Venus, currently is not in the habitable/Goldilocks zone. However once it had deep oceans of water, millions of years ago. based on computer modellings of the climate of the ancient Venus by scientists at NASA’s Goddard Institute for Space Studies (GISS).
This was because at that time Venus actually was in the habitable zone. This shift was because Goldilock's zone radius from the central body, depends upon it's thermodynamic temperature, as more heat is more black body radiation. The temperature is lower in ZAM age, or medium, because the helium fused would have sank down to the core, providing gravitational contraction, which would in turn heat it up.
The solar irradiance was low that time, because the temperature was low therefore the black-body radiation emitted that time was comparatively less. Because of this the Venus was actually in the habitable zone, until, the Sun brightened and made the oceans photocatalyze due to UV rays producing electronegative oxygen readily reacting with the carbon (maybe the comet deposits or solar wind?) making it's CO2 rich atmosphere (96%!).
But, if we somehow manage to deplete the CO2 level, by capturing the 90 bars in carbonates or other techniques, we probably may in fact be able to terraform Venus. Although it is practically possible only for Type II civilisations, theoretically, if we remove the CO2 and replace it with gases with higher albedo, we can cool down Venus. According to the inverse square law, the solar constant for Venus would be approximately 2800 watts per square meter. If somehow we manage to absorb only 50% of that solar energy and reflect the rest 50%, the temperature of Venus would be roughly be comparable to that of Earth with polar ice caps.
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