Earth at Aphelion 2016

Universe Today ^ | 07/04/2016 | David Dickinson

[BenLurkin]

Having a great July 4th? The day gives us another cause to celebrate, as the Earth reaches aphelion today, or our farthest point to our host star.

Aphelion is the opposite of the closest point of the year, known as perihelion. Note that the ‘helion’ part only applies to things in solar orbit, perigee/apogee for orbit ’round the Earth, apolune/perilune for orbit around the Moon, and so on. You’ll hear the words apijove and perijove bandied about this week a bit, as NASA’s Juno spacecraft enters orbit around Jupiter tonight. And there are crazier and even more obscure counterparts out there, such as peribothron and apobothron (orbiting a black hole) and apastron/periastron (orbiting a star other than our Sun). And finally, there’s the one-size fits all generic periapsis and apoapsis, good for all occasions and ending pedantic arguments.

In the 21st century, aphelion for the Earth can actually fall anywhere from July 2nd to the 7th. The once every four year leap day is the primary driver in this oscillation, and the inclusion of a century leap day in 2100 — the first since 1900 — will reset things even farther astray.

[BraveMan]

So Far Away

[SunkenCiv]

Thanks BenLurkin, extra to APoD. Not surprisingly, perihelion happens in January, which means, the winters of the northern hemisphere are a little warmer than those of the southern, and the summers a little cooler in the northern. Most of the world's dry land is also in the north, so, all the way around, it's a pretty good deal.

[Verginius Rufus]

"Apolune"? Apo- is Greek and luna is Latin. Why not "aposelene" using the Greek word for the moon?