attain. English Collins Dictionary-English synonyms & Thesaurus &nbsp. attain (attains 3rd person present) (attaining present participle) (attained past tense & past participle) 1 verb If you attain something, you gain it or achieve it, often after a lot of effort. FORMAL Jim is halfway to attaining his pilot's licence.
The length of day on Mercury is 58.646 Earth days. This is a sidereal day, which is the amount of time it takes Mercury to turn once on its axis compared to the background stars. If you could look down from above Mercuryâs north pole, it would take almost 59 days to turn in a counter-clockwise direction. Mosaic of Mercury. Credit: NASA / JHUAPL / CIW / mosaic by Jason Perry. Things get unusual because a year on Mercury only lasts 88 days. And a solar day on Mercury lasts 176 Earth days. In other words, if you could stand on the surface of Mercury, it would take 176 days for the Sun to return to the same spot in the sky. Astronomers used to suspect that Mercury was tidally locked to the Sun, and always showed the same face to the Sun; similar to how the Moon is tidally locked to the Earth.
However, on Mercury these two days are quite different! The time it takes for the Sun to reach the highest point in the sky two consecutive times on Mercury (the solar day) is 176 Earth days whereas a sidereal day on Mercury with respect to the stars is 59 Earth days.