ⓘ Outer space ..

Interplanetary dust cloud

The interplanetary dust cloud, or zodiacal cloud, consists of cosmic dust that pervades the space between planets within planetary systems such as the Solar System. This system of particles has been studied for many years in order to understand its nature, origin, and relationship to larger bodies. In our Solar System, the interplanetary dust particles have a role in scattering sunlight and in emitting thermal radiation, which is the most prominent feature of the night skys radiation with wavelengths ranging 5–50 μm. The particle sizes of grains characterizing the infrared emission near Ea ...

Space geodesy

Space geodesy is geodesy by means of sources external to Earth, mainly artificial satellites but also quasars and the retroreflectors on the Moon.

Interplanetary medium

The interplanetary medium is the material which fills the Solar System, and through which all the larger Solar System bodies, such as planets, dwarf planets, asteroids, and comets, move.

Karman line

The Karman line is an attempt to define a boundary between Earths atmosphere and outer space. This is important for legal and regulatory measures; aircraft and spacecraft fall under different jurisdictions and are subject to different treaties. The Federation Aeronautique Internationale FAI; English: World Air Sports Federation, an international standard-setting and record-keeping body for aeronautics and astronautics, defines the Karman line as the altitude of 100 kilometres 62 miles; 330.000 feet above Earths mean sea level. Other organizations do not use this definition. For instance, t ...

Interplanetary magnetic field

The interplanetary magnetic field, now more commonly referred to as the heliospheric magnetic field, is the component of the solar magnetic field that is dragged out from the solar corona by the solar wind flow to fill the Solar System.

Interstellar medium

In astronomy, the interstellar medium is the matter and radiation that exists in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, as well as dust and cosmic rays. It fills interstellar space and blends smoothly into the surrounding intergalactic space. The energy that occupies the same volume, in the form of electromagnetic radiation, is the interstellar radiation field. The interstellar medium is composed of multiple phases distinguished by whether matter is ionic, atomic, or molecular, and the temperature and density of the ma ...

Intracluster medium

In astronomy, the intracluster medium is the superheated plasma that permeates a galaxy cluster. The gas consists mainly of ionized hydrogen and helium and accounts for most of the baryonic material in galaxy clusters. The ICM is heated to temperatures on the order of 10 to 100 megakelvins, emitting strong X-ray radiation.

Space force

A space force is a military branch that prepares for or conducts space warfare. As of January 2020, the only nation with an independent space force is the United States, which established the United States Space Force in December 2019. Russia has had an organized and independent military branch space force twice, first from 1992 to 1997, and then from 2001 to 2011.