Meteors are lumps of rock which are floating about in space. There are always meteors which are entering the earth’s atmosphere. They normally burn up in the atmosphere. A few very large ones that hit the earth are called 'meteorites'. Most meteors are only tiny specks of dust. As they enter the atmosphere the heat made by air friction rips off electrons. This produces an ionized trail. This trail can reflect radio waves in the same way that a wire would.