An international team of scientists, has observed six stars similar to the Sun with extraordinary dust belts. The newly discovered debris disks are not only bigger than the Kuiper belt. Above all they are extremely cold with a temperature of about minus 250C they are the coldest debris disks known so far. The Kuiper belt is about 70C degree warmer, some of the dust disks even reach room temperature. The six debris disks are lacking the characteristic dust which is always released when the rocks collide.
Small dust particles are much hotter than the temperatures. According to this, the cold debris disks only consist of bigger but at the same time not-too-big rocks. The radius of the particles lies between several millimeters and several kilometers maximum. The debris disks are caught with the help of the Herschel Space Observatory the largest telescope that was ever launched into space.