Post by: paulggriffiths on 17/07/2017 00:13:58
Mathmatics:
The temperature just outside Earths Atmosphere 120 Degrees Celcius /
(
Earth's distance from the Sun 149.6 million km /
Axial Tilt, about 1/3 the width of earth (6,371 km / 3 = 2,123.66)
= 70444.42142339169
)
= 0.0017034705882353 degrees Celcius.
Not anywhere near enough to produce the Seasons.
Traveling Sun Producing The Seasons?
Earth along with it,
When the Earth is somewhere behind the Suns path, it receives more heat as moving nearer to where the Sun was thus Summer. When in front of the Suns path, no more additional heat thus winter.
Post by: RD on 17/07/2017 04:38:01
... Axial Tilt, about 1/3 the width of earth ...The diameter of Earth is negligible compared with its distance from the sun.
But Earth's axial tilt is responsible for the seasons : the angle of illumination does make a difference ...
https://youtu.be/KUU7IyfR34o?t=1m33s (https://youtu.be/KUU7IyfR34o?t=1m33s)
Light from the sun hitting the Earth at an oblique angle, like at the poles, is spread over a larger area than light hitting Earth at a right angles, like at the equator. So the solar energy per unit area is higher at the equator that at the poles, so the equator is hotter than the poles, even though they are essentially at the same distance from the sun.
Post by: Kryptid on 17/07/2017 04:56:38
Current theory, Axial Tilt.
Mathmatics:
The temperature just outside Earths Atmosphere 120 Degrees Celcius /
(
Earth's distance from the Sun 149.6 million km /
Axial Tilt, about 1/3 the width of earth (6,371 km / 3 = 2,123.66)
= 70444.42142339169
)
= 0.0017034705882353 degrees Celcius.
Not anywhere near enough to produce the Seasons.
Traveling Sun Producing The Seasons?
Earth along with it,
When the Earth is somewhere behind the Suns path, it receives more heat as moving nearer to where the Sun was thus Summer. When in front of the Suns path, no more additional heat thus winter.
Your calculations are incomplete. Can you show them in their entirety?
Post by: paulggriffiths on 17/07/2017 11:08:26
Problem is with oblique angles, in Britain why is Summers Night not colder that Winters Day?
Check the attached diagram. I don't think Mr Tilt thought it through...
That's evidence for my theory. 8) My Theory works with oblique angles, Axial Tilt doesn't.
Post by: paulggriffiths on 17/07/2017 11:17:15
Current theory, Axial Tilt.
Mathmatics:
The temperature just outside Earths Atmosphere 120 Degrees Celcius /
(
Earth's distance from the Sun 149.6 million km /
Axial Tilt, about 1/3 the width of earth (6,371 km / 3 = 2,123.66)
= 70444.42142339169
)
= 0.0017034705882353 degrees Celcius.
Not anywhere near enough to produce the Seasons.
Traveling Sun Producing The Seasons?
Earth along with it,
When the Earth is somewhere behind the Suns path, it receives more heat as moving nearer to where the Sun was thus Summer. When in front of the Suns path, no more additional heat thus winter.
Your calculations are incomplete. Can you show them in their entirety?
If your stating with oblique angles? Yea right...
There's an error in my theory I posted ,here's corrected:
Traveling Sun Producing The Seasons?
Earth along with it,
When the Earth is somewhere behind the Suns path, it receives additional heat as moving in to the radiation where the Sun was thus Summer. When in front of the Suns path, it receives no more additional heat other than whats being radiated from the Sun thus Winter.
Post by: evan_au on 17/07/2017 11:42:16
Quote from: paulggriffiths
The temperature just outside Earths Atmosphere 120 Degrees CelciusWhat matters is the "black body" temperature at the Earth-Sun distance, which I understand is about -15C.
What brings it up to "Room Temperature" is the greenhouse effect of Earth's atmosphere (this includes water vapor, carbon dioxide and other gases).
Quote
Earth's distance from the Sun 149.6 million km ... Axial TiltEarth's eccentricity has a much larger distance impact than the axial tilt.
- As you say, the axial tilt would make a difference of a few thousand km in the distance between the Sun's surface and Earth's surface.
- Through it's 12 month orbit, the Earth ranges from 152 to 147 million km, a difference of 5 million km (3%)
What you do with this is not very clear, but I would point out that light intensity follows an inverse square law, or 6% more.
If we apply a +/- 3% variation to a black body temperature of -15C (258K), we come up with a temperature range of +/- 8C, which is far greater than your estimate of 0.002C.
Quote
Axial Tilt, about 1/3 the width of earthAccording to the axial tilt "strawman", Winter should occur when the Earth's surface is farthest from the Sun's surface.
The Earth's surface is farthest from the Sun's surface around 4th June (aphelion) - which is summer in the Northern hemisphere.
So there is more to it than just distance from the Sun.
Quote
Axial TiltAs you say, the longer path through the atmosphere in winter doesn't help!
We can put some numbers on a more significant effect: the incoming radiation from the Sun is about 700W/m2 at ground level when the Sun is directly overhead at midday.
The axial tilt is an angle of 23.4 degrees.
If you pick a temperate climate with a latitude of 30 degrees.
- In summer at midday, the Sun is 30-23.4 = 6.6 degrees from vertical.
- The solar power at ground level is about 700W x COS(6.6) = 695W
- In winter at midday, the Sun is 30+23.4 =53 degrees from vertical
- The solar power at ground level is about 700W x COS(53) = 421W
So the ground feels distinctly colder in winter than in summer, because the solar radiation strikes the ground at an angle.
Humans don't feel these extremes quite so much, because our vertical stance means we present less area in Summer midday than at winter midday.
Quote
When the Earth is somewhere behind the Suns path, it receives more heat as moving nearer to where the Sun was thus Summer. When in front of the Suns path, no more additional heat thus winter.I'm not quite sure what these sentences are trying to get at, but it seems to ignore the fact that the Earth's path around the Sun is the same for me in Australia as it is for the UK.
And yet today, in mid-July, UK is in mid-summer, and Australia is in mid-winter.
So the Earth's path around the Sun (or movement of the Sun) can't account for the seasons.
I suggest that you look at the angle of sunlight, and the impact of the COS (cosine) function.
Post by: paulggriffiths on 17/07/2017 11:52:16
My Theory works with oblique angles, Axial Tilt doesn't.
Thanks for the post "Dorothy", a lot of maths with no real calculations on how each effects the other to producean accurate result down to say 5% tollerance.
"So the ground feels distinctly colder in winter than in summer, because the solar radiation strikes the ground at an angle. "
Problem is with oblique angles, in Britain why is Summers Night not colder that Winters Day?
Check the attached diagram.
Axial Tilt Theory Error.jpg (121.09 kB . 1468x586 - viewed 11851 times)Don't belive you can look at the diagram and dismiss the fact that "Cold" and "Very Cold" should be swopped around!
That's evidence for my theory. 8) My Theory works with oblique angles, Axial Tilt by itself doesn't.
So The Seasons are produced by The forward moving Sun & Axial Tilt. The Moving Sun producing it and Axial Tilt effecting it..
Guess Ill be a little bit famous as far as the everyday person. Me Mr Paul G Seasons Griffiths.
You may be wondering why the poles were/are frozen? I sort of believe because there magnetic.
That's where all this started.
Guess were heading towards the poles reversing.
If the poles reverse will the earth flip over afterwards like holding a flipped magnet near another? The Sun and the Earth.
The sun reverses too...
This is getting real strange, yes my theory fits in with Britain but not with Australia.
What nobody yet has thought of though is the sun goes over Britain but the diagram would sort of go around it!
I'm thinking Einstein Theory of Gravity Bending Space so it appears the Sun goes over.
Does anyone have the sun that does not go over above? vs 12.00 Noon for everybody.
I rsort of emember wondering about some of this years ago.
Guess drawing an X for the sun was not a good idea...
Have to keep in mind my fact of distance does not change the size of an obect as far as the big picture goes.
Think ill use Blender and make a 3D moving model of our sun and earth... hope have not got to include stars..
Having a break for a while :)
Post by: RD on 17/07/2017 15:57:08
(https://www.thenakedscientists.com/forum/index.php?action=dlattach;topic=70967.0;attach=23683;image)
The areas you've coloured green are not equal ...
(https://www.thenakedscientists.com/forum/index.php?action=dlattach;topic=70967.0;attach=23685;image)
Light from the sun hitting the Earth at an oblique angle, like at the poles, is spread over a larger area than light hitting Earth at a right angles, like at the equator. So the solar energy per unit area is higher at the equator that at the poles, so the equator is hotter than the poles, even though they are essentially at the same distance from the sun.
Post by: timey on 17/07/2017 16:17:42
When the Earth is somewhere behind the Suns path, it receives more heat as moving nearer to where the Sun was thus Summer. When in front of the Suns path, no more additional heat thus winter.
I'm not quite sure if I'm totally on track with this observation, but as I understand it, the earth does not get 'in' the Sun's forward path. All the planets are being dragged, in their orbits of the sun, by the sun's motion. For a loose analogy, the tail of a comet does not get 'in' the comet's path. If you think of the sun as moving in a direction, the planets are dragged in their orbit 'behind' this forward motion.
Post by: Colin2B on 17/07/2017 17:04:29
as I understand it, the earth does not get 'in' the Sun's forward path.
Timey is right, the planet's movement is always perpendicular to the sun's face. We are never moving into the Sun's path.
Although the distance between earth and sun varies this is due to the elliptical orbit and we are never following or moving ahead of the sun.
Post by: paulggriffiths on 17/07/2017 17:31:31
(https://www.thenakedscientists.com/forum/index.php?action=dlattach;topic=70967.0;attach=23683;image)
The areas you've coloured green are not equal ...
(https://www.thenakedscientists.com/forum/index.php?action=dlattach;topic=70967.0;attach=23685;image)Light from the sun hitting the Earth at an oblique angle, like at the poles, is spread over a larger area than light hitting Earth at a right angles, like at the equator. So the solar energy per unit area is higher at the equator that at the poles, so the equator is hotter than the poles, even though they are essentially at the same distance from the sun.
The green lines are Britain at day and night
Post by: paulggriffiths on 17/07/2017 17:45:30
So you could say when the earth is behind the sun in it's X direction the earth is moving in to space where the suns radiation is stronger.
My theory works for Britain but not australia and vice versa.
Axis Tilt does not work alone because then Britains Summer night would be colder than Wintors Day, work this out on the diagram.
summer.jpg (147.45 kB . 1468x586 - viewed 6169 times)What is sill strange is even with Axis Tilt put in to the diagram Africa and the summer and winter is very simular.
The only thing I can think of is some strange up.and down yearly oscillating force producing heat.
Currently I'm not convinced the Axis Tilt currently understood is correct as Im quite sure the sun goes over me resnably consistent. But the diagram shows depending on time of year it either goes in a sort of upward or downward fashion.
Post by: paulggriffiths on 17/07/2017 18:33:28
ring.jpg (100.73 kB . 3142x586 - viewed 6226 times)It does solve the "Britains Summer night would be colder than Winters Day" problem I'm having but unfortunately can't prove it here at home.
Post by: Janus on 17/07/2017 21:20:47
Why do people say spread? What I can understand is it's very hot on the outside and cools down the more the light goes thru the atmosphere.
Problem is with oblique angles, in Britain why is Summers Night not colder that Winters Day?
There are two factors the axial tilt induces that cause seasonal effects.
The first has already been mentioned, the change of the angle at which the Sun light hits the surface and the reduction in heating this causes. The second factor is that it also changes what percentage of the 24 hr day the surface is subject to solar heating. The following image illustrates this:
[ Invalid Attachment ]
The top image shows the Earth with the Northern hemisphere tilted way from the Sun (to the right) as it is in winter. The red line represents the line of latitude which we are considering, Any point on the line will remain on that line as the Earth rotates. Here we can see how the effectiveness of the lighting falls off as you move away from the part of the Earth directly facing right.
The lower image is the same situation, but looking down at the North pole. The red line is the path the surface at our latitude follows as the Earth rotates Note how much more of the line is shaded than lit by the Sun. This means that as the Earth rotates any given point on that latitude will spend less of the day being warmed by the Sun and more o fit cooling in the shadow. This means that, day by day, the point ends up losing more heat than it receives and gets cooler and cooler. By the dead of winter, it will have lost a lot of heat. Even after the Tilt of the Earth causes the Northern hemisphere to start tipping back to the Sun, you will for a while still be losing more heat than you are gaining. This is why typically the coldest winter days occur after the Winter soltice.
During the Summer, when the North pole is tilted towards the Sun, the opposite happens; the surface is heated by the Sun for a greater part of the day and accumulates heat more than it loses it, This leads to warmer and warmer days as summer wears on. (which is why late July and early August are generally warmer than late June, when the Sun is at its highest.)
So, the Seasons are not just a product of the "right now" heating caused by the angle of the Sun, but also the day to day accumulative effect caused by the changing ratio of daytime and nighttime hrs.
Post by: evan_au on 17/07/2017 21:32:56
Quote from: paulggriffiths
Britains Summer night would be colder than Wintors DayYou are forgetting "thermal inertia": When you heat up the land and the sea during the day, it takes all night to cool down before it starts warming up again. So the average temperature over 24 hours is higher in the summer than the average temperature over 24 hours in the winter.
You also need to take into account the length of daylight. Summer daylight can stretch to 15 hours in some European countries, and shrink to a corresponding 9 hours in Winter. This means that:
- In Summer, the land and sea spend a long time warming up in sunlight, and a short time cooling down at night
- In Winter, the land and sea spend a short time warming up, and a long time cooling down
(Janus just made the same point, but with pretty pictures)
So it would be very rare to have a Summer's night cooler than a Winter's day.
Post by: Colin2B on 17/07/2017 22:47:57
Axis Tilt does not work alone because then Britains Summer night would be colder than Wintors Day,In addition to what Evan said, this would be true if the earth had no atmosphere or oceans. On the moon the side facing away from sun sun has 'nighttime' temperatures well below freezing. On earth, atmosphere acts as an insulator reducing loss of heat gained during the day. Cloud cover and atmospheric stability/instability also play a part in nighttime radiation and convection losses. Thermal inertial in the water surrounding Britain also results in a reduction of day/night temperature differentials.
To fully understand the temperatures in a particular area of earth you also need to understand the part played by air masses in moving heat from one zone to another. For example Britain is strongly affected by Polar Maritime (mP) and Continental (cP) , and Tropical Maritime (mT) and Continental (cT) air masses and the associated frontal conveyer belts.
Post by: paulggriffiths on 18/07/2017 04:24:52
Try this then!
The left is britains winter and the right is britains summer. Why has winter got more hours of sunlight?
In britain theres definatly more hours of sun in summer than winter.
Definate contridiction going on here!
Untitled.png (23.03 kB . 1053x606 - viewed 6030 times)I'm wondering if my Sun Ring produces light or has a lens effect?
ring.jpg (100.73 kB . 3142x586 - viewed 6003 times)
Post by: paulggriffiths on 18/07/2017 05:06:09
In the top 2 earths it looks like the opposite.
Guess I did not draw it too well.
Post by: paulggriffiths on 18/07/2017 05:24:13
The green line is say london going around and yes the green line is a curve.
If that is a curve then the vertical shadow line probably should curve too.
Also an hours worth of semi shadow is wider at the equator than at london.
I'm now thinking summer heat vs winter cold difference is also based on time.
Post by: paulggriffiths on 18/07/2017 05:47:36
Shadow time.jpg (45.87 kB . 1053x606 - viewed 5992 times)May be should not think of the sun as a whole and use an individual atom, sends a light photon or partical of radiation, hits earth, produces heat...
The current peoples view of light spread over a wider area for winter is seeming less likely. But due to diffent angle the partical will travel through more atmosphere still applies.
Post by: Colin2B on 18/07/2017 09:08:27
The current peoples view of light spread over a wider area for winter is seeming less likely.
Only in your view ;)
You can do an experiment with a solar panel. Hold it so it's front face is directly towards the sun, if you slowly rotate it so it finally has the edge pointing at the sun you will find the output decreases from a maximum when facing directly at right angles getting less as the angle is increased and the light hits at an oblique angle. No effect from atmospheric depth which is constant in this case. The important consideration is what effective area is pointing directly at the sun.
Post by: paulggriffiths on 18/07/2017 10:15:04
The current peoples view of light spread over a wider area for winter is seeming less likely.
Only in your view ;)
You can do an experiment with a solar panel. Hold it so it's front face is directly towards the sun, if you slowly rotate it so it finally has the edge pointing at the sun you will find the output decreases from a maximum when facing directly at right angles getting less as the angle is increased and the light hits at an oblique angle. No effect from atmospheric depth which is constant in this case. The important consideration is what effective area is pointing directly at the sun.
Nice try, if looking straight on it's the power of 10 cm wide, if rotated some it's only the power of 5 cm wide.
Have you round one?
Post by: paulggriffiths on 18/07/2017 10:25:54
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Post by: paulggriffiths on 18/07/2017 12:21:41
And this https://earth.nullschool.net
Neither got the tilt though. :(
Post by: Colin2B on 18/07/2017 12:38:59
Nice try, if looking straight on it's the power of 10 cm wide, if rotated some it's only the power of 5 cm wide.It's nothing to do with it being flat or round.
Have you round one?
Look to your diagram here
There's such a large difference between summer and winter but the earth is pretty much hit the same, it's only at a 23 degree after allNo, the earth is not hit the same all over as explained by Evan.
Look at you diagram in #22. Place the solar panel at the equator it will point directly at the sun and gather the maximum energy, place it in the higher latitudes it will be at an angle much greater than 23° and collecting less sunlight - the available photons are spread over a larger area. You can work out the effective collection area using simple geometry.
Post by: RD on 18/07/2017 18:50:56
You can do an experiment with a solar panel ...Solar panel demonstration here ... https://youtu.be/KUU7IyfR34o?t=3m5s (https://youtu.be/KUU7IyfR34o?t=3m5s)