Radiant (meteor shower) Radiant (meteor shower) The radiant or apparent radiant of a meteor shower is the celestial point in the sky from which (from the point of view of a terrestrial observer) the paths of meteors appear to originate. The Perseids, for example, are meteors which appear to come from a point within the constellation of Perseus. Meteor paths appear at random locations in the sky, but the apparent paths of two or more meteors from the same shower will converge at the radiant. The radiant is the vanishing point of the meteor paths, which are parallel lines in three-dimensional space, as
Distance from a point to a line the perpendicular "R". Draw the vertical line through "P" and label its intersection with the given line "S". At any point "T" on the line, draw a right triangle "TVU" whose sides are horizontal and vertical line segments with hypotenuse "TU" on the given line and horizontal side of length |"B"| (see diagram). The vertical side of ∆"TVU" will have length |"A"| since the line has slope -"A"/"B". ∆"PRS" and ∆"TVU" are similar triangles, since they are both right triangles and ∠"PSR" ≅ ∠"TUV" since they are corresponding angles of a transversal to the parallel lines "PS" and "UV" (both