Friday, 27 September 2013

A Newbies guide to Ison part 4

What is Perihelion?

Perihelion is term we use to mean that a comet has reached its closest point to the sun. Comet Ison's perihelion is on the 28th of November at approximately 23:00 GMT when she will pass the Sun at a distance of around 1,200,000 Km (800,000 miles)

What is A.U?

A.U is a measurement of distance, and stands for Astronomical Unit.
A.U is the distance between the Earth and the Sun which is 149,597,870,700 km (92,955,807,273 miles). So if you see Ison's distance from earth as 2.0 A.U this means it is twice as far away as the Earth is from the Sun. 

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