It's Aphelion Day!! !

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Happy Aphelion Day!! !

At 14:44 UJT this morning, the Earth was at the farthest point in its elliptical orbit around the Sun!

Time to party!

ROFL what??

Check out this Wikipedia Article on Apsis.

Basically, the Earth's orbit is elliptical, with one point on the orbit being closest to the Sun (Perihelion) and one point being the farthest from the Sun (Aphelion). Both Aphelion and Perihelion occur only once each year - January 2 at 04:38 for Perihelion, and July 5, 14:44 for Aphelion (times are UJT, year is 2013).

So, today is Aphelion Day!

Couple these days with the Solstices and the Equinoxes, and the scientific-minded among us have six "holidays" of our own to observe.

It sure doesn't FEEL like we're farthest from the sun

The people in the freezing Southern hemisphere would agree with you.

It is winter in Australia and New Zealand. And the Hottentots of Tierra del Fuego are freezing their butts off.

Given that both the apahelion and perihelion advance wait another 100,000 centuries and it will sort itself out.

ruveyn

The Earth's orbit is elliptical, this is also the reason ( I think) we (in Sunny Australia) have different dates for the change of seasons.

What I mean is at the beginning of a month, rather than the 22/23 of the month.

I doubt thats the reason.They would start the seasons on the fifth of the month if that were the case. Its just breaking with traditon for convenience.

To reiterate: We are farthest from the Sun in Summer (barely a fortnight after the Summer Soltice,in fact), and closest to the sun in the dead of winter. But thats just 'we' in the Northern Hemisphere. You antipodians in the southern hemisphere have it the logical way- but its 'the right thing for the wrong reason'- closest in summer, but farthest in winter. But its the tilt of the earth that causes the change of seasons. Not the planet's distance from the Sun.

In most countries the public officials go along with nature and peg the seasons to the soltices and equinoxes (the changing lengths of the day) as humans have done for thousands of years. In Australia they just dispense with astronomy and peg the seasons the first of the month. In my mind summer does starts on June first ( I dont really wait until June 23rd to think of it as 'summer'), and apparently so do most consumers in every temperate zone country in both hemispheres because they start filling the stores with 'summer seasonal' merchandise in May. So Australia just goes with how most modern folks think, and divorces the seasons from the length of the day changes- and just declares that Summer starts on June first ( kinda like Buckminster Fuller who just declared that "Pi is exactly three").

Earths orbit is not truly elliptical. It precesses partly because it is perturbed by Jupiter and partly because earths gravitational field interact with the gravitational field of the Sun which is predicted rather precisely by the General Theory of Relativity. Elliptical orbits are a first order approximation to our true orbit.

ruveyn