Happy aphelion!

Today - July 5, 2012 - at about 04:00 UTC (a few hours ago as I write this) the Earth reached aphelion, the point in its elliptical orbit when it's farthest from the Sun. According to the US Naval Observatory, we were 1.016675058 Astronomical Units from the Sun at that time. An AU is the average distance from the Earth to the Sun, and is defined as 149,597,870.7 kilometers (92,955,807.2 miles). That means that at aphelion the center of the Earth was 152,092,424 km (94,505,851 miles) from the center of the Sun. Over the next six months we'll slowly approach the Sun again until we reach perihelion - the closest point in the Earth's orbit to the Sun - on January 2, 2013, at about 05:00 UTC. When we're farther from the Sun it appears a little bit smaller in the sky, but you'd never notice. For one thing, staring ...