1620:
1618:Pioneer plaque
1615:
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1573:
1568:
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1529:
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1478:
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1468:Northern Light
1465:
1460:
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1445:
1440:
1435:
1430:
1425:
1420:
1415:
1410:
1409:
1408:
1395:
1392:Europa Clipper
1388:
1383:
1378:
1371:
1364:
1356:
1351:
1346:
1340:
1338:
1336:Space missions
1332:
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1318:
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1207:
1205:
1201:
1200:
1197:
1196:
1194:
1193:
1191:(radio signal)
1185:
1177:
1175:(inconclusive)
1169:
1167:(radio source)
1160:
1158:
1154:
1153:
1151:
1150:
1142:
1134:
1129:EPIC 204278916
1126:
1117:
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1111:
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928:
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843:
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747:
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615:
603:
590:
589:
587:
584:
581:
580:
566:
565:
563:
560:
521:
518:
514:Giordano Bruno
482:laws of motion
461:Eppur si muove
441:Galilean moons
339:Main article:
336:
333:
309:On the Heavens
294:Thomas Aquinas
271:
268:
228:with his book
208:Aristotle and
57:Main article:
54:
53:Ancient Greece
51:
26:Ancient Greece
15:
9:
6:
4:
3:
2:
2004:
1993:
1990:
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1983:
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1788:
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1784:Fermi paradox
1781:
1775:
1772:
1770:
1767:
1765:
1762:
1760:
1757:
1755:
1752:
1750:
1749:Fermi paradox
1747:
1745:
1742:
1740:
1737:
1735:
1732:
1730:
1727:
1726:
1724:
1720:
1714:
1711:
1709:
1708:Nordic aliens
1706:
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1688:Energy beings
1686:
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1538:communication
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1248:
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1244:
1238:
1232:
1231:Life on Titan
1229:
1227:
1224:
1222:
1221:Life on Venus
1219:
1217:
1214:
1212:
1209:
1208:
1206:
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1189:
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1127:
1122:
1119:
1118:
1116:
1112:
1103:
1100:
1095:
1092:
1091:
1089:
1087:Misidentified
1085:
1082:
1078:
1071:
1068:
1065:
1064:Yamato 000593
1062:
1059:
1056:
1053:
1050:
1047:
1044:
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1038:
1035:
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1003:
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996:
994:
989:
988:
985:
977:
971:
967:
963:
958:
954:
948:
944:
940:
936:
935:Shostak, Seth
931:
930:
918:
913:
906:
901:
894:
889:
882:
877:
875:
867:
862:
855:
850:
848:
840:
835:
828:
823:
816:
811:
804:
799:
792:
787:
780:
775:
768:
763:
756:
751:
744:
739:
732:
727:
720:
715:
708:
703:
696:
691:
684:
679:
672:
667:
660:
655:
648:
643:
636:
631:
624:
619:
612:
607:
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595:
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571:
567:
559:
555:
553:
548:
544:
540:
536:
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528:
517:
515:
511:
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499:
495:
489:
487:
483:
479:
478:
473:
469:
464:
462:
458:
452:
450:
446:
442:
438:
437:many features
434:
430:
426:
422:
418:
414:
406:
402:
398:
394:
392:
388:
383:
379:
374:
372:
368:
367:
362:
355:
351:
347:
342:
332:
329:
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321:
319:
315:
311:
310:
305:
301:
300:
295:
291:
287:
283:
277:
267:
265:
261:
257:
253:
249:
245:
241:
237:
233:
232:
227:
223:
219:
214:
211:
206:
203:
199:
195:
191:
187:
186:Aristotelians
183:
179:
170:
166:
162:
158:
154:
150:
148:
143:
139:
135:
131:
126:
122:
118:
114:
109:
107:
102:
97:
93:
91:
87:
82:
78:
70:
65:
60:
50:
48:
43:
39:
35:
34:Aristotelians
31:
27:
22:
1946:UFO religion
1900:
1891:Extremophile
1871:Biosignature
1866:Astroecology
1861:Astrobiology
1813:Great Filter
1628:Project Ozma
1536:Interstellar
1523:
1516:
1494:
1482:Perseverance
1481:
1473:
1403:
1390:
1373:
1366:
1359:
1261:Earth analog
1243:habitability
1226:Life on Mars
961:
938:
927:Bibliography
919:, p. 51
912:
907:, p. 50
900:
895:, p. 35
888:
861:
856:, p. 29
834:
822:
817:, p. 37
810:
805:, p. 25
798:
793:, p. 27
786:
781:, p. 21
774:
762:
757:, p. 17
750:
745:, p. 15
738:
733:, p. 24
726:
714:
709:, p. 23
702:
697:, p. 13
690:
678:
666:
654:
642:
630:
618:
606:
594:
575:
570:
556:
552:astrobiology
535:biochemistry
523:
520:Modern times
507:
503:
497:
493:
490:
475:
474:in his book
472:Isaac Newton
467:
465:
460:
453:
424:
409:
400:
375:
364:
359:
322:
307:
297:
279:
270:Christianity
229:
222:Roman Empire
218:Epicureanism
215:
207:
174:
168:
160:
110:
94:
74:
47:astrobiology
38:Christianity
18:
1881:Exotheology
1693:Grey aliens
1546:Active SETI
1474:Opportunity
1354:BioSentinel
1172:Wow! signal
1121:KIC 8462852
1070:CI1 fossils
721:, p. 5
685:, p. 9
673:, p. 8
637:, p. 4
539:abiogenesis
510:lunar mares
421:a supernova
378:Tycho Brahe
356:observatory
350:Tycho Brahe
117:Anaximander
1966:Categories
1916:Noogenesis
1896:Hemolithin
1774:Panspermia
1722:Hypotheses
1698:Insectoids
1663:Water hole
1164:SHGb02+14a
1137:VVV-WIT-07
893:Crowe 2008
815:Crowe 2008
791:Crowe 2008
779:Crowe 2008
767:Crowe 2008
755:Crowe 2008
743:Crowe 2008
719:Crowe 2008
695:Crowe 2008
683:Crowe 2008
671:Crowe 2008
659:Crowe 2008
635:Crowe 2008
586:References
363:published
274:See also:
244:Alexandria
198:Democritus
125:Pythagoras
113:flat Earth
67:The Greek
1786:solutions
1653:setiQuest
1648:SETI@home
1463:Mars 2020
1438:Laplace-P
1375:Dragonfly
1360:Curiosity
1241:Planetary
576:planetary
531:chemistry
449:Milky Way
429:telescope
354:naked eye
304:John 1:10
226:Lucretius
194:Leucippus
165:Aristotle
130:naked eye
81:night sky
1638:SERENDIP
1613:NIROSETI
1525:Viking 2
1518:Viking 1
1423:Foton-M3
1413:ExoLance
1344:Beagle 2
937:(2016).
433:sunspots
387:ellipses
202:Epicurus
182:Atomists
106:geometry
69:Epicurus
30:atomists
1502:Tanpopo
1398:ExoMars
1102:CTA-102
1094:CP 1919
968:Press.
943:Pearson
543:Physics
527:Biology
352:in his
252:Baghdad
1906:MERMOZ
1495:Spirit
1418:EXPOSE
1368:Darwin
1326:Tholin
1072:(2011)
1066:(2000)
1060:(1984)
1054:(1977)
1048:(1976)
1042:(1969)
1036:(1911)
1030:(1865)
972:
949:
286:Origen
282:heresy
190:Aether
163:) and
40:. The
1497:rover
1484:rover
1476:rover
1406:rover
1362:rover
1157:Other
1114:Stars
562:Notes
210:Plato
169:right
157:Plato
1188:BLC1
970:ISBN
947:ISBN
533:and
196:and
161:left
498:why
494:how
468:why
1968::
945:.
873:^
846:^
554:.
425:do
393:.
266:.
234:.
140:.
49:.
1006:e
999:t
992:v
978:.
955:.
167:(
159:(
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
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