Gaia (spacecraft)

Gaia is a space observatory of the European Space Agency (ESA) designed for astrometry. The mission aims to construct a 3D space catalog of approximately 1 billion astronomical objects, mainly stars (approximately 1% of the Milky Way population) brighter than 20 G magnitude, where G is the Gaia magnitude passband between about 400 and 1000 nanometres light wavelengths. Additionally Gaia is expected to detect thousands to tens of thousands of Jupiter-sized planets beyond the Solar System, 500,000 quasars and tens of thousands of new asteroids and comets within the Solar System. The spacecraft will monitor each of its target stars about 70 times over a period of five years.

Gaia will create a precise three-dimensional map of astronomical objects throughout the Milky Way and map their motions, which encode the origin and subsequent evolution of the Milky Way. The spectrophotometric measurements will provide the detailed physical properties of all stars observed, characterizing their luminosity, effective temperature, gravity and elemental composition. This massive stellar census will provide the basic observational data to tackle a wide range of important questions related to the origin, structure, and evolutionary history of our galaxy.

Gaia

Gaia or Gaea may refer to:

Environmentalism

Science and technology

Film and television

Milky Way

The Milky Way is the galaxy that contains our Solar System. Its name "milky" is derived from its appearance as a dim glowing band arching across the night sky whose individual stars cannot be distinguished by the naked eye. The term "Milky Way" is a translation of the Latin via lactea, from the Greek γαλαξίας κύκλος (galaxías kýklos, "milky circle"). From Earth, the Milky Way appears as a band because its disk-shaped structure is viewed from within. Galileo Galilei first resolved the band of light into individual stars with his telescope in 1610. Until the early 1920s, most astronomers thought that the Milky Way contained all the stars in the Universe. Following the 1920 Great Debate between the astronomers Harlow Shapley and Heber Curtis, observations by Edwin Hubble showed that the Milky Way is just one of many galaxies—now estimated to number as many as 200 billion galaxies in the observable universe.

The Milky Way is a barred spiral galaxy that has a diameter usually considered to be about 100,000–120,000 light-years but may be 150,000–180,000 light-years. The Milky Way is estimated to contain 100–400 billion stars, although this number may be as high as one trillion. There are probably at least 100 billion planets in the Milky Way. The Solar System is located within the disk, about 27,000 light-years from the Galactic Center, on the inner edge of one of the spiral-shaped concentrations of gas and dust called the Orion Arm. The stars in the inner ≈10,000 light-years form a bulge and one or more bars that radiate from the bulge. The very center is marked by an intense radio source, named Sagittarius A*, which is likely to be a supermassive black hole.

List of government space agencies

This is a list of government agencies engaged in activities related to outer space and space exploration.

As of 2015, 70 different government space agencies are in existence; 13 of those have launch capability. Six government space agencies - the China National Space Administration (CNSA), the European Space Agency (ESA), the Indian Space Research Organisation (ISRO), the Japan Aerospace Exploration Agency (JAXA), the National Aeronautics and Space Administration (NASA) and the Russian Federal Space Agency (RFSA or Roscosmos) - have full launch capabilities; these include the ability to launch and recover multiple satellites, deploy cryogenic rocket engines and operate extraterrestrial probes. Only three currently operating government space agencies in the world - NASA, the RFSA and the CNSA - are capable of human spaceflight.

The name given is the English version, with the native language version below. The acronym given is the most common acronym: this can either be the acronym of the English version (e.g. JAXA), or the acronym in the native language. Where there are multiple acronyms in common use, the English one is given first.

European Space Agency

The European Space Agency (ESA) is an intergovernmental organisation dedicated to the exploration of space, with 22 member states. Established in 1975 and headquartered in Paris, France, ESA has a staff of more than 2,000 with an annual budget of about €4.28 billion / US$5.51 billion (2013).

ESA's space flight programme includes human spaceflight, mainly through the participation in the International Space Station programme, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. The main European launch vehicle Ariane 5 is operated through Arianespace with ESA sharing in the costs of launching and further developing this launch vehicle.

Its facilities are distributed among the following 5 research centres: