How does the heat from the Sun reach ground level....

[thatone1967]

if when you are flying at say 40,000 ft, it's 30 - 40 below zero outside?

[tenohfive]

thatone1967 said:

if when you are flying at say 40,000 ft, it's 30 - 40 below zero outside?

Because the light isn't hitting anything to warm up at those heights. Just passing through air.

[Puggit]

The air at 40,000 feet is much thinner - so it can't heat up as much. There just isn't enough matter to get hot.

Also the ground and especially the sea store huge amounts of heat, and release it back in to the atmosphere at ground level.

[TheEnd]

Sun light hits ground, warms ground, ground warms air.

At 30k ft, sunlight goes straight past, air is cold

[thatone1967]

cheers guys!

[Eric Mc]

Im think it's a bit more complicated than that. At even higher altitudes, temperatures can be much higher than at ground level. In earth orbit (i.e. in the vacuum of space) temperatures can excceed over 200 degrees C in direct sunlight.

The explanation is to do wiith the difference between conductive heat and radiative heat.

[king arthur]

Gravity, surely?

[hugo a gogo]

http://www.windows.ucar.edu/tour/link=/kids_space/...

[chimera40]

In space it is radiation that will burn you up, there is no heat.

[Eric Mc]

chimera40 said:

In space it is radiation that will burn you up, there is no heat.

Hmm - does that mean NASA have spent tens of millions of dollars ensuring their spacecraft and astronauts stay cool for nothing?

[mackie1]

chimera40 said:

In space it is radiation that will burn you up, there is no heat.

There's no conductive heat because there's nothing to store or conduct it. Is that what you mean?

[The Excession]

Eric Mc said:

chimera40 said:

In space it is radiation that will burn you up, there is no heat.

Hmm - does that mean NASA have spent tens of millions of dollars ensuring their spacecraft and astronauts stay cool for nothing?

Oh, common Eric everyone knows it was twelvety millions of dollars.

[chimera40]

Eric Mc said:

chimera40 said:

In space it is radiation that will burn you up, there is no heat.

Hmm - does that mean NASA have spent tens of millions of dollars ensuring their spacecraft and astronauts stay cool for nothing?

There is no heat in a vacuum, in this environment heat as we know it travels as ultra violet radiation. Nasa spend there money to protect there equipment from the radiation and effectively reflect it to a degree as it will interact with matter when it comes in contact, producing heat. Hence my statement that it is radiation that will burn you in space as there is no heat.

[him_over_there]

The Excession said:

Eric Mc said:

chimera40 said:

In space it is radiation that will burn you up, there is no heat.

Hmm - does that mean NASA have spent tens of millions of dollars ensuring their spacecraft and astronauts stay cool for nothing?

Oh, common Eric everyone knows it was twelvety millions of dollars.

The only way for heat to travel in space is radiative heating, convective and conductive heating don't take place due to there being 'nothing' to store or conduct the heat.

Radiative heating is inefficient but once the heat does reach the astronauts they will heat up so they will need protection from that heat.

I'm guessing the worst heat a spacecraft and the astronauts inside have to deal with is on re-entry when the intense heat is a result of friction.

As for why is it cold up higher, the heat from the sun gets to the ground and the ground radiates the heat and warms the air up. As you go higher there is less air to heat up so it's colder.

[Simpo Two]

Eric Mc said:

At even higher altitudes, temperatures can be much higher than at ground level. In earth orbit (i.e. in the vacuum of space) temperatures can excceed over 200 degrees C in direct sunlight.

But only when it hits something - like your spaceship or a thermometer. In the same vein you can't see light unless it hits something, like matter or dust.

[GreenV8S]

him_over_there said:

As for why is it cold up higher, the heat from the sun gets to the ground and the ground radiates the heat and warms the air up. As you go higher there is less air to heat up so it's colder.

As I understand it most of the heat going into the atmosphere comes from the ground (the amount of sunshine absorbed by air is relatively small) and the higher levels are mainly heated by convection from the lower levels. As air rises the pressure drops, so it expands and cools. This effect means that convection effectively stops when the temperature distribution matches the pressure distribution, which is why the atmosphere as a whole has reached an equilibrium with the temperature dropping more or less linearly with height until it gets to more or less nothing as you reach the edge of the atmosphere.

[sadako]

chimera40 said:

Eric Mc said:

chimera40 said:

In space it is radiation that will burn you up, there is no heat.

Hmm - does that mean NASA have spent tens of millions of dollars ensuring their spacecraft and astronauts stay cool for nothing?

There is no heat in a vacuum, in this environment heat as we know it travels as ultra violet radiation. Nasa spend there money to protect there equipment from the radiation and effectively reflect it to a degree as it will interact with matter when it comes in contact, producing heat. Hence my statement that it is radiation that will burn you in space as there is no heat.

Try infra red radiation...

Heat travels in 3 ways. Conduction, convection, radiation.

Conduction - heat travels along the object you are welding into your hand.

Convection - Heaters in your house heat air, which then rises, drawing cooler air into the area where the heater is, forming a current of air as it gets hot, rises, cools down, falls, and gets heated up again.

Radiation - infra red. It is the only way heat can travel in a vaccuum and why the inside of thermos flasks is silver to prevent it happening. Reflected by reflective surfaces and absorbed by dark surfaces hense why back cars get hotter in the sun than white ones.

[chimera40]

GreenV8S said:

him_over_there said:

As for why is it cold up higher, the heat from the sun gets to the ground and the ground radiates the heat and warms the air up. As you go higher there is less air to heat up so it's colder.

As I understand it most of the heat going into the atmosphere comes from the ground (the amount of sunshine absorbed by air is relatively small) and the higher levels are mainly heated by convection from the lower levels. As air rises the pressure drops, so it expands and cools. This effect means that convection effectively stops when the temperature distribution matches the pressure distribution, which is why the atmosphere as a whole has reached an equilibrium with the temperature dropping more or less linearly with height until it gets to more or less nothing as you reach the edge of the atmosphere.

Not quite, there are several layers of atmosphere that are hotter, the most notable of these are the ozone layer and the CO2 layer. Both very emotive subjects. But as there names suggest they are both gaseous layers with particular properties, Ozone deflects ultraviolet rays to an extent, without this layer we would super heat, CO2 acts to reflect heat back in, without it we would be an ice planet, with too much the earth temperature rises. CO2 is very self regulating though, the oceans absorb the majority of this by means of plankton production, when there is a lot of excess CO2 the green/blue (plankton) algae blooms are much larger, this has the added benefit of increasing ocean species numbers as plankton is the first rung in the food chain. When it dies it then sinks to the bottom of the ocean and is responsible for much of the oil in the world today.

As for global warming and excess CO2 produced by mankind, that is another argument. One thing to note though is that ocean plankton blooms in the last few years have vastly increased and these blooms are sucking up CO2 like a hoover. When you think about it, it is in fact a great system. CO2 is produced by fossil fuels (among other things) plankton feed on CO2, plankton then become fossil fuels. Notice a pattern here.

[chimera40]

sadako said:

chimera40 said:

Eric Mc said:

chimera40 said:

In space it is radiation that will burn you up, there is no heat.

Hmm - does that mean NASA have spent tens of millions of dollars ensuring their spacecraft and astronauts stay cool for nothing?

There is no heat in a vacuum, in this environment heat as we know it travels as ultra violet radiation. Nasa spend there money to protect there equipment from the radiation and effectively reflect it to a degree as it will interact with matter when it comes in contact, producing heat. Hence my statement that it is radiation that will burn you in space as there is no heat.

Try infra red radiation...

Heat travels in 3 ways. Conduction, convection, radiation.

Conduction - heat travels along the object you are welding into your hand.

Convection - Heaters in your house heat air, which then rises, drawing cooler air into the area where the heater is, forming a current of air as it gets hot, rises, cools down, falls, and gets heated up again.

Radiation - infra red. It is the only way heat can travel in a vaccuum and why the inside of thermos flasks is silver to prevent it happening. Reflected by reflective surfaces and absorbed by dark surfaces hense why back cars get hotter in the sun than white ones.

Doh, stand corrected, got my ultra and my infra mixed up.

[Uncle Fester]

It's because there are few men at that altitude.

At ground level the men are warming it up.

It's a well known fact among supporters of MMGW that the planet is now so globaly warmed by men that it is now heating up the Sun.

Thankfully it's only MMGW not Wimmin MGW as well. If we were non-gender specific global warming the whole Solar system would be fried to a crisp.

HTH