Originally posted by jjw004:
I will stay with the objects I referred to. It is common knowledge that astronomers blame the extraordinary heat of Venus on a Greenhouse effect along the lines of which you would like me to ponder. I pondered that issue long ago and feel it is simply a conclusion due to a lack of imagination as to other possible causes. On the surface it appears to work and academics cannot leave things in Limbo, they must have an answer so why not a Greenhouse effect? As I see it if the heat from the sun can get in through the clouds then a lot can get out again. We are talking temperatures that could melt lead not a place where plants can flourish.
The greenhouse effect is not about heat in only one form that can pass as easily through the atmosphere in the outward direction as the inward direction.
It is about energy from the sun that comes in as radiation that interacts with the planet's surface and is converted to thermal energy that is re-radiated as mostly infrared radiation.
The incoming solar radiation (mostly ultraviolet) can pass easily into the planet's atmosphere, however when it becomes infrared energy the greenhouse gasses cause it to be reflected back down to the surface.
It is this one way effect that traps the heat in the planet's atmosphere and surface and drives the extreme temperature found on Venus.
That is why scientists are worried about increasing greenhouse gasses in our atmosphere. It doesn't matter if they are manmade, natural, or a combination; they will have the same effect either way.
Also, Venus is a lot closer to the sun than Earth and therefore recieves more energy per square mile of surface than the earth. Don't forget the square of the distance law for any radiated energy (other than coherent energy as from a laser) that says that if the earth were twice the distance from the sun as venus it would not recieve half the energy concentration but rather one fourth as much per square mile of surface. So while the earth will probably never reach the temperature of Venus regardless of the amount of greenhouse gasses; it still could get pretty warm and change our climate and the locations where man could survive. Imagine having to move closer to the arctic and antarctic areas because the equatorial band became too hot to allow us to live life as we know it in the open atmosphere.
