Re:Why Venus Is So Bright Right Now
by drivers99 on Sunday June 04, 2023 @10:30AM
(#36185874)
So if it's at its brightest when it's at the greatest apparent distance (angle) in the sky from the sun, but it's only half-lit in terms of the phase, why doesn't it get brighter when it gets closer to being a "full" Venus?
[ Parent
| on HN ]
Because it is* much farther away from Earth and closer to the sun at that point.
Thanks, I was mentally ignoring the distance thinking it was not a big factor.
Being close to the sun (in angles from our viewpoint) makes sense, since the sky would start getting light when it was visible.
It’s an interesting exercise to calculate the two components of irradiance as a function of Venus’s angular distance from the sun: the 1/r^2 component derived from the Earth–Venus distance, and the geometric factor that depends on the angle of illumination. Combining these and finding the maximum, you should get the result mentioned.