Quick Question about Solstice and Perihelion and the 4 Seasons. How does it work?

At one time I thought that the seasons were due to the Earth tilting back and forth on it's axis, then learned that's not true, that the seasonal procession is due to the Earth remaining on the same tilt on it's axis (perhaps aided by the moon?) and moving on an elliptical path in its annual orbit around the sun..

But that got me to thinking about winter, spring, summer and fall, and the question that then arises is - why the seasons wouldn't happen twice during each orbit around the sun?



Is the elliptical some sort of egg shape? I don't get it.

Can someone help me visualize what's really going on?

Thank you.

I guess ask a stupid question - get no response.

I just want to understand, and are there really stupid question in matter of scientific inquiry?

I was gonna say it’s was due to its tilt but you just schooled me on that hahaha

I have no idea but it has to have something to do with the tilt otherwise northern and Southern Hemispheres would be in sync instead of opposites

a reply to: AnkhMorpork

Its both m8. When it's one side of the sun it's tilting 1 way so northern hemisphere facing further away (winter) and when on opposite side it's facing towards (summer). Glad to be of assistance

a reply to: AnkhMorpork

Also remember not all countries experience 4 seasons as such at the equater they only really experience 2. Wet and dry. It depends what longitude your at and at what time in the orbit cycle we are at which determines how much sunshine you get.

a reply to: AnkhMorpork

Sorry not to put my 3 replies into 1 but let me add the earth does not tilt back and forth . It instead tilts on it's axis it's always tilting the same way but sort of wobbling in a fashion if that makes sense.

a reply to: AnkhMorpork

I have been looking into this since you asked this question. Honestly it’s kinda hard to find a straight answer. I’m sure tomorrow someone with more know how will chime in when they are up. Very good question you

originally posted by: Allaroundyou
a reply to: AnkhMorpork

I have been looking into this since you asked this question. Honestly it’s kinda hard to find a straight answer. I’m sure tomorrow someone with more know how will chime in when they are up. Very good question you

I think I answered his question mate. That's how I understand it anyhow.

a reply to: AnkhMorpork
This explains the seasons




However I am having trouble seeing how it makes sense when the globe spins every 24 hours. Should the opposite hemisphere have a larger angle of solar dispersion and therefore colder, and repeat the same the next day

They dont actually show the effect of the dispersion on the earth spinning on its axis in the explanation (model) - why is that?

I smell something off

The Earth's axis is tilted roughly 23° to the orbit around the Sun.
In December from the 22nd to the 25th (there about) the Northern Hemisphere is the further away from the Sun, experiencing it's Winter Solstice, while it's the Summer Solstice down in the South which is at it's closest point facing the Sun.

If we take that as the starting point, come March 20th the tilt is at such an angle that the Northern and Southern Hemispheres are about the same distance from the Sun and gives us our Equinox. The Northern Hemisphere, coming out of Winter is experiencing Spring, while it's Autumn down South.

Half way around our annual orbit brings us to June 22nd, when the axial tilt has the Northern Hemisphere pointing towards the Sun, in the Northern Summer Solstice. Yes, you guessed it, the opposite down South, in the middle of Winter during it's solstice and being further away from the Sun.

Now 3/4 the way around, September 23rd, we're at another equinox. This time The North is moving from Summer into Autumn (Fall) and it's Spring time down South.

Another 1/4 the way around and we're back where we started.

My old post (Solar System Orbiting the Hammar Axis) has a bit more detail.

The other part I don’t get is how the tilt makes such a massive difference.
I live in Melbourne Australia and the difference between summer and winter can be over 30 degrees Celsius.
The distance added or subtracted by the tilt is a tiny fraction of the distance between the earth and the sun so there must be more at play than a distance of a few 100 or 1000 kilometres?

Someone call phage

originally posted by: Oldskool88

originally posted by: Allaroundyou
a reply to: AnkhMorpork

I have been looking into this since you asked this question. Honestly it’s kinda hard to find a straight answer. I’m sure tomorrow someone with more know how will chime in when they are up. Very good question you

I think I answered his question mate. That's how I understand it anyhow.

Yes you did and sorry for not reading further. Most the time I do but after three glasses of wine I forgot to do so. My bad

a reply to: IkNOwSTuff

It is not the distance that matters but the angle.

en.wikipedia.org...

a reply to: moebius


Thank goodness - I thought for a moment that this might be another Flat Earth thread. Phew!

a reply to: IkNOwSTuff
To add to

originally posted by: moebius
a reply to: IkNOwSTuff
It is not the distance that matters but the angle.
en.wikipedia.org...

You know how even in the middle of our 40°C+ Summer days in Melbourne, the heat of the Sun at Sunrise and Sunset is no match for the heat from the Midday Sun, right?
That.
It's all due to the Angle.

a reply to: AnkhMorpork

I think we get the 4 seasons down to the axis tilt/wobble of the Earth if memory serves.

If it was spinning on a perfect axis you would not experience spring or autumn, in the same manner, depending on where you are north or south of the equator.

a reply to: Hammaraxx

Yeah. In Hawaii they have this phenomenon called Lahaina Noon. Lahaina means cruel sun. The sun shines down at 90 degrees and walls and poles throw no shadows. That is when you get a maximum of sun light.

Ok, I get it now. One side of the orbit, tilted towards sun, other, tilted away with the other hemisphere in summer/winter.

So the orbit might as well be a perfect circle and is only very slightly elliptical, which is why the sun, photographed at noon every day of the year from the same location carves out a figure 8 and doesn't just go straight up and down.

Can anyone clear this for me? Another way of asking is if it spins every 24 hours the northern hemisphere would end up being the southern hemisphere (and vice versa) and therefore receive the suns rays at a different angle and yet we have opposing seasons every 4-6 months not daily.

I am having trouble seeing how it makes sense when the globe spins every 24 hours.

In the video I posted...
They dont actually show the effect of the dispersion on the earth spinning on its axis in the explanation (model) - why is that?

a reply to: AnkhMorpork

Over the course of a year, the angle of tilt does not vary. In other words, Earth’s northern axis is always pointing the same direction in space. At this time, that direction is more or less toward the star we call Polaris, the North Star. But the orientation of Earth’s tilt with respect to the sun – our source of light and warmth – does change as we orbit the sun. In other words, the Northern Hemisphere is oriented toward the sun for half of the year and away from the sun for the other half. The same is true of the Southern Hemisphere.

When the Northern Hemisphere is oriented toward the sun, that region of Earth warms because of the corresponding increase in solar radiation. The sun’s rays are striking that part of Earth at a more direct angle. It’s summer.

When the Northern Hemisphere is oriented away from the sun, the sun’s rays are less direct, and that part of Earth cools. It’s winter.

Seasons in the southern hemisphere occur at opposite times of the year from those in the northern hemisphere. Northern summer = southern winter.

earthsky.org - Why Earth has 4 seasons.

Using your ellipse, on the far right hand side, hold a pen or pencil tilted towards the left. Slowly move the pencil along the curve (upwards). At the far end, the pencil is still pointing the same direction as it did on the other side. Since the sunlight is arriving at less direct of an angle, the atmosphere/air does not heat up as much when it is directly pointing at the sun (i.e., summer).

Your question about the seasons happening twice is, actually they do! Just that when transitioning in one direction it is called "fall"
and going in the other direction, "spring". That is your eclipse is cut in half, lengthwise, which means two,... or twice. Just that our agricultural heritage makes us differentiate between the two.

The other question often asked is, "When we move through the solstice, why does it not get warmer/colder at that moment?" The answer is "convection currents". It takes a while for the hot summer air to mix with cold autumn air even as we move further and further (from the northern hemisphere point of view) from summer solstice.

The earthsky article describes it way better with a couple diagrams to help explain things.

Hope this helped!