Movatterモバイル変換


[0]ホーム

URL:


Jump to content
WikipediaThe Free Encyclopedia
Search

Portal:Outer space

From Wikipedia, the free encyclopedia
Wikipedia's portal for exploring content related to Outer space
Portal maintenance status:(April 2019)
  • This portal'ssubpageshave been checked by an editor, and are needed.
Pleasetake care when editing, especially if usingautomated editing software. Learn how toupdate the maintenance information here.
The Outer Space Portal

Introduction

The lower half shows a blue planet with patchy white clouds. The upper half has a man in a white spacesuit and maneuvering unit against a black background.
Because of the hazards of a vacuum, astronauts must wear a pressurizedspace suit while off-Earth and outside their spacecraft.

Outer space, or simplyspace, is the expanse that exists beyondEarth's atmosphere and betweencelestial bodies. It contains ultra-lowlevels of particle densities, constituting anear-perfect vacuum of predominantlyhydrogen andheliumplasma, permeated byelectromagnetic radiation,cosmic rays,neutrinos,magnetic fields anddust. The baselinetemperature of outer space, as set by thebackground radiation from theBig Bang, is 2.7 kelvins (−270 °C; −455 °F).

Theplasma between galaxies is thought to account for about half of thebaryonic (ordinary) matter in the universe, having anumber density of less than onehydrogen atom per cubic metre and akinetic temperature of millions ofkelvins. Local concentrations of matter have condensed intostars andgalaxies. Intergalactic space takes up most of the volume of theuniverse, but even galaxies andstar systems consist almost entirely of empty space. Most of the remainingmass-energy in theobservable universe is made up of an unknown form, dubbeddark matter anddark energy.

Outer space does not begin at a definite altitude above Earth's surface. TheKármán line, an altitude of 100 km (62 mi) abovesea level, is conventionally used as the start of outer space in space treaties and for aerospace records keeping. Certain portions of the upperstratosphere and themesosphere are sometimes referred to as "near space". The framework for internationalspace law was established by theOuter Space Treaty, which entered into force on 10 October 1967. This treaty precludes any claims ofnational sovereignty and permits all states to freelyexplore outer space. Despite the drafting ofUN resolutions for the peaceful uses of outer space,anti-satellite weapons have been tested inEarth orbit.

The concept that the space between the Earth and the Moon must be a vacuum was first proposed in the 17th century after scientists discovered thatair pressure decreased with altitude. The immense scale of outer space was grasped in the 20th century when the distance to theAndromeda Galaxy was first measured. Humans began the physical exploration of space later in the same century with the advent of high-altitudeballoon flights. This was followed by crewedrocket flights and, then, crewed Earth orbit, first achieved byYuri Gagarin of theSoviet Union in 1961. The economic cost of putting objects, including humans, into space is very high, limiting humanspaceflight tolow Earth orbit and theMoon. On the other hand,uncrewed spacecraft have reached all of the knownplanets in theSolar System. Outer space represents a challenging environment forhuman exploration because of the hazards ofvacuum andradiation.Microgravity has a negative effect on humanphysiology that causes bothmuscle atrophy andbone loss. (Full article...)

Selected article

The Earth seen from Apollo 17

Planetary habitability is the measure of an astronomical body's potential for developing and sustaining life. It may be applied both toplanets and to thenatural satellites of planets. The only absolute requirement for life is anenergy source (usually but not necessarilysolar energy), but the notion of planetary habitability implies that many othergeophysical,geochemical, andastrophysical criteria must be met before an astronomical body is able to support life. The idea that planets beyond Earth might host life is an ancient one, though historically it was framed byphilosophy as much asphysical science. The late 20th century saw two breakthroughs in the field. To begin with, the observation and roboticexploration of other planets and moons within the solar system has provided critical information on defining habitability criteria and allowed for substantial geophysical comparisons between the Earth and other bodies. The discovery ofextrasolar planets—beginning in 1995 and accelerating thereafter—was the second milestone. It confirmed that the Sun is not unique in hosting planets and expanded the habitability research horizon beyond our own solar system.

Selected picture

Space-related portals

General images

The following are images from various outer space-related articles on Wikipedia.

Did you know(auto-generated)

Space news

2025 in space
Space probe launchesSpace probes launched in 2025


SelectedNEOs
Discoveries
ExoplanetsExoplanets discovered in 2025
CometsComets in 2025
Novae
Space exploration
Miscellaneous events

Upcoming spaceflight launches

For a full schedule of launches and deep-space rendezvous, see2025 in spaceflight.

Astronomical events

Celestial events by month
2025
2024
2023
2022
2021
2020
2019
2018
2017
2016
2015
2014
2013
2012
2011
2010
2009
2008
2007
2006
2005

Topics

Molecules
Diatomic








Triatomic
Four
atoms
Five
atoms
Six
atoms
Seven
atoms
Eight
atoms
Nine
atoms
Ten
atoms
or more
Deuterated
molecules
Unconfirmed
Related
By year
2020 in space
Space probe
launches
Space probes launched in 2020


Impact events
Selected
NEOs
ExoplanetsExoplanets discovered in 2020
Discoveries
CometsComets in 2020
Space
exploration
2019 in space
Space probe
launches
Space probes launched in 2019


Impact events
SelectedNEOs
ExoplanetsExoplanets discovered in 2019
Discoveries
CometsComets in 2019
Space exploration
2018 in space
Space probe
launches
Space probes launched in 2018


Impact events
SelectedNEOs
ExoplanetsExoplanets discovered in 2018
Discoveries
Novae
CometsComets in 2018
Space exploration
2017 in space
Space probe launchesSpace probes launched in 2017
  • ASTERIA (miniature space telescope; August 2017)


Impact events
SelectedNEOs
ExoplanetsExoplanets discovered in 2017
Discoveries
CometsComets in 2017
Space exploration
2016 in space
Space probe launchesSpace probes launched in 2016

Juno spacecraft with Jupiter in the background
Depiction of a planet with a rocky landscape orbiting the Alpha Centauri star system.
Impact events
SelectedNEOs
ExoplanetsExoplanets discovered in 2016
Discoveries
Novae
CometsComets in 2016
Space exploration
2015 in space
Space probe launchesSpace probes launched in 2015
Space probes
Space observatories
  • DSCOVR (weather satellite; Feb 2015)
  • Astrosat (space telescope; Sep 2015)


Impact events
SelectedNEOs
ExoplanetsExoplanets discovered in 2015
Discoveries
CometsComets in 2015
Space exploration

Categories

Wikimedia

The followingWikimedia Foundation sister projects provide more on this subject:

Discover Wikipedia usingportals
Purge server cache
Retrieved from "https://en.wikipedia.org/w/index.php?title=Portal:Outer_space&oldid=1298416202"
Categories:
Hidden categories:

[8]ページ先頭

©2009-2025 Movatter.jp