Re: re: Is this an average? as I thought the Earth's orbit was elliptical?
Yes, it's the mean of aphelion and perihelion. My point was that due to the elliptical orbit, that value is not the same as the mean or "average" distance from the Sun. It is a lazy approximation.
To visualize this, imagine the orbit is a big train track in an ellipse. There's a point very near one end of the ellipse. Now the train spends a year going around the track and every day you note down the distance of the train from that point at one end. At the end of its journey you add up all the distances and divide by 365 (it's not a leap year). This value will not be the same as adding up the nearest and furthest point and dividing by two. And you can visualize why not just picturing that train's journey. Most days, it's not going to be at the near end.
The real average distance is nearer the furthest distance than it is near the nearest distance. I expect better from El Reg. ;) Actually, Wikipedia commits the same grievous error.