... Hurtling through a cosmic dust cloud a mere 400 light-years away, the lovely Pleiades or Seven Sisters star cluster is well-known in astronomical images for its striking blue reflection nebulae. At visible wavelengths.. ... Better known as M106, bright spiral galaxy NGC 4258 is about 30 thousand light years across and 21 million light years away toward the northern constellation Canes Venatici. ... Aurora rarely reach below 60 kilometers, and can range up to 1000 kilometers. ... 2005 2006 . ...