Why is it colder in high elevations? (think about it)

[JTsyo]

True, except you do radiate heat as a black body. (roughly race independent)

is there radiation if there's no 2nd body? Don't you need T2-T1? Guess the IR waves can just radiate out without having to hit anything.

 

[AyashiKaibutsu]

http://en.wikipedia.org/wiki/Earth's_atmosphere#Principal_layers

 

[FoBoT]

is there radiation if there's no 2nd body? Don't you need T2-T1? Guess the IR waves can just radiate out without having to hit anything.

they'll hit something, eventually
and space isn't a perfect vacuum, there is a small amount of dust and gases

It is often a misconception that space is a vacuum or simply empty. Space is a nearly perfect vacuum, even better than the best ones made in labs on earth, but it is not devoid of everything. The fact is that space is filled with tiny particles called cosmic dust and elements like hydrogen and helium. This applies for interstellar space also and all the previously mention particles make up what is known as the interstellar medium.

The interstellar medium is mainly made of lone hydrogen atoms. They do not even exist as pairs as they do on earth. I mentioned before that space is filled with hydrogen atoms. The actual density of hydrogen as it exist in interstellar space is on the average of about 1 atom per cubic centimeter. In the extremes, as low as 0.1 atom per cubic centimeter has been found in the space between the spiral arms and as high as 1000 atoms per cubic centimeter are known to exist near the galactic core.

The interstellar medium also contains cosmic dust. These particles are much bigger than hydrogen atoms. However, there are far fewer particles of cosmic dust than there are hydrogen atoms in the same volume of space. It is estimated that cosmic dust is 1000 times less common than hydrogen atoms in the interstellar medium.

 

[JDub02]

that's the way god made it. are you questioning god?

 

[HardcoreRobot]

that's the way god made it. are you questioning god?

this mystery proves there is an Intelligent Designer

 

[JDub02]

this mystery proves there is an Intelligent Designer

and his name is steve jobs. just ask any iphone owner.

 

[nerp]

Space is not cold nor hot. It is just an empty vacuum, hence a perfect insulator.

Wrong.

 

[HardcoreRobot]

and his name is steve jobs. just ask any iphone owner.

iDesigner™

 

[Red Squirrel]

iDesigner™

Actually he probably used the iPad, that's why it took 6 days. with anything else he could of just started off 6 seperate threads and do it all at once. :biggrin: while taking his day of rest right then.

 

[ConstipatedVigilante]

Oh my god people are retarded.

 

[Jeff7]

is there radiation if there's no 2nd body? Don't you need T2-T1? Guess the IR waves can just radiate out without having to hit anything.

Yup, that's how I understand it, or at least this is what I came up with for how it works:
I think the whole T1 & T2 thing with radiation is a result of the second object, or background, or whatever it is, radiating EM back at you.
So let's say you're in a room that's got 60° walls.
Both of you have a temperature above absolute zero, so you're both going to be radiating some kind of EM radiation. But since you're warmer, you're putting out more radiation than the wall is, so you'll tend to lose energy to the wall faster than the wall can dump energy back onto you.

In empty space, disregarding stars and so on, I think the main source of EM is going to be from the cosmic background radiation - the Big Bang's shockwave, of sorts - and there's not too terribly much there in the way of energy density by the time it reaches you.

 

[speg]

Threads like this make me wish I didn't have a science degree.

 

[Hayabusa Rider]

Threads like this make me wish I didn't have a science degree.

Win!

As linked to wiki by another:

TroposphereThe troposphere begins at the surface and extends to between 7 km (23,000 ft) at the poles and 17 km (56,000 ft) at the equator, with some variation due to weather. The troposphere is mostly heated by transfer of energy from the surface, so on average the lowest part of the troposphere is warmest and temperature decreases with altitude. This promotes vertical mixing (hence the origin of its name in the Greek word "τροπή", trope, meaning turn or overturn). The troposphere contains roughly 80%[citation needed] of the mass of the atmosphere. The tropopause is the boundary between the troposphere and stratosphere.

So the air is cooler at higher altitudes because there's less land on "average". That's why plateaus are still cool, because the air that moves onto it is cooler to begin with. Also, one has to take moisture into consideration. If you travel by plane you will notice that the lower atmosphere tends to be hazy. Water vapor being heavier than air sinks, and it blocks IR radiation into space. That's why cloudy nights tend to be warmer in winter than clear ones. At altitude, there is less to block heat from re-radiating, so the atmosphere cools faster. Those are the two main reasons as I understand things.

 

[SphinxnihpS]

This thread is terrible

Agreed