Image Credit & Copyright: NASA Solar Dynamics Observatory (SDO). CLICK image for larger view and look below for information and related links.
Happy 4th of July to my American friends and Happy Aphelion to the entire world! Today you are as far from the Sun as you will be, well, until about this time again next year. Technically it occurred at 00:05 UTC (20:05 EDT on the 3rd) so really yesterday’s Sun and today’s Sun are about the same distance.
The word aphelion is derived from two Greek words; Apo, which means “off or away”, and Helios which is the name of the Greek GOD of the Sun. Today we are 94,506,460 mi (152,093,475 km) or about 1.02 AU from the Sun (AU means “Astronomical Unit” and represents Earth’s average distance from the Sun). So you can see we have moved away from our rough average distance of about 93 million miles (150 million km) or 1AU just a bit.
This happens quite simply, because the Earth’s orbit isn’t exactly circular but slightly eccentric. I say “slightly” eccentric because as you can see there’s only really a 1/100th of a change in distance from average to aphelion. The opposite is true for Earth’s closest approach during perihelion in January.
Ok, wait; the fact that we’re farthest from the Sun in the Northern hemisphere Summer and closest to the Sun during Northern hemisphere Winter may confound some, so here’s the post that I completed earlier in the year detailing this very system: https://danspace77.com/seasons-temperatures/