Most of the exoplanets that we detect today are very large and orbit very close to their star, and happen to pass between us and the star during their orbit. Th

Most of the exoplanets that we detect today are very large and orbit very close to their star, and happen to pass between us and the star during their orbit. This is why they are often referred to as "hot jupiters". We see them by seeing the dimming effect on the star as they transit between us, and we need to see a few tramsits to be sure that we are looking at an orbiting object and what orbital period it has. There are just a mind-boggling number of stars out there, making 5,000 hot jupiters a small number.