The 10 weirdest facts about Venus

The article commented "A day on Venus lasts 243 Earth days (that's how long it takes Venus to make one rotation), while a year on Venus (its revolution period around the sun) is shorter, at just 224.7 Earth days."

Venus spins retrograde vs. the Sun's solar rotation or Earth's rotation and Earth's length of day (LOD) so very different than Venus LOD. Interesting how *tiny dust grains* in the solar nebula evolved with so many differences that developed between Earth and Venus, like the retrograde spin and atmosphere differences or LOD :)
Nov 25, 2019
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The weirdest thing about Venus is that the atmosphere at ground level is so hot and pressurized that it's no longer a gas - it's supercritical CO2, with a density of about 4 lbs per cubic foot. The surface of the planet has more in common with the bottom of an ocean than with dry land under an atmosphere - for example, the "atmosphere" can dissolve and carry away materials that would ordinarily be solids.
This article is confusing about a "day" on Venus.

It says that a "day" on Venus "last 243 Earth days". But, that is a "sidereal day", which is the time it takes for an observer on Venus (if there was one and he/she could see through the thick atmosphere) to see the same star (other than the sun) at the same point in the sky after one rotation.

That is different than the time that it takes Venus to rotate to the point where the sun is in the same point in the sky after a rotation, because Venus is orbiting the sun in a (nearly) circular path, and that alone changes the angle of the sun after one sidereal rotation. Because Venus rotates "retrograde", its rotation brings the sun to "high noon" faster than the sidereal day length would indicate. So a solar day on Venus is only 116.75 Earth days.

That means that the period of light on Venus is about 58 Earth days long, followed by a similar period of darkness. And, those are what we think of as "day" and "night".

See .