Temperature of the Sun

Post Reply New Topic

I was wondering has the of the sun been giving us less, the same or greater heat compared to the the past 200 or so years?

Its temperature is slowly climbing.

How much? I dont know.

But the science says it is, that it will continue to grow in size(letting off more heat and light) as it ages, until it runs out of fuel(in a few billion years), at which point it will shrink, then expand greatly(enveloping earth even), thereafter it will be much cooler.

However, its heat doesnt reach us. What we get is thermal effects from the increased radiation(light, infrared, et al).

That is its heat. There are three types of heat transfer: conduction, convection, and radiation.

From what I understand, astronomers believe we are in a solar cooling phase having to do with solar flare activity and such, but global warming is still occurring none-the-less from all the greenhouse gas accumulation. Though this has less to do with the average temperature of the sun than the amount of its heat that reaches us, methinks.

Please tell me you can find a citation for that. I'm getting so sick of the "argument from the sun" among global warming skeptics, and I need something definitive to knock them off their feet.

It's from some show that was on the History Channel a while back, but I'll try to find one for you.

This is the closest thing I could find to the subject with a reputable source:

http://science.nasa.gov/headlines/y2008 ... arwind.htm

A general falloff in the number of sunspots has been observed. The last time the number of sunspots counted was this low was during the period known as the Little Ice Age, in the 1600s.

However, this is generalizing from a single data point. No reputable scientist is going to assume that because a solar minimum accompanied a global cooling cycle once, means that the two are always linked. It's rather like wearing a particular pair of underwear when your favorite sports team wins a game, then refusing to change your underwear because they're obviously "lucky" for your team - after all, they won that one time...

Actually that link suggests climate change is promoted by the slowing of the solar wind. Specifically the 13th paragraph. I dont think he will find this article useful.

Thanks for you help guys I hope I can find the temperature soon or my project goes out the frakin door unfinished

Woah, electromagnetic radiation is not heat. It can be a method of transferring heat, but radiation itself is not heat. Saying it is heat is as sensible as saying "the temperature of yellow".

Also the current solar cycle is a bit low on sunspots, iirc, and since sunspots are cool spots...

I have four separate Chemical and Mechanical Engineering textbooks within two feet of me that would disagree with you. No, not all electromagnetic radiation transfers heat directly, but to say the energy the infrared radiation the sun gives off isn't heat is to say energy given off by conduction and convection isn't heat. The sun loses energy giving off said radiation, we gain energy and increase in temperature until it's given off or stored in some other manner. Sure sounds like heat to me.

This may just come down our ASD tendency to argue arbitrary and tiny points, so let us just agree on the following equation.

Kittens = Poptarts

What hath science wrought?

---

Plus your right anyways, I was getting temperature and heat mixed up. I blame this on my early-morning lecture.

Just the cutest little breakfast treat ever, that's all...

The sun is gradually becoming hotter. As hydrogen is used up and helium is fused the temperature will increase. This means the sun will boil off the earth's oceans long before it becomes a red giant.

ruveyn

The sun emits radiation close to black body radiation of a temperature of approximately 5800K. This radiation is electromagnetic radiation spanning the entire known range of energies. The intensity of some wavelengths is reduced due to absorption in the outer layers of the sun. We can, for instance, observe the spectral lines of hydrogen in the solar spectrum.

Electromagnetic radiation covers all wavelengths or frequencies if you prefer. Infrared, which we humans feel as heat, is also part of the spectrum. Therefore, the sun does emit heat. If the energy emitted by the sun is absorbed by an object, it has a high likelihood to transform into thermal energy, often after an excitation phase. This may then be interpreted as heat.

If you like to split hairs, electromagnetic radiation is not just heat and there is a large difference between heat and energy. I am a bit of an energy enthusiast, so I never use the word heat to denote enthalpy. Heat is, after all, the energy quantity related to specific enthalpy changes.

The surface temperature of the sun is for all intents and purposes constant, even on the time span of a hundred years. There are known solar intensity cycles of 7, 30, and approximately 100 years. These have all coincided recently. The solar radiation is however strongly affected by the distance to earth, which changes with the seasons, and the occurence of solar spots, solar flares, and other effects in the corona.

I have purposely left out any effects relating to the earths atmosphere as they would require pages upon pages to explain.

Heat is energy that is transferred because of a temperature difference.

Infrared radiation is a kind of light.

ruveyn