Quote
OCaptain
> And who exactly created them to invalidate
> Velikovsky?
>

Quote

The Discovery of Global Warming
> June 2011
> Venus & Mars
>
> In the 1960s and 1970s, observations of Mars and
> Venus showed that planets that seemed much like
> the Earth could have frightfully different
> atmospheres. The greenhouse effect had made Venus
> a furnace, while lack of atmosphere had locked
> Mars in a deep freeze. This was visible evidence
> that climate can be delicately balanced, so that a
> planet's atmosphere could flip from a livable
> state to a deadly one.

Quote

Already back in 1940, Rupert Wildt had made
> a rough calculation of the greenhouse effect from
> the large amount of CO2 that others had found in
> telescope studies of Venus; he predicted the
> effect could raise the surface temperature above
> the boiling point of water. But raising it as high
> as 600°K seemed impossible.(4*) Nobody mounted a
> serious attack on the problem (after all, very few
> people were doing any kind of planetary astronomy
> in those decades). Finally in 1960 a young
> doctoral student, Carl Sagan, took up the problem
> and got a solution that made his name known among
> astronomers. Using what he later recalled as
> "embarrassingly crude" methods, taking data from
> tables designed for steam boiler engineering, he
> confirmed that Venus could indeed be a greenhouse
> effect furnace.(5) The atmosphere would have
> to be almost totally opaque, and this "very
> efficient greenhouse effect" couldn't all be due
> to CO2. He pointed to absorption of radiation by
> water vapor as the likely culprit

Quote

The discovery that Venus's atmosphere
> had a composition, and probably a history, very
> different from Earth's prompted scientists to
> abandon their old assumption that planetary
> atmospheres were fixed forever by simple
> chemistry[/b

Quote

The atmosphere of Venus was filled not only
> with CO2 but also with an opaque haze. Its nature
> was unknown, and in the 1960s scientists could
> only say that the haze was probably caused by some
> kind of tiny particles.(10) "The clouds on Venus
> had long been a mystery," as one expert recalled,
> "in which stratospheric aerosols now appeared to
> play a key role. The unraveling of the precise
> role of aerosols in the Venus atmosphere would
> certainly benefit studies of chemical
> contamination of Earth's atmosphere." (11*) In the
> early 1970s, ground-based telescope observations
> produced extraordinarily precise data on the
> optical properties of these aerosols, and at last
> they were identified. The haze was from sulfur
> compounds.(12*)
> The greenhouse effect of the sulfates could be
> calculated, and by the late 1970s, NASA climate
> modeler James Hansen stated confidently that the
> sulfates together with CO2 "are responsible for
> the basic climatic state on Venus." Hansen had
> originally become interested in the greenhouse
> effect when, in response to Sagan's primitive
> calculations, he tried to derive a better
> explanation of why the planet's atmosphere was so
> hot. Now Hansen's findings about sulfate
> aerosols strengthened his belief that these
> particles could make a serious difference for the
> Earth's climate as well. Sulfates were emitted by
> volcanoes and, increasingly, by human industry, so
> Venus had things to tell us about climate change
> at home.(13*) (CO2 was by far the largest factor
> in warming Venus, and the effect of sulfates would
> be debated for decades. It turned out that the
> greenhouse effect of sulfate clouds reflecting
> heat back to the surface of Venus was outweighed
> by cooling due to their reflection of incoming
> sunlight.)