The planet Venus resembles in some respects the picture painted by Oscar Wilde of Reading Gaol. In his famous Ballad of that institution, Wilde wrote: I know not whether laws be right
Or whether laws be wrong;
All that we know who lie in gaol
Is that the wall is strong,
And that each day is like a year,
A year whose days are long.
The last two lines describe exactly how it is on Venus. Of all the planets in our solar system, Venus rotates most slowly on its axis; it takes a full 243 of our days to complete one revolution. This is slightly longer than the Venusian "year", the 225 Earth days it takes the planet to journey around the sun. So a "day" on Venus is longer than its year.
Mercury is even more confusing. It rotates on its axis once every 59 Earth days; a person standing on its surface would see the sun apparently moving from east to west across the Mercurian sky, just as it does when viewed from Earth, albeit much more slowly.
But Mercury's passage around the sun is rapid, taking only 88 Earth days; this rapid motion also tends to change the sun's position in the sky, but in the opposite direction from the planet's own rotation. The "daily" movement of the sun across the sky, therefore, is effectively slowed down, so the period from "noon to noon", a "day" on Mercury, is increased from 59 to 176 Earth days - if you still follow me.
The other planets, thankfully, are more straightforward. A day on Mars, for example, is much the same as ours. Jupiter, despite being the largest of our neighbours, spins more rapidly than any other planet on its axis, and each "day" is over just 10 hours after it began. Saturn's day is similar, about 11 hours, while that of Uranus is 17, Neptune 16, and Pluto a more lengthy six of our Earthly days
The lengths of the various years increase with increasing distance from the sun. Mercury's year, as we have seen, is only 88 days long, Venus's is 225 days, and a Martian year is twice as long as Earth's. Jupiter has a 4,333-day year, Saturn's is 10,740 days, that of Uranus 30,680 days.
In the case of Neptune and Pluto, with years of about 60,000 and 90,000 Earth days respectively, their year is much longer than a human lifetime, so no one could ever hope to celebrate even a first birthday on either of these planets.