In particular, it is located 58 million km from our star, just over a third of the distance that separates the Earth from the Sun. At this distance corresponds a revolution period, the Mercurian year, of 88 days.
Like all other celestial objects, Mercury also rotates on its axis. Unlike other planets like Earth or Mars, Mercury rotates on itself very slowly, completing a full rotation every 59 days.
In the title of this post, I wrote that a day on Mercury lasts more than a year, but if math is objective, 59 is smaller than 88, so in theory, the year is the longer period of time between the two.
However, this depends on the definition we want to give to the word "day". If by day we mean the period it takes for a planet to complete one rotation on its axis, then a year on Mercury lasts more than a day. This definition is known as a sidereal day.
However, we could consider the day to be the time that elapses between two consecutive culminations of the Sun (that is, when the Sun passes the meridian and reaches its maximum height in the sky). This day is known as the solar day.
The solar day is longer than the sidereal day, since due to the revolution around the Sun the planet must rotate a little more to bring the Sun back to culmination compared to the previous day.
The difference between the two days on Earth is minimal, only 4 minutes. However, on Mercury, while the sidereal day lasts 59 Earth days, the solar day lasts a whopping 176 Earth days! This means that between two consecutive passages of the Sun in the same position in the Mercurian sky, a full 176 days pass!
Depending on the definition of day we choose, here is how on Mercury a day can last longer than a year.
Credit: NASA.