What is in space besides planets and stars?
Most of the universe is empty space, called a vacuum, but it is an imperfect vacuum. There are clouds of interstellar dust and the tiny particles that make up the solar wind. There are many isolated particles and hydrogen atoms, which sometimes form clouds over a billion kilometers wide called “nebulae.” Besides nebulae and interstellar dust, there are also bits of rubble as big as small moons to as small as grains of sand. These bits of rubble are called planetoids and asteroids. Radio, heat, and x-rays all echo through space, as do beams of light. There is radiation bursting forth in solar flares. The Orion Nebula. Image from NASA’s Observatorium, http://observe.ivv.nasa.gov/nasa/core.shtml In addition, we humans are putting quite a lot into space around our planets, both satellites and probes and “space junk” caused by spacecraft falling apart in space. Perhaps there are similar rings of manufactured items around other planets far, far away…
