Outer space
Outer space, or simply space, is the expanse that exists beyond Earth's air around a planet and between celestial bodies. It contains ultra-low levels of particle densities. Constituting a near-perfect vacuum of predominantly hydrogen and helium plasma, permeated by electromagnetic radiation, cosmic rays, neutrinos, magnetic fields and dust.
Visste du att?
- A lightning bolt can be up to five times hotter than the surface of the sun!
- It can rain fish and frogs! This happens when strong winds lift them from water.
- The coldest temperature ever recorded was -89°C in Antarctica!
The baseline how hot or cold of outer space. As set by the background radiation from the Big Bang, is 2.7 kelvins (−270 °C; −455 °F). The plasma between galaxies is thought to account for about half of the baryonic (ordinary) matter in the universe.
Having a number how tightly packed of less than one hydrogen atom per cubic metre and a kinetic how hot or cold of millions of kelvins. Local concentrations of matter have condensed into stars and galaxies. Intergalactic space takes up most of the volume of the universe, but even galaxies and star systems consist almost entirely of empty space.
Most of the remaining mass-energy in the observable universe is made up of an unknown form. Dubbed dark matter and dark energy. Outer space does not begin at a definite height above Earth's surface.
The Kármán line, an height of 100 km (62 mi) above sea level, is conventionally used.
Vad betyder det här?
Texten kommer från Wikipedia och har förenklats för barn. CC BY-SA 4.0 | Från Wikipedia