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.
Eclipses occur due to the special coincidence of the moon and the Sun being the same angular size. The Sun is 400 times wider than the moon, but it is also 400 times farther away, so they coincidentally appear to be the same size in our sky. This is what allows us the phenomenal beauty of the total solar eclipse.
A lunar eclipse occurs during a Full Moon when the Earth is between the Sun and the Moon and when the Moon passes through some of the Earth's shadow.. 1  Date. Type. 2  25 April 2013. Partial Eclipse. 3  15 April 2017. Total Eclipse.  8 October 2017. Total 1  Eclipse. 4 April 2017. Total Eclipse.  28 September 2017. Total Eclipse.