The Kuiper belt (/ ˈ k aɪ p ər /) is a circumstellar disc in the outer Solar System, extending from the orbit of Neptune at 30 astronomical units (AU) to approximately 50 AU from the Sun. It is similar to the asteroid belt, but is far larger—20 times as wide and 20–200 times as massive. Like the asteroid belt, it consists mainly of small bodies or remnants from when the Solar System …

The Space Shuttle orbiter is the spaceplane component of the Space Shuttle, a partially reusable orbital spacecraft system that was part of the discontinued Space Shuttle program.Operated from 1977 to 2011 by NASA, the U.S. space agency, this vehicle could carry astronauts and payloads into low Earth orbit, perform in-space operations, then re-enter the …

A nebula ('cloud' or 'fog' in Latin; pl. nebulae, nebulæ or nebulas) is a distinct luminescent part of interstellar medium, which can consist of ionized, neutral or molecular hydrogen and also cosmic dust.Nebulae are often star-forming regions, such as in the "Pillars of Creation" in the Eagle Nebula.In these regions, the formations of gas, dust, and other materials "clump" together to …

Helium accumulates in the cores of stars as a result of the proton–proton chain reaction and the carbon–nitrogen–oxygen cycle.. Nuclear fusion reaction of two helium-4 nuclei produces beryllium-8, which is highly unstable, and decays back into smaller nuclei with a half-life of 8.19 × 10 −17 s, unless within that time a third alpha particle fuses with the beryllium-8 nucleus to ...

Use of NASA logos, insignia and emblems is restricted per U.S. law 14 CFR 1221.; The NASA website hosts a large number of images from the Soviet/Russian space agency, and other non-American space agencies.These are not necessarily in the public domain.; Materials based on Hubble Space Telescope data may be copyrighted if they are not explicitly produced by the …

Jump to the list of frequently discussed sources. The following presents a non-exhaustive list of sources whose reliability and use on Wikipedia are frequently discussed. This list summarizes prior consensus and consolidates links to the most in-depth and recent discussions from the reliable sources noticeboard and elsewhere on Wikipedia.. Context matters tremendously, and …

This is an index of lists of shipwrecks, sorted by different criteria.

Outer space is the closest known approximation to a perfect vacuum.It has effectively no friction, allowing stars, planets, and moons to move freely along their ideal orbits, following the initial formation stage. The deep vacuum of intergalactic space is not devoid of matter, as it contains a few hydrogen atoms per cubic meter. By comparison, the air humans breathe contains about …

Vital articles on Wikipedia are written about important topics, organized into five list levels in decreasing importance: 1 (10 articles), 2 (100 articles), 3 (1000 articles), 4 (10,000 articles) and 5 (50,000 articles).. The articles are organized into groups of topics, with lower levels having more granular subdivisions. The lists serve as guidance to prioritize improvement of important ...

The economy of Luxembourg is largely dependent on the banking, steel, and industrial sectors. Luxembourgers enjoy the highest per capita gross domestic product in the world (IMF 2022 est.). Although Luxembourg in tourist literature is aptly called the "Green Heart of Europe", its pastoral land coexists with a highly industrialized and export-intensive area. Luxembourg's economy is …