Trousers

Trousers (pants in North America) are an item of clothing worn from the waist to the ankles, covering both legs separately (rather than with cloth extending across both legs as in robes, skirts, and dresses).

In the UK the word "pants" generally means underwear and not trousers.Shorts are similar to trousers, but with legs that come down only to around the area of the knee, higher or lower depending on the style of the garment. To distinguish them from shorts, trousers may be called "long trousers" in certain contexts such as school uniform, where tailored shorts may be called "short trousers", especially in the UK.

In most of the Western world, trousers have been worn since ancient times and throughout the Medieval period, becoming the most common form of lower-body clothing for adult males in the modern world, although shorts are also widely worn, and kilts and other garments may be worn in various regions and cultures. Breeches were worn instead of trousers in early modern Europe by some men in higher classes of society. Since the mid-20th century, trousers have increasingly been worn by women as well. Jeans, made of denim, are a form of trousers for casual wear, now widely worn all over the world by both sexes. Shorts are often preferred in hot weather or for some sports and also often by children and teenagers. Trousers are worn on the hips or waist and may be held up by their own fastenings, a belt or suspenders (braces). Leggings are form-fitting trousers, of a clingy material, often knitted cotton and spandex (elastane).

Space observatory

A space observatory is any instrument (such as a telescope) in outer space that is used for observation of distant planets, galaxies and other outer space objects. The first such space observatory was the Hubble Space Telescope launched in 1990. Space observatories avoid many of the problems of ground observatories, such as light pollution and the filtering and distortion of electromagnetic radiation (scintillation).

This category is distinct from other observatories located in space that are pointed toward Earth for the purpose of reconnaissance and other types of information gathering.

History

In 1946, American theoretical astrophysicist Lyman Spitzer was the first to conceive the idea of a telescope in outer space, a decade before the Soviet Union launched the first satellite, Sputnik 1.

Spitzer's proposal called for a large telescope that would not be hindered by Earth's atmosphere. After lobbying in the 1960s and 70s for such a system to be built, Spitzer's vision ultimately materialized into the Hubble Space Telescope, which was launched on April 24, 1990 by the Space Shuttle Discovery (STS-31).

Spitzer Space Telescope

The Spitzer Space Telescope (SST), formerly the Space Infrared Telescope Facility (SIRTF), is an infrared space observatory launched in 2003. It is the fourth and final of the NASA Great Observatories program.

The planned mission period was to be 2.5 years with a pre-launch expectation that the mission could extend to five or slightly more years until the onboard liquid helium supply was exhausted. This occurred on 15 May 2009. Without liquid helium to cool the telescope to the very low temperatures needed to operate, most of the instruments are no longer usable. However, the two shortest-wavelength modules of the IRAC camera are still operable with the same sensitivity as before the cryogen was exhausted, and will continue to be used in the Spitzer Warm Mission. All Spitzer data, from both the primary and warm phases, are archived at the Infrared Science Archive (IRSA).

In keeping with NASA tradition, the telescope was renamed after its successful demonstration of operation, on 18 December 2003. Unlike most telescopes that are named after famous deceased astronomers by a board of scientists, the new name for SIRTF was obtained from a contest open to the general public.

NASA

Coordinates: 38°52′59″N 77°0′59″W / 38.88306°N 77.01639°W / 38.88306; -77.01639

The National Aeronautics and Space Administration (NASA) is the agency of the United States Federal Government responsible for the civilian space program as well as aeronautics and aerospace research.

President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA's predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

Since that time, most US space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle, the Space Launch System and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches.

Solar System

The Solar System is the gravitationally bound system comprising the Sun and the objects that orbit it, either directly or indirectly. Of those objects that orbit the Sun directly, the largest eight are the planets, with the remainder being significantly smaller objects, such as dwarf planets and small Solar System bodies. Of the objects that orbit the Sun indirectly, the moons, two are larger than the smallest planet, Mercury.

The Solar System formed 4.6 billion years ago from the gravitational collapse of a giant interstellar molecular cloud. The vast majority of the system's mass is in the Sun, with most of the remaining mass contained in Jupiter. The four smaller inner planets, Mercury, Venus, Earth and Mars, are terrestrial planets, being primarily composed of rock and metal. The four outer planets are giant planets, being substantially more massive than the terrestrials. The two largest, Jupiter and Saturn, are gas giants, being composed mainly of hydrogen and helium; the two outermost planets, Uranus and Neptune, are ice giants, being composed mostly of substances with relatively high melting points compared with hydrogen and helium, called ices, such as water, ammonia and methane. All planets have almost circular orbits that lie within a nearly flat disc called the ecliptic.