The Jupiter Trojans, commonly called Trojans or Trojan asteroids, are a large group of objects that share the orbit of the planet Jupiter around the Sun. Relative to Jupiter, each Trojan librates around one of the planet's two Lagrangian points of stability, L4 and L5, that respectively lie 60° ahead of and behind the planet in its orbit. Trojan asteroids are distributed in two elongated, curved regions around these Lagrangian points with an average semi-major axis of about 5.2 AU.The first Trojan discovered, 588 Achilles, was spotted in 1906 by the German astronomer Max Wolf.A total of 2,909 Jupiter Trojans have been found as of January 2009. The term "Trojan" derives from the fact that, by convention, they are each named after a mythological figure from the Trojan War. The total number of Jupiter Trojans larger than 1 km is believed to be about 1 million, approximately equal to the number of asteroids larger than 1 km in the main asteroid belt.[1] Like main belt asteroids, Trojans form families.
Jupiter Trojans are dark bodies with reddish, featureless spectra. No firm evidence of the presence of water, organic matter or other chemical compounds on their surfaces has been obtained. The Trojans' densities (as measured by studying binaries or rotational lightcurves) vary from 0.8 to 2.5 g·cm−3. Trojans are thought to have been captured into their orbits during the early stages of the Solar System's formation or slightly later, during the migration of giant planets.

History of science

Science is a body of empirical, theoretical, and practical knowledge about the natural world, produced by researchers making use of scientific methods, which emphasize the observation, explanation, and prediction of real world phenomena by experiment. Given the dual status of science as objective knowledge and as a human construct, good historiography of science draws on the historical methods of both intellectual history and social history.
Tracing the exact origins of modern science is possible through the many important texts which have survived from the classical world. However, the word scientist is relatively recent—first coined by William Whewell in the 19th century. Previously, people investigating nature called themselves natural philosophers.
While empirical investigations of the natural world have been described since classical antiquity (for example, by Thales, Aristotle, and others), and scientific methods have been employed since the Middle Ages (for example, by Ibn al-Haytham, Abū Rayhān al-Bīrūnī and Roger Bacon), the dawn of modern science is generally traced back to the early modern period, during what is known as the Scientific Revolution that took place in 16th and 17th century Europe.
Scientific methods are considered to be so fundamental to modern science that some — especially philosophers of science and practicing scientists — consider earlier inquiries into nature to be pre-scientific. Traditionally, historians of science have defined science sufficiently broadly to include those inquiries.