Short answers, pulled from the story.
Venus is hotter than Mercury because of a runaway greenhouse effect driven by its atmosphere, which is 96.5% carbon dioxide. This atmosphere traps heat so effectively that surface temperatures average 737 Kelvin, while Mercury, which receives about four times more solar energy per square meter, reaches lower temperatures because it has almost no atmosphere to retain heat.
A Venusian sidereal day lasts 243 Earth days, which is longer than a Venusian year of 224.7 Earth days. The solar day, from noon to noon, works out to 116.75 Earth days, roughly half a Venusian year.
Venus has retrograde rotation, meaning it rotates clockwise while orbiting the Sun counterclockwise. Scientists believe competing forces shaped this: the Sun's gravitational tidal pull tends to slow rotation, while the thick atmosphere, heated unevenly by solar energy, exerts a countering torque. The current spin may represent an equilibrium between these two forces, reached over billions of years.
Scientists have identified atmospheric conditions between 48 and 59 km altitude where temperature, pressure, and radiation are similar to Earth's surface. Carl Sagan and Harold J. Morowitz raised this possibility in a 1967 Nature article. A putative detection of phosphine in 2020 drew further interest, though later research attributed the signal to sulfur dioxide. The Venus Life Finder mission, targeting a launch no earlier than summer 2026, will probe the atmosphere directly for organic compounds.
More than 85,000 volcanoes on Venus have been identified and mapped, including 167 large ones exceeding 100 km across. The high count reflects the planet's old, uneroded crust rather than a higher rate of activity; without plate tectonics, volcanic structures accumulate rather than being recycled.
Mariner 2, a United States probe, completed the first successful interplanetary mission on the 14th of December 1962, passing Venus at 34,833 km above the surface and returning the first scientific data from another planet. The Soviet Venera 1 had been launched first in 1961 but lost contact before reaching Venus.
The most recent pair of Venus transits occurred on the 8th of June 2004 and the 5th-the 6th of June 2012. Only seven Venus transits have ever been observed since their occurrences were first calculated in 1621 by Johannes Kepler. The next transit will not occur until December 2117.