Coins were invented in the Kingdom of Lydia, in what is now western Turkey, in about 620 BCE. (They were independently invented in China in about 1000 BCE, but this was not known in Europe.) The idea soon spread to the independent city states of Ionia on the Aegean coast, and then to the rest of the Greek world, which extended at that time from the Black Sea to Sicily and southern Italy. The...
The Greeks are believed to have migrated southward into the Greek peninsula in several waves beginning in the late 3rd millennium BC, the last being the Dorian invasion. The period from 1600 BC to about 1100 BC is described in History of Mycenaean Greece known for the reign of King Agamemnon and the wars against Troy as narrated in the epics of Homer. The period from 1100 BC to the 8th century BC...
The ancient Egyptian calendar was a solar calendar with a 365-day year. The year consisted of three seasons of 120 days each, plus an intercalary month of 5 epagomenal days treated as outside of the year proper. Each season was divided into four months of 30 days. These twelve months were initially numbered within each season but came to also be known by the names of their principal festivals...
Mercury is the innermost planet in the Solar System. It is also the smallest, and its orbit is the most eccentric (that is, the least perfectly circular) of the eight planets. It orbits the Sun once in about 88 Earth days, completing three rotations about its axis for every two orbits. The planet is named after the Roman god Mercury, the messenger to the gods. Mercury’s surface is heavily...
March 13, 2013 Martians … Entities from Mars … are all part of the things we read about or see in media. We find references to Martians in films, literature, channelings, art, alien abductions, and perhaps physical evidence found across the landscape of planet Earth and below the surface. Many believe. Others don’t. None of it seems important without the physical proof so many...
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System after Mercury. In English, Mars carries a name of the Roman god of war, and is often referred to as the “Red Planet” because the iron oxide prevalent on its surface gives it a reddish appearance that is distinctive among the astronomical bodies visible to the naked eye. Mars is a terrestrial...
Lagrange Points also L-points, are the five positions in an orbital configuration where a small object affected only by gravity can theoretically be stationary relative to two larger objects (such as a satellite with respect to the Earth and Moon). The Lagrange points mark positions where the combined gravitational pull of the two large masses provides precisely the centripetal force required to...
A small but bright northern constellation lying between DECL=+30 and DECL=+40 and RA=18h and RA=19h. The fifth-brightest star of the sky, alpha Lyr, called Vega (arabic for “stone eagle”), radiates from the top Lyra with a pure white colour. Together with alpha Cyg, Deneb , and alpha Aql, Atair, Vega forms the Summer Triangle. Stars and other objects Beta Lyr is a half separated (i.e...
The Kuiper belt is an area of the solar system extending from the orbit of Neptune (at 30 AU) to 50 AU from the Sun. The Kuiper belt is similar to the asteroid belt, although it is vastly larger. It consists mainly of small bodies; remenants from the Solar System’s formation, though a fair portion of its material has condensed into dwarf planets. But while the asteroid belt is composed...
The exploration of Jupiter has been conducted via close observations by automated spacecraft. It began with the arrival of Pioneer 10 into the Jovian system in 1973, and, as of 2014, has continued with seven further spacecraft missions. All of these missions were undertaken by the National Aeronautics and Space Administration (NASA), and all but one have been flybys that take detailed...