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Post by Midi-Chlorian_Count on Dec 16, 2019 20:15:04 GMT
I know there is a Science board here but looks like it doesn't get many regular viewers so here's my question:-
Why is it hot in the summer yet cold in the winter?
I'm obviously aware of the earth's tilt and that it causes the season depending upon the angle, light striking the earth, etc. But my question is still why?
The Earth is about 91 million miles from the Sun but does not go around it in a perfect orbit. In fact it can vary by ~ 3 million miles either way. So why is the effect of the tilt so pronounced compared with the effect of distance?
Answers on a postcard please...
Edit: Is it just photons not losing energy over the relatively small distance?
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Post by Deleted on Dec 16, 2019 20:24:36 GMT
It is simply the earth's tilt.
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Post by screamingtreefrogs on Dec 16, 2019 20:27:54 GMT
I bet Bigfoot knows.
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Post by masterofallgoons on Dec 16, 2019 20:29:44 GMT
I don't know, I've heard that Big Foot is into the whole 'flat earther' thing, so I wouldn't trust him. He's changed, man.
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Post by klawrencio79 on Dec 16, 2019 20:30:12 GMT
I keep my office warm by tearing ass all day long.
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Post by Aj_June on Dec 16, 2019 21:33:35 GMT
The earth's tilt is always nearly the same which means the actual position of both hemispheres remains the same throughout the winters and summers. But the positions of hemisphere change in relation to the Sun. When it is summer in any particular hemisphere it means that sunlight hits the earth at a more direct angle (as Sun is relatively higher in the sky) which means energy would be concentrated in smaller space than when sunlight hits earth at a shallow angle. When it is winter the sun is relatively lower in the sky and thus the sunlight will come at a shallow angle and thus spread out more and will be less dense.
As an experiment try to light a torch right from above. You will see it will spread more light in a limited area. Now hold the torch at a slanted angle and you will see that even though it will spread light in a greater area the light will not be as bright as before.
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Post by TheGoodMan19 on Dec 16, 2019 22:37:18 GMT
I always thought it had to do with the Amount of daylight we get. Right now, it’s dark at 5 pm and doesn’t get light until after 7. Only 10 hours of daylight. In summer it gets light at 4:30 am and dark after 9:30 pm. 17 hours. More sun, warmer air. Now most of our weather comes from the north which sees almost no daylight
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Post by millar70 on Dec 16, 2019 23:51:55 GMT
Cuz that's how God made it.
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Post by NJtoTX on Dec 17, 2019 1:15:11 GMT
Because we define the hot part of the year as summer and the cold part as winter.
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Post by Midi-Chlorian_Count on Dec 17, 2019 8:53:06 GMT
Ha ha, last two answers are interesting! So looks like no advance on it just being the tilt and angle light strikes the hemispheres in summer / winter.
BUT it is amazing that that given range is within the zone of being able to cause molecules and elements to change state, etc... Makes you wonder. I remember reading 2001 and Arthur C Clarke goes off at one point from what I remember on beings of gas or something existing either within Jupiter itself or one of its moons, and living an existence unfathomable to humans.
Maybe the same thing is at play here - given the distance of millions of millions and even allowing for tilt and slight variation in light intensity caused, maybe the seemingly incredible variation, and changes of state it can cause, is only incredible to us and in the greater scheme insignificant...
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Post by masterofallgoons on Dec 17, 2019 12:13:05 GMT
Ha ha, last two answers are interesting! So looks like no advance on it just being the tilt and angle light strikes the hemispheres in summer / winter. BUT it is amazing that that given range is within the zone of being able to cause molecules and elements to change state, etc... Makes you wonder. I remember reading 2001 and Arthur C Clarke goes off at one point from what I remember on beings of gas or something existing either within Jupiter itself or one of its moons, and living an existence unfathomable to humans. Maybe the same thing is at play here - given the distance of millions of millions and even allowing for tilt and slight variation in light intensity caused, maybe the seemingly incredible variation, and changes of state it can cause, is only incredible to us and in the greater scheme insignificant... I don't think so. I think maybe the particulars of scientific knowledge are not necessarily best acquired or understood from this forum. Scientists are not flabbergasted by this. Although, I do think you got some decent responses above that went beyond just 'it's the tilt' and actually attempted to make sense unlike those previous two responses.
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Post by Deleted on Dec 17, 2019 12:13:49 GMT
Ha ha, last two answers are interesting! So looks like no advance on it just being the tilt and angle light strikes the hemispheres in summer / winter. BUT it is amazing that that given range is within the zone of being able to cause molecules and elements to change state, etc... Makes you wonder. I remember reading 2001 and Arthur C Clarke goes off at one point from what I remember on beings of gas or something existing either within Jupiter itself or one of its moons, and living an existence unfathomable to humans. Maybe the same thing is at play here - given the distance of millions of millions and even allowing for tilt and slight variation in light intensity caused, maybe the seemingly incredible variation, and changes of state it can cause, is only incredible to us and in the greater scheme insignificant... I don't think so. I think maybe the particulars of scientific knowledge are not necessarily best acquired or understood from this forum. Scientists are not flabbergasted by this. Although, I do think you got some decent responses above that went beyond just 'it's the tilt' and actually attempted to make sense unlike those previous two responses. It is the tilt though. That is the answer 🤷♀️
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Post by NJtoTX on Dec 17, 2019 12:24:34 GMT
So this explains the basics. But the hottest part of the year in the Northern hemisphere is 1-3 months after June 21 because of retained heat. It takes time for the atmosphere to warm up. It's similar to the fact that the hottest time of the day is mid afternoon, even though the Sun is the highest at mid-day.
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Post by masterofallgoons on Dec 17, 2019 12:52:31 GMT
I don't think so. I think maybe the particulars of scientific knowledge are not necessarily best acquired or understood from this forum. Scientists are not flabbergasted by this. Although, I do think you got some decent responses above that went beyond just 'it's the tilt' and actually attempted to make sense unlike those previous two responses. It is the tilt though. That is the answer 🤷♀️ Yeah, but the question went into more detail, therefore the answer should require more detail.
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Post by Rey Kahuka on Dec 17, 2019 13:13:54 GMT
Is this supposed to be a joke? Yes it's the tilt of our axis. As it turns out, our Sun is a star and it's very hot. So the more direct exposure we have to it, the warmer it gets. This is a conversation I had with my 5 year old son recently.
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Post by Midi-Chlorian_Count on Dec 17, 2019 13:20:09 GMT
I don't think so. I think maybe the particulars of scientific knowledge are not necessarily best acquired or understood from this forum. Scientists are not flabbergasted by this. Although, I do think you got some decent responses above that went beyond just 'it's the tilt' and actually attempted to make sense unlike those previous two responses. It is the tilt though. That is the answer 🤷♀️ Yes, I agree - but I was thinking that initially. Question of why - I think the torch explanation above is a good visualisation but then it's not really a change to / from such acute angles and the light comes millions of miles away... So why does the change cause such a pronounced effect? e.g. changing that torch example to shining on a rugby ball 50 metres away. If you tilted the ball 20° or whatever one way or the other, the effect at that distance and those angles would appear negligible.
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Post by Midi-Chlorian_Count on Dec 17, 2019 13:24:14 GMT
Is this supposed to be a joke? Yes it's the tilt of our axis. As it turns out, our Sun is a star and it's very hot. So the more direct exposure we have to it, the warmer it gets. This is a conversation I had with my 5 year old son recently. It's no joke. This is a very serious issue. Yes the sun is very hot. But the sun is also more than 91 million miles away. So how can a tilt causing what can only be thousands of miles of difference at a point cause such an effect? Are you aware that the Earth is actually closest to the sun in January, less than 90 million miles away? It's a million miles + closer and yet it is colder.
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Post by Rey Kahuka on Dec 17, 2019 14:46:56 GMT
Is this supposed to be a joke? Yes it's the tilt of our axis. As it turns out, our Sun is a star and it's very hot. So the more direct exposure we have to it, the warmer it gets. This is a conversation I had with my 5 year old son recently. It's no joke. This is a very serious issue. Yes the sun is very hot. But the sun is also more than 91 million miles away. So how can a tilt causing what can only be thousands of miles of difference at a point cause such an effect? Are you aware that the Earth is actually closest to the sun in January, less than 90 million miles away? It's a million miles + closer and yet it is colder. Yes I'm aware, because I'm an adult. I'll say it again. The more exposure you have to the Sun, the greater the effect it has. Find your local theater. Have them shine a spotlight on the stage. Stand just outside of the spotlight while closer to it, and then stand directly in the spotlight while farther to the back of the stage and see if you notice a difference.
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Post by Midi-Chlorian_Count on Dec 17, 2019 15:05:21 GMT
It's no joke. This is a very serious issue. Yes the sun is very hot. But the sun is also more than 91 million miles away. So how can a tilt causing what can only be thousands of miles of difference at a point cause such an effect? Are you aware that the Earth is actually closest to the sun in January, less than 90 million miles away? It's a million miles + closer and yet it is colder. Yes I'm aware, because I'm an adult. I'll say it again. The more exposure you have to the Sun, the greater the effect it has. Find your local theater. Have them shine a spotlight on the stage. Stand just outside of the spotlight while closer to it, and then stand directly in the spotlight while farther to the back of the stage and see if you notice a difference. Wow. You were genuinely aware that the Earth is closest to the sun in January because you are an adult? Incroyable! That's amazing - good on ya 👍
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Post by NJtoTX on Dec 17, 2019 15:22:06 GMT
There are three physical Laws of Thermodynamics:
1. Heat cannot be created or destroyed but heat may be converted into other forms;
2. Heat flows from a hot body to a cold (or comparatively cooler) body;
3. Entropy increases with time.
There are also three mechanisms of Heat flow from a hot body to a cold (or comparatively cooler) body:
1. Conduction (Heat flow through a heat conducting material, such as a solid or an ideal/assumed non-moving liquid);
2. Convection (Heat flow through the movement of a liquid, gas or plasma);
3. Radiation (Heat flow through space, or a vacuum on Earth, or an ideal/assumed non-moving gas).
For discussion purposes of this question; only Laws 1 and 2 and the Radiation mechanism for Heat flow, are of most relevance.
The best mathematical theoretical model Physics has about how the Sun generates energy in various forms, including Heat, is through thermonuclear fusion. In stars like the Sun, most of the mass is made up of mainly Hydrogen, with some other chemical elements including Helium in relatively small quantities. The Sun has enough mass in its interior, generating a sufficiently strong gravitational force, that Hydrogen nuclei can go through the process of thermonuclear fusion.
Deep enough inside the Sun, 600 million tons of Hydrogen nuclei are forced together per second, to generate the energy, by thermonuclear fusion, that eventually takes 500,000 years to make its way through the dense hot plasma, from the interior to eventually escape from the surface of the Sun into space.
What happens to the 600 million tons of Hydrogen per second consumed by the Sun?
During the process of thermonuclear fusion, four Hydrogen nuclei (or protons) are forced together due to the strong gravitational force in the Sun’s interior, and as a result a great deal of energy in the form of two gamma ray photons are released. Two of the four protons release neutrinos and are converted into neutrons. The two neutrons and two protons form the nucleus of the element Helium. Essentially the Helium is the ash of the thermonuclear fusion reaction of the four Hydrogen nuclei.
The gamma ray photons are either scattered by the nuclei, making up the dense hot mainly Hydrogen plasma, as they make their way from the interior of the Sun to the surface, or the gamma ray photons are absorbed and re-emitted by the stray electrons in the hot dense plasma. The gamma ray photons are scattered as a result of collisions with stray electrons or predominantly Hydrogen nuclei and sometimes perhaps with much less abundant Helium nuclei. In Compton Scattering, a gamma ray photon interacting with a stray electron in an inelastic collision, will have some of the gamma ray photon energy absorbed by the electron, and the electron will re-emit the gamma ray photon at a lower energy.
By the time the photons reach the Sun’s surface (after countless interactions with the hot dense layers of Solar plasma and stray electrons), they escape with a range of energies or wavelengths, ranging from X rays to Ultra Violet to visible light to infra red. The heat energy from the sun is in the invisible infra red energy or wavelength region of the Sun.
Please note that the higher energy gamma ray photons escaping out to space, from the hotter Sun’s interior to the cooler surface, is consistent with the First and Second Laws of Thermodynamics. Also note that stars including the Sun, generating energy as a result of Hydrogen thermonuclear fusion, are referred to in Astrophysics as Main Sequence stars.
Approximately 174,000,000,000,000,000 watts out of the approximately 386,000,000,000,000,000,000,000,000 watts, reaches the Earth. The reduced amount of power happens because of the Inverse Square Law of the propagation of electromagnetic radiation, and not every part of the Sun is facing the Earth at the same time. Not all of the 174,000,000,000,000,000 watts reaches the ground because the Earth’s atmosphere is opaque to the X-ray to extreme UV and some of the infra red wavelengths.
According to some estimates 8% of the incident Solar energy is reflected back to space by air molecules, 17% is reflected back to space by clouds, and 6% is reflected back to space by the Earth’s surface. Out of the remaining 69% of the incident Solar energy that is absorbed by the Earth’s surface, 19% gets absorbed directly by dust, ozone and water vapor in the upper atmosphere, 4% gets absorbed by clouds, leaving 46% of the Solar energy making it to the ground.
Still, enough Solar energy reaches the ground to heat the Earth’s surface with an average power of 164 Watts per square meter, and to allow us to feel the Sun’s heat on our faces.
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