Happy 4th of Aphelion

It is July 4, 2020 and Earth is at aphelion. That means the planet is at its most distant point from the Sun. Here in Paradelle, it happened early this morning. Aphelion comes from the Greek words apo meaning away, off or apart and helios, for the Greek god of the Sun.

The fact that for most of the Northern Hemisphere it is a hot summer day today should make you realize that the distance of Earth from the sun is NOT what creates the seasons. The seasons result from Earth’s tilt on its axis and today the Northern Hemisphere is tilted most toward the Sun giving us the heat of summer.

Despite diagrams you may have seen, Earth’s orbit is not quite circular – but close – so the distance from the sun doesn’t change much. If you ask most people how far we are from the Sun, the common answer is 93 million miles (150 million km) which is our average distance. Today, Today we are about 3 million miles (5 million km) farther from away from when we are closest in about six months.

At Aphelion

Well, Earth is at its most distant point from the Sun today.

This position is called aphelion That is a word that came into English in the mid-17th century as an alteration of modern Latin aphelium with a substitution of the Greek inflection -on. Originally, it was the Greek aphhēlion meaning “from the sun.”

But don’t it expect it to seem colder outside. In Paradelle, we are in the midst of a heat wave. It’s summer here and it’s winter in the Southern Hemisphere which reminds us that  our distance from the sun is not what causes the seasons.

When the Earth is closest to the Sun it is called perihelion.

 

Today the Earth Is the Closest It Will Be to the Sun All Year But…

Yes, the Earth is closest to sun on January 2/3 for this entire year, but don’t expect to feel it.

It certainly will not feel any warmer where I am (actually it’s colder than yesterday and tomorrow is even colder). This perihelion will happen at night (10:35 p.m. EST) for me and it will be quite cold then. (It happens on the morning of January 3 5:35 UTC in Europe and Africa.) Perihelion, from the Greek roots peri (near) and helios (sun), will bring us within 91,401,983 miles (147,097,233 km) of the Sun. Though we won’t feel any hotter, Earth is about 3 million miles (5 million km) closer to the sun in early January than it is in early July. This happens every year in early January. And we will be farthest away (aphelion) from the sun in early July. Seems counterintuitive to us in the Northern Hemisphere.

The difference in distance between perihelion and aphelion isn’t that much because Earth’s orbit is very nearly circular. That is why the tilt of our world’s axis is what creates winter and summer on Earth. My Northern Hemisphere is tilted away from the sun now, so it is winter.  The day of maximum tilt toward or away from the sun is the December or June solstice, but even that won’t make for the hottest or coldest days of the year. This tilting may make seasons, but atmospheric conditions make our weather change. I blame those Arctic blasts for my car’s dead battery this morning.

Aphelion

The Sun seen from the International Space Station (ISS).

It’s quite hot on this summer day here in Paradelle, but the Earth is just reaching its most distant point from the sun for 2015 as I type this line.

July 6, at 19:41 Universal Time or 3:41 p.m. Eastern Daylight Time in Paradelle is when our home planet is farthest from the sun. This happens every year in early July.

But it’s a hot day as I walked outside today to get lunch.  We may be at our furthest distance (called aphelion) now, but, like most things, it is temporary.

Our journey around that precious star is not quite circular, so we are farther away from the sun in early July than at other times of the year. It’s five million kilometers farther from the sun than we will be in January but in the numbers of space and time that’s not a lot.

Look up at the ball of fire. It is 94,506,507 miles away (that’s 152,093,480 kilometers to most Earthlings) away.  Not so far away; not too close. A nice cosmic distance.

Aphelion

We have circled the Sun once again.

Today we’re as far away as possible.

Apo – away – from Helios, Greek Sun god.

A summer-hot day, an imperfect circular journey.

Aphelion and 3,000,000 miles doesn’t matter much.