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Re: your mail = Greenhouse
>> No sunlight is hotter in the IR band, and your not talking about the amount
>> that gets to the ground, your talking about what hits the top of the
>> atmosphere. IR reflective gasses would reflect that back out. Thus lowering
>> the solar heat gain. Thus lowering the Earth surface temp during the day.
>
>It isn't that sunlight is stronger or lower in the IR bands, it's that
>earth-light is much much loser in the UV and visible bands.
What do you mean by loser?
>the gases (or whatever) keeps IR from passing, so both solar IR and
>earthly IR are reflected. The UV and Visible portions of the spectrum
>usually pass right through and then strike the ground, but the ground
>doesn't heat up enough to produce visible or UV radiation, so it's sent
>out as IR. The diving force of the greenhouse is not the difference
>between earthly IR and Solar IR, it is the difference between solar
>Visible and UV and Earthly visible and UV (~0)
That is what I thought and it has a certain truth but I think I was wrong
using the term reflection, it is better to assume that IR is absorbed on it
way through the atmosphere.
>> that a lot of IR reflective gas has been added to the atmosphere without
>> changing the temp, and no one has a coherent explanation for how it would
>
>that is not true. the _has_ been a temp rise over the last 90-100
>years. It is small, and it cannot be _proven_ to be caused by the
>greenhouse gases, but it has occured.
Indeed, NASA is only one experiment. Ground-based weather data show a clear
increase. I am interested though why both methods seem to disagree. (CSIRO
writes in an article that global temperature did increase the last century,
so it is not just a story from the newspapers and environmentalist)
>> increase the temp, and the whole idea is vigorously debated, I'ld say it
>
>Only by those who are afraid to have industrial society collapse around
>thier ears if the environmentalists win. The Industrialists are right
>about one thing, we can't stop yet. if we quit burning petrochemicals,
>we would be starving inside of three months. But the environmentalists
>are right about something too, we _will_ one day have to stop burning
>oil, because we are going to run out one day.
How convenient, whatever we do, we're gonna die anyway ;)
>BTW, Space-based solar energy beamed down by microwave will not solve the
>greenhouse problem, but will make it worse instead. Energy (microwaves)
>would be entering the earth's atmosphere, (we'd choose a particularly
>transparent frequency, to avoid losses) and then be consumed by various
>items (television, motors, light-bulbs etc) which waste large amounts of
>energy as heat. The heat would be held in just as it is now, (when
>talking about a planet, radiation is the only means of heat shedding) But
>there would be a much larger influx, because solar panels would be
>collecting sunlight that would have otherwise missed the earth.
I thought of this before and calculated:
World energy usage: 10^10 kWh=3.6 10^13 Watt
Solar Input at the Earth disc: Pi*(6.378 10^6)^2*1400=1.8 10^17 Watt
So Solar radiation is about 5000 times more than current electric power use.
(I don't know how much other power, like gass and oil is used)
I wonder if this effect is big enough to make a difference, if it does we
always could remove some greenhouse gasses or decrease the normal solar input.
Besides that, we will move heavy industry to space like Kelly said before.
Also appliances will become more efficient than today.
>> > I now don't understand anymore why does it become warm
>> > in a greenhouse?
>>
>> The glass keeps the cold wind out and is a slight insulator. It only works
>> if its not really cold, and theirs still a lot of sunlight to warm it up in
>> the day time.
>
>Glass works, because it restricts the heat balance to radiation only by
>preventing convection (i.e. it keeps the cold wind out.) or conduction
>(i.e. it is a slight insulator) in that respect, it is just like the
>vacuum of space, that vacuum prevents convection and conduction, and
>restricts the heat-balance to radiation terms only.
Yeps, I see that now.
Timothy