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 total solar eclipse occurs when the Moon completely covers the Sun, as seen from Earth. Totality during such an eclipse can only be seen from a very small area on Earth. This area is usually about 100 miles (160 kms) wide and 10,000 miles (16,100 kms) long. Areas outside this track may be able to see a partial eclipse of the Sun.