astronomy

History of astronomy

Astronomy is the oldest of the natural sciences, dating back to antiquity, with its origins in the religious, mythological, and astrological practices of pre-history: vestiges of these are still found in astrology, a discipline long interwoven with public and governmental astronomy, and not completely disentangled from it until a few centuries ago in the Western World (see astrology and astronomy). Early astronomy involved observing the regular patterns of the motions of visible celestial objects, especially the Sun, Moon, stars and naked eye planets. An example of this early astronomy might involve a study of the changing position of the Sun along the horizon or the changing appearances of stars in the course of the year, which could be used to establish an agricultural or ritual calendar. In some cultures astronomical data was used for astrological prognostication.

People in the history

Background
Pythagoras
Ptolemy
Copernicus
Johannes Kepler
Galileo Galilei
Sir Isaac Newton
Edmund Halley
Albert Einstein
Stephen Hawking

What is the Universe?

The Universe is defined as everything that physically exists: the entirety of space and time, all forms of matter, energy and momentum, and the physical laws and constants that govern them. However, the term Universe may be used in slightly different contextual senses, denoting such concepts as the cosmos, the world or Nature

Milky Way

The Milky Way is the galaxy which is the home of our Solar System together with at least 200 billion other stars (more recent estimates have given numbers around 400 billion) and their planets, and thousands of clusters and nebulae, including at least almost all objects of Messier's catalog which are not galaxies on their own (one might consider two globular clusters as possible exceptions, as probably they are just being, or have recently been, incorporated or imported into our Galaxy from dwarf galaxies which are currently in close encounters with the Milky Way: M54 from SagDEG, and possibly M79 from the Canis Major Dwarf). See our Messier Objects in the Milky Way page, where details are given for each object to which part of our Galaxy it is related. All the objects in the Milky Way Galaxy orbit their common center of mass, called the Galactic Center (see below).

The Sun

The Sun (Latin: Sol), a yellow dwarf, is the star at the center of the Solar System. The Earth and other matter (including other planets, asteroids, meteoroids, comets, and dust) orbit the Sun,[9] which by itself accounts for about 98.6% of the Solar System's mass. The mean distance of the Sun from the Earth is approximately 149,600,000 kilometers, or 92,960,000 miles, and its light travels this distance in 8 minutes and 19 seconds. Energy from the Sun, in the form of sunlight, supports almost all life on Earth via photosynthesis,[10] and drives the Earth's climate and weather.

The moon

The Moon (Latin: Luna) is Earth's only natural satellite and the fifth largest satellite in the Solar System. The average centre-to-centre distance from the Earth to the Moon is 384,403 km, about thirty times the diameter of the Earth. The common centre of mass of the system (the barycentre) is located about 1,700 km—a quarter the Earth's radius—beneath the surface of the Earth. The Moon makes a complete orbit around the Earth every 27.3 days (the orbital period), and the periodic variations in the geometry of the Earth–Moon–Sun system are responsible for the lunar phases that repeat every 29.5 days (the synodic period).

Comets

A comet is a Small Solar System Body that orbits the Sun. When close enough to the Sun, a comet exhibits a visible coma (fuzzy "atmosphere"), and sometimes a tail, both because of the effects of solar radiation upon the comet's nucleus. Comet nuclei are themselves loose collections of ice, dust and small rocky particles, ranging from a few kilometers to tens of kilometers across. The word "comet" came to the English language through the Latin cometes from the Greek word komē, meaning "hair of the head"; Aristotle first used the derivation komētēs to depict comets as "stars with hair." The astronomical symbol for comets (☄) accordingly consists of a disc with a hairlike tail.

Planets
A planet is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.


The Earth
Earth, our home planet, is a beautiful blue and white ball when seen from space. The third planet from the Sun, it is the largest of the inner planets. Earth is the only planet known to support life and to have liquid water at the surface

The atmosphere
The atmosphere surrounds Earth and protects us by blocking out dangerous rays from the sun. The atmosphere is a mixture of gases that becomes thinner until it gradually reaches space. It is composed of Nitrogen (78%), Oxygen (21%), and other gases (1%).
Oxygen is essential to life because it allows us to breathe. Some of the oxygen has changed over time to ozone. The the ozone layer filters out the sun's harmful rays. Recently, there have been many studies on how humans have caused a hole in the ozone layer.
Humans are also affecting Earth's atmosphere through the greenhouse effect. Due to increases in gases, like carbon dioxide, that trap heat being radiated from the Earth, scientists believe that the atmosphere is having trouble staying in balance creating the greenhouse effect .
The atmosphere is divided into five layers depending on how temperature changes with height. Most of the weather and clouds are found in the first layer.

The forest

The forest is a complex ecosystem consisting mainly of trees that buffer the earth and support a myriad of life forms. The trees help create a special environment which, in turn, affects the kinds of animals and plants that can exist in the forest. Trees are an important component of the environment. They clean the air, cool it on hot days, conserve heat at night, and act as excellent sound absorbers.

Arboletum lussich

On October 5, 1896, Antonio Lussich, owner of a marine salvage company, bought a plot of 1800 hectares, extending from the Potrero Creek in the Sierra de la Ballena and the Silver River to the Laguna del Sauce , at which time there were only rocks and sand dunes. The following year Lussich Antonio began the work of afforestation which were, first afforest the hills, trying to stop the winds, and secondly, once formed the woods, populated with birds. To this end Antonio Lussich through the maritime salvage company and earned worldwide contacts, it was able to obtain seeds and plants from all continents. In an unprecedented move for the time purchased plants and trees from all regions of the world, and next to the mansion as his residence, built sombráculos for plants and aviaries for birds brought in from around the world.
The east side of the mountains, sheltered from the strongest winds from the southwest, was the place for the preparation of seedlings and nursery. Once germinated, and with some development, the plants were carried by the thousands across the mountains, without the shelter. The first to be planted were Tamarix, maritime pines, Eucalyptus and Acacia trinervis to fight the wind and sand. After 30 years were introduced during the most diverse. In December 1979, 182 has passed into the hands of the Municipality of Maldonado, who after being reconditioned, are open to the public. The year 1990 has added 10 more to the 192 currently has the Park. The Arboretum is one of the largest forest reserves worldwide.