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ersonally, I find having global warming shoved down my throat ... distasteful. Not wishing to swim with the crowd on this one, let me proceed to "muddy" the waters just a little.

The general idea of global warming is bolstered by observations of the planet Venus which is considered to be an example of "runaway greenhouse effect", i.e. the heating up of an atmosphere due to "solar retentive gases" in that atmoshere.

Venus Facts:

MEAN DIAMETER: 7500 miles
MASS: 0.8 (Earth=1)
GRAVITY: 0.9 (Earth=1)
ORBIT PERIOD: 225 Earth days
ROTATION PERIOD: 243 Earth days (retro)
SURFACE TEMPERATURE:  900 F
ATMOSPHERIC PRESSURE:
~ 90 times denser than Earth
ATMOSPHERE: 
Carbon dioxide 96% Nitrogen 3%
ALBEDO:
Venus = 0.65 
Earth = 0.37 

Question: Rotation relative to the sun or to the backdrop of stars? I don't know. It might make some difference if the rotation is slow as is the case here.

Cropped Russian Venera Images #13L, #13R, #14, #9 These are images near the "foot" of each Venera. Note the scale of the rubble. Small rocks & stones and some fine material. This is an important clue. Also, note that these sites were not preselected because no one knew then what was under the clouds. Hence, they are representative samples.

^Here^ are some "wind" streaks on Venus
(only ones I could find ... this is germane to our discussion).

<< Here is a cropped image I found on the Web showing the gradual increase in pressure and temperature toward the Venusian surface. Clouds are of the infamous Sulphuric Acid type ... from the hype you would think that the planet was swimming in it ;o). The whole atmosphere is just CO2 however.

All of Venus ... no water ...
just hot rock & assorted gashes, craters, faults and ...
hmmmm ...
Where's the sand ocean?

On with the discussion ...

All the other pics show indigenous small rocks and stones and fine grain ... which to me is reminiscent of worn and windblown asphalt. This appears to be the most common small scale feature of Venus.

And this is it's meaning.
There is no appreciable wind on Venus. For if there were there would be ocean upon ocean of sand covering the whole thing.

Why?

Because the atmosphere is 92 times as dense as Earth's. Imagine the force with which a 30 mph wind presses against you. You can stand up OK but what if that wind was made of a material 92 times as dense? ... Right ... Your body would be scraped into a million blood stained pieces of bone fragment as you were dragged over that rocky surface ... and this woud take about two minutes.

What chance then does a rock have? ... Correct ... none at all.

For that matter, what chance does Venera have ... It should have gone tumbling down the road as soon as it touched ground.

Note: There is wind on Venus as the photos show.
It simply isn't an important planetary factor.

OK ... Fine ... Then, Why is there no wind?

Without rotation, the only temperature difference to drive weather is the stationary "terminator" (the line where Venus day turns into Venus night). Well, yes, it does go round ... but not like the Earth. We're a spinnin' top!.

The Venus day just sits there and bakes. And bakes. And bakes.

Now then ... Why doesn't Venus rotate faster?

These are:

• The fact that the Venusian rotation rate is slow
• That it's rotation is retrograde
• That it's axis is very nearly perpendicular

First off, the reason that "prograde" rotation is most common is caused by the nature of the gravitational field which tapers off by the inverse square law in concert with angular momentum conservation.

When the planet condenses from whatever is available, the stuff farthest from the sun is going slower than the stuff nearer the sun. Therefore, when the stuff moves to the center of gravity of the system, the top speeds up and the bottom slows down. When all combine, we get topspin. Or, put another way (perhaps more accurately), the top stuff has more angular momentum than the bottom stuff ... that's why it's on top. When you pull down the top to meet the bottom stuff, the top still has more angular momentum than the bottom stuff (now stuck together) and therfore you get topspin.

Now, the vertical, retrograde rotation axis

The peculiarity here is retrograde rotation.

Why?

I can envision only one scenario which fits the present circumstances of Venus. It is this:

Venus was formed by the collision of two large, standard, planetary bodies which occupied roughly the same orbit.

Finally, they come too close and the bottom planetoid scrapes into the top 'toid and the two axis, passing at a distance of perhaps less than one radii, provide sufficient torque to offset the two, cumulative intrinsic spins. The resultant spin is small ... it has to cancel the other spins ... but it's retrograde.

What else is a consequence of the collision?

However, my theory is that the catastrophe is a one time occurence which is only as old as the beginning of the cratering.

What do I get with my theory that impinges on the greenhouse effect?

Heat ...

There is a smooth temperature gradient from the planet's center to the top of its atmosphere whether you want to say the surface temperature is caused by the sun or the interior. It cannot logically be ... that the gradient is not smooth, i.e. there can't be a place (in either case) where there is a lower temperature below the surface ... then higher and higher till the core is reached. Such a temperature inversion would have have been "heated up" long ago.

So it's a matter of "Is the glass half full or half empty?". We're both looking at the same gradient data and assigning different causes to it.

If you can throw out my present theory, there is little else to assign as the cause of the high surface temperature other than the sun. A planet has only a few major heat sources.

• Impacts
• Tidal effects
• Internal nuclear radiation
• Gravitational condensation
• Solar radiation

Of course, there may be a combination of the two causes.

In my scenario, the atmosphere acts as an insulator holding in the heat from the planet's interior and the solar radiation is basically irrelevant ... or, radiation accounts for say 100 F of the 900 F and the collision accounts for the other 800 F.

Such a result would bode ill for the conservationists cum destroyers of civilization who, if it were KNOWN that we were heading toward global doom, would jump on the anti-greenhouse effect bandwagon so as to insure the destruction of civilization as soon as possible.

What is the greenhouse effect anyway?

In the atmosphere the infrared radiation is reemitted and reabsorbed many times so that it's path is randomly changed continuously. It may head in the general direction of outer space or go back to Earth. Eventually it makes it back out into space where it doesn't return since there is nothing to reflect it back in our direction. The longer a photon spends bouncing around in the atmosphere, the greater the buildup of heat in the atmosphere.

Now, the hotter an object is the faster it cools down. That's why you put cream in your coffee right away ... it stays warm longer ... unless you're at McDonald's ... in which case you want to open it up and leave it black for a week ... then it will be cool enough to drink ;o)

Therefore, an equilibrium is reached wherein the amount of heat entering the atmosphere is exactly equaled by the amount leaving it.

The atmosphere is a simple blanket covering the planet. Thicker means warmer (as long as some constituent of the atmosphere is a heat absorber, e.g. CO₂).

Curious fact discovered while doing this page

At a given temperature in a gravitational field, the thickness of a planet's atmosphere is constant regardless of how much more gas you add to it. That is, if you pour ten times as much gas on the Earth as it presently has, it's thickness will remain the same. It will just become denser.

Proof:
Imagine a 1 inch square column of air going all the way to the top of the atmosphere. It will weigh ~14 pounds (14 pounds per square inch - remember?). Now take another just like it and pour it into the top of the first container. The column must now weigh 28 pounds. So the air pressure at the bottom of the column must be 28 lbs per sq.inch.

True, there may be some adiabatic heating from mixing, etc. so just let it cool down to the temperature of the rest of the atmosphere.

But how can the pressure at the bottom be 28 pounds unless the average number of air molecules hitting the bottom has doubled. That is, to maintain Boyle's Gas Law, every volume increment of the column must have doubled the number of molecules in it. Hence, the total height of the column could not have changed. This must be true for any conceivable density increase until the gas laws break down (as at a liquifaction point).

Q.E.D.

Yes, as is the case with some anatomical parts, heat will make the column rise. In fact if we double the temperature, we should double the height of the column of air (regardless of the amount of air in it). And, since the temperature of Venus atmosphere is approximately 3 times that of Earth (on the Kelvin scale ~750V / 280E = ~3 ), it should be three times as thick.

Now LOOK at the scale at the top of this page.
[Click on the picture to come back here]

See? It is about 3 times thicker. Fancy that.

Your car, last summer ...

Why does the car get hot? Because the windows are closed and the hot air can't get out. AND ... the infrared radiation can't get out either ... or rather, it can't get out fast enough until the car is hot enough to emit as fast as new heat is coming in from the sun.

It certainly has nothing to do with the windows. Windows pass infrared like a moth------er! Remember what it's like in the winter when you turn off your heater and sit there waiting for someone to come to the car? You wait about 4 minutes then turn the engine on again to generate some more heat 'cause you're freezing! And your car is like a greenhouse.

Actually, a greenhouse loses heat very fast once the sun goes down. If it retained heat to any acceptable degree, your roof would be a see through one. In fact you need insulation and ... skylights lose heat badly.

The greenhouse effect has nothing to do with radiation in the actual real greenhouse scenario. The problem is mainly one of convection.

Without convection, the hottest air doesn't move out. It just sits there and bakes. If the air on Venus moved a little better, it might display a much more temperate climate. More heat could get to the top of the clouds and be more easily radiated away ... faster ... so that equlibrium could be reached at lower temperatures.

But ... Venus hardly rotates and therefore doesn't have any convection to speak of (except at the terminator).

So where does this leave us? ... vis a vis ... Global Warming?

Because Venus runaway greenhouse effect is the result of a combination of no convection and internal heat production rather than what they say, this matter is probably being terribly overplayed. And if it's not ... it may be the least of our worries. We're certain to have a big die off in the next century ... due to overpopulation / food shortages ... not because the weather is too warm!
"Keep your eye on the prize."

Summing up ...

Yes.

One must simply measure the amount of energy coming into Venus and the amount leaving ... with great accuracy ... over many data points on the surface of Venus ... for a reasonable amount of time.

The difference between
1) the runaway greenhouse effect theory
2) and my collision theory
is that the temperature output of 1 will be less than 2 by a significant amount. Both temperature outputs will exceed solar input by some amount in excess of equilibrium ... even the opposition would acknowledge that some heat is generated by Venus' interior. However, my theory predicts much more than they expect. And it would show up quite well. In fact, since this is not my field ... perhaps the information is already available (though the only piece sent to Venus to do a Man's Job was Magellan ... and it just took pics to map the surface).

If the heat emitted by Venus is very close to that received by the sun ... then I'm wrong ... no two ways about it. The global warming trend might then be a significant long term threat to our current way of life ... but we still have much larger problems to contend with in the next century.