Scientists have solved a long-standing space mystery — the origin of the ‘theta aurora’. Auroras are the most visible manifestation of the Sun’s effect on Earth. They are seen as colorful displays in the night sky, known as the Northern or Southern Lights. They are caused by the solar wind, a stream of plasma — electrically charged atomic particles — carrying its own magnetic field, interacting with the earth’s magnetic field. Normally, the main region for this impressive display is the ‘auroral oval’, which lies at around 65-70 degrees north or south of the equator, encircling the polar caps. However, auroras can occur at even higher latitudes. One type is known as a ‘theta aurora’ because seen from above it looks like the Greek letter theta — an oval with a line crossing through the center.