Venus.
Its day is -243.0185 Earth days long. The "minus" means it rotates in the direction opposite to the Earth and all the other planets (except Uranus).
Another viewpoint: That's the time to spin once, called the "sidereal day".
The "solar day" is defined in a different way and is only about 116.75 Earth days long for Venus.
On that definition, it is Mercury that has the longest day (about 176 Earth days.)
Mercury. (It is NOT Venus).
Neptune has the longest orbital period, which is equal to 59,800 Earth days. Pluto's is even longer (90,588 Earth days), but it has since been reclassified as a dwarf planet.
No planet in our solar system has days longer than one Earth year. Venus has the longest day -- it's 243 Earth days.
There is no such planet known. The planet with the longest rotation period is Venus. That rotates in about 243 Earth days.
You would have to find the planet with the longest year and that would be your answer because as you knoe Earths year is 365 (about) days and Mercurys is 88 days so....
Pluto has the longest year, if it was still a planet that is, equal to 248.76 Earth years. Since Pluto is no longer considered a planet, the planet with the longest year is Neptune, at 164.8 Earth years per revolution around the Sun.
None. Venus has the longest rotation period of 243 days, less than a year.
Neptune has the longest year( Pluto would be but it isn't a planet) Mercury has the shortest year(1 year=88 earth days)
As Pluto is no longer considered a planet, the planet with the longest orbital period is Neptune. The Neptunian year is approximately 60,190 Earth days.
There are no planets in our solar system with a rotational period of 318 days. The longest is Venus, with a rotational period of 243 days.
The planet with the largest (or longest) rotation period is Venus, at 243 Earth days (retrograde, meaning clockwise, instead of counterclockwise like the Earth).
So far, the longest period of time of survival was 76 days on the episode 76 Days Adrift. However, this incident occurred around 1982 and was picked up as an episode for the show in 2010 by Animal Planet.