Are cell mutations always bad? A mutation is a change in the genetic material of an organism. We are made from trillions of cells, each with a nucleus composed of DNA â a set of instructions that tells the cell what to do. Cells copy themselves with astonishing accuracy, but every now and then a piece of code is copied incorrectly.
Seven eclipses occur in a minimum of 12 lunar months (about 354.37 days). Given that the calendar year is only about eleven days longer than 12 lunar months, the first of the seven eclipses has to come in early January for the seventh eclipse to occur before the end of the year.
Totality during the 1999 solar eclipse. Solar prominences can be seen along the limb (in red) as well as extensive coronal filaments. An eclipse is an astronomical event that occurs when an astronomical object is temporarily obscured, either by passing into the shadow of another body or by having another body pass between it and the viewer. An eclipse occurs during a syzygy. The term eclipse is most often used to describe either a solar eclipse, when the Moon's shadow crosses the Earth's surface, or a lunar eclipse, when the Moon moves into the Earth's shadow.